JP4587780B2 - Video playback device - Google Patents

Description

The present invention relates to a video playback device , and more particularly, to a video playback speed changing process.

  A video communication system that stores video content in a video server device as a still image sampled at a predetermined time interval, that is, a video frame, and plays back the video content on a video playback device connected to the video server device via a communication network. Are known. Here, the stored video frame is normally encoded.

  That is, control signals such as playback, slow playback, fast forward playback, and pause of the content are transmitted from the video playback device to the video server device, and the video server device transmits the encoded video frame according to these control signals. All or a part is transmitted at predetermined time intervals, or the transmission is stopped.

Then, the video reproduction device receives the transmitted video frame, decodes it, and displays it. As a result, the video playback device is known to operate in accordance with user instructions similar to those for devices that play back video cassettes and DVDs (see, for example, Patent Document 1).
JP 2002-112194 A (page 2-4, FIG. 4)

  However, in the method disclosed in Patent Document 1 described above, the user of the video playback device displays, for example, after giving the video playback device an instruction to change the playback speed from normal speed to slow or fast forward. There is a problem that it takes a long time for the moving image to change from the normal speed to the indicated speed.

This is because the video frame stored in the video playback device when the user instruction is input is displayed at a speed before the instruction, and the video server device receives a control signal based on the instruction. This is because the video frame transmitted before transmission at the speed according to the signal is displayed at the speed before the instruction.

The present invention has been made in order to solve the above-described problems. The user of the video playback device gives an instruction to change the playback speed to the video playback device, and then follows the above instruction within a short time. It is an object of the present invention to provide a video playback apparatus that can be changed to display a video.

In order to achieve the above object, a video playback apparatus according to the present invention receives a read instruction for an image frame designating a playback speed, and transmits a video frame in accordance with the read instruction from the video server apparatus and the video server apparatus. A video playback device of a video communication system connected via a communication line to a video playback device that plays back a received image frame, an instruction transmission means for transmitting the read instruction to the video server device, and the read instruction The image frame receiving means for receiving the image frame transmitted from the video server device according to the above and storing it in the buffer storage means, the reproducing means for transmitting the image frame stored in the buffer storage means to the video display means, and the image An image frame transmitted by the frame receiving means in response to a read instruction designating the first reproduction speed Received and stored in said buffer storage means, and said reproducing means slow reproduction instruction is input from the input means to said image frame in response to the first playback speed when transmitting to said image display means If so, the instruction transmission means transmits an instruction to stop reading the image frame, and after a predetermined waiting time has elapsed, a second reproduction speed that is slower than the first reproduction speed is designated and the image frame is designated. And slow reproduction control means for causing the reproduction means to transmit the image frame stored in the buffer storage means to the video display means in accordance with the second reproduction speed. And

The video playback device of the present invention receives an instruction to read out an image frame specifying a playback speed, and plays back the image frame received from the video server device and the video server device that transmits the image frame according to the read instruction. A video playback apparatus of a video communication system connected to the video playback apparatus via a communication line, an instruction transmitting means for transmitting the read instruction to the video server apparatus, and the video server apparatus according to the read instruction The image frame receiving means for receiving the transmitted image frame and storing it in the buffer storage means, the reproducing means for transmitting the image frame stored in the buffer storage means to the video display means, and the image frame receiving means are the first Receiving the image frame transmitted in response to the readout instruction designating the playback speed of the Stored in the storage means, and when said reproducing means instructs fast forward reproduction from the input means to said image frame in response to the first playback speed when transmitting to said image display means is input, the The instruction transmitting means designates a second reproduction speed that is faster than the first reproduction speed and transmits an instruction to read out the image frame, and the reproduction means transmits the image frame corresponding to the first reproduction speed. Fast-forward playback control means for sending image frames stored in the buffer storage means to the video display means in accordance with the second playback speed after a predetermined waiting time has elapsed after transmission to the video display means is stopped. It is characterized by having.

According to the present invention, the video playback device converts the video frame read at the playback speed before the shift stored in the device into the playback speed after the shift and plays back the video frame. Thus, it is possible to provide a video playback apparatus that can change to display of video in accordance with the instruction within a short time after giving an instruction to change the playback speed to the video playback apparatus .

Embodiments of a video reproduction apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a video communication system including a video playback device according to an embodiment of the present invention.

  This video communication system includes a video server device 1, a video playback device 2, and a communication network 3 that connects the video server device 1 and the video playback device 2.

  FIG. 2 is a block diagram showing the configuration of the video server device 1. The video server device 1 includes a control unit 11 that controls the entire device, a communication unit 12, a reproduction instruction reception unit 13, a packet transmission unit 14, and a video content storage unit 15.

  The video content storage unit 15 stores video content. FIG. 3 shows the format of the video content 15 a stored in the video content storage unit 15. The video content 15a includes a first video frame 15b1, a second video frame 15b2, a third video frame 15b3,.

  The first to third video frames 15b1 to 15b3 are information obtained by encoding a still image obtained by sampling a video at a predetermined time interval (hereinafter, the interval time width is referred to as DX). The encoding is performed by, for example, intra-frame encoding by the motion JPEG method, but is not limited to this, and intra-frame encoding by other methods may be performed.

  FIG. 4 is a block diagram showing the configuration of the video playback device 2. The video reproduction apparatus 2 controls the entire apparatus, and also includes a control unit 21 that includes a clock unit indicating real time, a communication unit 22, an input device 23, a reproduction instruction transmission unit 24, and a video buffer unit 25. And a decoder unit 26 and a video display unit 27 for displaying a still image.

  Video data 25 a is stored in the video buffer unit 25. FIG. 5 shows the format of the video data 25 a stored in the video buffer unit 25. The video data 25a includes a first video data packet 25b1, a second video data packet 25b2, a third video data packet 25b3,.

  The first video data packet 25b1 includes a packet number 25c1, a time stamp 25d1, and a first video frame 25e1. The second video data packet 25b2 includes a packet number 25c2, a time stamp 25d2, and a second video frame 25e2. The third video data packet 25b3 includes a packet number 25c3, a time stamp 25d3, and a third video frame 25e3. The fourth and subsequent m-th video data packets 25bm are composed of a packet number 25cm, a time stamp 25dm, and an m-th video frame 25em.

  Here, the video server device 1 transmits the video frames 15b1, 15b2, 15b3,... Of the video content 15a without going through the first video frame 15b1 and sequentially, as will be described later. When all the video frames 15b1, 15b2, 15b3,... Transmitted by the device 1 are received as will be described later, the first video frame 25e1 is the same information as the first video frame 15b1 of the video content 15a.

  Further, the second video frame 25e2 is the same information as the second video frame 15b2 of the video content 15a. The third video frame 25e3 is the same information as the third video frame 15b3 of the video content 15a. The mth video frame 25em is the same information as the mth video frame 15bm of the video content 15a.

  Further, the packet numbers 25c1, 25c2, 25c3,... Are serial numbers as will be described in detail later. The time stamps 25d1, 25d2, 25d3,... Are relative times for displaying the first, second, third,... Video frames 25e1, 25e2, 25e3,.

  The operation of the video communication system according to the embodiment of the present invention configured as described above will be described with reference to FIG.

  First, the operation of the communication unit 12 will be described. The communication unit 12 transmits a playback instruction for the video content 15 a according to the RTSP (Real Time Streaming Protocol) protocol received via the communication network 3 to the playback instruction receiving unit 13. The communication unit 12 transmits a response according to the RTSP protocol transmitted from the packet transmission unit 14 according to the RTSP protocol via the communication network 3 and the reproduction transmitted from the packet transmission unit 14. A packet according to the RTP (Real-time Transport Protocol) protocol composed of the video frame 15b corresponding to the instruction is transmitted via the communication network 3.

  Next, the operation of the reproduction instruction receiving unit 13 will be described. The reproduction instruction receiving unit 13 is an apparatus that receives the reproduction instruction of the video content 15a transmitted from the communication unit 12, and causes the packet transmission unit 14 to transmit the video content 15a via the communication unit 12 according to the received instruction. is there. The instructions include normal speed playback, slow playback with a specified playback speed coefficient, fast forward playback with a specified playback speed coefficient, frame-by-frame playback, and pause. The reproduction instruction receiving unit 13 stores the received instructions in a queue and processes them in the order received.

  Next, the operation of the packet transmission unit 14 will be described. First, the normal speed reproduction operation of the packet transmitter 14 will be described. When the video content 15a is played back from the first video frame 15b1, the packet transmission unit 14 sets “0” as the time stamp corresponding to the first video frame 15b1 and “1” as the packet number. explain. Here, the time stamp indicates the relative time at which the first video frame 15b1 is displayed, and the packet number indicates the serial number of the RTP packet that transmits the first video frame 15b1.

  Then, the packet transmission unit 14 causes the communication unit 12 to transmit the serial number of the first RTP packet transmitted by the normal speed reproduction operation as an RTSP response. Further, the communication unit 12 is caused to transmit an RTP packet including the set packet number, a time stamp, and the first video frame 15b1.

  FIG. 6 shows a format of an RTP packet for transmitting the video frame 15b. The RTP packet 31 includes a packet number 31a, a time stamp 31b, and a video frame 31c. As will be described in detail later, the above-described video data 25 a is obtained by storing the RTP packet 31 in the video buffer unit 25. Note that one video frame 15b1, 15b2, 15b3,... Is transmitted as a video frame 31c of one RTP packet 31.

  Next, the packet transmitting unit 14 sets the second video frame 15b2 as the video frame 31c, “DX” as the time stamp 31b, and “2” as the packet number 31a. Here, “DX” of the time stamp 31b is an interval time width in which still images are sampled from the video as described above, and the first to third video frames 15b1 to 15b3 are generated from the still images. Is done. That is, “DX” indicates a time width from when the first video frame 15b1 is displayed to when the second video frame 15b2 is displayed.

  Then, the packet transmission unit 14 sends the RTP packet 31 including the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 having the packet number 31a of “1”. After the “DX” has elapsed since the transmission, the communication unit 12 is caused to transmit.

  Next, the packet transmission unit 14 sets the third video frame 15b3 as the video frame 31c, “DX + DX” as the time stamp 31b, and “3” as the packet number 31a. Here, “DX + DX” of the time stamp 31b is the third video after the second video frame 15b2 is displayed at “DX” of the time stamp 31b included in the RTP packet 31 having the packet number 31a of “2”. A value obtained by adding a time width “DX” until the frame 15b3 is displayed is shown.

  Then, the packet transmission unit 14 sends the RTP packet 31 composed of the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 whose packet number 31a is “2”. After the “DX” has elapsed since the transmission, the communication unit 12 is caused to transmit. The packet transmitter 14 transmits the fourth and subsequent mth video frames 15bm in the same manner.

  Next, the operation of slow reproduction specifying the reproduction speed coefficient of the packet transmission unit 14 will be described. When the video content 15a is played slowly from the first video frame 15b1 with a playback speed coefficient (hereinafter, this coefficient is referred to as p. Here, since it is a slow playback process, p <1), the packet transmitter 14 Sets the first video frame 15b1 as the video frame 31c, "0" as the time stamp 31b, and "1" as the packet number 31a.

  Then, the packet transmission unit 14 causes the communication unit 12 to transmit the packet number 31a of the first RTP packet 31 transmitted by the slow reproduction operation specifying the reproduction speed coefficient as an RTSP response. Further, the communication unit 12 is caused to transmit the RTP packet 31 including the set packet number 31a, the time stamp 31b, and the video frame 31c.

  Next, the packet transmission unit 14 sets the second video frame 15b2 as the video frame 31c, “DX ÷ p” as the time stamp 31b, and “2” as the packet number 31a. Here, “DX ÷ p” of the time stamp 31b indicates a time width from when the first video frame 15b1 is displayed to when the second video frame 15b2 is displayed.

  Then, the packet transmission unit 14 sends the RTP packet 31 including the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 having the packet number 31a of “1”. After “DX ÷ p” has elapsed since the transmission, the communication unit 12 is caused to transmit.

  Next, the packet transmission unit 14 sets the third video frame 15b3 as the video frame 31c, “(DX ÷ p) + (DX ÷ p)” as the time stamp 31b, and “3” as the packet number 31a. . Here, “(DX ÷ p) + (DX ÷ p)” of the time stamp 31b is the second “DX ÷ p” of the time stamp 31b included in the RTP packet 31 with the packet number 31a “2”. A value obtained by adding a time width “DX ÷ p” from the display of the video frame 15b2 to the display of the third video frame 15b3 is shown.

  Then, the packet transmission unit 14 sends the RTP packet 31 composed of the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 whose packet number 31a is “2”. After “DX ÷ p” has elapsed since the transmission, the communication unit 12 is caused to transmit.

  The packet transmitter 14 transmits the fourth and subsequent mth video frames 15bm in the same manner. By this operation, the interval at which the RTP packets 31 are transmitted and the interval between the time stamps 31b included in the consecutive RTP packets 31 are increased and changed from “DX” during normal speed playback to “DX ÷ p”. As a result, the RTP packet 31 corresponding to the slow reproduction is transmitted.

  Next, the fast forward playback operation in which the playback speed coefficient of the packet transmission unit 14 is designated will be described. When the video content 15a is fast-forwarded from the first video frame 15b1 with a playback speed coefficient (p. Here, p> 1 because it is a fast-forward playback process), the packet transmitting unit 14 sets the first video frame 15c as the video frame 31c. One video frame 15b1 is set with “0” as the time stamp 31b and “1” as the packet number 31a.

  Then, the packet transmission unit 14 causes the communication unit 12 to transmit, as an RTSP response, the packet number 31a of the first RTP packet transmitted by the fast forward reproduction operation in which the reproduction speed coefficient is designated. Further, the communication unit 12 is caused to transmit the RTP packet 31 including the set packet number 31a, the time stamp 31b, and the video frame 31c.

  Next, the packet transmission unit 14 performs the above-described slow playback operation with the playback speed coefficient specified for the second video frame 15b2, the third video frame 15b3, and the fourth and subsequent mth video frames 15bm. The same operation is performed and the communication unit 12 is made to transmit. By this operation, the interval at which the RTP packets 31 are transmitted and the interval between the time stamps 31b included in the consecutive RTP packets 31 are changed from “DX” during normal speed reproduction to “DX ÷ p”. As a result, the RTP packet 31 corresponding to the fast-forward playback is transmitted.

  The number of RTP packets 31 transmitted by the communication unit 12 per unit time increases by the fast-forward reproduction operation in which the reproduction rate coefficient of the packet transmission unit 14 described above is designated. For example, when the increase is not preferable due to restrictions on the communication network 3, the video frames after the second video frame 15 b 2 may be thinned out and transmitted to the communication unit 12.

  That is, the packet transmission unit 14 sets the m-th video frame 15bm of the video content 15a as the video frame 31c, “DX” as the time stamp 31b, and “2” as the packet number 31a. Here, m is 1 + p, and 1 corresponds to the fact that the video frame 31c included in the RTP packet 31 whose packet number 31a is “1” is the first video frame 15b1. When 1 + p is not an integer, m is an integer closest to 1 + p.

  Then, the packet transmission unit 14 sends the RTP packet 31 including the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 having the packet number 31a of “1”. After the “DX” has elapsed since the transmission, the communication unit 12 is caused to transmit.

  Next, the packet transmitting unit 14 sets the nth video frame 15bn of the video content 15a as the video frame 31c, “DX + DX” as the time stamp 31b, and “3” as the packet number 31a. Here, n is 1 + 2 × p, and 1 corresponds to the fact that the video frame 31c included in the RTP packet 31 whose packet number 31a is “1” is the first video frame 15b1. When 1 + 2 × p is not an integer, n is an integer closest to 1 + 2 × p.

  Then, the packet transmission unit 14 sends the RTP packet 31 composed of the set packet number 31a, the time stamp 31b, and the video frame 31c to the communication unit 12 and the RTP packet 31 whose packet number 31a is “2”. After the “DX” has elapsed since the transmission, the communication unit 12 is caused to transmit.

  The packet transmitter 14 creates the subsequent RTP packet 31 in the same manner and causes the communication unit 12 to transmit it. By this operation, the interval at which the RTP packets 31 are transmitted and the interval between the time stamps 31b included in the consecutive RTP packets 31 are the same as those during normal speed reproduction, and the video frames 31c included in the consecutive RTP packets 31 are changed. Next to the mth video frame 15bm, the (m + p) th video frame 15bm + p is used to transmit the RTP packet 31 corresponding to fast-forward playback.

  Next, the frame feed playback operation of the packet transmitter 14 will be described. The packet number 31a transmitted as an element of the RTP packet 31 immediately before the frame advance playback instruction is received is p1, the time stamp 31b transmitted as the element of the RTP packet 31 is ts1, and the RTP packet 31 The video frame 31c transmitted as the element of is the m-th video frame 15bm of the video content 15a.

  The packet transmission unit 14 sets “(p1 + 1)” as the packet number 31a, sets “(ts1 + DX ÷ p)” as the time stamp 31b, and sets the video content 15a as the video frame 31c, depending on the playback speed coefficient p. The communication unit 12 is caused to transmit the RTP packet 31 in which the (m + 1) th video frame 15bm + 1 is set. Here, if the playback performed immediately before the frame advance playback operation is normal speed playback, p = 1, if the playback is slow playback, p <1, and if fast playback, p> 1.

  After transmitting the RTP packet 31 to the communication unit 12, the packet transmission unit 14 enters a state after performing a pause operation described below.

  Next, the operation of temporarily stopping the packet transmission unit 14 will be described. During normal playback, slow playback with a specified playback speed coefficient, or fast forward playback with a specified playback speed coefficient, the packet transmitter 14 stops transmission of the RTP packet 31 by pause. Then, the RTSP response is transmitted to the communication unit 12.

  Next, after normal speed playback, slow playback with a specified playback speed coefficient, or fast forward playback with a specified playback speed coefficient, the playback speed was changed to a different playback, that is, the playback before and after the change. The operation of the packet transmission unit 14 when the reproduction of different types of reproduction will be described.

  The packet number 31a transmitted in the RTP packet 31 immediately before the reproduction instruction after the change is received is p1, the time stamp 31b transmitted in the RTP packet 31 is ts1, and the RTP packet The video frame 31c transmitted by being included in 31 is set as the m-th video frame 15bm of the video content 15a. The playback speed coefficient (p) of the changed playback is a number less than 1 specified for slow playback, a number greater than 1 specified for fast forward playback, and 1 for normal speed playback. It is.

  When these instructions are received, the packet transmission unit 14 sets the first RTP packet 31 according to the reproduction rate coefficient before the change after the reproduction rate is changed, and sets the set RTP packet 31 to the communication unit 12. To send to.

  The content of the RTP packet 31 transmitted from the packet transmission unit 14 after the reproduction speed is changed is the normal speed reproduction after the change, the slow reproduction specifying the reproduction speed coefficient (p), or the reproduction speed. It differs depending on whether the fast-forward playback is performed by specifying a coefficient, and is the same as described in the playback operation after the second video frame 15b2 when the playback is already started from the first video frame 15b1, and the description is omitted. To do. The packet transmission unit 14 causes the communication unit 12 to transmit the packet number 31a “(p1 + 2)” of the RTP packet 31 transmitted second after the reproduction speed is changed as an RTSP response.

  Next, the operation of each unit of the video reproduction device 2 will be described from the operation of the communication unit 22 with reference to FIG. The communication unit 22 transmits a reproduction instruction for the video content 15 a according to the RTSP protocol transmitted from the reproduction instruction transmission unit 24 to the video server device 1 via the communication network 3. In addition, a response to the reproduction instruction according to the RTSP protocol transmitted from the video server device 1 and received via the communication network 3 is transmitted to the reproduction instruction transmission unit 24. Furthermore, RTP packets 31 received from the video server device 1 via the communication network 3 are stored in the video buffer unit 25 in the order of packet numbers 31 a included in the RTP packets 31.

  The input device 23 includes a plurality of keys. When a key of the input device 23 is operated, an identifier corresponding to the key is notified to the reproduction instruction transmission unit 24 via the control unit 21. With this notified identifier, an instruction regarding the reproduction of the video content 15a of the user is transmitted.

  Next, the operation of the reproduction instruction transmission unit 24 will be described. The reproduction instruction transmission unit 24 receives an instruction regarding reproduction of the video content 15a of the user. The instructions include normal speed playback, slow playback with a specified playback speed coefficient, fast forward playback with a specified playback speed coefficient, frame-by-frame playback, and pause.

  Among the above instructions, the instruction received first is either normal speed playback, slow playback with a specified playback speed coefficient, or fast forward playback with a specified playback speed coefficient. When these instructions other than reproduction are received, the reproduction instruction transmission unit 24 does not operate for the received instructions until these instructions are received. The reproduction instruction transmitting unit 24 transmits the received reproduction instruction to the communication unit 22 to be transmitted to the video server device 1. The received reproduction instruction is transmitted to the decoder unit 26.

  Subsequently, the reproduction instruction transmitting unit 24 receives a response to the instruction transmitted to the video server device 1 from the communication unit 22, so that the first RTP packet transmitted from the video server device 1 in response to the instruction is received. 31 packet number 31a is received. Then, it is checked at predetermined time intervals whether or not the RTP packet 31 including the RTP packet number 31a is included in the video data 25a, and the RTP packet 31 is transmitted to the communication unit 22 after the instruction is transmitted to the communication unit 22. Elapsed time until it is stored in 25 (hereinafter referred to as WT) is calculated.

  Then, the reproduction instruction transmission unit 24 stores the calculated WT in a predetermined storage unit (not shown) in the reproduction instruction transmission unit 24. This WT is used as will be described in detail later as the time from when the reproduction instruction transmission unit 24 transmits an instruction to the video server apparatus 1 until the RTP packet 31 according to the instruction is received.

  Next, the operation of the reproduction instruction transmitting unit 24 when the reproduction instruction is received and the reproduction instruction at the reproduction speed different from the reproduction speed is received after the operation for the instruction is executed. To do.

  First, in the case where an instruction for slow playback specifying a playback speed coefficient is received after the normal speed playback operation is executed, the slow playback control operation, that is, during playback at a certain playback speed, is slower than that playback speed. The operation when a playback instruction at the playback speed is received will be described with reference to FIGS. FIG. 7 is a flowchart showing the operation of the reproduction instruction transmitting unit 24 when a slow reproduction instruction specifying a reproduction speed coefficient is received after the normal speed reproduction operation is executed. FIG. 8 shows an outline of a change in the usage amount of the storage capacity of the video buffer unit 25 during the operation of the reproduction instruction transmission unit 24 shown in the flowchart of FIG.

  The reproduction instruction transmitting unit 24 receives a slow reproduction instruction specifying a reproduction speed coefficient (p, where p <1), and starts operation (step S24a). It is assumed that the time at this time is T0, and the usage amount of the storage capacity of the video buffer unit 25 is an appropriate average value. Subsequently, the reproduction instruction transmission unit 24 instructs the decoder unit 26 to perform reproduction with a predetermined speed coefficient p (step S24b), and instructs the video server device 1 to pause reproduction via the communication unit 22. (Step S24c), a predetermined time is waited (Step S24d).

  The reason why the reproduction instruction transmitting unit 24 does not immediately instruct the video server apparatus 1 to reproduce with the reproduction speed coefficient p in step S24d is as follows.

  That is, the number of RTP packets 31 that are newly stored in the video buffer unit 25 before the time T0 to T0 + WT (hereinafter, T0 + WT is referred to as T1) is determined by the decoder unit 26 between the times T0 and T1. In contrast to the number for normal speed reproduction, the number of video data packets 25b used by the decoder unit 26 between times T0 and T1 is the number for reproduction by the speed coefficient p. Here, since p <1, between time T0 and T1, as shown in FIG. 8, the usage amount of the storage capacity of the video buffer unit 25 continues to increase compared to an appropriate value.

The reproduction instruction transmitting unit 24 calculates the predetermined waiting time as follows. That is, the number of RTP packets 31 newly stored in the video buffer unit 25 during the time width WT from time T0 to T1 is WT during normal speed playback.
Is the displayed minute of the time.

On the other hand, the number of video data packets 25b used by the decoder unit 26 during this period is p × WT during normal speed playback.
The difference between these is a display amount of (1-p) × WT during normal speed reproduction.

By the time the decoder unit 26 uses this difference information,
(1-p) x WT / p
Real time.

That is, in order to return the usage amount of the storage capacity of the video buffer unit 25 once increased to an appropriate value, from T0 to WT + (1-p) × WT ÷ p
= WT ÷ p
It is the time when the real time of elapses. Hereinafter, this time is referred to as T2, and FIG. 8 shows a situation in which the usage amount of the storage capacity of the video buffer unit 25 returns to an appropriate value.

  In order to receive from the video server apparatus 1 the RTP packet 31 necessary for the decoder unit 26 to perform reproduction with the speed coefficient p after time T2, from time T0 to time (T2-WT) (hereinafter T2-WT). It is appropriate to wait for transmission of the slow reproduction instruction by the speed coefficient p to the video server apparatus 1 until T3.).

That is, the waiting time is
T3-T0
= (T2-WT) -T0
= (T0 + WT ÷ p) -WT-T0
= ((1-p) ÷ p) × WT
It is.

  When 0.5 <p <1, T3 <T1, and the video playback device 2 receives the RTSP response from the video server device 1 in response to transmission of the playback pause instruction before the playback speed coefficient. Although the playback instruction by p is transmitted, there is no problem because the video server apparatus 1 processes the instructions in the order of reception as described above.

Here, at time T0, it is assumed that the video buffer unit 25 stores RTP packets 31 corresponding to the AT time display by normal speed reproduction. This stored information is according to the reproduction by the speed coefficient p,
AT ÷ p
Used in real time.

On the other hand, in the steady state after time T2, the video buffer unit 25 is controlled to store information having the same data amount as that at time T0. In order to receive this information from the video server device 1 at the playback speed p,
AT ÷ p
Real time.

  That is, this time is equal to the time for using the information stored in the video buffer unit 25 at the time T0, and thus does not affect the calculation of the waiting time. Therefore, in the above description, in order to simplify the description, the amount of information stored in the video buffer unit 25 at time T0 is omitted.

  In order to control the data amount of information stored in the video buffer unit 25 in a steady state after time T2 to an amount different from the data amount of information stored in the video buffer unit 25 at time T0, Accordingly, the calculation similar to the calculation of the waiting time may be performed.

  In step S24d, after waiting for the above time, the playback instruction transmitting unit 24 instructs the video server device 1 to perform slow playback specifying the playback speed coefficient p via the communication unit 22 (step S24e). In response to the instruction, the packet number 31a of the RTP packet 31 transmitted first is received from the video server device 1 via the communication unit 22 (step S24f).

  Subsequently, the reproduction instruction transmission unit 24 transmits the packet number 31a received in step S24f to the decoder unit 26 (step S24g), and ends the operation (step S24h). The usage of the packet number 31a will be described when the operation of the decoder unit 26 is described.

  Next, taking the case where a fast-forward playback instruction specifying a playback speed coefficient is received after execution of the normal speed playback operation, the fast-forward playback control operation, i.e., during playback at a certain playback speed, The operation of the reproduction instruction transmitting unit 24 when a reproduction instruction at a high reproduction speed is received will be described with reference to FIGS.

  FIG. 9 is a flowchart showing the operation of the reproduction instruction transmitting unit 24 when a fast-forward reproduction instruction specifying a reproduction speed coefficient is received after execution of the normal speed reproduction operation. FIG. 10 shows an outline of a change in the usage amount of the storage capacity of the video buffer unit 25 during the operation of the reproduction instruction transmission unit 24 shown in the flowchart of FIG.

  The reproduction instruction transmitting unit 24 receives a fast-forward reproduction instruction designating a reproduction speed coefficient (p, where p> 1), and starts operation (step S24j). It is assumed that the time at this time is T0, and the usage amount of the storage capacity of the video buffer unit 25 is an appropriate average value. Subsequently, the playback instruction transmission unit 24 instructs the decoder unit 26 to pause playback (step S24k), and then specifies the playback speed coefficient p to the video server device 1 via the communication unit 22. A fast forward reproduction is instructed (step S24m), and a predetermined time is waited (step S24n).

  The reason why the reproduction instruction transmitting unit 24 does not immediately instruct the decoder unit 26 to reproduce with the predetermined speed coefficient p in step S24k is as follows.

  That is, if the decoder unit 26 is instructed to reproduce at a predetermined speed coefficient p in step S24k, the time is stored in the video buffer unit 25 from T0 to T0 + WT (hereinafter T0 + WT is referred to as T1). RTP packets 31 are the number for the decoder unit 26 to perform normal speed reproduction. On the other hand, the number of video data packets used by the decoder unit 26 is the number for reproduction by the speed coefficient p, and since p> 1, the usage amount of the storage capacity of the video buffer unit 25 is compared with an appropriate value. This is because it may decrease and underflow may occur.

The reproduction instruction transmitting unit 24 calculates the predetermined waiting time as follows. That is, the number of RTP packets 31 newly stored in the video buffer unit 25 from time T0 to T1, that is, during the time width WT, is WT during normal speed playback.
Is the displayed minute of the time. On the other hand, when the decoder unit 26 performs reproduction with the speed coefficient p, the decoder unit 26 converts this number of RTP packets 31 to WT ÷ p.
Use in real time.

On the other hand, the RTP packet 31 transmitted according to the fast-forward playback instruction specifying the playback speed coefficient p performed in step S24m starts to be stored in the video buffer unit 25 at time T1, that is, from T0 to WT.
This is the time when the real time has passed.

Therefore, in order to keep the usage amount of the storage capacity of the video buffer unit 25 to an appropriate value or more, from time T0, WT−WT ÷ p
= ((P-1) ÷ p) × WT
It is appropriate that the decoder unit 26 stops the reproduction only in the real time. Hereinafter, the time obtained by adding this time to the time T0 is referred to as T2. Until time T2, as shown in FIG. 10, the usage amount of the storage capacity of the video buffer unit 25 increases.

  Note that the influence on the waiting time due to the data amount of information stored in the video buffer unit 25 at time T0 has already been described in the explanation of the control operation of the slow reproduction, and the explanation is omitted here. .

  Note that the playback instruction transmission unit 24 instructs the decoder unit 26 to pause playback in step S24k, but the present invention is not limited to this. For example, the decoder unit 26 may continue to play back a still image that has been played back before. Alternatively, a predetermined still image stored in a predetermined storage unit (not shown) in the reproduction instruction transmission unit 24 may be continuously reproduced by the decoder unit 26. Furthermore, the predetermined video content stored in a predetermined storage unit (not shown) in the playback instruction transmission unit 24 may be played back by the decoder unit 26.

  In step S24n, after waiting for the above time, the reproduction instruction transmitting unit 24 instructs the decoder unit 26 to perform reproduction with a predetermined speed coefficient p (step S24o). Then, the packet number 31a of the RTP packet 31 first transmitted in response to the instruction to the video server device 1 performed in step S24m is received from the video server device 1 via the communication unit 22 (step S24p). The packet number 31a received in step S24p is transmitted to the decoder unit 26 (step S24q), and the operation is terminated (step S24r).

  Next, taking a case where a pause instruction is received during normal speed playback and then a normal speed playback instruction is received again, the storage capacity usage of the video buffer unit 25 is corrected to an appropriate value. The operation of the reproduction instruction transmitting unit 24 to be performed will be described with reference to FIG. 11 and FIG. In this example, the operation when a frame advance playback instruction is received will also be described.

  FIG. 11 is a flowchart showing the operation of the reproduction instruction transmitting unit 24 when a pause instruction is received during normal speed reproduction and then a normal speed reproduction instruction is received again. FIG. 12 is a diagram showing an outline of a change in the amount of use of the storage capacity of the video buffer unit 25 during the operation of the reproduction instruction transmitting unit 24 shown in the flowchart of FIG.

  The reproduction instruction transmission unit 24 receives a pause instruction during normal speed reproduction and starts operation (step S24s). It is assumed that the time at this time is T0, and the usage amount of the storage capacity of the video buffer unit 25 is an appropriate average value. Subsequently, the reproduction instruction transmitting unit 24 instructs the decoder unit 26 to pause (step S24t), and also instructs the video server device 1 to pause (step S24u).

  It is assumed that this state continues for a time width WT or more. Then, when the time is T0 + WT (hereinafter referred to as T1), the new storage of the RTP packet 31 in the video buffer unit 25 by the normal speed reproduction is finished, and the storage capacity of the video buffer unit 25 is shown in FIG. The increase in usage amount ends.

  Next, the reproduction instruction transmitting unit 24 receives an instruction for normal speed reproduction (step S24v). This time is T2. Then, a normal speed reproduction instruction is immediately transmitted to the decoder unit 26 (step S24w), and a predetermined time is awaited (step S24x).

Here, the reason why the normal speed reproduction is not immediately instructed to the video server apparatus 1 is as follows. In other words, between the pause instruction operation in step S24u and the reproduction instruction operation in step S24v, specifically, the normal speed playback is performed during the time T0 to T1.
RTP packets 31 corresponding to the display time are additionally stored in the video buffer unit 25. Therefore, it is appropriate to store the RTP packet 31 transmitted from the video server device 1 in the video buffer unit 25 after the decoder unit 26 uses the additionally stored RTP packet 31.

The reproduction instruction transmitting unit 24 calculates the predetermined waiting time as follows. That is, the number of RTP packets 31 stored in the video buffer unit 25 during the time T0 to T1, that is, the time width WT, is WT during normal speed playback.
Is the displayed minute of the time. The actual time required for the decoder unit 26 to use the RTP packet 31 for normal speed reproduction is WT
It is.

On the other hand, the actual time from when the normal speed reproduction is instructed to the video server apparatus 1 until the RTP packet 31 is received is WT
It is. Therefore, the waiting time is WT−WT = 0. Then, as shown in FIG. 12, at time T2 + WT (hereinafter referred to as T3), the storage capacity usage of the video buffer unit 25 returns to an appropriate average value.

  In step S24x, after waiting for the above time, the reproduction instruction transmission unit 24 instructs the video server device 1 to perform normal speed reproduction via the communication unit 22 (step S24y), and ends the operation (step S24x). S24z).

  The waiting time becomes 0 only when the reproduction speed at the start of this operation in step S24s is the same as the reproduction speed input in step S24v. When the instruction input in step S24v is slow playback specifying a playback speed coefficient or fast-forward playback specifying a playback speed coefficient, the waiting time in step S24x changes depending on the playback speed coefficient p.

That is, the number of RTP packets 31 newly stored in the video buffer unit 25 at times T0 to T1 is WT during normal speed playback.
Is the displayed minute of the time. The actual time required for the decoder unit 26 to use the RTP packet 31 for reproduction with the reproduction speed coefficient p is WT ÷ p
It is.

On the other hand, the actual time from when the normal speed reproduction is instructed to the video server apparatus 1 until the RTP packet 31 is received is WT
It is. Therefore, the waiting time is WT ÷ p−WT = ((1−p) ÷ p) × WT. That is, when the instruction input in step S24v is slow playback (p <1) specifying the playback speed coefficient, the above-described time waiting is performed in step S24x.

  On the other hand, when the instruction input in step S24v is fast-forward playback (p> 1) specifying a playback speed coefficient, ((1−p) ÷ p) × WT is a negative value. That is, the order of transmission of the instruction to the video server device 1 in step S24y and the transmission of the instruction to the decoder unit 26 in step S24w are reversed, and between these transmissions, ((p-1) ÷ p) × Take WT waiting time. That is, the above waiting time is taken from the transmission of the instruction to the video server apparatus 1 to the transmission of the instruction to the decoder unit 26.

  If a frame advance playback instruction is received between step S24u and step S24v of the above operation, the frame advance playback instruction is sent to the decoder unit 26 and the video server device 1 each time it is received. The outline of the change in the usage amount of the storage capacity of the video buffer unit 25 shown in FIG. 12 is not affected.

  As described above, the video server device 1 enters the pause state after executing the frame advance playback. Therefore, after sending the frame advance reproduction instruction to the video server apparatus 1, the reproduction instruction transmission unit 24 may be in a state where the operation of step S24u has been executed.

  Here, in steps S24f and S24g of the flowchart shown in FIG. 7 and steps S24p and S24q shown in FIG. 9, the reception of the packet number 31a and the transmission operation of the received packet number 31a to the decoder unit 26 are performed in step S24s. Since the playback speed at the start of this operation and the playback speed input in step S24v are the same, there is no need to perform the operation shown in the flowchart of FIG. When these two speeds are different, the operations of the above two steps are performed as described above when changing the reproduction speed.

  In addition, the influence of the data amount of information stored in the video buffer unit 25 on the waiting time of the above two steps at time T0 has already been described in the explanation of the slow playback control operation. Here, Description is omitted.

  Note that the playback instruction transmission unit 24 responds to the above instruction after the elapsed time (WT) is transmitted to the communication unit 22 by transmitting the playback instruction received first after the playback instruction transmission unit 24 starts operating. The time until the RTP packet 31 is stored in the video buffer unit 25 is calculated, but the present invention is not limited to this.

  The elapsed time (WT) may be calculated every time a playback instruction with a changed playback speed is transmitted to the communication unit 22. Alternatively, the elapsed time (WT) may be calculated as the time from when another instruction is transmitted to the communication unit 22 until the RTSP response corresponding to the instruction is received. Then, the elapsed time (WT) may be updated with the elapsed time (WT) calculated in these cases, and the elapsed time (WT) is calculated by calculating an average value of the calculated elapsed time (WT). ).

  Next, the operation of the decoder unit 26 will be described. The decoder unit 26 decodes the video frame 25e included in the video data packet 25b stored in the video buffer unit 25 based on the instruction transmitted from the reproduction instruction transmission unit 24, and a still image including the decoded video frame. Is displayed on the video display unit 27.

  The decoder unit 26 receives an instruction from the playback instruction transmitting unit 24 for normal speed playback, slow playback with a specified playback speed coefficient, or fast forward playback with a specified playback speed coefficient, and starts operation. Then, after waiting for the appropriate number of video data packets 25b to be stored in the video buffer unit 25, the video data packet 25b stored at the head of the video buffer unit 25, that is, the first video data packet 25b1 is read. . Then, the first video frame 25e1 is decoded, the decoded video frame is displayed on the video display unit 27, and the first video data packet 25b1 is deleted from the video buffer unit 25.

  At the time of this display, the time stamp 25d1 of the first video data packet 25b1 is stored in a predetermined storage unit (not shown) in the decoder unit 26 as a reference time stamp (hereinafter referred to as TSx). The actual time at the time of display is stored in a predetermined storage unit (not shown) in the decoder unit 26 as a reference time (hereinafter referred to as Tx).

  Next, after the first video data packet 25b1 is deleted from the video buffer unit 25, the decoder unit 26 stores the video data packet 25b stored at the head of the video buffer unit 25, that is, the second video data packet 25b2. And the second video frame 25e2 is decoded. When the actual time becomes (Tx + time stamp 25d2-TSx of the second video data packet 25b2), the decoded video frame is displayed on the video display unit 27, and the second video data packet 25b2 is displayed. Delete from the video buffer unit 25.

  Thereafter, the display of the video data packet 25b stored at the head of the video buffer unit 25, that is, the display after the third video data packet 25b3 is the same as described above, and the third video frame 25e3 is decoded, When the actual time reaches (Tx + time stamp 25d3-TSx of the third video data packet 25b3), the decoded video frame is displayed on the video display unit 27, and the third video data packet 25b3 is stored in the video buffer. Delete from section 25. Subsequent video data packets 25b are sequentially read, decoded, and displayed as described above.

  Next, an operation when the decoder unit 26 receives an instruction for frame advance reproduction from the reproduction instruction transmission unit 24 will be described. When receiving the frame advance playback instruction from the playback instruction transmitting unit 24, the decoder unit 26 reads the mth video data packet 25bm stored at the head of the video buffer unit 25, and the mth video data packet 25bm. The video frame 25em is decoded, the decoded video frame is continuously displayed on the video display unit 27, and the read m-th video data packet 25bm is deleted from the video buffer unit 25.

  Next, an operation when the decoder unit 26 receives a pause instruction from the reproduction instruction transmission unit 24 will be described. When the decoder unit 26 receives a pause instruction from the playback instruction transmitter unit 24, the decoder unit 26 stops the process of reading the video data packet 25b stored in the video buffer unit 25, and decodes the video frame 25e of the video data packet 25b. Stop processing to be displayed. Then, the still image displayed on the video display unit 27 is continuously displayed.

  When stopping the process of displaying the video frame on the video display unit 27, the decoder unit 26 continues to display the still image displayed on the video display unit 27. However, the present invention is not limited to this. For example, nothing may be displayed, and a predetermined still image stored in a predetermined storage unit (not shown) in the decoder unit 26 may be continuously displayed. Furthermore, a predetermined video content stored in a predetermined storage unit (not shown) in the decoder unit 26 may be displayed.

  Next, the decoder unit 26 performs an operation based on an instruction of normal speed playback, slow playback with a specified playback speed coefficient, or fast-forward playback with a specified playback speed coefficient, and then pauses and / or An operation when a frame advance operation is performed and a playback instruction at the same speed as that performed before the pause and / or frame advance operation is received again will be described.

  The decoder unit 26 receives the reproduction instruction at the same speed from the reproduction instruction transmission unit 24 and starts the operation. Then, the above-described operation when the decoder unit 26 starts operating when the appropriate number of video data packets 25b are stored in the video buffer unit 25 is performed.

  However, the operation is performed regardless of the number of video data packets 25b stored in the video buffer unit 25. Further, the time stamp 25 dm of the head m-th video data packet 25 bm is updated and stored in a predetermined storage unit in the decoder unit 26 as a reference time stamp (TSx). In addition, a predetermined storage unit in the decoder unit 26 is set with the actual time when the m-th video frame 25em of the head m-th video data packet 25bm is decoded and displayed on the video display unit 27 as a reference time (Tx). Update and store.

  Next, the decoder unit 26 performs an operation based on an instruction of normal speed playback, slow playback with a specified playback speed coefficient, or fast-forward playback with a specified playback speed coefficient, and then pauses and / or An operation when a playback instruction is received at a speed different from the speed based on the above instruction, that is, with a change in speed, regardless of whether or not the frame advance operation is performed will be described. Here, it is assumed that the playback speed after the change is q times the playback speed before the change. Here, q is not 1.

  FIG. 13 shows a flowchart of the operation when a reproduction instruction accompanied with a change in the speed of the decoder unit 26 is received. The decoder unit 26 receives a playback instruction accompanied by a change in the playback speed and starts its operation (step S26a). Subsequently, as described above, the m-th video stored at the head of the video buffer unit 25. Read data packet 25bm. Then, the mth video frame 25em included in the mth video data packet 25bm is decoded, and the decoded video frame is displayed on the video display unit 27.

  The display time is determined by the time stamp 25 dm, the reference time stamp (TSx), and the reference time (Tx) according to the playback speed before the change. If the actual time is later than the determined time, it is displayed immediately. Then, the m-th video data packet 25bm is deleted from the video buffer unit 25 (step S26b).

  Subsequently, the decoder unit 26 updates and stores the time stamp 25dm of the m-th video data packet 25bm read in step S26b in a predetermined storage unit in the decoder unit 26 as a reference time stamp (TSx). In addition, the actual time when the mth video frame 25em of the mth video data packet 25bm is decoded and displayed on the video display unit 27 is stored in a predetermined storage unit in the decoder unit 26 as a reference time (Tx). Update and store (step S26c).

  Subsequently, the decoder unit 26 performs the same operation as that described in step S26b, but the time stamp 25d of the read video data packet 25b stores a value depending on the reproduction speed before the change. Therefore, the actual time for displaying the decoded video frame on the video display unit 27 is adjusted as (Tx + (time stamp 25d-TSx of the video data packet 25b) ÷ q) (step S26d). By displaying at the adjusted time, the video frame 25e of the video data packet 25b including the time stamp 25d depending on the playback speed before the change can be played back at the playback speed after the change.

  Note that the operation of step S26d for reproducing the video frame 25e of the video data packet 25b including the time stamp 25d depending on the reproduction speed before the change at the reproduction speed after the change is not limited to the adjustment of the time stamp 25d. Absent.

  When the reproduction speed after the change is higher than the reproduction speed before the change (q> 1), the decoder unit 26 reads out only one video data packet 25b from the q video data packets 25b from the video buffer unit 25. The video frame 25e of the read video data packet 25b may be decoded and displayed at the adjusted actual time.

  In this case, the video data packet 25b that has not been read is deleted from the video buffer unit 25 without the video frame 25e of the video data packet 25b being decoded and displayed. This can prevent the number of video data packets 25b processed per unit time of the decoder unit 26 from increasing.

  As already explained in the explanation of the operation of the reproduction instruction receiving unit 13 and the explanation of the operation of the reproduction instruction transmitting unit 24, the packet number 25c of the first video data packet 25b including the time stamp 25d depending on the changed reproduction speed is the decoder unit 26. (Not shown in FIG. 13).

  Therefore, the decoder unit 26 compares the packet number 25c of the video data packet 25b processed in step S26d with the packet number 25c of the first video data packet 25b depending on the notified reproduction speed after the change (step S26d). S26e). If the former packet number 25c is less than the latter packet number 25c (“YES” in step S26e), the process returns to step S26d to decode the video frame 25e of the first video data packet 25b, and the decoded video frame Is displayed at the adjusted time, and the leading video data packet 25b is deleted.

  When the former packet number 25c is greater than or equal to the latter packet number 25c (“NO” in step S26e), the decoder unit 26 uses the time stamp 25d of the video data packet 25b processed in step S26d as a reference time stamp (TSx). The data is updated and stored in a predetermined storage unit in the decoder unit 26. Also, the actual time when the video frame of the video data packet is decoded and displayed on the video display unit 27 is updated and stored in the predetermined storage unit in the decoder unit 26 as the reference time (Tx) (step S26f).

  Subsequently, the decoder unit 26 decodes the video frame 25e of the head video data packet 25b, displays the decoded video frame on the video display unit 27, and repeats the operation of deleting the head video data packet 25b. (Step S26g). Here, the display time is (Tx + time stamp 25d-TSx of the video data packet 25b), and the above adjustment is not performed. This is because the time stamp 25d of the video data packet 25b to be processed has a value depending on the reproduction speed after the change.

  As described above, in slow playback and fast forward playback, if the video data packet 25b is stored based on the RTP packet 31 transmitted from the video server device 1 according to the changed playback speed, the video data packet 25b The time stamp 25d stores the relative reproduction time in real time. Therefore, the decoder unit 27 may calculate the time for displaying the video frame 25e of the video data packet 25b from the time stamp 25d regardless of the playback speed.

  However, the decoder unit 27 processes the video data packet 25b stored based on the RTP packet 31 transmitted from the video server device 1 in accordance with the changed playback speed after the input device 23 is instructed to change the playback speed. There is a delay. Therefore, the decoder unit 27 displays the video frame 25e of the video data packet 25b stored based on the RTP packet 31 transmitted from the video server device 1 according to the playback speed before the change at the playback speed after the change. The display time is calculated after adjusting the time stamp 25d of the video data packet 25b.

  In the above description, the video frame 15b is included in one RTP packet 31, but the present invention is not limited to this. When the video frame 15b is large, the video frame 15b may be divided, and the divided video frames 15b may be included in different RTP packets 31, respectively. The same value is stored in the time stamp 31b included in these RTP packets 31.

  In addition, the video frames 15b1 to 15b3... Are information obtained by encoding a still image obtained by sampling a video at a predetermined time interval “DX”. However, the present invention is not limited to this, and the previous video frame is sampled. The time interval from when the next video frame is sampled may vary depending on the video frames 15b1 to 15b3.

  Further, although the encoding of the video frame 15b is the intra-frame encoding by the motion JPEG method, it is not limited to this. For example, interframe coding may be performed by the MPEG-4 system. In the case of inter-frame encoding, in the process of thinning out the video frame 15b, the intra-frame encoded video frame 15b may be used and the inter-frame encoded video frame 15b may be thinned out.

  In the process of thinning out the video data packet 25b, a packet obtained by intra-coding the video frame 25e of the video data packet 25b is used, and a packet obtained by inter-frame coding the video frame 25e2 is thinned out. good.

  Further, when interframe coding is performed, the interval at which the RTP packet 31 including the video frame 15b is transmitted differs depending on whether the video frame 15b is intraframe encoded or interframe encoded. The average of these intervals may be the interval at which the RTP packet 31 is transmitted.

  In addition, when intra-frame coding is performed by the motion JPEG method or the like, the information amount of the video frame 15b is not necessarily constant. Therefore, the interval at which the RTP packet 31 including the video frame 15b is transmitted is not necessarily constant. The average of these intervals may be the interval at which the RTP packet 31 is transmitted.

  In addition, the above description has been about video reproduction. However, the video content 15a further includes information of an audio frame, and the video reproduction device 2 further includes sound generation means such as a speaker, and In addition, sound may be reproduced. The audio may be played back only during normal speed playback, and may not be played back during slow playback and fast forward playback, and the video server device 1 plays back the audio in slow playback and fast forward playback. It is also possible that the video reproduction device 2 reproduces the audio having undergone the transformation in accordance with the transformation.

  Furthermore, although the above description was about the reproduction in the forward direction, the reproduction in the reverse direction may be performed. That is, the packet transmission unit 14 may be configured to transmit the video content 15a in reverse order from the end.

  In addition, although the video server device 1 and the video playback device 2 are connected by the communication network 3, the present invention is not limited to this. For example, it may be connected by a signal line. Furthermore, it may be stored in one housing. The present invention is not limited to the above configuration, and various modifications are possible.

1 is a block diagram showing a configuration of a video communication system according to an embodiment of the present invention. The block diagram which shows the structure of the video server apparatus which concerns on embodiment of this invention. The figure which shows the format of the video content which concerns on embodiment of this invention. 1 is a block diagram showing a configuration of a video reproduction device according to an embodiment of the present invention. The figure which shows the format of the video data which concerns on embodiment of this invention. The figure which shows the format of the data packet which concerns on embodiment of this invention. The flowchart which shows the operation | movement which changes the reproduction speed of the reproduction | regeneration instruction | indication transmission part which concerns on embodiment of this invention to slow. The figure which shows the change of the usage-amount of the storage capacity of the video buffer part which concerns on embodiment of this invention (example which changes reproduction speed to slow). The flowchart which shows the operation | movement which changes the reproduction speed of the reproduction | regeneration instruction | indication transmission part which concerns on embodiment of this invention to fast forward. The figure which shows the change of the usage-amount of the storage capacity of the video buffer part which concerns on embodiment of this invention (example which changes reproduction speed to fast-forward). The flowchart which shows the operation | movement including the pause of reproduction | regeneration of the reproduction | regeneration instruction | indication transmission part which concerns on embodiment of this invention. The figure which shows the change of the usage-amount of the storage capacity of the video buffer part which concerns on embodiment of this invention (example including the pause of reproduction | regeneration). The flowchart which shows operation | movement of the decoder part which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image | video server apparatus 2 Image | video reproduction | regeneration apparatus 3 Communication network 13 The reproduction | regeneration instruction | indication receiving part 14 Packet transmission part 15 The image | video content storage part 15a The image | video content 15b The image | video frame 23 The input device 24 The reproduction | regeneration instruction | indication transmission part 25 The image | video buffer part 25a The image | video data 25b 25c Packet number 25d Time stamp 25e Video frame 26 Decoder 27 Video display 31 RTP packet 31a Packet number 31b Time stamp 31c Video frame

Claims (3)

A video server device that receives an image frame reading instruction that specifies a playback speed is received, and a video server device that transmits the image frame and a video playback device that plays back the image frame received from the video server device according to the read command via a communication line. A video playback device of a video communication system connected to each other,
Instruction transmitting means for transmitting the read instruction to the video server device;
Image frame receiving means for receiving an image frame transmitted from the video server device in accordance with the read instruction and storing it in a buffer storage means;
Reproduction means for transmitting the image frames stored in the buffer storage means to video display means;
The image frame receiving means receives the image frame transmitted in response to the read instruction designating the first reproduction speed, stores it in the buffer storage means, and the reproduction means responds to the first reproduction speed. When an instruction for slow playback is input from the input means while the image frame is being transmitted to the video display means, the instruction transmission means is instructed to transmit an instruction to stop reading the image frame and wait for a predetermined time. An instruction to read out the image frame by designating a second playback speed slower than the first playback speed after the time has passed, and causing the playback means to store the image frame stored in the buffer storage means A video playback apparatus comprising: slow playback control means for transmitting to the video display means in accordance with a second playback speed. A video server device that receives an image frame reading instruction that specifies a playback speed is received, and a video server device that transmits the image frame and a video playback device that plays back the image frame received from the video server device according to the read command via a communication line. A video playback device of a video communication system connected to each other,
Instruction transmitting means for transmitting the read instruction to the video server device;
Image frame receiving means for receiving an image frame transmitted from the video server device in accordance with the read instruction and storing it in a buffer storage means;
Reproduction means for transmitting the image frames stored in the buffer storage means to video display means;
The image frame receiving means receives the image frame transmitted in response to the read instruction designating the first reproduction speed, stores it in the buffer storage means, and the reproduction means responds to the first reproduction speed. When a fast-forward playback instruction is input from the input means while the image frame is being transmitted to the video display means, a second playback speed that is faster than the first playback speed is specified to the instruction transmission means. The image frame reading instruction is transmitted, and the reproduction unit stops transmission of the image frame to the video display unit according to the first reproduction speed, and the predetermined waiting time elapses. Video playback comprising: fast-forward playback control means for sending the image frame stored in the buffer storage means to the video display means in accordance with the second playback speed Location. The reproduction means transmits the image frame transmitted according to the read instruction designating the first reproduction speed to the video display means, and then transmitted according to the read instruction designated the second reproduction speed. 3. The video reproducing apparatus according to claim 1, wherein the image frame is transmitted to the video display means.

Images