JP2008092180A - Digital broadcast receiver and receiving program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast receiver and a receiving program, reducing a load of a CPU in outputting a PES packet to a decoding part while suppressing delay of the PES packet from the time of reproduction start. <P>SOLUTION: The digital broadcast receiver 100 determines an individual output individually outputting an AU when reception of a PES packet is not completed before decoding start time. While a collective output collectively outputting a plurality of AUs is determined when the reception of the PES packet is completed before the decoding start time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital broadcast receiver including a decoding unit that decodes a packet and a reception program.

  In terrestrial digital broadcasting for mobile terminals and terrestrial digital audio broadcasting, Video and audio encoded by H.264 / AVC are stored in PES (Packetized Elementary Stream) packets, and each PES packet is stored in program time reference value information (Program Clock Reference: PCR) and TS (Transport Stream). Multiplexed and transmitted. In the header of the PES packet, a reproduction start time indicating a time at which reproduction of the PES packet should be started is described (for example, Patent Document 1). A plurality of access units AU (Access Units) are stored in the payload of the PES packet. FIG. 2 schematically shows a state where an H.264 / AVC ES (Elementary Stream) is packetized into PES packets.

The conventional digital broadcast receiver shown in FIG. 2 outputs the PES packet to the video decoding unit and the audio decoding unit in an individual output format for individually outputting AU.
JP 2005-347919 A

  Therefore, when outputting a PES packet, it is necessary to sequentially search for an AU delimiter indicating the head of the AU in order to output the AU from the PES packet to the decoding unit one by one, increasing the load on the CPU.

  Here, it can be considered that the PES packet is output in a batch output format in which a plurality of AUs are output at once, thereby omitting the search for the AU delimiter and reducing the load on the CPU.

  However, when outputting in the batch output format, it is necessary to wait for the completion of reception of the PES packet, and therefore, the time for completing the reception of the PES packet may elapse from the decoding start time. Here, the decoding start time is the time at which the decoding process of the PES packet should be started, that is, the time at which the operation for outputting the PES packet to the decoding unit should be started. Therefore, the decoding start time is calculated by subtracting a predetermined time required for AU delimiter search and decoding from the reproduction start time.

  FIG. 3 is a schematic diagram showing how the time to complete the reception of the PES packet passes the decoding start time. When the reception completion time of the PES packet has passed the decoding start time calculated for each AU included in the PES packet, the video or audio stored in the AU that has passed the decoding start time is delayed from the reproduction start time. Played.

  As described above, when the output is performed in the individual output format, the load on the CPU is increased. On the other hand, when the output is performed in the batch output format, the reproduction of the PES packet may be delayed from the reproduction start time.

  Therefore, the present invention has been made in view of the above problems, and can reduce the load on the CPU in outputting the PES packet to the decoding unit while suppressing the delay from the reproduction start time of the PES packet. An object is to provide a broadcast receiver.

  A digital broadcast receiver according to a first aspect of the present invention is a digital broadcast receiver including a decoding unit that decodes a packet including a plurality of access units in which encoded data is stored, and starts reproduction of the packet. A decoding start time calculation unit that calculates a decoding start time that indicates a time to start decoding the packet and calculates a decoding start time that is earlier than the reproduction start time based on a reproduction start time indicating a power time; A determination unit that determines whether or not reception of the packet is completed before reaching the decoding start time, and an output format determination unit that determines a format for outputting the packet to the decoding unit, When the reception of the packet is not completed before the reference time reaches the decoding start time, the output format determination unit determines the access unit included in the packet. If the reception of the packet is completed before the reference time reaches the decoding start time, all of the packets included in the packet are all output. The output is determined in a batch output format in which the access units are collectively output to the decoding unit.

  According to the digital broadcast receiver of the first feature of the present invention, whether or not reception of the PES packet is completed before the reference time reaches the decoding start time limit (k) of the PES packet (first AU). Thus, it is determined whether to output in a batch output format or to output in an individual output format. That is, as long as reception of the PES packet is completed by the decoding start time limit (k) of the AU stored at the head of the PES packet, all AUs stored in the PES are output in a batch output format. The CPU load due to the AU delimiter search in the output of the PES packet to the decoding unit can be reduced while suppressing the delay from the reproduction start time.

  A second feature of the present invention relates to the first feature, wherein the decoding start time calculation unit calculates the decoding start time of the access unit included in the packet based on the reproduction start time. Calculated for each unit, and the determination unit determines whether reception of the packet is completed before the reference time reaches the calculated decoding start time of the access unit, and determines the output format. The unit, when the reception of the packet is not completed before the reference time reaches the decoding start time of the access unit, the access unit included in the packet that has reached the decoding start time And determining the output in the individual output format, and the reception of the packet is completed before the reference time reaches the decoding start time of the access unit. When, for the access unit of undecoded included in the packet, and summarized in that determining an output by said collective output format.

  A third feature of the present invention relates to the first feature or the second feature, wherein the decoding start time calculation unit is a time within a range in which a delay in reproduction of the packet is allowed at the reproduction start time. The gist is to calculate the decoding start time based on the time to which the delay allowable time is added.

  According to a fourth aspect of the present invention, the decoding start time calculation unit includes at least the reproduction start time and a search stored in the access unit and required for searching for an access unit delimiter indicating the head of the access unit. The gist is to calculate the decoding start time based on time.

  A program according to the fifth aspect of the present invention is a program for decoding a packet including a plurality of access units in which encoded data is stored, and a reproduction start time indicating a time at which the reproduction of the packet should be started to the computer Based on the step A for calculating a decoding start time that is earlier than the reproduction start time, indicating a time at which the decoding process of the packet should be started, and before the reference time reaches the calculated decoding start time. The step B for determining whether or not the reception of the packet is completed and the step C for determining the format for outputting the packet are executed. In the step C, the reference time is set to the decoding start time. An individual output that individually outputs the access unit included in the packet if reception of the packet is not completed before reaching Batch output that determines all the output units included in the packet when the packet reception is completed before the reference time reaches the decoding start time. The gist is to determine the output by format.

  According to the present invention, it is possible to provide a digital broadcast receiver and a reception program capable of suppressing a delay from the reproduction start time of a PES packet while reducing the load on the CPU in the decoding process of the PES packet.

[First embodiment]
Next, a first embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

<< Outline Block Configuration of Digital Broadcasting Receiver 100 >>
The digital broadcast receiver 100 according to the present invention receives and decodes a TS in which PES packets including a plurality of AUs in which encoded data are stored are multiplexed.

  FIG. 4 is a schematic block diagram of the digital broadcast receiver according to this embodiment. The digital broadcast receiver 100 according to this embodiment includes a DEMUX processing unit 102, a video PES analysis unit 104a, a reproduction start time calculation unit 106a, a decoding start time calculation unit 108a, a determination unit 110a, an output format determination unit 111a, and an output control unit. 112a, video decoding unit 118a, audio PES analysis unit 104b, reproduction start time calculation unit 106b, decoding start time calculation unit 108b, determination unit 110b, output format determination unit 111b, output control unit 112b, audio decoding unit 118b, and synchronization control unit 120. In addition, since the following is the outline | summary about the main parts relevant to this invention, the digital broadcast receiver 100 may be provided with the essential block (for example, power supply part) which is not illustrated or abbreviate | omits description. Please keep in mind.

  The DEMUX processing unit 102 uses the TS (Transport Stream) restored from the high frequency (RF) signal in the tuner / demodulation unit, the video PES, the audio PES, and the reference time (System Time Clock: STC) of the transmitter that transmits the program. ) Are separated into PCRs in which values sampled at predetermined intervals are stored. The video PES and audio PES output from the DEMUX processing unit 102 store AUs. As shown in FIG. The AU in H.264 / AVC is classified into IDR (Instanteneous Decoder Refresh) -AU and non-IDR-AU. Since the data size of IDR-AU includes decoding start information and the like, it is larger than the data size of non-IDR-AU. An AU delimiter (Access Unit Delimiter) is arranged at the head of the AU, and a break between AUs can be detected by searching for the AU delimiter.

  The video PES analysis unit 104a sequentially outputs AUs related to the video data to the output control unit 112a, and also displays the display time information (Presentation Time Stamp: PTS) described in the header of the video PES packet as the playback start time calculation unit 106a. Output to. Here, the display time information indicates a reproduction start time PTS (k) indicating a time at which the reproduction process of the PES packet should be started, that is, a time at which the reproduction process of the AU stored at the head of the payload should be started.

  When the video PES analysis unit 104a detects a header of a new PES packet, the video PES analysis unit 104a notifies the determination unit 110a to that effect.

  The reproduction start time calculation unit 106a acquires the reproduction start time PTS (k) of the AU stored at the head of the PES packet from the display time information. The reproduction start time calculation unit 106a sequentially calculates the AU reproduction start times PTSk (i) stored in the second and subsequent PES packets based on the display time information and the AU parameter information. The method of calculating the playback start time PTSk (i) (ARIB TR-B14 standard) is a buffering period SEI, picture timing SEI, and VUI (Video Usability) when the frame rate is variable. Information) parameter, and in the case of a fixed frame rate, it is calculated based on the VUI parameter.

  The decoding start time calculation unit 108a calculates the decoding start time limit (k) of the PES packet based on the reproduction start time PTS (k). More specifically, the delay start time PTS (k) is added with a delay allowable time which is a time within a range in which the delay of the playback of the PES packet is allowed, and the time required for searching or decoding the AU delimiter The decoding start time limit (k) is calculated by subtracting a certain processing delay time.

  Here, it is sufficient that the allowable delay time is set to such a time that the viewer does not feel uncomfortable even if the playback of the video or audio is delayed. Generally, the allowable delay time is about several hundred milliseconds. . The processing delay time can be set based on the average data amount of IDR-AU, and can be updated by feeding back an actual measurement value.

  The determination unit 110a determines whether or not the reception of the PES packet is completed before the reference time acquired from the synchronization control unit 120 reaches the decoding start time limit (k) acquired from the decoding start time calculation unit 108a. . The completion of reception of the PES packet is recognized by receiving a notification from the video PES analysis unit 104a that a header of the next PES packet has been newly detected. In other words, whether or not the determination unit 110a has received a notification from the video PES analysis unit 104a before the reference time reaches the decoding start time limit (k) of the AU stored at the head of the PES packet. Determine.

  If the reception of the PES packet is not completed before the reference time reaches the decoding start time limit (k), the output format determination unit 111a uses an individual output format that individually outputs AU to the video decoding unit 118a. It determines that it should output, and notifies the said determination to the output control part 112a. On the other hand, when the reception of the PES packet is completed before the reference time reaches the decoding start time limit (k), the output format determination unit 111a collectively outputs a plurality of AUs to the video decoding unit 118a. The output format is determined to be output, and the output control unit 112a is notified of the determination.

  The output control unit 112a includes a SEL 114a and an AU extraction unit 116a.

  The SEL 114a sequentially receives and temporarily holds AUs related to video data input from the video PES analysis unit 104a. In response to the determination by the output format determination unit 111a, the SEL 114a outputs all AUs included in the PES packet to the video decoding unit 118a in a batch output format.

  The AU extraction unit 116a detects a break between AUs by sequentially searching the AU delimiters of the AUs held in the SEL 114a in accordance with an instruction from the output format determination unit 111a, and images each AU in an individual output format. It outputs to the decoding part 118a.

  As described above, according to the present embodiment, whether the batch output format is used or not based on whether or not the reception of the PES packet is completed by the decoding start time limit (k) of the AU stored at the head of the PES packet. The format will be decided once.

  The video decoding unit 118a decodes the AU input from the output control unit 112a. The decrypted AU is output according to each reproduction start time.

  On the other hand, the AU that stores the audio data output from the DEMUX processing unit 102 is in the ADTS frame format. Since the audio PES packet stores a plurality of ADTS frames, it can be processed in the same manner as the video PES packet described above. Therefore, in the present embodiment, description of the voice PES packet is omitted.

  The synchronization control unit 120 generates a transmitter reference time (System Time Clock: STC) based on the PCR reception timing and the PCR value. Specifically, the reference time can be obtained by correcting the self-running counter of the synchronization control unit 120 with the PCR value every time the PCR is received. Further, the reference time may be obtained by correcting the self-running counter by a generally known method using PLL (Phase Locked Loop). Here, the reference time is the reference time of the system when video and audio are encoded in the transmitter.

  The synchronization control unit 120 outputs the generated reference time and the reproduction start time PTS (k) input from the reproduction start time calculation unit 106a to the video decoding unit 118a. The video decoding unit 118a calculates the playback start time of each AU included in the video PES from the AU parameter information extracted at the time of decoding, and when the reference time reaches the playback start time, the decoded AU Is output.

  Similarly for the audio, the synchronization control unit 120 outputs the generated reference time and the reproduction start time PTS (k) input from the reproduction start time calculation unit 106b to the audio decoding unit 118b. The audio decoding unit 118b calculates the reproduction start time of each AU included in the audio PES from the AU parameter information extracted at the time of decoding. When the reference time reaches the reproduction start time, the decoded AU Is output.

  As a result, the corresponding video and audio are reproduced without any deviation.

<< Operation of Digital Broadcasting Receiver 100 >>
Next, the operation of the digital broadcast receiver 100 will be described. FIG. 6 shows an output flow of the PES packet to the video decoding unit 118a. Note that, as described above, the voice PES packet can be performed in the same manner, and thus the description thereof is omitted.

  As shown in FIG. 6, in step S101, the decoding start time calculation unit 108a adds the allowable delay time and subtracts the processing delay time to the reproduction start time PTS (k) and stores it at the head of the PES packet. The AU decoding start time limit (k) is calculated.

  In step S102, the determination unit 110a determines whether reception of the PES packet is completed before the reference time reaches the decoding start time limit (k). The completion of the reception of the PES packet can be known by notification from the video PES analysis unit 104a that a new PES packet header has been detected.

  If the reception of the PES packet is completed before the reference time reaches the decoding start time limit (k), in step S103, the SEL 114a displays all AUs included in the PES packet in a batch output format in the video decoding unit 118a. Output to.

  If the reception of the PES packet is not completed before the reference time reaches the decoding start time limit (k), in step S104, the AU extraction unit 116a determines the PES packet temporarily held in the SEL 114a. The AU delimiter of the AU stored second is searched, and the AU stored at the head is output to the video decoding unit 118a in the individual output format. In this way, output is performed in the AU individual output format stored at the head of the PES packet.

  In step S106, the AU extraction unit 116a determines whether all AUs included in the PES packet have been output to the video decoding unit 118a. The AU extraction unit 116a can detect that the reception of the PES packet has been completed by detecting the header of the new PES packet or in response to an instruction from the output format determination unit 111a.

  Next, the AU extraction unit 116a determines that the PES packet is not completed when the AU delimiter of the AU stored in the second PES packet is detected, and the second AU of the PES packet is determined from S104. Perform the operation.

  The AU extraction unit 116a repeatedly performs output in the individual output format until the output of the AU stored at the end of the PES packet is completed.

  As described above, when the reception of the PES packet is completed by the decoding start time limit (k), all the AUs are output in the batch output format. On the other hand, when the reception is not completed, all the AUs are output. Is output in the individual output format.

《Action ・ Effect》
According to the digital broadcast receiver according to the present embodiment, depending on whether or not the reception of the PES packet is completed before the reference time reaches the decoding start time limit (k) of the PES packet (first AU). It is determined whether to output in the output format or to output in the individual output format. That is, as long as reception of the PES packet is completed by the decoding start time limit (k) of the AU stored at the head of the PES packet, all the AUs stored in the PES are output in a batch output format.

  Therefore, it is possible to reduce the CPU load due to the AU delimiter search in the output of the PES packet to the decoding unit while suppressing the delay from the reproduction start time of the PES packet. Further, by reducing the CPU load, the response speed for the user of the digital broadcast receiver 100 can be improved.

  Further, by assigning tasks to the CPUs in the priority order as shown in FIG. 8, it is possible to shift to the sleep task, that is, to detect the CPU IDLE. Because the CPU load is reduced, the transition to the sleep task is easily performed, so that an operation with a low-speed CPU clock (power save mode) can be performed, and a power-saving portable terminal type digital broadcast receiver is realized.

  Further, according to the digital broadcast receiver according to the present embodiment, the decoding start time is obtained by adding the allowable delay time, which is the time within the allowable range of the reproduction delay of the PES packet, to the reproduction start time PTS (k). limit (k) is calculated. As a result, the number of PES packets output in the batch output format can be increased without causing the viewer to feel uncomfortable due to a delay in playback, thereby further reducing the CPU load.

  Further, according to the digital broadcast receiver according to the present embodiment, the decoding start time limit (k) is based on the reproduction start time PTS (k) and the processing delay time that is the time required for AU delimiter search and decoding. ) Is calculated. As a result, the decoding start time limit (k) considering the search time of the AU delimiter is calculated, so that the time for starting the output process of the PES packet can be accurately calculated.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The digital broadcast receiver 100 according to the present embodiment performs output in the individual output format while sequentially updating the decoding start time limit (k) for each AU, and outputs in the batch output format when reception of the PES packet is completed. I do.

  In the following, the different parts from the digital broadcast receiver 100 according to the first embodiment of the present invention will be mainly described, and the description of the same parts will be omitted.

<< Block Configuration of Digital Broadcast Receiver 100 >>
The digital broadcast receiver 100 according to the present embodiment is composed of the same blocks as in the first embodiment. Hereinafter, a description will be given with reference to FIG.

  In the present embodiment, the DEMUX processing unit 102, the video PES analysis unit 104a, the reproduction start time calculation unit 106a, the video decoding unit 118a, and the synchronization control unit 120 perform the same functions as the blocks in the first embodiment. Also in this embodiment, the output of the audio PES packet to the audio decoding unit 118b is the same as the decoding process of the video PES packet, and thus the description thereof is omitted.

  The decoding start time calculation unit 108a calculates the decoding start time limit (k) of the PES packet based on the reproduction start time PTS (k). When the decoding start time calculation unit 108a cannot output in the batch output format, the decoding start time calculation unit 108a next performs the following based on the reproduction start time PTSk (i) acquired from the reproduction start time calculation unit 106a and the AU parameter information. The decoding start time limitk (i) of the AU to be output is calculated. In addition, the decoding start time calculation unit 108a updates the decoding start time limit (k) as limit (i) = limit (k).

  The determination unit 110a determines whether or not the reception of the PES packet is completed before the reference time acquired from the synchronization control unit 120 reaches the decoding start time limit (k) acquired from the decoding start time calculation unit 108a. . The completion of reception of the PES packet is recognized by receiving a notification from the video PES analysis unit 104a that a header of the next PES packet has been newly detected.

  If the reception of the PES packet is not completed before the reference time reaches the decoding start time limit (k), the output format determination unit 111a individually outputs the AU that has reached the decoding start time limit (k). Decide what to output by format. On the other hand, if the reception of the PES packet is completed before the decoding start time limit (k) is reached, the output format determination unit 111a should output the undecoded AU included in the PES packet in a batch output format. To decide.

  The output control unit 112a includes a SEL 114a and an AU extraction unit 116a.

  The SEL 114a sequentially receives and temporarily holds AUs related to video data output from the video PES analysis unit 104a. The SEL 114a outputs the undecoded AU included in the PES packet to the video decoding unit 118a in a batch output format in response to the determination by the output format determination unit 111a.

  The AU extraction unit 116a detects a break between AUs by sequentially searching the AU delimiters of the AUs held in the SEL 114a in accordance with an instruction from the output format determination unit 111a, and images each AU in an individual output format. It outputs to the decoding part 118a.

  As described above, in the present embodiment, unlike the first embodiment, the output format determination unit 111a updates the AU decoding start time limit (k) as needed and waits for the reception of the PES packet to be completed. When the reception of the packet is completed, a decoding process in the batch output format is instructed for the undecoded AU included in the PES packet.

<< Operation of Digital Broadcasting Receiver 100 >>
Next, the operation of the digital broadcast receiver 100 will be described. FIG. 7 shows an output flow of the PES packet to the video decoding unit 118a. Note that, as described above, the voice PES packet can be performed in the same manner, and thus the description thereof is omitted.

  As shown in FIG. 7, in step S201, the decoding start time calculation unit 108a adds the allowable delay time and subtracts the processing delay time to the reproduction start time PTS (k) and stores it at the head of the PES packet. The AU decoding start time limit (k) is calculated.

  In step S202, the determination unit 110a determines whether reception of the PES packet is completed before the reference time reaches the decoding start time limit (k). The completion of the reception of the PES packet can be known by notification from the video PES analysis unit 104a that a new PES packet header has been detected.

  If reception of the PES packet is completed before the decoding start time limit (k) is reached, in step S203, the SEL 114a outputs all AUs included in the PES packet to the video decoding unit 118a in a batch output format. .

  If reception of the PES packet is not completed before the decoding start time limit (k) is reached, in step S204, the AU extraction unit 116a selects the second PES packet temporarily held in the SEL 114a. The AU delimiter of the stored AU is searched.

  In step S205, the AU extraction unit 116a outputs the AU stored at the head of the PES packet to the video decoding unit 118a in the individual output format. In step S205, the reproduction start time calculation unit 106a that has received the notification that the AU stored at the head of the PES packet has been input to the video decoding unit 118a, the reproduction start time PTSk of the second AU of the PES packet. (I) is calculated.

  In step S206, the decoding start time calculation unit 108a calculates the decoding start time limit (i) of the AU stored in the second payload, and sets the decoding start time limit (k) = limitk (i). The decoding start time limit (k) is updated.

Thereafter, the process returns to step S202 again, and it is determined whether or not the reception of the PES packet is completed before reaching the decoding start time limit (k) with the updated reference time.
The above operation is repeated until reception of the PES packet is completed, and when reception of the PES packet is completed, undecoded AU included in the PES packet is output in a batch output format.

《Action ・ Effect》
The digital broadcast receiver according to the present embodiment determines whether or not the reception of the PES packet is completed before reaching the decoding start time for each AU stored in the payload of the PES packet. When the output is completed, the output in the batch output format for outputting a plurality of AUs at a time is determined. Therefore, the output in the individual output format for outputting AUs individually can be reduced to the minimum necessary number. Thereby, it is possible to further reduce the CPU load due to the AU delimiter search while suppressing delay from the packet reproduction start time.

[Other Embodiments]
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

 For example, in the above embodiment, the decoding start time limit (k) is calculated based on the reproduction start time PTS (k) or the reproduction start time PTSk (i) plus a delay allowable time. The allowable delay time is not necessarily added.

 In the above embodiment, the audio PES packet is decoded in the same manner as the video PES packet. However, the audio PES packet may be output only in the individual output format. In this case, since the AU storing the audio data is an ADTS frame in which the frame length is described in the frame itself, it is not necessary to search for the AU delimiter and the load on the CPU is small.

It is a schematic diagram which shows packetization of ES which concerns on an image | video. It is a schematic block block diagram of the conventional digital broadcast receiver. It is a schematic diagram which shows the relationship between the reception time of a PES packet, and a decoding start time. It is a block block diagram of the digital broadcast receiver which concerns on embodiment of this invention. It is a figure which shows the data structure of AU which concerns on an image | video. It is an operation | movement flowchart of the digital broadcast receiver which concerns on 1st Embodiment of this invention. It is an operation | movement flowchart of the digital broadcast receiver which concerns on 2nd Embodiment of this invention. It is a figure which shows the prioritization of the task which implement | achieves the transfer determination to power saving mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Digital broadcast receiver, 102 ... DEMUX processing part, 104a ... Analysis part, 104b ... Analysis part, 106a ... Reproduction start time calculation part, 106b ... Reproduction start time calculation part, 108a ... Decoding start time calculation part, 108b ... Decoding Start time calculation unit, 110a ... determination unit, 110b ... determination unit, 111a ... output format determination unit, 111b ... output format determination unit, 112a ... output control unit, 112b ... output control unit, 114a ... SEL, 116a ... AU extraction unit 118a ... Video decoding unit, 118b ... Audio decoding unit, 120 ... Synchronization control unit

Claims (5)

A digital broadcast receiver including a decoding unit that decodes a packet including a plurality of access units in which encoded data is stored,
A decoding start time calculation unit that indicates a time at which decoding processing of the packet should be started based on a reproduction start time indicating a time at which reproduction of the packet should be started, and calculates a decoding start time that is before the reproduction start time When,
A determination unit that determines whether reception of the packet is completed before a reference time reaches the calculated decoding start time;
An output format determining unit that determines a format for outputting the packet to the decoding unit;
The output format determination unit
If reception of the packet is not completed before the reference time reaches the decoding start time, an output in an individual output format for individually outputting the access unit included in the packet to the decoding unit is performed. Decide
When the reception of the packet is completed before the reference time reaches the decoding start time, all the access units included in the packet are output to the decoding unit in a batch output format. A digital broadcast receiver characterized by determining. The decoding start time calculation unit calculates, based on the reproduction start time, the decoding start time of the access unit included in the packet for each access unit,
The determination unit determines whether the reception of the packet is completed before the reference time reaches the calculated decoding start time of the access unit;
The output format determination unit
If reception of the packet is not completed before the reference time reaches the decoding start time of the access unit, the individual access unit included in the packet that has reached the decoding start time Determine the output format,
If reception of the packet is completed before the reference time reaches the decoding start time of the access unit, output in the batch output format is determined for the undecoded access unit included in the packet. The digital broadcast receiver according to claim 1, wherein: The decoding start time calculation unit calculates the decoding start time based on a time obtained by adding a delay allowable time that is a time within a range in which the packet reproduction delay is allowed to the reproduction start time. The digital broadcast receiver according to claim 1 or 2. The decoding start time calculation unit is based on at least the reproduction start time and a search time stored in the access unit and required for searching for an access unit delimiter indicating the head of the access unit. The digital broadcast receiver according to claim 1, wherein the digital broadcast receiver is calculated. A program for decoding a packet including a plurality of access units in which encoded data is stored,
A step A for indicating a time to start decoding the packet based on a reproduction start time indicating a time to start reproduction of the packet, and calculating a decoding start time that is earlier than the reproduction start time;
Determining whether the reception of the packet is completed before the reference time reaches the calculated decoding start time; and
Performing step C for determining a format for outputting the packet;
In step C,
If the reception of the packet is not completed before the reference time reaches the decoding start time, determine an output in an individual output format for individually outputting the access unit included in the packet;
If the reception of the packet is completed before the reference time reaches the decoding start time, the output in a batch output format for collectively outputting all the access units included in the packet is determined. A program characterized by

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