JP2008135845A - Transport stream recording and reproducing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transport stream recording and reproducing method for shortening the detection time of an I picture of a transport stream and for coping with special reproduction, and a transport stream recording and reproducing device. <P>SOLUTION: A packet detector 103 detects a starting I picture as a starting packet among I picture video packets from the transport stream. A packet memory 102 stores packets from the starting I picture to right before a starting packet among next I picture video packets in the transport stream. A position packet generator 106 generates packets relating to positional information of the I picture video packets. In a recording medium 108, the output of a switch 107 is recorded. A positional information detector 109 detects the positional information on I picture video packets read out of the recording medium 108. An AV decoder 110 decodes video data or audio data of the output of the recording medium 108. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transport stream recording / reproducing method and apparatus for recording or reproducing an MPEG-compliant transport stream (TS).

  In digital broadcasting, MPEG-2 is adopted as a video encoding method. MPEG-2 performs not only intraframe coding but also interframe predictive coding in order to increase coding efficiency. There are two types of inter-frame predictive encoding, one is performed in the forward direction and the other is performed in the forward and backward directions. A frame that performs intraframe coding is referred to as an I picture, a frame that performs forward predictive coding is referred to as a P picture, and a frame that performs bidirectional predictive coding is referred to as a B picture. The amount of information after encoding decreases in the order of B picture, P picture, and I picture. In general, a GOP (Group Of Picture) configuration in which the interval between I pictures is 15 frames and the interval between I pictures and P pictures or between P pictures is 3 frames has greatly reduced the amount of information. .

  An I picture can be decoded only with data of the picture, but data of other pictures is required for decoding of a P picture and a B picture. Therefore, decoding must always start from an I picture, not an arbitrary position. For example, when viewing a digital broadcast, when the receiver is turned on and a channel is selected, it is necessary to first receive and decode the I picture, and depending on the timing, it may be waited until the video is displayed. Sometimes. This time is a maximum of 0.5 seconds when the interval between I pictures is 15 frames.

  Digital broadcasting is performed by MPEG-2 TS. The transport stream is obtained by dividing and multiplexing data such as video and audio into small 188-byte TS packets, and the type of content (for example, by the identifier called PID in the packet header (4 bytes)) , Video, audio). That is, in video, one TS is created by dividing an image encoded into an I picture, a P picture, and a B picture.

When the TS is recorded on the recording medium, the MPEG picture analysis is performed to obtain the position information of the I picture, and the obtained position information of the preceding I picture is described in the TS format as an I reference packet. Are periodically inserted (recorded every fixed number of packets) into the TS and recorded, the inserted I reference packet is obtained, the TS of the I picture is extracted based on this, and fast-forward playback or rewind playback is performed. It has been proposed to perform special reproduction (for example, Patent Document 1).
JP 2005-197829 A

  When a TS is recorded on a recording medium and reproduced, that is, when it is decoded as a video signal, it is necessary to detect an I picture and perform decoding based on the I picture. For this purpose, it is necessary to acquire an I picture at an early stage, and the TS packet of each video is examined one by one to determine the type of picture, but a lot of packet processing is required.

  In addition, a TS file in which a program for several hours is recorded has a capacity of several gigabytes to several tens of gigabytes, so that a long time is required for processing. High-speed processing requires a high-performance arithmetic device (for example, a CPU) and a recording medium (for example, a hard disk), which increases costs.

  Further, during special playback such as rewinding or fast-forwarding, it is necessary to perform processing faster than the normal playback processing time for high-speed operation, and the processing time is limited in the conventional TS recording / playback apparatus.

  An object of the present invention is to provide a transport stream recording / reproducing method and apparatus capable of shortening the detection time of an I picture of TS and also supporting special reproduction such as rewind reproduction and fast forward reproduction. is there.

According to the present invention, there is provided a transport stream recording / reproducing method according to claim 1.
Input an MPEG compliant transport stream containing at least one null packet;
Detecting a leading I picture that is a leading packet of an I picture video packet from the transport stream;
Generating I picture position information based on the first I picture;
Generating a position packet storing the I picture position information at a predetermined position;
A transport stream in which the position packet is written at a position immediately after the first I picture is recorded on a recording medium,
The transport stream recorded on the recording medium is specially reproduced based on the position packet.

According to the present invention, there is provided a transport stream recording / reproducing method according to claim 2.
The I picture position information is
The number of packets from the first I picture to the immediately preceding first I picture;
The number of packets from the first I picture to the next first I picture;
It is composed of the number of packets from the first I picture to the last I picture.

According to the present invention, there is provided a transport stream recording / reproducing method according to claim 3.
The predetermined position is configured by an adaptation field of the transport stream.

According to the present invention, there is provided a transport stream recording / reproducing apparatus according to claim 4.
An input means for inputting an MPEG-compliant transport stream including at least one null packet;
Detecting means for detecting a leading I picture that is a leading packet of an I picture video packet from the transport stream;
A packet counter for counting the number of packets in the transport stream;
A packet memory for storing from the transport stream to the packet immediately before the head packet of the next I picture video packet from the head I picture;
Position packet generation means for generating a packet relating to position information of the I picture video packet;
A switch for switching between the output of the packet memory and the output of the position packet generating means;
Control means for controlling the packet memory, the position packet generation means and the switch based on the result of the packet detection means and the result of the packet counter;
A recording medium for recording the output of the switch;
Recording medium control means for controlling recording and reproduction of the recording medium;
Position information detecting means for detecting position information of the I picture video packet read from the recording medium;
And an AV decoder for decoding video data or audio data from the output of the recording medium.

  According to the first aspect of the present invention, the I picture position information is recorded on the recording medium immediately after the head I picture, so that the position information of the I picture can be quickly acquired during reproduction. Therefore, if the recording medium is controlled based on the I-picture position information, the I-picture video information can be acquired quickly, and can be decoded as a video signal during special playback such as rewind playback or fast-forward playback. Can be done quickly. Since the I picture video information is the reference, if the I picture video information is acquired quickly, the video signal can be decoded more quickly than the conventional one using the P picture video information and the B picture video information. As a result, it is possible to reduce the detection time of the I picture of the TS and to cope with special playback such as rewind playback and fast forward playback.

  According to the second aspect of the invention, since the position information can be configured by the number of packets, the position information can be configured only by a packet counter that counts TS packets. Therefore, it is possible to shorten the detection time of the I picture of the TS with a simple configuration and to cope with special reproduction such as rewind reproduction and fast forward reproduction.

  According to the third aspect of the invention, by using the adaptation field as the predetermined position, the I picture position information can be identified in a short time from the adaptation field control even if the I picture position information is not adjacent to the I picture head packet. can do.

  According to the fourth aspect of the present invention, it is possible to reduce the I picture detection time with a small configuration with a small number of components, and to cope with special playback such as rewind playback and fast forward playback. Therefore, the present invention can be realized with a small addition even when an apparatus currently in use is improved.

  Also, there is always a null packet in the input TS, and even if a position packet is inserted, instead of discarding one null packet, the system clock information called PCR (Program Clock Reference) contained in the TS is obtained. It has the effect that there is no need to change.

  When the I picture position information is inserted, the packet position is changed, a PCR error (jitter) occurs, which may adversely affect the processing of the MPEG-2 decoder or the like. In order to avoid such an adverse effect, the PCR value is changed by using information such as the TS bit rate by the amount of packet position deviation. According to the present invention, since the null packet is deleted and the adjustment is made after inserting the I picture position information, no error occurs. Therefore, there is no need to change the PCR.

An embodiment of a transport stream recording / reproducing method and apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a transport stream recording / reproducing apparatus according to the present invention. A transport stream recording / reproducing apparatus shown in FIG. 1 includes a TS input terminal 101, a packet memory 102, a packet detector 103, a packet counter 104, a controller 105, a position packet generator 106, a switch 107, A recording medium 108, a position information detector 109, an AV decoder 110, an image output terminal 111, and an audio output terminal 112 are provided.

  An MPEG-compliant TS is input to the TS input terminal 101. The packet memory 102 is a memory for storing a packet constituting the TS. In the present embodiment, the packet memory 102 stores from the first packet of the I picture to immediately before the next packet of the next I picture. The packet detector 103 detects a specific packet from the TS, and in this embodiment, detects an I picture video packet or a null packet. The detection result of the packet detector 103 is transmitted to the controller 105.

  The packet counter 104 is a counter that counts input TS packets, and detects and counts the synchronization byte of each packet. The controller 105 obtains information from the packet detector 103, the packet counter 104, and the position information detector 109, and controls the packet counter 104, the position packet generator 106, and the switch 107. Also, control information related to rewind playback and fast forward playback is transmitted to the control unit of the recording medium 108.

  The position packet generator 106 newly generates a packet from information from the controller 105. The switch 107 switches between the output of the packet memory 102 and the output of the position packet generator 106 under the control of the controller 105. The recording medium 108 is realized by a hard disk, a DVD-RAM, or the like. When the position information detector 109 reads the TS recorded on the recording medium 108, the position information detector 109 reads the position information from the packet generated by the position packet generator 106 and transmits the position information to the controller 105. The AV coder 110 decodes the video signal and the audio signal from the TS, and outputs the decoded video signal and the audio signal from the video output terminal 111 and the audio output terminal 112, respectively.

In describing the operation of the present embodiment, first the recording system will be described.
An MPEG-compliant TS having a packet structure of 188 bytes is input to the TS input terminal 101. The input TS is input to the packet memory 102, and the packet memory 102 stores packets from the first packet of the I picture to immediately before the next packet of the next I picture. The packet detector 103 detects the packet type of the input TS. Since an I picture packet, which is a video packet, is normally composed of a plurality of packets instead of one packet, the leading I packet is detected.

  A TS packet payload unit start indicator with a TS including video indicates that it starts from the first byte of the PES packet. Therefore, this packet is the head of the picture. The picture coding type (3 bits) in the picture header of the payload of this packet indicates the picture type, and if it is a binary number 001, it is an I picture. Since the picture header starts from a 32-bit unique code picture start code (0x00000100), it can be easily identified.

  When the head of the I picture is detected in this way, the controller 105 is notified that the I picture has been detected. The packet counter 104 identifies the synchronization byte (0x47) in the TS, counts the number of packets, and sends the result to the controller 105.

The operation of the controller 105 will be described in detail with reference to FIGS.
FIG. 2 is a diagram for explaining the operation of the transport stream recording / reproducing apparatus of FIG. Since TS is limited to 188 bytes per packet, one picture is divided. The I picture packet is also divided into a plurality of packets.

  In this embodiment, in relation to an I picture, the number of packets from the leading I picture to the immediately preceding I picture, the number of packets from the leading I picture to the immediately following I picture, and the currently detected packet Three data are created from the number of consecutive I-picture packets based on the count from the packet counter 104. In FIG. 2, K ′ represents the number of packets from the head of the I picture (GOP) to the head of the immediately preceding I picture (GOP), J represents the number of packets of the currently detected I picture, and K represents the I picture. (GOP) Indicates the number of packets from the head to the next I picture (GOP) head, each of which requires a maximum of 4 bytes (32 bits) and is 188 bits or less in total. Can do.

  Based on these three packet numbers, the controller 105 sends counts of J, K, and K ′ to the position packet generator 106. The position packet generator 106 receives position packets as shown in FIG. 3 or FIG. create. FIG. 3 shows a case other than a null packet, and FIG. 4 shows a case of a null packet.

  After the count numbers of J, K, and K ′ are sent to the position packet generator 106, the head I picture packet is read from the packet memory 102, and then the switch 107 generates a packet X generated by the position packet generator 106. Only one packet is switched, and then the packets are read from the packet memory 102 in the order stored. If the packet following the first I picture packet is a null packet, it is discarded when it is read from the bucket memory 102.

  Therefore, the TS written in the storage medium 108 is delayed from the TS input to the TS input terminal 101 by the packet from the first I picture packet to the next first I picture packet. There will be no inconvenience.

  The position packet generator 106 generates a packet of I picture position information (J, K, and K ′) to be inserted. FIG. 3 is a diagram illustrating an example when position information is inserted into an adaptation field. Therefore, FIG. 3 shows a case where information is embedded by generating a packet having the same PID as that of a TS packet including video and having only an adaptation field, that is, adaptation field control (2 bits) of 10 in binary.

  In this case, since it is clear that the I picture position information corresponds to the video of the PID in the TS header, it is not necessary to embed the PID in the adaptation field. The adaptation field transport private data flag, transport private data length and private data byte can be used.

FIG. 4 shows an example in which position information is embedded in the payload of a null packet instead of the adaptation field. A null packet is a packet that is inserted to match the TS bit rate with the transmission path. The PID is 0x1FFF in hexadecimal, and an arbitrary value can be assigned to the data byte of the payload. In order to specify a video for which I-picture position information can be referred to, PID (PIDa in FIG. 4) is also stored. The remaining part of the rear part of the I picture position information is an arbitrary data byte.
Other than video packets are stored in the recording medium 108 without being processed.

Next, the reproduction system will be described.
The packet read from the storage medium 108 is input to the AV decoder 110 in normal playback without rewind playback or fast forward playback, and in the case of a video packet, the video signal is decoded from the I, P, and B pictures and output to the video. The video signal is output from the terminal 111. A position packet recorded immediately after the first packet of the I picture is discarded as an unnecessary packet. Similarly, the audio is decoded into an audio signal by the AV decoder 110, and the decoded audio signal is output from the audio output terminal 111.

Next, special reproduction will be described.
When a rewind playback switch (not shown) is pressed, position information of the video packet read from the storage medium 108 is read by the position information detector 109. The position information is J, K, and K ′ at the time of storage. Information necessary for rewind playback is the number of packets K ′ up to the head of the immediately preceding I picture (GOP) and the number of packets J of the currently detected I picture. These two pieces of information are transmitted to the controller 105, and then these two pieces of information are transmitted from the controller 105 to a reproduction control unit (not shown) of the storage medium 108 so as to perform control based on K ′ and J. , I picture information is acquired early.

  As an example, when K ′ = 1000 and J = 200, the control unit (not shown) of the storage medium 108 returns the reading position for K ′ = 1000 packets. Thereafter, I picture data for 200 packets is read to obtain I picture data. Thereafter, when the rewind regeneration switch is pressed again, these operations are repeated.

  When a fast forward playback switch (not shown) is pressed, the necessary information is J, which is the number of packets of the currently detected I picture, and K, which is the number of packets up to the beginning of the next I picture (GOP). The control is the same as the rewind playback. In this way, special reproduction is performed from the information of J, K, and K ′.

  For example, when K = 1500 and J = 150, the control unit of the recording medium 108 fast-forwards the reading position for K = 1500 packets. Thereafter, I picture data for 150 packets is read to obtain I picture data. Thereafter, when the fast forward reproduction switch is pressed again, these operations are repeated.

  Further, when reproduction is performed from a designated position, the nearest I picture can be specified and reproduced while referring to the I picture position information. In this way, the operation can be performed with a small amount of processing without examining all the packets.

The present invention is not limited to the above-described embodiment, and many changes and modifications can be made.
For example, in the above embodiment, the position packet generator 106 generates a position packet, and the switch 107 switches to the packet memory 102. However, the position immediately after the leading I picture is left by one packet, A configuration in which a packet is generated and written into the packet memory 102 may be employed.

  Further, the storage location of the I picture position information can be generated in a packet subsequent to the I picture head packet. In this case, even if the I picture position information is not adjacent to the I picture head packet, the I picture position information can be identified in a short time from the adaptation field control.

  Further, even if the I picture position information is not fixed, an empty packet is generated in advance, and the stored packet (packet X in FIG. 3) can be stored when the I picture position information is fixed.

It is a figure which shows embodiment of the transport stream recording / reproducing apparatus by this invention. FIG. 6 is a diagram for explaining the operation of the transport stream recording / reproducing apparatus of FIG. 1. 3 is a detailed view of a packet X. FIG. FIG. 10 is a detailed view of another packet X.

Explanation of symbols

101 TS input terminal 102 packet memory 103 packet detector 104 packet counter 105 controller 106 position packet generator 107 switch 108 recording medium 109 position information detector 110 AV decoder 111 image output terminal 112 audio output terminal

Claims (4)

Input an MPEG compliant transport stream containing at least one null packet;
Detecting a leading I picture that is a leading packet of an I picture video packet from the transport stream;
Generating I picture position information based on the first I picture;
Generating a position packet storing the I picture position information at a predetermined position;
A transport stream in which the position packet is written at a position immediately after the first I picture is recorded on a recording medium,
A transport stream recording / reproducing method, wherein the transport stream recorded on the recording medium is specially reproduced based on the position packet. The I picture position information is
The number of packets from the first I picture to the immediately preceding first I picture;
The number of packets from the first I picture to the next first I picture;
2. The transport stream recording / reproducing method according to claim 1, wherein the number of packets from the first I picture to the last I picture is included.   3. The transport stream recording / reproducing method according to claim 1, wherein the predetermined position includes an adaptation field of the transport stream. An input means for inputting an MPEG-compliant transport stream including at least one null packet;
Detecting means for detecting a leading I picture that is a leading packet of an I picture video packet from the transport stream;
A packet counter for counting the number of packets in the transport stream;
A packet memory for storing from the transport stream to the packet immediately before the head packet of the next I picture video packet from the head I picture;
Position packet generation means for generating a packet relating to position information of the I picture video packet;
A switch for switching between the output of the packet memory and the output of the position packet generating means;
Control means for controlling the packet memory, the position packet generation means and the switch based on the result of the packet detection means and the result of the packet counter;
A recording medium for recording the output of the switch;
Recording medium control means for controlling recording and reproduction of the recording medium;
Position information detecting means for detecting position information of the I picture video packet read from the recording medium;
A transport stream recording / reproducing apparatus comprising: an AV decoder for decoding video data or audio data from an output of the recording medium.

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