JP2005318255A - Digital video signal processing apparatus, digital video signal processing method, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily prevent the occurrence of operation trouble in software or a decoder which processes the omission of a digital video signal. <P>SOLUTION: A discontinuity detection part 2 judges whether a transport packet succeeds to the last transport packet from discontinuity counters in the transport packets and also judges whether the transport packet is at the head of a GOP, and then discards a transport packet judged not to be successive and a transport packet judged not to be at the head of the GOP, and a reconstitution storage part 3 restructures a transport stream so that transport packets which are not discarded are successive. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital video signal processing apparatus, a digital video signal processing method, and a computer program that process a digital video signal that is sent in a missing manner.

  In recent years, software for decoding or displaying a moving image by decoding an MPEG2-transport stream (hereinafter referred to as MPEG2-TS) from a digital TV broadcast or an external device on a computer, or a decoder (externally attached to a computer) Hardware) is known. When MPEG2-TS is imported from an external device (for example, a digital VTR) to a computer, the external device packetizes and transmits MPEG2-TS into IEEE 1394 isochronous packets, so the computer removes the header from the isochronous packets. MPEG2-TS is restored and stored in a recording medium. At this time, for example, if foreign matter adheres to the head portion during recording or reproduction in a digital VTR, part of the MPEG2-TS that is originally continuous is lost, and reproduction of MPEG2-TS in a certain section is difficult. There is a case.

In addition, as a conventional example of “compensating” a digital video signal transmitted due to omission, for example, there are those disclosed in Patent Documents 1 to 7 below.
JP-A-10-327400 (abstract) Japanese Patent Application Laid-Open No. 11-110952 (abstract) JP-A-10-199149 (abstract) Japanese Patent Laid-Open No. 10-200854 (abstract) JP-A-10-210402 (abstract) Japanese Patent Laid-Open No. 11-88878 (abstract) JP 2002-330407 A (Abstract)

  However, moving image display software and moving image editing software that handles MPEG2-TS as a general-purpose image file on a computer determines the legitimacy of data by an original method, performs error processing, and is missing MPEG2-TS. When TS is input, for example, (1) it is determined that the data is inappropriate and processing is stopped, (2) processing is abnormally stopped due to unexpected data, and (3) an abnormal image is obtained by decoding processing. There is a problem of causing an operation failure such as display.

  In view of the above-described problems of the conventional example, the present invention provides a software for processing a digital video signal even if it is missing, a digital video signal processing apparatus capable of easily preventing an operation failure of a decoder, and a digital An object is to provide a video signal processing method and a computer program.

In order to achieve the above object, the present invention groups a plurality of pictures obtained by intra-frame coding and inter-frame prediction coding of a video signal into GOPs, and divides the GOPs into packetized transport packets. , When processing a transport stream obtained by streaming the plurality of transport packets,
Determining whether the packetized transport packet is contiguous with a previous transport packet based on a discontinuity counter in the plurality of transport packets, and the transport packet is a GOP To determine whether it is the first packet of
Discard transport packets that are determined not to be continuous and transport packets that are not the first packet of a GOP;
The transport stream is reconstructed so that transport packets that are not discarded are continuous.
With this configuration, when transport packets are missing and not continuous, unlike the conventional example that performs “compensation” processing, all GOP packets with missing packets are discarded and the transport stream is reconstructed. Is done.

  According to the present invention, when transport packets are missing and are not continuous, all the GOP packets with missing packets are discarded and the transport stream is reconstructed. However, it is possible to easily prevent the software or the decoder that processes the operation from causing an operation failure.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing an embodiment of a digital video signal processing apparatus, digital video signal processing method and computer program according to the present invention, and FIG. 2 is an explanatory diagram showing the structure of a transport packet of MPEG2-TS. 3 is a flowchart for explaining the processing of the discontinuity detection unit and the reconstruction / storage unit in FIG. 1, and FIG. 4 is an explanatory diagram showing a specific example of the processing of the discontinuity detection unit and the reconstruction / storage unit in FIG. It is.

  In FIG. 1, the buffer 1 stores MPEG2-TS input via an interface from an external device or the like, and MPEG2-TS temporarily stored in a storage destination recording medium 4 such as an HDD. Here, in the MPEG2 standard, image data is subjected to intra-frame coding and inter-frame predictive coding and compressed into I, P, and B pictures, and 1 GOP is obtained by a plurality of frames (generally, about 15 frames are often used). (Group Of Pictures) is configured. In addition, a GOP header is added to the head of each GOP, and a sequence header is added when a sequence layer is always included in each GOP. Further, one GOP is divided, and each divided data is stored in a data field in a transport packet as shown in FIG. 2 and packetized to form a video packet. This video packet is streamed so as to be continuous with other transport packets in which audio data or the like is stored in the data field, and MPEG2-TS is configured.

  The transport packet of MPEG2-TS is composed of a fixed length of 188 bytes including a 4-byte header and a 184-byte data field (GOP video, audio, etc.), and the header is a 4-bit continuity counter (continuity). counter). This continuity counter is determined to be incremented for each packet type. Therefore, when the discontinuity detector 2 shown in FIG. 1 does not increment between packets of the same packet type, the previous packet is missing. Can be determined.

  Next, processing of the discontinuity detection unit 2 and the reconstruction / storage unit 3 will be described with reference to FIG. First, the discontinuity detection unit 2 reads one packet from the buffer 1 (step S1), and then, if this packet is a video packet, is it continuous with the previous packet based on the continuity counter in the header? It is determined whether or not (step S2). If the packet is not a continuous packet, the “previous GOP head packet position” is cleared (step S3), then the packet in the buffer 1 is discarded (step S4), and then the process returns to step S1 for each packet. Determine whether it is a packet.

  On the other hand, when the discontinuity detection unit 2 determines that the packet is a continuous packet in step S2, it determines whether or not it is a “first packet of GOP” based on the presence or absence of the GOP header or sequence header in the continuous packet (step S5). If it is not the head packet, the packet in the buffer 1 is discarded (step S4), and then the process returns to step S1 to detect the head packet of the GOP. That is, even if it is a continuous packet, a packet that is not the first packet of the GOP is discarded, so that all packets of the GOP that lack a packet are discarded.

  If the discontinuity detecting unit 2 determines that the packet is the first packet of the GOP in step S5, the reconfiguration / storing unit 3 stores the packet as the “first packet position of the GOP” (step S6), and then “the previous GOP first packet The presence / absence of “position” is determined (step S7). If there is no “previous GOP head packet position”, the process returns to step S1. If there is, the recording medium is such that the packet from “previous GOP head packet position” to the packet before “GOP head packet position” continues. 4 (step S8). At this time, the continuity counter is rewritten to be continuous. Next, it is determined whether or not the data is finished (step S9). If the data is not finished, the process returns to step S1. If the data is finished, the process is finished.

  FIG. 4A shows an original signal in which A, B, C, D, E, and F GOPs are continuous, and FIG. 4B shows the C and D GOPs among the original signals. Indicates that the packet is missing. FIG. 4 (c) shows the processing of the present invention, in which the packets of the two GOPs C and D with missing packets are all discarded, and the GOPs after E after the B GOP are transported. The state where the stream (TS) is reconstructed is shown. When the number of frames constituting a GOP is 15 and the frame rate of an image is 30 frames / second, although 15 × 2 frames (about 1 second) of the original signal are skipped, the operation of the software or decoder that processes this TS Can be prevented.

1 is a functional block diagram illustrating an embodiment of a digital video signal processing apparatus, a digital video signal processing method, and a computer program according to the present invention. It is explanatory drawing which shows the structure of the transport packet of MPEG2-TS. 3 is a flowchart for explaining processing of a discontinuity detection unit and a reconstruction / storage unit in FIG. 1. It is explanatory drawing which shows the specific example of the process of the discontinuity detection part of FIG. 1, and a reconstruction / preservation | save part.

Explanation of symbols

1 buffer 2 discontinuity detection unit 3 reconstruction / storage unit 4 recording medium

Claims (3)

A plurality of pictures obtained by intra-frame coding and inter-frame prediction coding of a video signal are grouped into GOPs, the GOPs are divided and packetized into transport packets, and the plurality of transport packets are streamed A digital video signal processing device for processing a transport stream,
Determining whether the packetized transport packet is contiguous with a previous transport packet based on a discontinuity counter in the plurality of transport packets, and the transport packet is a GOP Determining means for determining whether or not the first packet of
A packet discarding unit for discarding a transport packet that is determined not to be continuous by the determining unit and a transport packet that is not the first packet of the GOP;
Means for reconstructing the transport stream such that transport packets that are not discarded by the packet discarding means are continuous;
A digital video signal processing apparatus. A plurality of pictures obtained by intra-frame coding and inter-frame prediction coding of a video signal are grouped into GOPs, the GOPs are divided and packetized into transport packets, and the plurality of transport packets are streamed A digital video signal processing method for processing a transport stream,
Determining whether the packetized transport packet is contiguous with a previous transport packet based on a discontinuity counter in the plurality of transport packets, and the transport packet is a GOP A determination step of determining whether or not the first packet of
A packet discarding step of discarding the transport packet determined not to be continuous by the determining step and the transport packet that is not the first packet of the GOP;
Restructuring the transport stream such that transport packets that are not discarded by the packet discarding step are continuous.
A digital video signal processing method. A plurality of pictures obtained by intra-frame coding and inter-frame prediction coding of a video signal are grouped into GOPs, the GOPs are divided and packetized into transport packets, and the plurality of transport packets are streamed A computer program for processing a transport stream,
Based on the discontinuity counter in the plurality of transport packets, it is determined whether the transport packet is continuous with the previous transport packet, and whether the transport packet is the first packet of the GOP. A determination step for determining whether or not,
A packet discarding step of discarding the transport packet determined not to be continuous by the determining step and the transport packet that is not the first packet of the GOP;
Restructuring the transport stream such that transport packets that are not discarded by the packet discarding step are continuous.
A computer program that is executed by a computer.

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