JP2000331421A - Information recorder and information recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the special reproduction by taking out only the part having the frame structure required for the special reproduction from the digital information conforming to the transport stream specification of MPEG2. SOLUTION: Identification data showing the frame structure conformed to the MPEG2 video specification are inserted to the digital information 10 with the format conformed to the transport stream specification of MPEG2 by using an identification data inserting device 12 of the MPEG frame structure. When the special reproduction is performed, by using an identification data detecting device 18 of the MPEG frame structure, only one frame required for the special reproduction is sorted and decoded by the inserted identification data before decoding the frame structure of recorded picture data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an information recording apparatus for recording MPEG data in a format conforming to the MPEG standard, and an information reproducing apparatus for implementing special reproduction of MPEG data.

[0002]

2. Description of the Related Art In recent years, techniques for compressing image information such as MPEG data have been established, and digital broadcasting and various multimedia services have been rapidly spread. Technologies that have greatly contributed to the development of image information compression technology using MPEG data include spatial (DCT: discrete cosine transform), temporal (motion compensation),
This is a statistical (variable length coding) information compression technique, and MPEG standards such as a moving picture coding method have been established.

Conventional MPEG data has an image configuration shown in FIG. One of the features of the MPEG data is that it adopts bidirectional prediction of moving image frames by motion compensation. By incorporating bidirectional prediction,
MPEG data has three frame structures. These frame structures are classified into I frames, P frames, and B frames, respectively, and the encoding methods are different from each other.

[0004] An I frame is an intra-coded image (Intra-coded image).
picture), which is encoded along the time sequence of the original image and is independent of the preceding and following images. The I frame maintains the integrity as an image. P frame is an inter-frame forward predictive coded picture (Predictive-picture)
, And is encoded with reference to an I frame. The B frame is a bidirectionally coded image (Bidirectionally predicti
ve-picture), which is encoded with reference to the I and P frames and inserted between the I and P frames. Since the B frame requires a small code allocation amount, it is possible to obtain a moving image with high motion tracking. B-frames are also one of the biggest features of MPEG data.

By appropriately combining the three frame structures I, P, and B, a GOP (screen group structure:
Group of Pictures) is created. Normally, the number N of frames included in a GOP is set to N = 15, and the period M in which an I frame or a P frame appears is set to M = 3. In the case of random access, the GOP is a unit of random access, and a setting of N = 15 enables random access in units of 0.5 seconds. When the special reproduction is performed, an operation of detecting only an I frame that maintains the integrity as an image is performed. For example, when performing fast forward playback, I
When playing back only frames and performing reverse playback, MPEG
After decoding the data, the I-frame is stored in the memory, and read and reproduced in the reverse direction.

When transmitting image data, ancillary information such as reproduction conditions of the image information must be transmitted, and various information such as audio data is often transmitted separately from the image data. Therefore, signals with different attributes are combined into one by multiplexing and transmitted. Currently, a multiplexing method generally employed is called a packet multiplexing method. In the packet multiplexing method, first, main data such as audio data and image data is divided into small units of packets called PES (Packetized Elementary Stream). At this time, a header is added to the PES packet, and various information such as a stream ID for identifying the type of data is incorporated in the header.
The PES-encoded data is multiplexed by a packet multiplexing method called a TS (Transport Stream) packet adopted in the MPEG2 system standard. That is, the MPEG data is a transport stream having a configuration in which TS packets are continuous without gaps.

[0007] The structure of a conventional TS packet is shown. FIG. 4 is a schematic diagram of TS packets forming a transport stream. One TS packet has a fixed-length packet size of 188 bytes, and a packet header contains 4 bytes.
Byte size is allocated. 184 bytes excluding the packet header of the TS packet are composed of an adaptation field and / or a payload (data portion). When the adaptation field and the payload coexist, the adaptation field always exists in front of the payload. That is, the TS packet has three types of structures: header + payload, header + adaptation field, and header + adaptation field + payload. Since the payload is composed of PES packets of main data such as audio and images, a PES header of the divided main data exists at the beginning of the payload.

Further, a detailed structure of a conventional TS packet will be described. FIG. 5 is an explanatory diagram showing a detailed structure of a header and an adaptation field of a TS packet. TS
The packet header is an 8-bit synchronization byte indicating the head of the TS packet by hexadecimal “47”, T
1-bit error indication indicating the presence or absence of a bit error in the S packet, 1-bit payload unit start indication indicating that a new PES packet starts from the payload of the transport packet, 1-bit indication indicating the importance of the TS packet 13-bit PID indicating transport packet priority, attribute of individual stream of TS packet
(Packet Identification), 2-bit transport scramble control indicating the presence or absence of payload scrambling, 2-bit adaptation field control indicating the presence / absence of an adaptation field and payload, 4-bit indicating detection of a packet having the same PID. It consists of a cyclic counter.

The adaptation field obtained by expanding the header has an adaptation field length of 8 bits (A
F length), 1-bit discontinuous indication to indicate new contents in the subsequent TS packet having the same PID, 1-bit random access indication to indicate start of image or audio frame, importance of payload 1-bit elementary stream priority indication, 5-bit flag, 48-bit PCR for recording timing information for decoding at the time of encoding (Program Clock Reference: Program Clock
Reference) and 48-bit OPCR (Original Program Clock Reference), 8-bit splice countdown indicating the number of TS packets of the same PID, private data of up to 8-bit private data whose usage is undefined, and adaptation field extension , A stuffing byte of 8 × N bits for correcting the data length.

[0010] The adaptation field extension has an adaptation field extension data length of 8 bits and an LTW of 1 bit (timing allowable range: Legal Time Window).
w) Display, 1-bit PW (individual stream: Piecewis)
e) Rate flag, 1-bit seamless splice flag and 5-bit reserve, 1-bit LTW valid flag indicating the allowable movement range of remultiplexing timing,
5-bit LTW offset, 2-bit reserve, 22-bit P indicating transport stream rate
It comprises a W rate, a 4-bit seamless splice type indicating a combination of parameters and control, and a 36-bit next access unit DTS indicating decoding time management information.

The execution condition of the succeeding information linked to the flag is determined by the on / off condition of the flag. For example, if the PCR flag is 1, the data recorded in the subsequent PCR becomes valid. The same applies to other flags. In FIG. 4, the execution path linked by the flag is indicated by an arrow.

The basic flow of the recording and reproduction processing of MPEG data is as follows. In the case of recording MPEG data, first, image data and audio data are classified by type, and each is separately encoded. Further, the encoded data is multiplexed by an MUX (multiplexer) to create MPEG data in a format conforming to a standard such as the transport stream. On the other hand, when reproducing MPEG data, MPEG
The data is separated into image data, audio data, and the like by a DMUX (demultiplexer) and sent to a decoder. The decoder decodes the data and outputs it to an output device such as a video monitor or a speaker.

Japanese Patent Application Laid-Open No. Hei 9-270994 discloses a method in which MPEG data is separated into I-frames and data other than I-frames to form separate transport streams. JP-A-9-116
No. 862 discloses a method of rearranging data at the time of special reproduction by giving an area order ID on a frame basis using a special reproduction data array circuit. In Japanese Patent Application Laid-Open No. Hei 8-205085, a special reproduction stream is created by collecting only special reproduction frames, and information indicating that the packet is a frame boundary packet is recorded in the PID of the PAT or PMT, whereby the special reproduction An apparatus for clarifying a boundary of a playback frame is disclosed.

[0014]

The MPEG2 transport stream standard (ISO / IEC13818-
In 1), an identifier indicating a rough content of data to be transmitted, such as a type of data such as an image and a sound, is inserted. However, the MPEG2 video standard (ISO / IEC138) is used.
The information indicating the detailed contents in 18-2) is not inserted. For this reason, it is difficult to identify the type of frame structure from information transmitted according to the MPEG2 transport stream standard.

[0015] When the recorded data is converted into a structure suitable for special reproduction, the recorded data is transmitted again when the recorded data is transmitted.
An operation must be performed to convert to a format conforming to the EG2 transport stream standard. Such operation requires new hardware, and the hardware configuration becomes large, which does not lead to realization of inexpensive equipment.

According to the present invention, the MPEG-2 transport stream standard
It is an object of the present invention to provide an information recording device and an information reproducing device that can identify the type of a frame structure of a video image.

[0017]

According to the present invention, in view of the above-mentioned conventional problems, private data bytes of an adaptation field which can be freely set according to the TS packet standard have identifiers indicating I, P and B frame structures. Is created. This TS packet is inserted into the conventional MPEG data so that the TS packet having the frame structure indicated by this TS packet in the payload follows. This allows MPEG data to be converted to MP
Even without separating and decoding to the state of the EG2 video standard,
It becomes possible to detect an I frame in the state of a transport stream. Therefore, only the I frame can be decoded at the time of special reproduction, and the efficiency of special reproduction can be increased.

That is, according to the present invention, means for judging each frame structure of image data conforming to the MPEG2 video standard, which constitutes input digital information, and according to the judgment result by the judging means, While inserting an identifier for identifying each of the frame structures at a desired position in the digital information, the MPEG2
There is provided an information recording apparatus having means for creating new digital information conforming to a transport stream standard, and means for recording the new digital information on a recording medium.

According to the present invention, the digital information read from the recording medium includes an MPEG2 transport
An identifier inserted in a format conforming to the stream standard, wherein the MPEG
2 means for reading the identifier indicating the frame structure of image data conforming to the 2 video standard; and when trick play is requested, the means necessary for the trick play are specified according to the identifier read by the read means. Means for extracting only a portion having a frame structure from the digital information and performing the trick play.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method of incorporating an identifier according to the present invention will be described with reference to an explanatory diagram showing a detailed structure of a header and an adaptation field of a TS packet in FIG.

The MPEG2 transport stream standard defines that the private data bytes of the adaptation field can be used freely. Into this private data byte, three types of frame structures of MPEG data, that is, identifiers indicating I frame, P frame, and B frame are incorporated. In front of the TS packet having the image data in the payload, the TS packet in which the identifier indicating the frame structure of the image data is embedded in the private data byte is inserted. Thus, the type of the frame structure of the image data can be identified while the MPEG data is in a transport stream state.

When TS packets recording the same type of frame structure are continuous, a TS packet incorporating an identifier for identifying the frame structure is inserted only at the head of the continuous TS packets. Is also good. Thereby, a plurality of continuous TSs having the same type of frame structure
The frame structure of the packet can be represented by one identifier. Note that, since all of these insert TS packets, they do not violate the MPEG2 transport stream standard and can be output directly to the transmission system.

Next, an embodiment of the information recording apparatus and the information reproducing apparatus of the present invention shown in FIG. 1 will be described. First, a process of inserting an identifier for identifying a frame structure into MPEG data will be described. Conventional MPEG data 10 is input to an MPEG frame structure identifier insertion device 12. M entered
The PEG data 10 is once separated and decoded in the MPEG frame structure identifier insertion device 12 to detect the type of the frame structure. As shown in FIG. 2, according to the detected frame structure, a TS packet in which an identifier for identifying the frame structure is embedded in the private data byte of the adaptation field is inserted into the MPEG data. TS recording the same type of frame structure
When packets are continuous, a TS packet incorporating an identifier for identifying a frame structure is inserted only at the head of the continuous TS packets. The MPEG data with the identifier inserted is recorded on the recording medium 14. Note that the recording medium 14 includes not only a data storage medium such as a CD-ROM and a memory but also a data transmission medium such as a cable, a radio wave, and a network. It can be said that.

In the special reproduction of the MPEG data with the identifier inserted, first, the MPEG data 16 having the TS packet with the identifier inserted is input to the MPEG frame structure identifier detector 18. In this device, the type of frame structure is identified for each TS packet, and only I frames are selected and decoded to perform special reproduction.
Also, since the MPEG data 16 with the identifier inserted therein conforms to the same standard as the conventional MPEG data 10,
Data transmission and normal reproduction can be performed in a conventional manner.

The effects of the above operation are as follows. By inserting an identifier that identifies the frame structure, M
Without decoding to the PEG2 video standard, the type of frame structure can be identified in the state of a transport stream. That is, conventionally, it was impossible to identify the type of the frame structure unless the transport stream was separated by the DMUX and further decoded by the decoder. However, by inserting the identifier for identifying the frame structure, the decoding is performed. Without doing so, the type of frame structure can be identified. As a result, for example, when performing special reproduction such as reverse reproduction or fast-forward reproduction, it becomes possible to select and decode only I frames necessary for special reproduction, thereby improving the efficiency of special reproduction.

In the above embodiment, the MPEG data is input to the MPEG frame structure identifier insertion device.
It is also possible to input digital image data or analog image data different from the G data. In this case, in such a device, at the same time as converting the image data into MPEG data, an identifier for identifying the frame structure is inserted. Further, in the present invention, by using an identifier incorporated in the private data byte and an identification table indicating the correspondence between the data information recorded in the payload, any information of the MPEG2 video standard that does not appear unless it is decoded can be transported. -It is possible to know by the state of the stream.

[0027]

As described above, according to the present invention,
Each frame structure of the MPEG image data is determined, new digital information incorporating an identifier for identifying each frame structure is created and recorded, and when the recorded digital information is specially reproduced, an identifier in the digital information is used. Is read, and only TS packets having a frame structure necessary for special reproduction are selected and decoded, so that special reproduction can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment according to an information recording apparatus and an information reproducing apparatus of the present invention.

FIG. 2 is a schematic diagram showing a state where a TS packet in which an identifier for identifying a frame structure is incorporated in a private data byte of an adaptation field is inserted into MPEG data.

FIG. 3 is a schematic diagram illustrating an image configuration of MPEG data.

FIG. 4 is a schematic diagram showing a configuration of a TS packet of MPEG data.

FIG. 5 is an explanatory diagram schematically showing a detailed structure of a header and an adaptation field of a TS packet.

[Explanation of symbols]

 Reference Signs List 10 MPEG data (digital information) 12 MPEG frame structure identifier insertion device 14 Recording medium 16 MPEG data with identifier inserted 18 MPEG frame structure identifier detection device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) H04N 7/24 F term (reference) 5C053 FA23 FA27 GB04 GB06 GB08 GB11 GB21 GB22 GB38 HA21 HA24 HA25 JA21 JA22 JA24 KA24 LA06 5C059 KK40 LA01 MA00 MA04 MA05 MA23 MC38 ME01 PP05 PP06 PP07 RB01 RB09 RB16 RC01 RC04 RC32 SS17 SS18 SS30 UA05 5D044 AB07 DE03 DE49 DE57 EF05 FG18 FG23 GK08 GK12

Claims (2)

[Claims] 1. An information processing apparatus comprising:
Means for determining each frame structure of the image data conforming to the PEG2 video standard; and inserting an identifier for identifying each frame structure at a desired position in the digital information according to a result of the determination by the determining means. Meanwhile, the digital information
2. An information recording apparatus comprising: means for creating new digital information conforming to the transport stream standard; and means for recording the new digital information on a recording medium. 2. An identifier inserted in digital information read from a recording medium in a format conforming to the MPEG2 transport stream standard,
Means for reading the identifier indicating the frame structure of the image data conforming to the MPEG2 video standard in the digital information; and, when trick play is requested, according to the identifier read by the reading means. Means for extracting only a portion having a frame structure necessary for the trick play from the digital information and performing the trick play.