JP3953285B2 - MPEG encoding processing apparatus and processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an MPEG encoding processing apparatus and processing method, and more particularly to an MPEG encoding processing apparatus and processing method for generating an MPEG bit stream that is data obtained by compressing and encoding an input analog video signal according to the MPEG standard.
[0002]
[Prior art]
MPEG (Moving Picture Experts Group) is defined by ISO / IEC (International Organization for Standardization / International Electrotechnical Commission) 1381 as a standard moving image compression coding technique, and is used for images such as broadcasting and AV (Audio-Video) equipment. It is widely used as an information compression technique for voice, data, etc.
[0003]
First, the outline of the operation of a moving picture coding apparatus that generates MPEG data will be described. This moving picture coding apparatus employs motion compensation interframe predictive coding that reduces redundancy in the time direction of moving pictures.
[0004]
In motion compensation interframe predictive coding, first, an input image is divided into macroblocks of, for example, 16 pixels × 16 lines, and a region of an image closest to each macroblock using a decoded image of an already encoded image as a reference image. Is searched from the reference image to create a predicted image, and the position of the predicted image is encoded as a motion vector. There are two types of encoded images that perform inter-frame prediction: a P picture that performs forward prediction and a B picture that performs bidirectional prediction. In addition, there is an I picture that is encoded in one screen without performing inter-frame prediction for an initial state of encoding or when a transmission error occurs.
[0005]
In the case of forward prediction, the reference image is an already encoded image and is an image temporally preceding the input image. In the case of bi-directional prediction, the reference image is an already encoded image, and both the images before and after the input image are used temporally. That is, it is necessary to change the order of input images before encoding. In this case, the predicted image includes a predicted image when the previous image is used as a reference image, a predicted image when the later image is used as a reference image, and an average of these predicted images. Of the three images taken, select the one with the least prediction error. The difference between the input image and the predicted image is encoded using a discrete cosine transform (hereinafter referred to as DCT transform), quantization, and variable length coding as a prediction error.
[0006]
MPEG encoded moving image data is called a stream. A value of a period in which an I picture or P picture appears in a stream is referred to as an encoding mode M. The figure which shows typically the relationship between the input order and encoding order of the video frame FV in the video encoding part 105 in case the value of M is 3 (henceforth M = 3), ie, the output order of stream BS, with explanatory drawing. Referring to FIG. 3 (A), the I / P / B symbol shown in this figure indicates the image type (picture) when the video frame is encoded, and the subsequent numbers indicate the input order. The M value generally used is 3 because of the relationship between the image quality and the code amount. As shown in the figure, when M = 3, the order of frame input and the order of encoding occur. In this example, a video frame FV is input in the order of pictures B0, B1, I2, B3, B4, and P5, and encoding is performed in the order of pictures I2, B0, B1, P5, B3, and B4.
[0007]
With the recent trend toward digitization of equipment, for example, video (image) recording methods at home are also shifting from analog methods such as VHS to digital methods. For example, there may be a need to store an analog image desired to be stored at home in a digital format. In such a case, as a digital system, it is common to digitize by compression coding (hereinafter, MPEG coding) according to the MPEG standard.
[0008]
For example, when video recorded on a video tape divided into several times in the VHS format, that is, a series of a plurality of independent recorded videos is reproduced, and this is MPEG-recorded as a master and recorded on a digital recording medium Consider. In this case, the analog video to be reproduced is an independent video for each of the division units, and there is naturally no signal synchronization relationship between them. In other words, the analog video is disconnected from the next video at the end of the video for each division. Therefore, when such a series of analog video is MPEG-encoded, the video signal is out of synchronization at the boundary between the previously reproduced video and the next video, and MPEG encoding cannot be normally performed. is there. Here, the loss of synchronization means that the synchronization signal inserted at regular time intervals for synchronizing the video signal does not appear at a predetermined interval. The interval of the synchronization signal is determined by the video signal standard.
[0009]
That is, in the video that is divided and recorded, the video signal is out of synchronization at the boundary of each recording, but when the recorded video of the recording medium is continuously reproduced and MPEG encoded, it is viewed from the MPEG encoding device side. , It becomes a processing target in one sequence. Also, in the case of digital recording by MPEG encoding of a broadcast program, loss of synchronization of video signals is inevitable even when the broadcast channel is switched during MPEG encoding. In this case as well, when viewed from the side of the MPEG encoding device, it becomes a processing target within one sequence. Further, when the reception electric field is weak and normal reception is not possible, and when there is no signal, video signals such as VTR fast forward and rewind continuously lose synchronization. In these cases, normal MPEG encoding cannot be performed at the time of loss of synchronization, and an incomplete stream or no stream can be generated.
[0010]
The conventional MPEG coding described in Japanese Patent Application Laid-Open No. 2000-23101 is intended to solve the above problems and to enable smooth MPEG coding of an analog video signal even when out-of-synchronization occurs. Referring to FIG. 4 showing the processing device in block form, the conventional MPEG encoding processing device shown in this figure receives an analog video signal V and outputs a vertical synchronizing signal (hereinafter referred to as synchronizing signal) SY and video data DV. Unit 101, synchronization signal generation unit 102 that outputs the next pseudo-synchronization signal YQ at the timing calculated by inputting the synchronization signal SY, and the synchronization signal SY and the pseudo-synchronization signal YQ are input and the synchronization signal YU is out of synchronization. A synchronization signal comparison unit 103 that outputs an out-of-synchronization notification signal NY for notifying that it has been performed, a plurality of frame memories, and an effective synchronization signal YU and video data. DV is input, video data DV is stored in the frame memory, the video frame FV is output, and the address of this frame memory is output as the memory address AM. The memory address AM and the out-of-synchronization notification signal NY are input. And a video encoding unit 105 that outputs a stream signal BS that is converted data.
[0011]
Next, the operation of the conventional MPEG encoding processing apparatus will be described with reference to FIG. 4. First, the video input unit 101 receives video data DV according to the input analog video signal V and the extracted synchronization signal SY. And the video data DV is supplied to the memory unit 104, and the synchronization signal SY is supplied to the synchronization signal generation unit 102 and the synchronization signal comparison unit 103. The memory unit 104 sequentially stores the supplied video data DV in a plurality of frame memories, outputs the addresses as memory addresses AM, and supplies them to the video encoding unit 105. The video encoding unit 105 specifies a frame to be encoded based on the memory address AM. When the memory unit 104 stores frames (hereinafter referred to as video frames) FV of the number of video data necessary for encoding (predetermined number), the video encoding unit 105 reads out the video frame FV to be encoded first, and performs encoding. Start.
[0012]
The synchronization signal generator 102 calculates the timing of the next synchronization signal corresponding to the next video frame from the supplied current synchronization signal SY corresponding to the current video frame, and outputs the pseudo synchronization signal YQ at that timing. The synchronization signal comparison unit 103 outputs, as the effective synchronization signal YU, the signal that has arrived first among the synchronization signal SY and the pseudo synchronization signal YQ. Further, the synchronization signal SY is compared with the pseudo synchronization signal YQ, and when the shift of the synchronization signal SY with respect to the pseudo synchronization signal YQ exceeds a certain value, it is detected as out of synchronization. When out-of-synchronization is detected, the out-of-synchronization notification signal NY is output and supplied to the video encoding unit 105 for notification. The video encoding unit 105 stops the video encoding when the loss of synchronization is notified by the supply of the synchronization loss notification signal NY. Specifically, when encoding is completed up to the video frame being read when the synchronization is notified, encoding of the subsequent video frames is stopped. When the out-of-synchronization notification signal NY disappears, encoding is resumed.
[0013]
This conventional MPEG encoding processing apparatus requires a synchronization signal generation unit, but can operate without a synchronization signal generation unit. However, in this case, when an out-of-synchronization video signal is encoded with M = 3, which is a commonly used encoding mode, from the relationship between the image quality and the code amount, an intermediate B in the picture display order in the decoder. There are cases where a picture is lost and an incomplete stream is created. This phenomenon is remarkable particularly when out-of-synchronization occurs.
[0014]
Referring to FIG. 3A schematically showing the relationship of the output order of the stream BS when M = 3, the reason is that the timing signal for starting encoding the picture I2 of the stream BS is a video frame. The timing signal for starting the encoding of the pictures B0 and B1 of the stream BS is based on the input signals of the pictures B4 and P5 of the video frame FV. In this case, for example, when the picture B3 of the video frame FV is not normal due to loss of synchronization, the picture B0 of the stream BS cannot be encoded and is lost, and the synchronization loss notification signal NY is generated and the picture I2 is encoded. To stop the encoding process. For this reason, there occurs a phenomenon that there is no picture to be displayed at the timing when the pictures B0 and B1 are to be displayed by the decoder.
[0015]
The incomplete stream here means that a discontinuous picture is included in the display order in the stream. For example, in the stream of this example, when a loss of synchronization occurs during the encoding of the picture P5, the encoding is stopped at the picture P5. When this stream is decoded and displayed, there is no picture to be displayed between the pictures I2 and P5 where the pictures B3 and B4 are supposed to be displayed in the video frame FV, and there is a space for two.
[0016]
[Problems to be solved by the invention]
The conventional MPEG encoding processing apparatus and processing method described above is out of synchronization when encoding with M = 3, which is a commonly used encoding mode, because of the relationship between image quality and code amount. When a certain video signal is encoded, there is a drawback that an intermediate B picture may be lost in the picture display order in the decoder, and an incomplete stream may be generated.
[0017]
An object of the present invention is to solve the above-described drawbacks and to provide an MPEG encoding processing apparatus that prevents the creation of an incomplete stream even when a video signal that is continuously out of synchronization is encoded in the encoding mode M = 3. It is to provide a processing method.
[0018]
[Means for Solving the Problems]
The MPEG encoding processing apparatus according to the first aspect of the present invention is an MPEG encoding apparatus having encoding means for generating an MPEG bit stream (hereinafter referred to as a stream) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard. In the processing device,
When resuming encoding after the stop of encoding due to out-of-synchronization that causes the synchronization signal included in the input analog video signal to become irregular, an intra-frame encoded image in the stream is sent to the encoding means. The encoding mode value, which is the value of the period in which a certain I picture or P picture, which is a forward predictive encoded image, appears, is changed from a first value, which is a normal initial setting value, to a second value for loss of synchronization relief. The encoding mode changing means for changing is provided.
[0019]
An MPEG encoding processing apparatus according to a second aspect of the present invention is an MPEG code having encoding means for generating an MPEG bit stream (hereinafter referred to as stream signal) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard. In the processing equipment,
A video input unit for inputting the input analog video signal and outputting a synchronization signal and video data;
An out-of-synchronization detection unit that inputs the synchronization signal and outputs an out-of-synchronization detection signal indicating that an out-of-synchronization occurs in which the synchronization signal becomes irregular;
It is a value of a period in which an I picture which is an intra-frame encoded image or a P picture which is a forward prediction encoded image appears in the stream when the out-of-sync detection signal and an encoding state signal indicating an encoding state are input. A video encoding control unit for outputting a mode value signal for specifying a value of the encoding mode and an encoding control signal for controlling stop / restart of video encoding;
Provided with a plurality of frame memories, inputs the synchronization signal and the video data, stores the video data in the frame memory, outputs a video frame in response to reading of the encoding means, and sets the address of the frame memory as a memory address A memory unit that outputs as
The code that inputs the memory address, the encoding control signal, and the mode value signal, reads the video frame corresponding to the memory address, performs motion compensation interframe prediction encoding, and outputs the stream signal and the encoding state signal A video encoding unit which is an encoding means,
When the video encoding control unit restarts encoding after the stop of encoding due to out-of-synchronization occurrence in which a synchronization signal included in the input analog video signal becomes irregular, the video encoding unit The encoding mode value setting unit is configured to change the encoding mode value from the first value which is the initial set value in the normal state to the second value for loss of synchronization relief.
[0020]
According to a third aspect of the present invention, in the MPEG encoding processing apparatus according to the first or second aspect, the first value of the encoding mode value is 3, and the second value is 1. It is characterized by this.
[0021]
According to a fourth aspect of the present invention, there is provided an MPEG encoding method comprising an encoding means for generating an MPEG bit stream (hereinafter referred to as a stream) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard. In the processing method,
When resuming encoding after the stop of encoding due to out-of-synchronization that causes the synchronization signal included in the input analog video signal to become irregular, an intra-frame encoded image in the stream is sent to the encoding means. The encoding mode value, which is the value of the period in which a certain I picture or P picture, which is a forward predictive encoded image, appears, is changed from a first value, which is a normal initial setting value, to a second value for loss of synchronization relief. It is characterized by changing.
[0022]
According to a fifth aspect of the present invention, there is provided an MPEG encoding method comprising MPEG encoding means for generating an MPEG bit stream (hereinafter referred to as stream) which is data encoded by compressing and encoding an input analog video signal in accordance with the MPEG standard. In the processing method,
A synchronization signal extracting step of extracting a synchronization signal from the input analog video signal;
A synchronization loss detection step of monitoring the synchronization signal and detecting a synchronization loss;
When detecting out-of-synchronization in the out-of-synchronization detection step, out-of-synchronization detection notifying step for notifying the encoding means of out-of-synchronization detection; and
Video encoding stop request step for detecting occurrence of loss of synchronization by the out of sync detection notification and requesting the encoding means to stop video encoding;
In response to a stop request by the encoding control signal, a video encoding stop step for stopping video encoding at the completion of encoding of the video frame being encoded at that time;
An encoding stop state notifying step for notifying an encoding stop state;
An encoding stop confirmation step for confirming that the encoding has been stopped by the encoding stop state notification;
When encoding is stopped in the encoding stop confirmation step, an encoding mode that is a value of a cycle in which an I picture that is an intra-frame encoded image or a P picture that is a forward prediction encoded image appears in the stream A second value setting step of setting a second value for out-of-synchronization relief in place of the first value which is a normal initial setting value;
A video encoding restart request step for requesting restart of the video encoding;
Resuming a video encoding step of resuming the video encoding with a second value of the encoding mode based on the video encoding restart request;
A set number encoding determination step for determining whether or not a predetermined number of video frames that the synchronization signal can be regarded as stable have been encoded;
A step of confirming that there is no loss of synchronization;
A first value setting step for returning the encoding mode to the first value;
A video encoding continuation step of continuing the video encoding with the first value of the encoding mode.
[0023]
The invention according to claim 6 is the MPEG encoding processing method according to claim 4 or 5, wherein the first value of the encoding mode value is 3, and the second value is 1. It is characterized by this.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
The MPEG (Moving Picture Experts Group) encoding processing apparatus and processing method according to the present embodiment is a code for generating an MPEG bit stream (hereinafter referred to as a stream) that is data obtained by compressing and encoding an input analog video signal according to the MPEG standard. In the MPEG encoding processing apparatus having the encoding means, when the encoding is resumed after the encoding is stopped after the out-of-synchronization occurs in which the synchronization signal included in the input analog video signal becomes irregular, Synchronizes the value of the encoding mode, which is the value of the period in which an I picture that is an intra-frame encoded image or a P picture that is a forward prediction encoded image, appears in the stream from the first value that is a normal initial setting value. Coding mode changing means for changing to the second value for out-of-phase relief is provided, When resuming encoding after stopping the encoding, the M value, which is the MPEG encoding mode, is set to the second value, 1, so that an incomplete stream is not generated when continuous loss of synchronization occurs. It is characterized by that.
[0026]
Next, referring to FIG. 1 showing the embodiment of the present invention in block form, the MPEG coding processing apparatus of the present embodiment shown in this figure receives an analog video signal V and receives a vertical synchronization signal (hereinafter referred to as a synchronization signal). A video input unit 1 that outputs SY and video data DV, an out-of-synchronization detection unit 2 that inputs a synchronization signal SY and outputs an out-of-synchronization detection signal DY indicating that out-of-synchronization has occurred, and an out-of-synchronization detection signal DY Video encoding for inputting an encoding state signal SM indicating an encoding state and outputting an M value signal M for specifying an encoding mode M value, which will be described later, and an encoding control signal CM for controlling stop / restart of video encoding The control unit 3 is provided with a plurality of frame memories, receives the synchronization signal SY and the video data DV, stores the video data DV in the frame memory, and reads the video frame in accordance with the reading of the video encoding unit 5 described later. The memory unit 4 outputs FV and outputs the address of the frame memory as the memory address AM, and inputs the memory address AM, the encoding control signal CM, and the M value signal M, and reads the video frame FV corresponding to the memory address AM. It includes a video encoding unit 5 that outputs a stream signal BS and encoding state signal SM, which are data that has been motion-compensated interframe prediction encoded and MPEG encoded (hereinafter encoded).
[0027]
The video encoding control unit 3 includes an M value setting unit 31 that sets an encoding mode M value.
[0028]
Next, with reference to FIG. 1 and FIG. 2 showing the processing of each unit in a flowchart, the MPEG encoding processing method as the operation of the present embodiment will be described. First, the video encoding unit 5 will be described in the prior art. As described above, each video frame FV is an image of either a P picture that is a forward prediction encoded image, a B picture that is a bidirectional prediction encoded image that performs bidirectional prediction, or an I picture that is an intra-frame encoded image. Encoding and generating a stream that is MPEG encoded moving image data.
[0029]
A value of a period in which an I picture or P picture appears in a stream is referred to as an encoding mode M. The relationship between the input order of the video frame FV in the memory unit 4 and the encoding order in the video encoding unit 5, that is, the output order of the stream BS when the value of M is 3 (hereinafter, M = 3) is schematically described. Referring to FIG. 3A, the I / P / B symbol shown in this figure indicates the image type (picture) when the video frame is encoded, and the subsequent numbers indicate the input order. To express. The M value generally used is 3 because of the relationship between the image quality and the code amount. As shown in the figure, when M = 3, the order of frame input and the order of encoding occur. In this example, a video frame FV is input in the order of pictures B0, B1, I2, B3, B4, and P5, and encoding is performed in the order of pictures I2, B0, B1, P5, B3, and B4.
[0030]
In the video encoding process, control such as switching of the writing area of the frame memory is performed based on the synchronization signal of the video input. If the video signal is out of sync, the order of the frames to be encoded will be wrong, or another image will be inserted above and below one frame. Processing is stopped, and encoding is resumed after the video signal returns to normal.
[0031]
Here, the loss of synchronization means that the synchronization signal inserted at regular time intervals for synchronizing the video signal does not appear at a predetermined interval. The interval of the synchronization signal is determined by the video signal standard.
[0032]
First, the video input unit 1 extracts a synchronization signal SY from the input analog video signal V (synchronization signal extraction step S1), the video data DV is stored in the memory unit 4, and the extracted synchronization signal SY is extracted from the synchronization detection unit 2. To the memory unit 4.
[0033]
Hereinafter, for convenience of explanation, it is assumed that the analog video signal is an NTSC standard TV signal, the synchronization signal SY is a vertical synchronization signal, and the setting value (initial value) of the encoding mode M is 3. Therefore, M = 3 is set as an initial value in the M value setting unit 31 of the video encoding control unit 3.
[0034]
The memory unit 4 has a plurality of frame memories for storing images in units of one frame, and stores the video data DV output from the video input unit 1 in the frame memory in units of one frame. Called video frame FV). A frame delimiter can be determined by the synchronization signal SY. If the number of frames to be stored before the start of encoding is determined in advance, the encoded frames can be identified by managing the number of stored frames and their storage order. By overwriting a certain frame memory, the video frames FV corresponding to the sequentially input video data DV are stored. The memory unit 4 outputs the address of the frame memory storing the video frame FV as the memory address AM. The stored video frame FV can be specified from the memory address AM.
[0035]
The video encoding unit 5 starts encoding after storing the required number of video frames FV in the memory unit 4. By monitoring the memory address AM, the number of video frames FV stored in the memory unit 4 can be known, and by storing the memory address AM, the input order of the video frames FV can be known. For example, when encoding is performed in the encoding mode M = 3 in this example, since the input order and the encoding order are switched, it is necessary to store at least three video frames FV. Encoding is performed in the encoding mode M value, in this example, in the video frame order according to M = 3 (FIG. 3A).
[0036]
The out-of-synchronization detection unit 2 monitors the input synchronization signal SY and detects out-of-synchronization (out-of-synchronization detection step S2). Since the interval of the synchronization signal is determined according to the standard of the video signal to be input, the current video is started from the synchronization signal (hereinafter referred to as the previous synchronization signal) SYP of the video frame FVP immediately before the currently processed video frame (hereinafter referred to as the current video frame) FV. The loss of synchronization can be detected by measuring the time until the synchronization signal SY of the frame FV, that is, the synchronization signal period. In this example, as described above, since it is an NTSC standard TV vertical synchronizing signal, the synchronizing signal period T is 1/60 s, that is, 16.67 ms. Therefore, if the detected synchronization signal period T exceeds the above value by a certain time, for example, 5 ms or more, it is detected as out of synchronization.
[0037]
The out-of-synchronization detection unit 2 outputs an out-of-synchronization detection signal DY (H level) when the out-of-synchronization is detected in the out-of-synchronization detection step S2, and supplies it to the video encoding control unit 3 to notify the out-of-synchronization detection. (Out of synchronization detection notification step S3). If no loss of synchronization is detected, encoding is continued in the encoding mode M = 3.
[0038]
Next, the video encoding control unit 3 detects that a synchronization loss has occurred from the input of the synchronization loss detection signal DY. In order to stop the video encoding, an encoding control signal CM for requesting the video encoding stop is output to the video encoding unit 5 (video encoding stop request step S4).
[0039]
When a stop request is sent by the encoding control signal CM, the video encoding unit 5 stops video encoding at the time when encoding of the video frame being encoded is completed (video encoding stop step S5). The encoding stop signal is output by the encoding state signal SM and notified to the video encoding control unit 3 (encoding stop state notification step S6).
[0040]
The video encoding control unit 3 confirms that the encoding is stopped by the encoding state signal SM output from the video encoding unit 5 (encoding stop confirmation step S7). When the encoding is stopped, the M value setting unit 31 sets the M value signal M = 1 for losing synchronization instead of the initial setting value M = 3 (set step S8 where M = 1) Then, an encoding control signal CM for requesting restart of video encoding is output (video encoding restart request step S9).
[0041]
When a restart request is sent with the encoding control signal CM, the video encoding unit 5 stores the necessary number of frames out of synchronization in the memory unit 4 and then performs video encoding as in the case of encoding start. Restart (video encoding restart step S10). When the video encoding is resumed, the encoding mode M = 1 set in the M-value signal M in the setting step S8 of M = 1 is used.
[0042]
The video encoding unit 5 resumes video encoding in this encoding mode M = 1. When a predetermined number of video frames that can be regarded as being stable is decoded (set number decoding determination step S12), the M value setting unit 31 sets the encoding mode M at the start of video encoding. The initial value M of the encoding mode M is returned to 3 (set to M = 3, step S13). The video encoding control unit 3 confirms the out-of-synchronization detection signal from the out-of-synchronization detecting unit 2 while encoding the set number of sheets (step S11 for confirming no out-of-synchronization), and starts again from the video encoding stop process. The set number of sheets is, for example, GOP (Group of Pictures) which is a unit of several pictures. Generally, there are about 15 pictures included in one GOP, so in this example, 15 pictures are used.
[0043]
The video encoding unit 5 continues video encoding in this encoding mode M = 3 (video encoding step S14).
[0044]
The relationship between the input order of the video frame FV in the memory unit 4 and the encoding order in the video encoding unit 5, that is, the output order of the stream BS when the value of the encoding mode M is 1 (hereinafter, M = 1) is schematically shown. Referring to FIG. 3B, which is an explanatory diagram, in the encoding mode M = 1, the video frame input order and encoding order are the same as shown in FIG. In this example, video frames FV are input in the order of pictures I0, P1, P2, P3, P4, and P5, and encoding is similarly performed for pictures I0, P1, P2, P3, P4, and P5. It is done in the order.
[0045]
Therefore, even if M = 1 and a loss of synchronization occurs continuously and video encoding is stopped, since the encoding is continued in the order of input when video encoding is resumed, an intermediate picture may be lost. Since there is no incomplete stream at the second and subsequent video encoding stop portions, the pictures continue in the display order.
[0046]
In addition, when a stream obtained by encoding a video signal that continuously loses synchronization is decoded by a decoder and displayed, an I / P picture exists in the second or subsequent video encoding stop stream. There is no loss of the B picture to be displayed before the I / P picture.
[0047]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, M may be an arbitrary value larger than 1 without being limited to the initial value M = 3 of the encoding mode. Of course, the number of sheets for confirming that there is no loss of synchronization is appropriately set without being limited to 15, so long as it does not depart from the gist of the present invention.
[0048]
【The invention's effect】
As described above, the MPEG encoding processing apparatus and processing method according to the present invention allows an I picture or a P picture in a stream to the encoding means when encoding is resumed after the encoding is stopped due to out-of-synchronization. Coding mode change means for changing the value of the encoding mode, which is the value of the period in which the error occurs, from the first value, which is the initial setting value in the normal state, to the second value for out-of-synchronization relief, and detects loss of synchronization Then, by switching the encoding mode value M to M = 1 and restarting the encoding, even if a loss of synchronization occurs continuously and the video encoding is stopped, this M = 1 when the video encoding is resumed. Since encoding is performed in the order of input, which is a feature, there is no loss of intermediate pictures, so an incomplete stream is not created at the second and subsequent video encoding stop portions, and pictures are consecutive in display order. There is a cormorant effect.
[0049]
In addition, when a stream obtained by encoding a video signal that continuously loses synchronization is decoded by a decoder and displayed, an I / P picture exists in the second or subsequent video encoding stop stream. There is an effect that the B picture to be displayed before the I / P picture is not lost and can be normally displayed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of an MPEG encoding processing apparatus according to the present invention.
FIG. 2 is a flowchart showing an example of an MPEG encoding processing method that is an operation in the MPEG encoding processing apparatus according to the present embodiment;
FIG. 3 is an explanatory diagram schematically showing a relationship between an input order of video frames in a memory unit and an encoding order in a video encoding unit.
FIG. 4 is a block diagram showing an example of a conventional MPEG encoding processing apparatus.
[Explanation of symbols]
1,101 Video input section
2 Out of sync detector
3 Video encoding control unit
4,104 Memory part
5,105 video encoding unit
31 M value setting section
102 Sync signal generator
103 Sync signal comparator

Claims (6)

In an MPEG encoding processing apparatus having encoding means for generating an MPEG bit stream (hereinafter referred to as a stream) that is data obtained by compressing and encoding an input analog video signal according to the MPEG standard,
When resuming encoding after stopping the encoding due to out-of-synchronization occurring in which the synchronization signal included in the input analog video signal becomes irregular,
An encoding mode value that is a value of a period in which an I picture that is an intra-frame encoded image or a P picture that is a forward prediction encoded image appears in the stream with respect to the encoding means. An MPEG encoding processing apparatus comprising encoding mode changing means for changing from a first value of 1 to 1 which is a second value for out-of-sync relief. In an MPEG encoding processing apparatus having encoding means for generating an MPEG bit stream (hereinafter referred to as a stream signal) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard,
A video input unit for inputting the input analog video signal and outputting a synchronization signal and video data;
An out-of-synchronization detection unit that inputs the synchronization signal and outputs an out-of-synchronization detection signal indicating that an out-of-synchronization occurs in which the synchronization signal becomes irregular;
It is a value of a period in which an I picture which is an intra-frame encoded image or a P picture which is a forward prediction encoded image appears in the stream when the out-of-sync detection signal and an encoding state signal indicating an encoding state are input. A video encoding control unit for outputting a mode value signal for specifying a value of the encoding mode and an encoding control signal for controlling stop / restart of video encoding;
Provided with a plurality of frame memories, inputs the synchronization signal and the video data, stores the video data in the frame memory, outputs a video frame in response to reading of the encoding means, and sets the address of the frame memory as a memory address A memory unit that outputs the memory address, the encoding control signal, and the mode value signal, reads the video frame corresponding to the memory address, performs motion compensation inter-frame predictive encoding, the stream signal, and the encoding state A video encoding unit which is the encoding means for outputting a signal,
When the video encoding control unit restarts encoding after the stop of encoding due to out-of-synchronization occurrence in which a synchronization signal included in the input analog video signal becomes irregular, the video encoding unit MPEG encoding, characterized in that it comprises the coding mode setting unit to change the value of the encoding mode to 1 which is the second value of the out-of-sync for relief from a first value is a default value for the normal Processing equipment. 3. The MPEG encoding processing apparatus according to claim 1, wherein the first value of the encoding mode value is 3. In an MPEG encoding processing method having encoding means for generating an MPEG bit stream (hereinafter referred to as stream) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard,
When resuming encoding after the stop of encoding due to out-of-synchronization that causes the synchronization signal included in the input analog video signal to become irregular, an intra-frame encoded image in the stream is sent to the encoding means. in a second value for the relief out of synchronization values for certain I-picture or forward a predictive coded picture of the period of appearance of P-picture is a value encoding mode from a first value is a default value for the normal An MPEG encoding processing method characterized by changing to one . In an MPEG encoding processing method having encoding means for generating an MPEG bit stream (hereinafter referred to as stream) which is data obtained by compressing and encoding an input analog video signal according to the MPEG standard,
A synchronization signal extracting step of extracting a synchronization signal from the input analog video signal;
A synchronization loss detection step of monitoring the synchronization signal and detecting a synchronization loss;
When detecting out-of-synchronization in the out-of-synchronization detection step, out-of-synchronization detection notifying step for notifying the encoding means of out-of-synchronization detection; and
Video encoding stop request step for detecting occurrence of loss of synchronization by the out of sync detection notification and requesting the encoding means to stop video encoding;
In response to a stop request by the encoding control signal, a video encoding stop step for stopping video encoding at the completion of encoding of the video frame being encoded at that time;
An encoding stop state notifying step for notifying an encoding stop state;
An encoding stop confirmation step for confirming that the encoding has been stopped by the encoding stop state notification;
When encoding is stopped in the encoding stop confirmation step, an encoding mode that is a value of a cycle in which an I picture that is an intra-frame encoded image or a P picture that is a forward prediction encoded image appears in the stream A second value setting step of setting 1 which is a second value for out-of-synchronization relief in place of the first value which is a normal initial setting value;
A video encoding restart request step for requesting restart of the video encoding;
A video encoding restarting step for restarting the video encoding with the encoding mode being the second value of 1 based on the video encoding restart request;
A set number encoding determination step for determining whether or not a predetermined number of video frames that the synchronization signal can be regarded as stable have been encoded;
A step of confirming that there is no loss of synchronization;
A first value setting step for returning the encoding mode to the first value;
And a video encoding continuation step for continuing the video encoding with the first value of the encoding mode. 6. The MPEG encoding processing method according to claim 4, wherein the first value of the encoding mode value is 3.

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