JP4250150B2 - DIGITAL VIDEO SIGNAL RECORDING / REPRODUCING DEVICE, DIGITAL VIDEO SIGNAL RECORDING / REPRODUCING PROGRAM, AND COMPUTER-READABLE RECORDING MEDIUM CONTAINING THE PROGRAM - Google Patents

Description

  The present invention relates to a digital video signal recording / reproducing apparatus, a digital video signal recording / reproducing program, and a computer-readable recording medium on which the program is recorded, and more particularly to a digital for recording and reproducing digitally encoded video data on a recording medium. The present invention relates to a video signal recording / reproducing apparatus, a digital video signal recording / reproducing program, and a computer-readable recording medium on which the program is recorded.

  In digital broadcasting, MPEG2 (Moving Picture Experts Group Phase 2) is used as an image compression method. Further, for transmission of the compressed digital video signal, a transport stream system used for real-time transmission such as broadcasting is used as a multiplexing system. The digital video signal is received and played back by the tuner, but the signal received by the tuner is scrambled and cannot be displayed clearly even if played back. After extracting the compressed image data, the video decoder performs a decoding process. The video signal obtained by the decoding process is displayed as a moving image on the display (see, for example, Patent Document 1).

  MPEG2 images include I picture (Intra-Picture: intra-frame encoded image), P picture (Predictive-Picture: inter-frame forward prediction encoded image) and B picture (Bidirectionally Predictive-Picture: bidirectional predictive encoded image). ) Of three types of pictures.

  Fast forward playback (double speed playback), which is one of special playback in a digital video signal recording / playback apparatus, is realized by playing back only an I picture from a recording medium. The playback speed during fast forward playback is controlled by thinning out the output target picture every m (m is a positive integer) and outputting it (that is, 2 for double-speed playback). Only one picture is thinned out at the rate of reproduction, and in quadruple speed reproduction, only one out of every four pictures is thinned out.)

  The conventional double speed reproduction will be briefly described below with reference to the drawings. In normal playback, a stream is composed of an I picture, a B picture, and a P picture. In double-speed playback, as shown in FIG. 7, frames to be played are skipped by thinning out between I pictures, thereby realizing double-speed display. In the case of double speed, the I picture is thinned out once.

In order to play back the thinned-out double speed stream by the decoder, the PCR (PCR: Program Clock Reference) in the adaptation field is updated. PCR is time reference information of the program.
In addition, in order to play back the thinned double-speed stream with a decoder, a time stamp PTS (Presentation Time Stamp: time information for performing playback operation) / DTS (DTS: Decoding Time) in a PES header (PES: Packetized Elementary Stream) Stamp: Time information for performing the decoding operation) is updated.

  Next, the relationship between the transport stream (TS) 100 and the PES stream 101 will be described with reference to FIG. As shown in FIG. 8, the transport stream (TS) 100 includes a plurality of 188-byte transport packets (TS packets) 103. Each transport packet (TS packet) 103 includes a transport header (TS header) 104 that is a control header and a payload 105 that includes video signal data. At this time, the PES stream 101 is obtained by extracting and combining only these payloads 105. The PES stream 101 is composed of a plurality of PES packets 106 as shown in FIG. Each PES packet 106 includes a PES header 107 and ES (Elementary Stream) data (video signal) 108. Note that the length of the PES packet 106 is arbitrary.

  Here, the structure of the TS packet 103 shown in FIG. 8 will be described with reference to FIG. As described above, the TS packet 103 is composed of 188 bytes and includes a transport header (TS header) 104 and a payload 105. As shown in FIG. 9, the transport header (TS header) 104 includes an 8-bit sync byte, a 1-bit payload unit start indicator, and a payload 105. 13-bit PID (Packet Identification) for identification, 2-bit transport scrambling control (encryption presence / absence) indicating encryption / non-encryption, and 2-bit adaptation field control (adaptation field control) And an adaptation field. Note that the payload 105 having a payload unit start indicator (payload unit start indicator) of “1” is the payload that becomes the head of the picture (PES packet 106).

  Next, the structure of the PES header 107 shown in FIG. 8 will be described with reference to FIG. As shown in FIG. 10, the PES header 107 includes a 24-bit packet start code prefix, a 16-bit PES packet length, and an 8-bit PES header data. It has a length (PES header data length) and PES header data (PES header data). Note that an option data field is provided in the PES header data, and time stamp PTS / DTS data is stored.

  Next, the structure of the TS packet 103 and the picture will be described with reference to FIG. As described above, the PES packet 106 is obtained by combining the payload 105 of the TS packet 103. The PES packet 106 includes a PES header 107 and ES data (video signal) 108. The payload 105 whose payload unit start indicator in the TS header 104 is “1” is the payload that becomes the head of the PES packet 106, and the PES header 107 exists at that time. A PES packet 106 is configured for each picture type. In addition, a picture type field exists in the head part (or the vicinity thereof) of the ES data 108 which is the data part of the PES packet 106, and indicates the type of picture.

  Next, the structure of the encryption stream will be described with reference to FIG. Since the structure of the encrypted stream 103A is basically the same as the structure of the TS packet 103 shown in FIG. 9, detailed description thereof is omitted. The encrypted stream is encrypted in units of TS packets. Also, only the portion of the payload 105 is encrypted. In addition, a 2-bit transport scrambling control (transport scrambling control) flag in the TS header 104 indicates an encryption state indicating whether or not the payload 105 of the TS packet 103 is encrypted.

JP 2003-174620 A

  As described above, the payload 105 of the encrypted stream 103A is encrypted. Therefore, as shown in FIG. 13, when the PES packet 106 is generated from the encrypted stream 103, it is provided to determine the type of picture provided in the head part (or the vicinity thereof) of the ES data 108. Since the picture type field is encrypted, there is a problem that an index for double speed cannot be created unless the encryption is broken at the time of storage.

  In addition, the PCR that is updated during double-speed playback is in the non-encrypted part, but the time stamp PTS / DTS in the PES header 107 is encrypted, so that there is a problem that it is necessary to decrypt them. .

  Further, in the case of a processing method that does not create an index, there has been a problem that in order to realize n-times speed, reading at n-times speed and encryption / decryption processing capability at n-times speed are required.

  The present invention has been made to solve such a problem, and improves the processing performance without the need for decoding at the time of storage, and the digital video signal recording / reproducing apparatus and digital video that do not require n-times speed capability An object is to obtain a signal recording / reproducing program and a computer-readable recording medium on which the program is recorded.

The present invention is a digital video signal recording / reproducing apparatus for recording and reproducing a video signal using an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part. there, the information indicating the cipher stream storage means for storing a pre-Symbol cipher stream, prior Symbol the TS packets in the TS header included in each of said TS packets that constitute the cipher stream is whether the head of the picture Based on the value of the payload unit start indicator storing index, index creating means for creating position information including the position information of the head position of the picture, index storage means for storing the index, and the encrypted stream A reproduction instruction receiving means for receiving the reproduction instruction, and the reproduction instruction receiving means A picture type field that stores the information indicating the type of the picture in the payload of the TS packet that is the head of the picture when the head of the picture is obtained based on the position information of the index when the recording / playback instruction is received The picture type determination means for determining the picture type of the picture type field that has been decrypted and the picture type information obtained by the picture type determination means are added to the index. Then, the index completion means for completing the index and updating the index of the index storage means, the payload decoding means for decoding the payload of the I picture based on the completed index, the payload of the I picture After decoding, the payload in the TS packet A flag update means for updating a flag indicating the presence or absence of encryption to indicate non-encryption, a time stamp update means for updating a time stamp of the TS packet, and a payload of the decoded I picture Is a digital video signal recording / reproducing apparatus provided with video signal reproducing means for reproducing the video .

The present invention is a digital video signal recording / reproducing apparatus for recording and reproducing a video signal using an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part. there, the information indicating the cipher stream storage means for storing a pre-Symbol cipher stream, prior Symbol the TS packets in the TS header included in each of said TS packets that constitute the cipher stream is whether the head of the picture Based on the value of the payload unit start indicator storing index, index creating means for creating position information including the position information of the head position of the picture, index storage means for storing the index, and the encrypted stream A reproduction instruction receiving means for receiving the reproduction instruction, and the reproduction instruction receiving means A picture type field that stores the information indicating the type of the picture in the payload of the TS packet that is the head of the picture when the head of the picture is obtained based on the position information of the index when the recording / playback instruction is received The picture type determination means for determining the picture type of the picture type field that has been decrypted and the picture type information obtained by the picture type determination means are added to the index. Then, the index completion means for completing the index and updating the index of the index storage means, the payload decoding means for decoding the payload of the I picture based on the completed index, the payload of the I picture After decoding, the payload in the TS packet A flag update means for updating a flag indicating the presence or absence of encryption to indicate non-encryption, a time stamp update means for updating a time stamp of the TS packet, and a payload of the decoded I picture Since this is a digital video signal recording / reproducing device equipped with a video signal reproducing means for reproducing data, it is possible to improve the processing performance by eliminating the processing of decrypting the encryption at the time of storage, and to reproduce without requiring n-times speed capability It can be performed.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of a digital video signal recording / reproducing apparatus according to Embodiment 1 of the present invention. The digital video signal recording / reproducing apparatus according to the present embodiment receives an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part, and records and records a video signal. It is a device for playback. Therefore, it has a configuration for storing video signals and a configuration for reproducing video signals.
First, a configuration for storing video signals will be described. As shown in FIG. 1, the digital video signal recording / reproducing apparatus according to the present embodiment includes a recording instruction receiving unit 1, a receiving unit 2, an encrypted stream storage unit 3, an index for storing video signals. A creation unit 4 and an index storage unit 5 are provided.
The recording instruction receiving unit 1 receives an instruction for recording an encrypted stream input by a user.
The receiving unit 2 receives an encrypted stream including a video signal when the recording instruction receiving unit 1 receives a recording instruction.
The cipher stream storage unit 3 stores the cipher stream received by the receiving unit 2 and includes an HDD (hard disk) or the like.
The index creating means 4 is a payload that stores information indicating whether or not the TS packet is the head of a picture in the TS header of each TS packet constituting the encrypted stream received by the receiving means 2. Based on the value of the unit start indicator, an index having information on only the head position of the picture is created.
The index storage means 5 stores the created index. The index storage means 5 is also composed of an HDD (hard disk) or the like.

Next, a configuration for reproducing a video signal will be described. As shown in FIG. 1, the digital video signal recording / reproducing apparatus according to the present embodiment includes a reproduction instruction receiving unit 6, a picture type determination unit 7, an index completion unit 8, A payload decoding unit 9, a time stamp update unit 10, and a video signal reproduction unit 11 are provided.
The reproduction instruction receiving unit 6 receives an instruction to reproduce the encrypted stream input by the user.
When the playback instruction receiving unit 6 receives the playback instruction, the picture type determination unit 7 obtains the head of the picture based on the index created by the index creation unit 4 and the picture type in the payload of the TS packet that is the head of the picture The picture type field storing information indicating the type of the picture is decoded to determine the picture type.
The index completion means 8 adds the picture type information obtained by the picture type determination means 7 to the index stored in the index storage means 5 to complete the index, and updates the index of the index storage means 5. Is.
The payload decoding means 9 decodes the payload of the I picture based on the completed index.
The time stamp update unit 10 updates the time stamp of the TS packet.
The video signal reproduction means 11 reproduces the video signal using the decoded payload of the I picture.

  Next, the operation will be described. The operation of the digital video signal recording / reproducing apparatus in the present embodiment is roughly composed of two phases. Phase 1 is when digital video signals are stored. Phase 2 is when the stored digital video signal is played back.

  First, the operation in phase 1 (during accumulation) will be described with reference to FIGS. Based on the recording instruction signal from the user received by the recording instruction receiving means 1, the receiving means 2 receives the transport stream (TS) 100 which is multiplexed and compressed by MPEG2 and transmitted (step S1). This transport stream 100 is the encrypted stream shown in FIG. Therefore, the payload 105 portion of each TS packet 103A is encrypted, and the TS header 104 portion is not encrypted. In the TS header 104, as shown in FIG. 12, a payload unit start indicator is included. As described above, when the value is “1”, this indicates the head of the picture (that is, the head of the PES packet). Therefore, the index creating means 4 detects the TS packet 103A having a payload unit start indicator value of “1”, and stores the storage position 201 at the head position of the picture and the picture type. An index 200 having 202 is created (step S2). The index created at this time is the index 200 for only the frame in which the picture type 202 is empty as shown in FIG. Here, since the TS header 104 is not encrypted, the index 200 can be created in the phase 1 (during accumulation) without the need to decrypt the encryption. Next, the received transport stream 100 is accumulated in the encrypted stream storage means 3, and the created index 200 is stored in the index storage means 5 (steps S3 and S4).

  Next, the operation in phase 2 (during reproduction) will be described using FIG. 5 and FIG. When the reproduction instruction receiving unit 6 receives a reception instruction from the user, the picture type determining unit 7 obtains the top of the picture based on the index created in step S2 in FIG. 3, and the payload 105 at the position indicated by the index. Only the picture type field is decrypted and the picture type is determined (step S10). The picture type field is the picture type field 109 shown in FIG. Next, as shown in FIG. 4B, the index completion means 8 displays the information of the determined picture type 202 (separate from I picture, P picture, and B picture) in the frame shown in FIG. Only the index 200 is added to complete the index 200 (step S11). Next, only the I picture is extracted based on the completed index 200, the payload 105 of the I picture to be reproduced is decoded by the payload decoding means 9 (step S12), and the thinned double-speed stream is reproduced by the decoder. Therefore, the time stamp PTS / DTS is updated by the time stamp updating means 10 in a state where the encryption is broken (step S13). The 2-bit transport scrambling control flag in the TS header 104 is updated so as to indicate non-encryption (step S14), and the video signal reproducing unit 11 (MPEG2-TS as a plaintext stream) is updated. The video is played back (step S15).

  As described above, in the present embodiment, since the payload is not decrypted at the time of accumulation, the processing performance can be improved. In addition, since only the TS packet to be updated at the time of reproduction is decrypted, the processing capacity can be reduced (the ability to decrypt the cipher at n times speed is not required). Further, at the time of reproduction, since the necessary TS packet is read based on the index, the capability can be reduced (the capability of n-times speed throughout is not required). In addition, once playback is performed, the index is completed, so that playback can be performed with the same processing ability as normal playback.

1 is a block diagram showing a configuration of a digital video signal recording / reproducing apparatus according to Embodiment 1 of the present invention. It is explanatory drawing which showed operation | movement of the digital video signal recording / reproducing apparatus based on Embodiment 1 of this invention. 3 is a flowchart showing the operation of the digital video signal recording / reproducing apparatus according to Embodiment 1 of the present invention. It is explanatory drawing which showed the index in the digital video signal recording / reproducing apparatus concerning Embodiment 1 of this invention. It is explanatory drawing which showed operation | movement of the digital video signal recording / reproducing apparatus based on Embodiment 1 of this invention. 3 is a flowchart showing the operation of the digital video signal recording / reproducing apparatus according to Embodiment 1 of the present invention. It is explanatory drawing which showed the operation | movement of software double speed. It is explanatory drawing which showed the relationship between a transport stream and a PES stream. It is explanatory drawing which showed the structure of TS packet. It is explanatory drawing which showed the structure of the PES header. It is explanatory drawing which showed the structure of TS packet and a picture. It is explanatory drawing which showed the structure of the encryption stream. It is explanatory drawing which showed the problem of the conventional double speed reproduction | regeneration in an encryption stream.

Explanation of symbols

  1 recording instruction receiving means, 2 receiving means, 3 encryption stream storage means, 4 index creation means, 5 index storage means, 6 playback instruction receiving means, 7 picture type determination means, 8 index completion means, 9 payload decoding means, 10 time Stamp update means, 11 video signal reproduction means, 100 transport stream, 101 PES stream, 103 TS packet, 103A TS packet, 104 TS header, 105 payload, 106 PES packet, 107 PES header, 108 ES data, 109 picture type field , 200 Index, 201 Storage position, 202 Picture type.

Claims (3)

A digital video signal recording / reproducing device for recording and reproducing a video signal using an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part ,
A cipher stream storage means for storing a pre-Symbol cipher stream,
The value before Symbol payload unit start indicator in which the TS packets in the TS header included in each of said TS packets that constitute the cipher stream stores information indicating whether a head picture An index creating means for creating an index including position information of a head position of the picture,
Index storage means for storing the index ;
Reproduction instruction receiving means for receiving an instruction to reproduce the encrypted stream;
When the playback instruction receiving means receives the playback instruction, the head of the picture is obtained based on the position information of the index, and information indicating the picture type is stored in the payload of the TS packet that is the head of the picture A picture type determination unit that decrypts the encrypted picture type field and determines the type of the picture of the picture type field that has been decrypted;
Index completion means for adding the picture type information obtained by the picture type determination means to the index to complete the index and updating the index of the index storage means;
Payload decoding means for decoding the payload of the I picture based on the completed index;
Flag update means for updating a flag indicating the presence or absence of encryption of the payload in the TS packet to indicate non-encryption after decoding of the payload of the I picture;
Time stamp update means for updating the time stamp of the TS packet;
A digital video signal recording / reproducing apparatus comprising: a video signal reproducing means for reproducing a video signal using a payload of a decoded I picture . A digital video signal recording / reproducing program for recording and reproducing a video signal using an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part ,
An encryption stream storage step for storing the encryption stream;
The value before Symbol payload unit start indicator in which the TS packets in the TS header included in each of said TS packets that constitute the cipher stream stores information indicating whether a head picture An index creating step for creating an index including position information of a head position of the picture ,
And the index storage step of storing the previous Symbol index,
A reproduction instruction receiving step for receiving an instruction to reproduce the encrypted stream;
When the playback instruction is received in the playback instruction receiving step, the head of the picture is obtained based on the position information of the index, and information indicating the picture type is included in the payload of the TS packet that is the head of the picture. A picture type determination step for decrypting the stored picture type field and determining the type of the picture of the picture type field that has been decrypted;
An index completion step for adding the picture type information obtained by the picture type determination step to the index to complete the index;
A payload decoding step for decoding the payload of the I picture based on the completed index;
A flag update step of updating a flag indicating the presence or absence of encryption of the payload in the TS packet to indicate non-encryption after decoding of the payload of the I picture;
A time stamp update step for updating a time stamp of the TS packet;
A digital video signal recording / reproducing program for causing a computer to execute a video signal reproducing step for reproducing a video signal using a payload of a decoded I picture . Computer-readable recording of a digital video signal recording / playback program for recording and playing back a video signal using an encrypted stream composed of one or more TS packets composed of a TS header of an unencrypted part and a payload of an encrypted part A possible recording medium ,
An encryption stream storage step for storing the encryption stream;
The value before Symbol payload unit start indicator in which the TS packets in the TS header included in each of said TS packets that constitute the cipher stream stores information indicating whether a head picture An index creating step for creating an index including position information of a head position of the picture ,
And the index storage step of storing the previous Symbol index,
A reproduction instruction receiving step for receiving an instruction to reproduce the encrypted stream;
When the playback instruction is received in the playback instruction receiving step, the head of the picture is obtained based on the position information of the index, and information indicating the picture type is included in the payload of the TS packet that is the head of the picture. A picture type determination step for decrypting the stored picture type field and determining the type of the picture of the picture type field that has been decrypted;
An index completion step for adding the picture type information obtained by the picture type determination step to the index to complete the index;
A payload decoding step for decoding the payload of the I picture based on the completed index;
A flag update step of updating a flag indicating the presence or absence of encryption of the payload in the TS packet to indicate non-encryption after decoding of the payload of the I picture;
A time stamp update step for updating a time stamp of the TS packet;
A computer-readable recording medium on which a digital video signal recording / reproducing program for causing a computer to execute a video signal reproducing step of reproducing a video signal using a decoded I picture payload is recorded.

Images