JP4458350B2 - Transport packet output device and operation method of transport packet output device - Google Patents

Description

  The present invention relates to a transport packet output device that outputs a transport packet sequence and an operation method of the transport packet output device.

  Nowadays, a transport stream is often used for transmission of data such as MPEG (Moving Picture Experts Group) 2. A transport stream is a data stream composed of transport packets having a fixed length of 188 bytes. By using such a transport stream, multi-channel television broadcasting, high-definition broadcasting, multimedia data broadcasting, and data input / output between AV devices are performed. Therefore, by recording a sequence of transport packets (hereinafter referred to as “transport packet sequence”) constituting the transport stream, high-quality video and audio can be reproduced.

  The transport stream is designed so that it can also be used for a transmission line in which an error may occur. For example, in reception of broadcasting or the like, transport packets are not always acquired continuously, but may be acquired at irregular timing due to an error or the like. A plurality of transport packet sequences are time-divided and transmitted. Therefore, when recording the transport packet to be acquired, in order to efficiently use the recording medium etc., it is partialized and arrives so that the timing when the transport packet is acquired at the time of playback can be played back. Recording is performed in association with a reproduction time stamp (Arrival Timestamp).

  FIG. 14 is a diagram illustrating recording and reproduction of a transport packet sequence. FIG. 14A describes recording of a transport packet sequence on a recording medium or the like. Hereinafter, “packet” means a transport packet. Assume that packet 0 is acquired at time t0, packet 1 is acquired at time t1, and packet 2 is subsequently acquired at time t2, due to the occurrence of an error in the subsequent transmission path. Further, it is assumed that the packet 3 and the packet 4 are acquired after the times t3 and t4 after a while. In this case, the packet sequence is not recorded on the recording medium as the packets are acquired, but an arrival reproduction time stamp indicating the acquisition time is associated with each packet, and between the recorded packets. Make a note of it. Recording a packet sequence in such a gap is called partialization.

  FIG. 14B explains the output of a transport packet sequence recorded on a recording medium or the like. With reference to the arrival reproduction time stamp associated with the recorded transport packet, each transport packet is output at a timing equivalent to the timing at which each transport packet is acquired. Here, “each transport packet is output at a timing equivalent to the timing at which each transport packet is acquired” means that in FIG. 14, packet 0, packet 1, packet 2, packet 3, packet 4 are output. Are output at t0 ', t1', t2 ', t3', and t4 ', respectively, t1-t0 and t1'-t0', t2-t0 and t2'-t0 ', and t3-t0 and t3'. -T0 ', t4-t0, and t4'-t0' are equal (it is not necessary to be strictly equal, and the apparatus may include an allowable error).

  FIG. 15 illustrates a functional block diagram of a recording apparatus that records a packet sequence (see, for example, Patent Document 1).

  The stream analysis unit 1501 stores PAT (Program Association Table), PMT (Program Map Table), and PCR (Program Clock Reference) with reference to PID (Packet Identifier Table) of each packet of the acquired transport packet sequence. The received packets are sequentially read, and the PCR is output to the PLL unit 1502. Further, the stream analysis unit 1501 counts the number of packets that are sequentially acquired, and outputs the result to the stream database creation unit 1503 as a packet number. In addition, the stream analysis unit 1501 detects a position (entry point) on the time axis that is a position on the time axis and can start playback from the middle of the acquired transport stream. Entry point data, which is information for specifying entry points, is output to the stream database creation unit 1503. As specific examples of entry points, there are a packet number describing the head of I picture data defined by MPEG2 and a PTS (Presentation Timestamp) of the I picture.

  The PLL unit 1502 generates, for example, a 27 MHz clock signal using PCR, and outputs the clock signal to the counter unit 1504.

  The counter unit 1504 counts up the arrival reproduction time clock for indicating the time when the packet is acquired by the recording device 1500 in synchronization with the clock signal generated by the PLL unit, and the arrival reproduction time stamp which is a sample value thereof. Is output to the TP_extra_header adding unit 1505. The arrival reproduction time clock is initialized to a predetermined value such as 0 when the first packet of the transport stream is acquired, for example.

  The TP_extra_header adding unit 1505 adds header information including an arrival reproduction time stamp acquired from the counter unit 1504 to the acquired packet simultaneously with the input of the packet, and outputs the packet to the recording unit 1506 as a source packet.

  FIG. 16 illustrates the structure of the source packet. According to FIG. 16A, the source packet is composed of a 4-byte TP_extra_header and a 188-byte transport packet. According to FIG. 16B, TP_extra_header is a kind of header information including a bit string for 2-bit duplication control and a 30-bit bit string indicating an arrival reproduction time stamp.

  The stream database creation unit 1503 generates an entry point map using the packet number output from the stream analysis unit 1501 and the entry point database, and records the entry point map in the recording unit 1506.

  The recording unit records the source packet and the entry point map on a recording medium. Examples of the recording medium include a hard disk and a Blu-ray disk.

  FIG. 17 exemplifies a functional block diagram of an apparatus that outputs a packet recorded as a source packet or the like in association with an arrival reproduction time stamp on a recording medium or the like for reproduction (for example, see Patent Document 2).

  The source packet reading unit 1702 reads the source packet recorded in the storage medium 1701 or the like and outputs it to the buffer unit 1703. The buffer unit performs buffering of the source packet for processing to be performed in the future.

  The time stamp reading unit 1704 sequentially acquires the source packets buffered in the buffer unit 1703, reads the arrival reproduction time stamp of the source packet, outputs it to the comparison unit 1706, and outputs the packet to the output unit 1707. If it is the first source packet, the value indicated by the arrival reproduction time stamp is set in the reference time generation unit 1705. The reference time generation unit 1705 generates clock information and outputs it to the comparison unit 1706.

  The comparison unit 1706 compares the arrival reproduction time stamp acquired from the time stamp reading unit 1704 with the clock information generated by the reference time generation unit 1705, and outputs the result to the output unit 1707. The output unit 1707 refers to the comparison result acquired from the comparison unit 1706, and the arrival reproduction time stamp read by the time stamp reading unit 1704 and the clock information generated by the reference time generation unit 1705 match or are equal to each other. , The packet is output.

  As a result, as exemplified in FIG. 14B, it is realized that each transport packet is output for reproduction or the like at a timing equivalent to the timing obtained for recording or the like. The

FIG. 18 illustrates a state where the transport packet output device 1801 is connected to a decoder 1802 that decodes MPEG data or the like indicated by the transport packet sequence. The decoder 1802 demultiplexes the transport packet for each program, for example, by the demultiplexer 1803, and outputs it to appropriate buffers 1804-1, 1804-2, ..., 1804-3. Thereafter, the respective decoding circuits 1805-1, 1805-2, ..., 1805-3 perform decoding.
JP 2001-167528 A JP 2003-284003 A

  According to the conventional transport packet output device, since the transport packet is output at the same timing as when it is acquired by receiving a broadcast or the like, high quality reproduction can be performed in the case of video. it can.

  However, in order to perform special playback such as playback while performing fast-forwarding or slow playback, it is necessary to read the entry point map and perform complicated control on the transport packet output device. Alternatively, when N-times reproduction is performed by outputting a transport packet sequence at N times (for example, refer to Patent Document 2), buffer overflow or buffer underflow in a decoder or the like is prevented. Ingenuity is necessary.

  Also, when multiple devices are connected to the transport packet output device, and packets are branched to the multiple devices and a copy is output, when special playback is performed on one device, buffer overflow or buffer The technology for performing control so that underflow does not occur is not known to the extent investigated by the applicant.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a transport packet output device capable of special reproduction and connecting a plurality of devices by simple control.

  In order to achieve this object, in the present invention, a unit that outputs a transport packet sequence at a timing equivalent to the timing at which a transport packet is acquired, and a unit that outputs a transport packet sequence based on flow control information; , A transport packet output device is provided.

  As a result, when special reproduction is performed, a transport packet sequence can be output based on the flow control information, and special reproduction can be performed by simple control.

  In addition, the present invention provides a transport packet output device that does not output a transport packet sequence to another device while a certain device is performing special reproduction.

  Thereby, it is possible to prevent a buffer overflow or a buffer underflow from occurring in another device.

  According to the present invention, special reproduction can be performed by simple control. Further, when a plurality of devices are connected to the transport packet output apparatus and one device performs special reproduction, it is possible to prevent buffer overflow and buffer underflow from occurring in other devices.

  Hereinafter, the best mode for carrying out the present invention will be described as an embodiment with reference to the drawings. In addition, this invention is not limited to these embodiment at all, and can be implemented with various aspects in the range which does not deviate from the summary.

(Embodiment 1)
As Embodiment 1 of the present invention, a transport having a unit that outputs a transport packet sequence at a timing equivalent to the timing at which a transport packet is acquired, and a unit that outputs a transport packet sequence based on flow control information The packet output device will be described.

(Embodiment 1: Configuration)
FIG. 1 illustrates a functional block diagram of a transport packet output apparatus according to Embodiment 1 of the present invention. The transport packet output device 100 includes a synchronization control output unit 101 and a flow control output unit 102.

  The transport packet output apparatus outputs a transport packet sequence associated with time stamp information indicating the acquired timing. However, the time stamp information may be deleted, and a transport packet sequence including only transport packets may be output to the outside. Here, “acquired timing” means the timing at which the transport packets constituting the transport packet sequence are acquired. An example of such a transport packet output device has been described with reference to FIG.

  The “synchronization control output unit” 101 outputs the transport packet sequence at a timing equivalent to the acquired timing based on the time stamp information. The “time stamp information” is information indicating the time when the transport packet constituting the transport packet sequence is acquired. As an example of this information, there is information stored in TP_extra_header as the above-mentioned arrival reproduction time stamp.

  The transport packet sequence output by the synchronization control output unit 101 is mainly used for reproducing information expressed in MPEG or the like at a normal speed.

  The “flow control output unit” 102 outputs the transport packet sequence based on the flow control information. Here, the “flow control information” is information obtained for intermittently outputting a transport packet sequence without being based on the time stamp information. The flow control information may be acquired from the outside of the transport packet output device 100, or may be generated inside the transport packet output device 100. The flow control information includes, for example, information indicating that the output of the transport packet sequence should be stopped, and information indicating that it should be paired with the information and indicate that the output of the transport packet should be resumed. May be. For example, the control S (^ S) of the ASCII code indicates that the output of the transport packet sequence should be stopped, and the output of the transport packet sequence should be restarted by the control Q (^ Q). Good. Alternatively, when the voltage of a certain signal line is high, it indicates that the output of the transport packet sequence is permitted, and when the voltage is low, it indicates that the output of the transport packet sequence is prohibited. It may be. The latter case is shown in FIG.

  In FIG. 2, the uppermost column shows a partial source packet sequence, the lowest number line shows a time axis, and a change in voltage indicating flow control information is shown above the time axis. . Since the voltage is high at times T0 and T1, packets are continuously output. Since the voltage becomes low at time T2, the output of the packet is stopped after the output of packet 1, and the output after packet 2 is restarted after the voltage becomes high at time T3. Although “intermittent” is written, if the voltage remains high, the transport packet sequence is continuously output. However, such a case is also included in “intermittent”. To do.

  The transport packet sequence output from the flow control output unit 102 is mainly used for special reproduction such as N-times reproduction of MPEG or the like.

  Further, the transport packets output from the synchronization control output unit 101 and the flow control output unit 102 may be output to the same device. Moreover, you may output with respect to a different apparatus.

  It can be said that the transport packet output device according to the present embodiment has a configuration in which the conventional transport packet output device illustrated in FIG. 17 includes a flow control output unit. FIG. 3 illustrates a functional block diagram of the transport packet output device having such a configuration.

  In FIG. 3, a transport packet output device 100 includes a recording medium 301, a source packet reading unit 302, a buffer unit 303, a time stamp reading unit 304, a reference time generation unit 305, a comparison unit 306, an output unit 307, and a flow control output unit. 102. Among these, the synchronization control output unit 101 corresponds to a time stamp reading unit 304, a reference time generation unit 305, a comparison unit 306, and an output unit 307. Further, the flow control output unit 102 may acquire and output the transport packet from which the arrival reproduction time stamp is removed from the source packet by the time stamp reading unit 304. Alternatively, the source packet may be acquired from the buffer unit 303, and the arrival reproduction time stamp may be removed and output. Alternatively, the source packet may be read directly from the recording medium. Further, the source packet reading unit and buffer unit for the synchronization control output unit 101 and the source packet reading unit and buffer unit for the flow control output unit 102 may be separated.

(Embodiment 1: Flow of processing)
The transport packet output device according to the present embodiment is also a device for using the operation method of the transport packet output device including the synchronization control output step and the flow control output step. The “synchronous control output step” is a step for operating the synchronous control output unit, and the “flow control output step” is a step for operating the flow control output unit.

  FIG. 4 illustrates a flowchart for explaining the flow of processing when operating the flow control output unit in the present embodiment. In step S401, it is determined whether or not a transport packet sequence may be output. Flow control information is used for this determination. For example, if the voltage of the signal line is high, it is determined that the transport packet sequence may be output, and the process proceeds to step S402. If it is determined that the transport packet sequence should not be output, the process waits until it is determined that the transport packet sequence may be output.

  In step S402, a transport packet is acquired. For example, it is acquired from the time stamp reading unit 304. The acquired transport packet is output in step S403. Thereafter, in step S404, it is determined whether or not to end the process of the flow control output unit. If it is determined not to end, the process returns to step S401. Determining whether to end the process of the flow control output unit may include determining whether to end the process of the entire transport packet output device.

(Embodiment 1: Main effects)
According to the present embodiment, since it is possible to output a transport packet based on the flow control information, when performing special reproduction based on the transport packet output from the transport packet output device, the flow control is performed. Since the output of the transport packet can be controlled according to the information, simple control is sufficient.

(Embodiment 2)
As a second embodiment of the present invention, a transport packet output device that selects and outputs a transport packet sequence output from the synchronization control output unit and a transport packet sequence output from the flow control output unit will be described.

(Embodiment 2: Configuration)
FIG. 5 illustrates a functional block diagram of a transport packet output apparatus according to Embodiment 2 of the present invention. The transport packet output device 500 includes a synchronization control output unit 101, a flow control output unit 102, and an output selection unit 501. Therefore, the transport output device according to the present embodiment is configured such that the transport packet output device according to the first embodiment includes the output selection unit 501.

  The “output selection unit” 501 selects the synchronization control output unit 101 or the flow control output unit 102 as a unit that outputs a transport packet sequence. For example, the output selection unit 501 is configured as a changeover switch, and switches between the transport packet sequence output from the synchronization control output unit 101 and the transport packet sequence output from the flow control output unit 102 and outputs the switched packet. It may be like this. Alternatively, the activation of the synchronization control output unit 101 and the flow control output unit 102 may be selected and performed. As one method of activation, there is a method of selectively supplying power to the synchronization control output unit 101 and the flow control output unit 102.

(Embodiment 2: Processing flow)
FIG. 6 exemplifies a flowchart for explaining the processing flow of the transport packet output apparatus according to this embodiment. In step S601, it is determined whether the synchronization control output unit is selected as a unit that outputs a transport packet sequence. If it is determined that the synchronization control output unit is selected as the unit that outputs the transport packet sequence, the process proceeds to step S602 so that the transport packet sequence output by the synchronization control output unit is output. Select the synchronization control output. If it is not determined that the synchronization control output unit is selected as the unit that outputs the transport packet sequence, in step S603, the flow control output unit outputs the transport packet sequence output by the flow control output unit. Select. In steps S602 and S603, for example, a predetermined number of transport packets are output, or transport packets are output for a predetermined length of time (this is described later in steps SS503, S504, and S1304). , S1305, S1307, S1308).

  After the processing of steps S602 and S603, the processing is shifted to step S604 to determine whether or not the processing of the entire transport packet output device should be ended. If it is determined that the processing should not be ended, the processing proceeds to step S601. Return control.

(Embodiment 2: Main effects)
According to the present embodiment, for example, the output of the synchronization control output unit and the output of the flow control output unit can be selected as necessary, and normal playback and special playback can be selected.

(Embodiment 3)
As a third embodiment of the present invention, a transport packet output device capable of selecting a transport packet sequence output from a synchronization control output unit and a transport packet sequence output from a flow control output unit according to the type of reproduction Will be described.

(Embodiment 3: Configuration)
FIG. 7 illustrates a functional block diagram of a transport packet output apparatus according to Embodiment 3 of the present invention. The transport packet output device 700 includes a synchronization control output unit 101, a flow control output unit 102, an output selection unit 501, and a reproduction type information acquisition unit 701. The output selection unit 501 depends on the reproduction type information. Selection means 702 is provided. Therefore, in the transport packet output device according to the present embodiment, the transport packet output device according to the second embodiment has a reproduction type information acquisition unit, and the output selection unit of the transport packet output device according to the second embodiment. Has a configuration including reproduction type information dependence selection means.

  The “reproduction type information acquisition unit” 701 acquires the reproduction type information of the transport packet sequence output from the synchronization control output unit 101 or the flow control output unit 102. “Reproduction type information” is information indicating in what manner the information represented by the transport packet sequence output from the synchronization control output unit 101 or the flow control output unit 102 is reproduced. For example, if the transport type string represents MPEG2 video information, whether the playback type information is played back at normal speed or special playback such as playback at normal N times speed. (If N is greater than 1, fast forward playback is performed, and if N is less than 1, slow playback is performed). Such reproduction type information may be acquired from, for example, a device to which a transport packet output device is connected, and a device that decodes a transport packet output by the transport packet output device. Good.

  “Reproduction type information dependence selection means” 702 performs the selection based on the reproduction type information acquired by the reproduction type information acquisition unit 701. “Selection” means that the synchronization control output unit 101 or the flow control output unit 102 is selected as a unit that outputs a transport packet sequence. For example, if the reproduction type information indicates that normal reproduction is performed, the synchronization control output unit 101 is selected as a unit that outputs a transport packet sequence. Further, if the reproduction type information indicates that special reproduction such as N-times speed reproduction is performed, the flow control output unit 102 is selected as a unit that outputs a transport packet sequence.

(Embodiment 3: Flow of processing)
FIG. 8 exemplifies a flowchart for explaining the processing flow of the transport packet output apparatus according to this embodiment. In step S801, reproduction type information is acquired (reproduction type information acquisition step). In step S802, based on the reproduction type information acquired in step S801, it is determined whether or not to perform synchronous control output. “Synchronous control output” means that the transport packet sequence output by the synchronous control output unit is output to the outside of the transport output device. If it is determined that the synchronization control output is to be performed, the process proceeds to step S503, the synchronization control output unit is selected to output the transport packet output by the synchronization control output unit to the outside, and the process proceeds to step S805. To migrate. If it is not determined that the synchronization control output is to be performed, the process proceeds to step S504, the flow control output unit is selected so that the transport packet sequence output by the flow control output unit is output to the outside, and the process proceeds to step S805. Migrate processing. In step S805, it is determined whether to end the entire process. If it is determined not to end the process, the process returns to step S801.

(Embodiment 3: Main effects)
According to the present embodiment, since it is possible to select whether or not to perform synchronization control output in accordance with the reproduction of the information represented by the transport packet, it is possible to cooperate with a device that performs decoding of the transport packet and the like.

(Embodiment 4)
As a fourth embodiment of the present invention, a transport packet output device that acquires flow control information according to the status of a buffer for processing an output transport packet sequence will be described.

(Embodiment 4: Configuration)
FIG. 9 illustrates a functional block diagram of a transport packet output apparatus according to Embodiment 4 of the present invention. The transport packet output device 900 includes a synchronization control output unit 101, a flow control output unit 102, a buffer status information acquisition unit 901, and a buffer status information dependent flow control information acquisition unit 902. Further, the transport packet output device 900 may include an output selection unit 501 as illustrated in FIG. 5 or a reproduction type information acquisition unit 701 as illustrated in FIG. The selection unit 501 may include a reproduction type information dependency selection unit 702. Therefore, the transport packet output device according to the present embodiment is the same as the transport packet output device according to any one of Embodiments 1 to 3, except that the buffer status information acquisition unit 901, the buffer status information dependent flow control information acquisition unit 902, It has composition which has.

  The “buffer status information acquisition unit” 901 acquires buffer status information. “Buffer status information” is information indicating the buffer status on the downstream side of the flow control output unit of the transport packet sequence output from the flow control output unit 102. For example, as illustrated in FIG. 18, this information is information indicating the states of the buffers 1804-1 to 1804-3 when the transport packet output device is connected to the decoder. If at least one of the buffers 1804-1 to 1804-3 is buffering more than a predetermined amount of transport packets, there is a possibility of buffer overflow. Therefore, transport packets that are buffered by the respective buffers. The buffer status information indicates the amount of data. Alternatively, the buffer status information may be information indicating whether any one of the buffers is likely to overflow (for example, whether buffering is being performed beyond the high water mark of the buffer).

  A “buffer status information-dependent flow control information acquisition unit” 902 acquires the flow control information based on the buffer status information acquired by the buffer status information acquisition unit 901. The “flow control information” is flow control information that a flow control output unit outputs a transport packet sequence based on the information. For example, the buffer status information-dependent flow control information acquisition unit 902 outputs the transport packet when at least one of the buffers 1804-1 to 1804-3 is buffering more than a predetermined amount of transport packets. Generate flow control information indicating what should be stopped. Further, the buffer status information and the flow control information may be the same or substantially the same. For example, information indicating the logical sum of whether or not there are more than a predetermined amount of transport packets buffered by the buffers 1804-1 to 1804-3 is the buffer status information, and the buffer status information is as it is or substantially. It may be flow control information. As a case where they are substantially the same, there is a case where the logical negation of the buffer status information is the flow control information.

(Embodiment 4: Main effects)
According to the present embodiment, it becomes possible to control and output a transport packet according to the buffer status on the downstream side of the flow control output unit, so that the occurrence of buffer overflow can be prevented.

(Embodiment 5)
As Embodiment 5 of the present invention, when a plurality of devices are connected and a packet is branched to the plurality of devices, while a special playback is being performed by a certain device, the buffer overflow or buffer underrun is performed by another device. A transport packet output device that performs control so as not to cause a flow will be described.

(Embodiment 5: Configuration)
FIG. 10 illustrates a functional block diagram of a transport packet output apparatus according to the fifth embodiment of the present invention. The transport packet output device 1000 includes a synchronization control output unit 101, a flow control output unit 102, and an output selection unit 501. The output selection unit 501 includes a branch output unit 1001 and a connection information acquisition unit 1002. Further, as shown in the figure, the transport packet output device 1000 may further include a reproduction type information acquisition unit 701, and the output selection unit 501 may include a reproduction type information dependency selection unit 702. Further, the transport packet output apparatus 1000 may further include a buffer status information acquisition unit 901 and a buffer status information dependent flow control information acquisition unit 902, as shown in FIG. Therefore, in the transport packet output device according to the present embodiment, the output selection unit 501 of the transport packet output device according to any one of the second to fourth embodiments includes the branch output unit 1001, the connection information acquisition unit 1002, It has a configuration.

  The “branch output unit” 1001 is a unit for branching and outputting the same output. Here, “output” means the output of the synchronization control output unit 101 or the flow control output unit 102 selected by the output selection unit 501. Further, “branching the same output” means that one output is duplicated so that output is possible from a plurality of output ports. The “output port” is an interface part that outputs to the outside of the transport packet output device. Therefore, the transport packet output device according to the present embodiment can output the same transport packet to a plurality of devices.

  The “connection information acquisition unit” 1002 acquires connection information. The “connection information” is information indicating whether or not the output of the transport packet by the branch output unit 1001 can be performed simultaneously with the flow control compatible device to the flow control non-compatible device. A “flow control compatible device” is a device capable of outputting flow control information to a transport packet output device. Therefore, the flow control information that can be output by the flow control-compatible device is acquired by the flow control output unit 102 of the transport packet output apparatus 1000. The “non-flow control compatible device” is a device that does not output flow control information. Note that “no flow control information is output” means that no data is output to the transport packet output apparatus 1000. For example, a device that does not support flow control does not have a function of outputting flow control information. In addition, a device that does not support flow control may output only to another device other than the transport packet output device 1000.

  In FIG. 11, the transport packet output device according to the present embodiment is connected to a flow control compatible device and a flow control non-compatible device, and the transport packet sequence from the transport packet output device is not compatible with the flow control compatible device. Shows the status of branching to the device. Among the flow control compatible device 1102 and the flow control non-compatible device 1103, the flow control information is output from the flow control compatible device 1102 to the transport packet output device 1101, but the transport packet output from the non-flow control compatible device 1103 is output. No flow control information is output to the device 1101.

  An example of a device that does not support flow control is a recording device configured as shown in the functional block diagram illustrated in FIG.

  As a method for acquiring connection information, for example, a method in which a user directly sets the transport packet output apparatus 1000, a flow control compatible device is connected to one output port of the branch output unit 1001, and another output port is provided. There is a method of detecting that the flow control non-compliant device is connected in advance to the other and that another output port and the flow control non-compliant device are connected. More specifically, the latter method can include a method of detecting an electrical connection between the other output port and a device that does not support flow control, or detecting establishment of a wireless link. . If an electrical connection of a device that does not support flow control is detected or link establishment is detected, the output from the branch output unit 1001 can be performed simultaneously with the device that does not support flow control. And

  In the present embodiment, when the connection information acquired by the connection information acquisition unit 1002 is information that the output from the branch output unit 1001 can be performed simultaneously with the flow control compatible device to the non-flow control compatible device. The branch output unit 1001 does not output the transport packet sequence output from the flow control output unit 102 to a device that does not support flow control.

  The reason for not outputting to a device not compatible with flow control is that the transport packet sequence output by the flow control output unit 102 is controlled based on the flow control information output by the device corresponding to flow control information. It is. That is, the transport packet sequence output by the flow control output unit 102 is output at a pace that can be processed by the flow control compatible device regardless of the processing of the flow control non-compatible device. Therefore, if the transport packet sequence output from the flow control output unit 102 is also output to a device that does not support flow control, the device that does not support flow control cannot process the transport packet sequence, and buffer overflow or A buffer underflow may occur or the device may hang up. Therefore, the transport packet sequence output by the flow control output unit 102 is not output to a device that does not support flow control. Further, when the flow control non-compliant device is a recording device configured as shown in the functional block diagram illustrated in FIG. 15, the flow control output unit 102 outputs a transport packet sequence having an incorrect interval. This is because even if such a transport packet sequence is recorded by the recording device, it cannot be reproduced correctly. Here, the “transport packet sequence with an incorrect interval” means, for example, when the transport packet output device reproduces and outputs a broadcast transport packet sequence, It means that the interval is not reproduced.

  An example of a device that does not support flow control is one that is connected to an IEEE 1394 circuit connected to a transport packet output device. An example of this is shown in FIG.

  In FIG. 12, a transport packet output device 1201 is connected to a decoder 1202 which is a flow control compatible device and an IEEE 1394 circuit 1203. The transport packet output device 1201 may include an IEEE 1394 circuit 1203. The IEEE 1394 circuit 1203 is connected to a device 1204 that does not support flow control via, for example, an IEEE 1394 bus. Note that IEEE 1394 is used as an external interface standard for many digital video and audio devices, including set-top boxes that receive MPEG2 data from satellite broadcasts, etc., so various devices can be connected by adopting IEEE 1394. It becomes possible.

(Embodiment 5: Flow of processing)
FIG. 13 exemplifies a flowchart for explaining the processing flow of the transport packet output apparatus according to the present embodiment. In step S1301, connection information is acquired. This acquisition process is performed by the connection information acquisition unit 1002. Next, in step S1302, it is determined whether a transport packet can be output to a device that does not support flow control. For this determination, the connection information acquired in step S1301 is referred to. If a device that does not support flow control is connected, the process proceeds to step S1303; otherwise, the process proceeds to step S1306.

  In step S1303, it is determined whether to perform synchronous output control. That is, the output selection unit 501 determines whether the synchronization control output unit 101 is selected as a unit that outputs a transport packet sequence. If so, the process proceeds to step S1305; otherwise, the process proceeds to step S1304.

  In step S1305, the branch output unit 1001 is controlled so that the transport packet output from the synchronization control output unit 101 is output to both the flow control compatible device and the flow control non-compatible device. In step S1304, the branch output unit 1001 is controlled so that the transport packet sequence output from the flow control output unit 102 is output only to the flow control compatible device. After steps S1305 and S1304, the process proceeds to step S1309.

  In step S1306, it is determined whether to perform synchronization control. If so, the process proceeds to step S1307, and the transport packet output by the synchronization control output unit 101 is output. If not, the process proceeds to step S1308, and the transport packet output by the flow control output unit 102 is output. After steps S1307 and S1308, the process proceeds to step S1309.

  In step S1309, it is determined whether or not to end the process of the transport packet output device. If it is determined not to end, the process returns to step S1301.

(Embodiment 5: Main effects)
According to this embodiment, it is possible to prevent a buffer overflow or a buffer underflow from occurring in a device that does not support flow control.

  The transport packet output device and the operation method of the transport packet output device according to the present invention enable special reproduction by simple control, and a plurality of devices are connected to the transport packet output device. When one device performs special reproduction, it is possible to prevent buffer overflow and buffer underflow in other devices, which is industrially useful.

Functional block diagram of a transport packet output apparatus according to Embodiment 1 of the present invention Example of relationship between transport packet sequence output and flow control information Functional block diagram of a transport packet output apparatus according to Embodiment 1 of the present invention Flow chart explaining the flow of processing of the flow control output unit Functional block diagram of a transport packet output apparatus according to Embodiment 2 of the present invention The flowchart explaining the flow of processing of the transport packet output device Functional block diagram of a transport packet output apparatus according to Embodiment 3 of the present invention The flowchart explaining the flow of processing of the transport packet output device Functional block diagram of a transport packet output apparatus according to Embodiment 4 of the present invention Functional block diagram of a transport packet output apparatus according to Embodiment 5 of the present invention Example of a state in which a device that supports flow control and a device that does not support flow control are connected to the transport packet output device An example of a state in which a decoder 1202, which is a flow control compatible device, and an IEEE 1394 circuit 1203 are connected to the transport packet output device 1201 The flowchart explaining the flow of processing of the transport packet output device The figure explaining the recording and reproduction | regeneration of a transport packet sequence Functional block diagram of a conventional recording apparatus for recording a transport packet sequence Example of source packet structure Functional block diagram of a conventional transport packet output device An example of a state in which the transport packet output device and the decoder are connected

Explanation of symbols

100 Transport Packet Output Device 101 Synchronization Control Output Unit 102 Flow Control Output Unit

Claims (5)

A transport packet output device that outputs a transport packet sequence associated with time stamp information indicating acquired timing,
Based on the time stamp information, a synchronization control output unit that outputs a transport packet sequence at a timing equivalent to the acquired timing;
A flow control output unit that outputs the transport packet sequence based on flow control information that is acquired from the outside in order to intermittently output the transport packet sequence without being based on the time stamp information;
An output selection unit that selects the synchronization control output unit or the flow control output unit as a unit that outputs the transport packet sequence;
Branch output means for branching and outputting the same output;
A connection that acquires connection information that is information indicating whether or not the output of the branch output means can be performed to a flow control-compatible device that does not output flow control information simultaneously with a flow control-compatible device that can output flow control information Information acquisition means;
Have
If the connection information acquired by the connection information acquisition means is information that the output from the branch output means can be performed simultaneously with the flow control compatible device to the flow control non-compatible device, the branch output means An output selection unit that does not output the transport packet sequence output by the flow control output unit to the flow control non-compliant device;
A transport packet output device. A reproduction type information acquisition unit that acquires reproduction type information that is information indicating in what manner the information represented by the transport packet sequence output from the synchronization control output unit or the flow control output unit is reproduced; ,
The transport packet output device according to claim 1 , wherein the output selection unit further includes a reproduction type information dependency selecting unit that performs the selection based on the reproduction type information acquired by the reproduction type information acquisition unit. A buffer status information acquisition unit for acquiring buffer status information that is information indicating a buffer status on the downstream side of the flow control output unit of the transport packet sequence output from the flow control output unit;
A buffer status information-dependent flow control information acquisition unit that generates and acquires the flow control information based on the buffer status information acquired by the buffer status information acquisition unit , or acquires the buffer status information as the flow control information; ,
The transport packet output device according to claim 1, further comprising: An operation method of a transport packet output device for transmitting a transport packet sequence associated with time stamp information indicating acquired timing,
A synchronous control output step for outputting a transport packet sequence at a timing equivalent to the acquired timing based on the time stamp information;
A flow control output step of outputting a transport packet sequence based on flow control information which is information acquired from the outside in order to intermittently output a transport packet sequence without being based on the time stamp information;
An output selection step of selecting an output of a transport packet by the synchronization control output step or the flow control output step,
A branch output substep for branching and outputting the same output;
Acquire connection information, which is information indicating whether or not the output by the branch output sub-step can be performed to a flow control-compatible device that does not output flow control information simultaneously with a flow control-compatible device that can output flow control information. A connection information acquisition substep;
Including
If the connection information acquired by the connection information acquisition sub-step is information that the output by the branch output sub-step can be performed simultaneously with the flow control compatible device to the flow control non-compatible device, the branch output sub An output selection step of not outputting the transport packet sequence output by the flow control output step to the flow control non-compliant device;
A method of operating a transport packet output device including: A reproduction type information acquisition step of acquiring reproduction type information, which is information indicating in what manner the information represented by the transport packet sequence output by the synchronization control output step or the flow control output step is reproduced; ,
The operation method of the transport packet output device according to claim 4, wherein the output selection step is executed based on the reproduction type information acquired in the reproduction type information acquisition step.

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