JP2004289871A - Method for reproducing mpeg data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reproduction method for realizing seamless reproduction with high quality without causing contradiction of overflow and underflow at the connection of the VBV buffer in the case of joining the first MPEG image data to the second MPEG image data and reproducing the resulting image data. <P>SOLUTION: Data of a joining interval A of the first MPEG image data and data of a joining interval B of the second MPEG image data are decoded and then re-encoded. The re-encoding is executed while being controlled so that transition of a VBV buffer occupied value is started from a VBV buffer occupied value at a position m and finished up to a VBV buffer occupied value at a position q. Then the first MPEG image data are reproduced until the position m of the first MPEG image data, and then re-encoded MPEG image data at the joining interval A+B are reproduced, and thereafter connection is made to the VBV buffer at its address position q of the second MPEG image data and the second MPEG image data after the position q are reproduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  According to the present invention, the first and second MPEG image data, which are the image data encoded by the MPEG encoding method, are converted into the first MPEG image at a specified joint designated position in the respective MPEG image data. The present invention relates to an MPEG data reproducing method for achieving seamless reproduction when data is connected to the second MPEG image data and reproduced.

MPEG, which is a conventional technique used in this patent, will be briefly described.
MPEG is described in detail in ISO-IEC11172-2 and ITU-T H.262 / ISO-IEC13818-2, so only an outline will be given here. MPEG was established in 1988 in ISO / IEC JTC1 / SC2 (International Organization for Standardization / International Electrotechnical Commission / Technical Committee 1 / Specialized Subcommittee 2, current SC29). Moving Pictures Expert Group). MPEG1 (MPEG Phase 1) is a standard for storage media of about 1.5 Mbps, and is intended for JPEG for still image coding and for moving image compression for low transfer rates of ISDN video conferences and videophones. It inherits the basic technology of H.261 (CCITT SGXV, standardized by the current ITU-T SG15) and introduces new technology for storage media. These were established in August 1993 as ISO / IEC 11172.

  MPEG1 is created by combining several technologies. FIG. 5 shows a conventional MPEG encoder that performs encoding according to the MPEG encoding method, and will be briefly described below. The difference between the input image and the image decoded by the motion compensation predictor 1 and the input image is calculated by a differentiator 2 to reduce a time redundant part.

  The prediction direction has three modes from the past, the future, and both. These can be switched and used for each 16 pixel × 16 pixel MB (Macroblock). The prediction direction is determined by the Picture Type given to the input image. A unidirectional inter-picture predictive coded image (P-picture) has two modes, a mode in which coding is performed by prediction from the past and a mode in which the MB is independently coded without performing prediction. In addition, there are four modes: bi-directional inter-picture prediction code, a mode of encoding by prediction from the future, a mode of encoding by prediction from the past, a mode of encoding by prediction from both, and a mode of independently encoding. This is a coded image (B-picture). It is an intra-picture independently coded picture (I-picture) that all MBs are independently coded.

  In motion compensation, a motion vector is detected by half-pel accuracy by performing pattern matching for each MB for each motion area, and is predicted after shifting by the amount of motion. The motion vector has a horizontal direction and a vertical direction, and is transmitted as additional information of the MB together with an MC (Motion Compensation) mode indicating where to predict the motion vector.

In general, a GOP (Group Of Picture) is called a GOP from an I picture to a picture before the next I picture, and when used in storage media, about 15 pictures are generally used as one GOP section. Is done. (However, one or more I pictures may be included in one GOP section. In short, one or more I pictures may be included in one GOP section.)
The difference image is subjected to orthogonal transformation in the DCT unit 3. DCT (Discrete Cosine Transform) is an orthogonal transform that discretely transforms an integral transform using a cosine function as an integral kernel into a finite space. In MPEG, MB is divided into four and two-dimensional DCT is performed on an 8 × 8 DCT block. In general, since a video signal has many low-frequency components and few high-frequency components, when DCT is performed, coefficients concentrate on low frequencies.

  The quantized image data (DCT coefficients) are quantized by the quantizer 4. The quantization is performed by quantizing the DCT coefficients by using the value obtained by multiplying the 8x8 two-dimensional frequency, called the quantization matrix, by the visual characteristics and the value obtained by multiplying the whole by a scalar multiplication scale as the quantization value. Calculate by value. When inverse quantization is performed by the MPEG decoder (decoder), a value close to the original DCT coefficient is obtained by multiplying by the quantization value.

  The quantized data is variable-length coded by the VLC unit 5. The direct current (DC) component of the quantized value uses DPCM (differential pulse code modulation) which is one of predictive coding. In addition, Huffman coding that performs a zigzag scan of the alternating current (AC) component from the low band to the high band, assigns a zero run length and an effective coefficient value to one event, and assigns a code with a short code length from the one with a high probability of occurrence. Is performed.

  The variable-length coded data is stored in a temporary buffer 6 and output as coded data at a predetermined transfer rate. The generated code amount of the output data for each macro block is transmitted to the code amount controller 21, and the error code amount between the generated code amount and the target code amount is fed back to the quantizer 4 to quantize the data. The code amount is controlled by adjusting.

  The quantized image data is inversely quantized by an inverse quantizer 7, inverse DCT by an inverse DCT unit 8, temporarily stored in an image memory 10 via an adder 9, and then stored in a motion compensation predictor 1. Is used as a reference decoded image for calculating a difference image.

FIG. 6 shows an MPEG decoder (decoder) that decodes the encoded data that has been MPEG-encoded as described above.
Incoming encoded data (stream) is buffered in a buffer 11, and data from the buffer 11 is input to a VLD unit 12. The VLD unit 12 performs variable length decoding to obtain a direct current (DC) component and an alternating current (AC) component. The alternating current (AC) component data is arranged in an 8 × 8 matrix in the order of zigzag scan from the low band to the high band. This data is input to the inverse quantizer 13 and is inversely quantized by the quantization matrix. The inversely quantized data is input to the inverse DCT unit 14, subjected to inverse DCT, and output as image data (decoded data). The decoded data is temporarily stored in the image memory 16 and then used by the motion compensation predictor 17 as a reference decoded image for calculating a difference image.

  In the case of video, the encoded bit stream has a variable length code amount for each picture. This is because MPEG uses information transforms such as DCT, quantization and Huffman coding.At the same time, it is necessary to adaptively change the amount of code allocated to each picture in order to improve image quality. This is because the entropy of the encoded image itself greatly changes, for example, in some cases, the input image is encoded as it is, and in some cases, the difference image, which is the difference between the predicted images, is encoded.

  In this case, in many cases, the code amount is controlled while allocating to the entropy ratio of the image and keeping the buffer limit. The buffer manager monitors the relationship between the generated code amount and the coding rate, and sets a target code amount so as to be within a predetermined buffer. This value is fed back to the variable-length encoder and enters the code amount controller, where the quantized value set in the quantizer is increased to suppress the generated code amount, or the quantized value is reduced to reduce the generated code amount. Or make it smaller.

  When such variable-length data is encoded at a fixed transfer rate (encoding rate), if the maximum buffer amount of the decoder is set as an upper limit, data is input at a constant speed and only a predetermined value is accumulated. From MPEG, it is prescribed by MPEG to use a model that performs instantaneous decoding at a predetermined time (NTSC video signal in units of 1 / 29.97 sec), and that the buffer does not overflow or underflow. ing. If this rule (VBV buffer rule) is adhered to, the rate in the VBV buffer changes locally, but if the observation time is long, the transfer rate will be fixed. In MPEG, this is a fixed rate. Has defined.

  In the case of the fixed transfer rate, if the generated code amount is small, the buffer occupancy is stuck at the upper limit. In this case, the code amount must be increased by adding an invalid bit so as not to overflow.

  In the case of the variable transfer rate, the definition of the fixed transfer rate is extended so that when the buffer occupancy reaches the upper limit, the reading of the decoder is stopped so that the overflow does not occur in principle. ing. FIG. 7 shows such a buffer transition. Even if the generated code amount is very small, the reading of the decoder is stopped, so there is no need to insert an invalid bit as in the case of the fixed transfer rate. Therefore, encoding is performed so that only underflow does not occur.

The MPEG system stipulates a method of multiplexing a bit stream encoded by MPEG video and audio into one bit stream and reproducing the bit stream while maintaining synchronization. The contents specified by the system are roughly divided into the following five points.
1) Synchronous playback of multiple encoded bit streams 2) Multiplexing of multiple encoded bit streams into a single bit stream 3) Initialization of buffer at the start of playback 4) Continuous buffer management 5) Determining the time for decryption and playback
In order to perform multiplexing in the MPEG system, it is necessary to packetize information. Multiplexing by packets means, for example, when multiplexing video and audio, each is divided into streams of appropriate length called packets, and additional information such as a header is added, and video and audio packets are switched as appropriate. And time-division transmission. The header includes information for identifying video, audio, and the like, and time information for synchronization. The packet length depends on the transmission medium and application, and ranges from 53 bytes as in ATM to as long as 4 Kbytes as in optical disks. In MPEG, the packet length is variable and can be arbitrarily specified.

  Data is packed and packetized, and one pack is composed of several packets. A pack start code and an SCR (System Clock Referance) are described at the head of each P pack, and a stream id and a time stamp are described at the head of the packet. The time stamp describes time information for synchronizing audio, video and the like, and there are two types of DTS (Decoding Time Stamp) and PTS (Presentation Time Stamp). PCR (Program Clock Reference) is described with a time accuracy of 27 MHz, and is information for locking the reference clock of the decoder. DTS indicates the decoding start time of the first access unit (1 picture for video, 1152 samples for audio, for example) in the packet data, and PTS indicates the display (reproduction) start time. As shown in FIG. 11, audio, video, and other decoders always monitor a common reference clock locked by PCR, and perform decoding and display when the time coincides with the DTS or PTS time. . The multiplexed data is buffered in each decoder, and a virtual decoder for performing synchronized display is called an STD (System Target Decoder), which is multiplexed so that this STD does not cause overflow or underflow. Must be.

  The MPEG system is roughly divided into TS (Transport Stream) and PS (Program Stream). These are composed of packets containing PES (Packetized Elementary Stream) and other necessary information. The PES is defined as an intermediate stream for enabling conversion between the two streams, and is a packetized video stream and audio data encoded by MPEG, as well as a private stream.

  The PS can multiplex video and audio of programs having a common reference time. The packet layer is called a PES, and as shown in FIG. 12, this structure is used in common with a TS described later, and enables mutual compatibility between them. In the PS STD model, the stream is switched by the stream id in the PES packet.

  TS can multiplex video and audio of programs with a common reference time like PS, but TS can also multiplex multi-programs such as communication and broadcasting with different reference times. And The TS is composed of a fixed-length packet of 188 bytes in consideration of the ATM cell length and the case of error correction coding, and is considered so that it can be used even in a system having an error. Although the structure of the TS packet itself is not so complex, its operation is complicated because it is a multi-program stream. The characteristic feature is that TS packets are (usually) shorter than PES packets, although they have a higher-level structure, and PES packets are divided and transmitted on TS packets. In the STD model of TS, the stream is switched by the PID (packet ID) in the TS packet.

  The TS of the MPEG system has a mechanism for instructing which PID is a packet relating to information of the multiplexed program. This will be described with reference to FIG. First, a TS packet group having a PID = 0 is searched. It is an information packet called a PAT (Program Association Table), in which an information PID corresponding to a PROGRAM number PR is described in a linked form. Next, when you read the packet of the PID corresponding to the target PR, there is an information packet called PMT (Program Map Table), which contains the PID of the video packet of the program corresponding to the PR and the audio packet. PID information is described.

The PAT and PMT are called PSI (Program Specific Information), and have an information system that allows access (entry) to a channel of a target program.
Also, according to the invention of JP-A-11-74799, when editing compressed data such as MPEG data recorded on a recording medium, the VBV buffer is always fixed at the editing point in order to maintain the continuity of the MPEG data. It describes a method of performing encoding in consideration of continuity, such as controlling the amount of generated codes so as to achieve the above or encoding a GOP as a closed GOP.

  Further, according to the invention of Japanese Patent Application Laid-Open No. 11-187354, the encoded data is not restricted at all, and information indicating the data extracted as the editing material among the partial sections of the data and the reproduction order thereof are given. A method is described in which information can be described and video editing can be realized on a single recording medium without changing recorded data.

However, in the above-described conventional method, if MPEG image data is simply connected, inconsistency occurs in the connection of the VBV buffer, and overflow or underflow occurs.
In the invention of Japanese Patent Laid-Open No. 11-74799, the amount of generated code is controlled so that the VBV buffer is always fixed for each GOP so that the GOP can be edited anywhere, and the GOP is encoded as a closed GOP. Coding restrictions in consideration of continuity are imposed, which is a disadvantageous factor in terms of coding efficiency.

  In the invention of JP-A-11-187354, reproduction and display are performed as if edited, but the continuity at the editing point is incomplete, and temporary stoppage such as initialization of the MPEG data decoder buffer is performed. A phenomenon could occur.

  The present invention relates to a packet-multiplexed first MPEG multiplexed data including first and second two MPEG image data (or a first MPEG multiplexed data including the first MPEG image data as elementary encoded data), and a second MPEG Packet-multiplexed second MPEG multiplexed data including image data as elementary encoded data) at each of the specified connection designated positions from the first MPEG image data to the second MPEG image data. When connecting and playing back (when connecting and playing back from the first MPEG multiplexed data to the second MPEG multiplexed data) the connection of the VBV buffer without overflow or underflow contradiction, An object of the present invention is to provide an MPEG data reproducing method capable of realizing seamless and high-quality reproduction.

Therefore, in order to solve the above problems, the present invention provides the following reproducing method.
(1) The first and second two MPEG image data, which are image data encoded by the MPEG encoding method, are converted into the first MPEG image data at the designated joint designated positions in the respective MPEG image data. An MPEG data reproducing method comprising a splicing reproducing step of performing splicing and reproducing from the second MPEG image data.
The connection reproduction step includes:
Obtaining the first MPEG image data from the first MPEG multiplexed data generated by performing packet multiplexing according to the MPEG method by including the first MPEG image data as elementary encoded data, and obtaining the second MPEG image data Is obtained as the second MPEG image data from the second MPEG multiplexed data generated by performing packet multiplexing according to the MPEG method by including as a component coded data, and a connection section recoding which is data for connection and reproduction. To obtain the connection section re-encoded data from the connection section MPEG multiplexed data generated by packet multiplexing in the MPEG method, including encoded data as elemental encoded data,
After reproducing the first MPEG image data up to the start position of the first connection section set in the first MPEG image data, the connection section re-encoded data is converted from the start position of the first connection section. The second MPEG image data is reproduced up to the end position of the second connection section set in the second MPEG image data, and then the second MPEG image data is reproduced from the end position of the second connection section in the second MPEG image data. Is a splicing playback step of playing back
The connection section re-encoded data has a start position that is a first predetermined time before the connection specification position in the first MPEG image data, and ends the connection specification position in the first MPEG image data. A section to be a position is set as the first connection section, the connection specified position in the second MPEG image data is set as a start position, and a second predetermined time from the connection specified position in the second MPEG image data is set. The section in which the position after the minute is the end position is the second connection section, and the section combining the first connection section and the second connection section is the third connection section, and the first connection First connected section decoded image data which is image data obtained by decoding the first MPEG image data of the section, and image obtained by decoding the second MPEG image data of the second connected section The second is the data A third connecting section decoded image data to be more and formic section decoded image data, a re-encoded data obtained by re-encoding by the MPEG encoding method,
The connection section re-encoded data is obtained by encoding the first MPEG image data at a position corresponding to a start position of the first connection section, wherein a transition of an information value relating to a VBV buffer occupancy value at the time of the re-encoding is performed. Starting from the information value regarding the VBV buffer occupancy value at the time and ending with the information value regarding the VBV buffer occupancy value at the time of encoding the second MPEG image data at a position corresponding to the end position of the second connection section. Code amount control is performed so that
A method for reproducing MPEG data, comprising:

  As described above, according to the present invention, packet-multiplexed first MPEG multiplexed data including the first and second two MPEG image data (or the first MPEG image data as elementary encoded data) And packet-multiplexed second MPEG multiplexed data including the second MPEG image data as elementary encoded data) at each of the specified joint specified positions from the first MPEG image data. When connecting and reproducing the second MPEG image data (when connecting and reproducing the first MPEG multiplexed data to the second MPEG multiplexed data), the connection of the VBV buffer may cause overflow or underflow. Seamless and high-quality reproduction can be realized without inconsistency.

  First, the concept of the connection reproduction that can be realized by the present invention will be described. As shown in FIG. 8, when there is the second MPEG image data like the one MPEG image data which is the image data encoded by the MPEG encoding method, the first MPEG image data is in the middle (specified). It is assumed that the second MPEG image data is connected to and reproduced from the connection specified position). Assuming that the connection point (the joint designation position in the first MPEG image data) is the position b, the reproduction is performed up to the position b of the first MPEG image data, and then the data is connected to the second MPEG image data. However, if MPEG image data is simply connected, inconsistency will occur in the connection of the VBV buffer, causing a problem of overflow or underflow.

  Therefore, first, when the first MPEG image data and the second MPEG image data are encoded by the MPEG encoding method, the information of the VBV buffer is divided into a predetermined section unit (the first predetermined MPEG image data has the first predetermined value). The side information is generated in units of sections (second predetermined section units in the second MPEG image data) and described in the recording medium.

Note that it is also possible to realize the connection reproduction without describing the information of the VBV buffer in the side information. In this case, two methods are conceivable, which will be described later.
The information of the VBV buffer relating to the first MPEG image data is related to the VBV buffer occupation value at the time of starting or ending the MPEG encoding of the last picture of the first MPEG image data for each first predetermined section. First VBV buffer occupancy value-related information indicating an information value, and first address information indicating at which position in the first MPEG image data the VBV buffer occupancy value is an information value relating to the VBV buffer occupancy value And

  The information of the VBV buffer relating to the second MPEG image data is related to the VBV buffer occupancy value at the start or end point of the MPEG encoding of the last picture of the second MPEG image data for each second predetermined section. Second VBV buffer occupancy value-related information indicating an information value and a second address indicating at which position of the second MPEG image data the VBV buffer occupancy value is an information value relating to the VBV buffer occupancy value With information.

The information value relating to the VBV buffer occupancy value is, for example, a VBV buffer occupancy value or a VBV delay value specified by MPEG.
One unit of the first and second predetermined sections may be, for example, about three frames or about one GOP as described later. It is assumed that the predetermined section unit is between a and b in FIG. 8 in the first MPEG image data and between cd in FIG. 8 in the second MPEG image data.

  The information list of the VBV buffer includes a position a (a boundary of the first predetermined section before a first predetermined time from the connection designation position in the first MPEG image data; that is, a start of a section A described later). The information of the VBV buffer at the position (position) and the information of the VBV buffer at the position b (the connection designation position in the first MPEG image data: that is, the end position of the section A described later) are described. In addition, the information of the VBV buffer at the position of c of the second MPEG image data (the boundary position of the second predetermined section before the second specified time from the specified connection position in the second MPEG image data) and There is also information on the VBV buffer at the position of the connection point d (the specified connection position in the second MPEG image data: the boundary position of the second predetermined section in this example).

  Therefore, data in the ab section (first connection section: here, section A) of the first MPEG image data is once decoded to obtain decoded image data, and the decoded image data (first connection section) is obtained. (Decoded image data) is re-encoded by the MPEG encoding method. The re-encoded data created thereby is referred to as re-encoded MPEG image data in section A (first re-encoded data in the connection section). In this re-encoding, the transition of the information value related to the VBV buffer occupancy value starts from the information value related to the VBV buffer occupancy value obtained based on the detected first VBV buffer occupancy value related information at the position a. , D, re-encoding by the MPEG encoding method by performing a rate control so that the processing ends with the information value on the VBV buffer occupancy value obtained based on the detected second VBV buffer occupancy value-related information. Do.

  The operation of performing the conventional connection reproduction operation, that is, reproduction to the position b of the first MPEG image data, and then connecting to the position d of the second MPEG image data to reproduce the data, is performed in a section A. The following operation is performed using the re-encoded MPEG image data. That is, the first MPEG image data is reproduced up to the position a (start position of the section A) of the first MPEG image data, and then the re-encoded MPEG image data of the section A is replaced with the start position of the section. To the end position, and then connect to the position d (joining designated position) of the second MPEG image data to reproduce the data of the second MPEG image data after d. This is realized by providing a link playback unit for performing this operation on the playback device side.

  By performing the connection reproduction operation, it is possible to realize seamless connection reproduction that has the same content contents as the original first and second MPEG image data and does not cause a breakdown of the VBV buffer.

In the case where re-encoded MPEG image data of a connection section is obtained based on only the first MPEG image data shown in FIG. 8, the position of the connection point d (the connection designation position in the second MPEG image data) ) Of the VBV buffer. As described above, since the information of the VBV buffer is information at the start or end of MPEG encoding of the last picture of a predetermined section of the MPEG image data, the information at the boundary position of the predetermined section It becomes. Therefore, the position of the connection point (connection specification position) needs to be specified as a boundary of the second predetermined section at least in the second MPEG image data. (That is, the position of the connection point d in the second MPEG image data needs to be specified as the boundary of the second predetermined section.)
Further, when re-encoding MPEG image data of a connection section is obtained based on only the first MPEG image data side, as described above, the VBV at the position a (the start position of the connection section A) shown in FIG. Buffer information is also needed. However, the position a is specified as the boundary of the first predetermined section before the first predetermined time from the connection point (connection specified position) b in the first MPEG image data. Regardless, at the position a, the information of the VBV buffer is obtained. Therefore, the position of the connection point b in the first MPEG image data does not necessarily need to be specified as the boundary of the first predetermined section.

  Next, application examples are shown in FIGS. 9 (2) and 9 (3). FIG. 1A is similar to the example shown in FIG. In the example shown in FIG. 8, the connection reproduction is realized by obtaining the re-encoded MPEG image data of the connection section based on only the first MPEG image data side. However, the connection is performed based on only the second MPEG image data side. It is also possible to obtain the re-encoded MPEG image data of the section and realize the link reproduction. An example thereof is shown in FIG. 9 (2), in which re-encoded MPEG image data of the connection section B in the second MPEG image data is used.

  In FIG. 9B, the connection point (connection specified position) in the first MPEG image data is set to the position i, and the connection point (connection specified position) in the second MPEG image data is set to the position k. One unit of the first and second predetermined sections, which are units having the information of the VBV buffer described above, is between i and j in the first MPEG image data and between k and l in the second MPEG image data. The position 1 is the boundary position of the second predetermined section after the second predetermined time from the connection point (connection specified position) k in the second MPEG image data. A section in which the connection point k is the start position and the position 1 is the end position is a connection section B (second connection section).

  The data of the section B (k-1 section) connecting the second MPEG image data is once decoded to obtain decoded image data, and the decoded image data (the second connected section decoded image data) is MPEG-coded. Re-encoding is performed by the encoding method. The re-encoded data created thereby is referred to as re-encoded MPEG image data of the connection section B (second re-encoded data of the connection section). In this re-encoding, the transition of the information value relating to the VBV buffer occupancy value is started from the information value relating to the VBV buffer occupancy value obtained based on the first VBV buffer occupancy value-related information at the position i. The rate control is performed so that the processing ends with the information value on the VBV buffer occupancy value obtained based on the second VBV buffer occupancy value related information at the position, and re-encoding is performed by the MPEG encoding method.

  Then, using the re-encoded MPEG image data in the connection section B, the connection reproduction from the first MPEG image data to the second MPEG image data is performed. That is, the first MPEG image data is reproduced up to the connection point i (connection designated position) of the first MPEG image data, and then the re-encoded MPEG image data of the section B is changed from the start position of the section to the end. To the position, and then connect to the position 1 (end position of the connection section B) of the second MPEG image data to reproduce the data of the second MPEG image data after the position l. . This is realized by providing a link playback unit for performing this operation on the playback device side.

  By performing the connection reproduction operation, it is possible to realize seamless connection reproduction that has the same content contents as the original first and second MPEG image data and does not cause a breakdown of the VBV buffer.

In the case where re-encoded MPEG image data of a connected section is obtained based on only the second MPEG image data shown in FIG. 9B, the position of the connection point i (the first MPEG image data The information of the VBV buffer at the connection designation position) is required. As described above, since the information of the VBV buffer is information at the start or end of MPEG encoding of the last picture of a predetermined section of the MPEG image data, the information at the boundary position of the predetermined section It becomes. Therefore, the position of the connection point (connection specification position) needs to be specified as a boundary of the first predetermined section at least in the first MPEG image data. (That is, the position of the connection point i in the first MPEG image data needs to be specified as the boundary of the first predetermined section.)
In addition, when re-encoding MPEG image data of a connection section is obtained based on only the second MPEG image data side, as described above, the position 1 (the end of the connection section B) shown in FIG. The position) VBV buffer information is also required. However, since the position of 1 is specified as the boundary of the second predetermined section after the second predetermined time from the connection point (connection specified position) k in the second MPEG image data, the position of 1 is set at the position of the connection point k. Regardless, at the position 1, information of the VBV buffer is obtained. Therefore, the position of the connection point k in the second MPEG image data does not necessarily need to be specified as the boundary of the second predetermined section.

Next, an application example shown in FIG. 9C will be described. In this example, the connection reproduction is realized by obtaining the re-encoded MPEG image data of the connection section based on the first and second MPEG image data before and after the connection point. (The type shown in FIG. 9 (3) is an embodiment of the present invention.)
In FIG. 9C, the connection point (connection specified position) in the first MPEG image data is set to the position n, and the connection point (connection specified position) in the second MPEG image data is set to the position p. One unit of the first and second predetermined sections, which is a unit having the information of the VBV buffer described above, is defined as m-n in the first MPEG image data and p-q in the second MPEG image data. I do.

  The position of m is the boundary position of the first predetermined section before the first predetermined time from the connection point (connection specified position) n in the first MPEG image data. A section in which the position of m is the start position and the position of the connection point n is the end position is referred to as a connection section A (first connection section). The position of q is the boundary position of the second predetermined section after the second predetermined time from the connection point (connection specified position) p in the second MPEG image data. A section in which the connection point p is the start position and the position of q is the end position is defined as a connection section B (second connection section).

  The data of the connection section A (mn section) of the first MPEG image data is once decoded to obtain decoded image data (connection section A decoded image data: first connection section decoded image data). Further, the data of the connection section B (pq section) connecting the second MPEG image data is once decoded, and the decoded image data (connection section B decoded image data: second connection section decoded image data) is obtained. obtain.

  The joint section A + B decoded image data (third joint section decoded image data) obtained by combining the joint section A decoded image data and the joint section B decoded image data is re-encoded by the MPEG encoding method. The re-encoded data created thereby is referred to as re-encoded MPEG image data of the connection section A + B (third connection-section re-encoded data). In this re-encoding, the transition of the information value relating to the VBV buffer occupancy value is started from the information value relating to the VBV buffer occupancy value obtained based on the first VBV buffer occupancy value-related information at the position of m. The rate control is performed so that the processing ends with the information value on the VBV buffer occupancy value obtained based on the second VBV buffer occupancy value related information at the position, and re-encoding is performed by the MPEG encoding method.

  Then, by using the re-encoded MPEG image data in the connection section A + B, the connection reproduction from the first MPEG image data to the second MPEG image data is performed. That is, the first MPEG image data is reproduced up to the start position m of the connection section A of the first MPEG image data, and then the re-encoded MPEG image data of the connection section A + B is ended from the start position of the section. Playback is performed up to the position, and thereafter, an operation is performed to connect to the end position q of the connection section B of the second MPEG image data and play back the data of the second MPEG image data after the position q. This is realized by providing a link playback unit for performing this operation on the playback device side.

  By performing the connection reproduction operation, it is possible to realize seamless connection reproduction that has the same content contents as the original first and second MPEG image data and does not cause a breakdown of the VBV buffer.

  In the example shown in FIG. 9C, information on the VBV buffer at the position m (the start position of the connection section A) is required as described above. Since the position of m is specified as a boundary of the first predetermined section before the first predetermined time from the connection point (connection specified position) n in the first MPEG image data, regardless of the position of the connection point n At the position of m, information of the VBV buffer is obtained. Therefore, the position of the connection point n in the first MPEG image data does not necessarily need to be specified as the boundary of the first predetermined section.

  Further, as described above, the information of the VBV buffer at the position of q (the end position of the connection section B) shown in FIG. 9C is also required. Since the position of q is specified as the boundary of the second predetermined section after the second predetermined time from the connection point (connection specified position) p in the second MPEG image data, regardless of the position of the connection point p At the position of q, information of the VBV buffer is obtained. Therefore, the position of the connection point p in the second MPEG image data does not necessarily need to be specified as the boundary of the second predetermined section.

As described above, any of the methods shown in FIGS. 9 (1) to 9 (3) can realize seamless and high-quality connected playback. As these advanced systems, as shown in FIG. It is also possible to realize a connection reproduction in which the MPEG image data, the second MPEG image data, and the third and fourth MPEG image data are branched in the middle as shown in the figure. As described above, according to the present invention, it is possible to freely connect to other MPEG data simply by generating and using the re-encoded MPEG image data of the connection section without processing the original MPEG image data itself. Therefore, even when encoding programs that compose various branch stories, the media can be used efficiently without recording redundant MPEG image data over the entire story for each branch story. (If the present invention is used, one set of each of the first to fourth MPEG image data and re-encoded MPEG image data of the connection section for each branch story may be prepared.)
Further, if the method shown in FIG. 9 (3) is used, as described above, the position of the connection point in the first MPEG image data does not necessarily need to be specified as the boundary of the first predetermined section. Since the position of the connection point in the MPEG image data need not always be specified as the boundary of the second predetermined section, the information of the VBV buffer is finer than the predetermined section unit described as side information in the predetermined section unit. It can be applied to the case of editing in accuracy, for example, in units of one frame. This example will be described with reference to FIG. The predetermined unit may be about three frames or about one GOP, but here is one GOP.

  It is assumed that there are two MPEG streams to be connected as shown in FIG. At the points of g and h indicated by arrows in the first MPEG stream, information of the VBV buffer at the position of g and information of the VBV buffer at the position of h are described in the VBV buffer information list. . The second MPEG image data also has information on the VBV buffer at the position i and information on the VBV buffer at the position j.

  When connecting from the position of p of the first MEPG stream 1 to the beginning of the second MPEG stream, the data of the section A from g to p of the first MPEG stream is decoded. The data in the section B from i to j is decoded, and both images are re-encoded so that the buffer transition starts from the buffer occupancy value at the position g and becomes the buffer occupancy value at the position j.

  Assuming that the data generated thereby is referred to as re-encoded MPEG image data in the section A + B, reproduction is performed up to the position p of the first MPEG image data, which is a conventional reproduction operation, and then the second MPEG image is reproduced. The operation of connecting to the data and reproducing the data is performed by reproducing the first MPEG image data to the position of g, then reproducing the re-encoded MPEG image data of the section A + B, and then reproducing the second MPEG image data. By performing the operation of connecting to the MPEG image data j and reproducing the data, it is possible to perform seamless connection reproduction with the same content contents and without causing a breakdown of the VBV buffer.

Next, two methods for realizing the joint reproduction similar to the above-described respective examples without describing the information of the VBV buffer as the side information will be described. (A method of calculating an information value related to the VBV buffer occupation value, which is necessary when generating the re-encoded data of the connection section, will be described.)
First, the first method will be described. In the MPEG standard, basically, in the case of a constant bit rate (CBR), that is, in the case of a fixed transfer rate, a VBV delay value indicating a buffer occupancy of a VBV buffer is defined in a picture layer of MPEG video. In this case, since the VBV delay value is described in picture units, the MPEG image bit stream is observed only with the picture header alone, so that the MPEG encoding start time of the picture corresponding to the predetermined position of the MPEG image data (or VBV buffer occupancy value at the end point) can be detected. In this case, for example, the function of the VBV buffer information detector 33 in FIG. 4 described below is to search for a picture header (a 4-byte code of 0x00000100 in MPEG) of a bit stream, and then search for a 10-bit temporal reference 10-bit This can be realized by detecting 16 bits of VBV delay following 3 bits of picture coding type. What is VBV delay value
VBV delay = 90000 x B / R
B: Buffer occupancy value R: Since it is defined by the bit rate, in the case of a fixed rate, the VBV buffer occupancy value can be calculated from the VBV delay value using this bit rate. (For example, the calculation is performed by the VBV buffer information detector 33 shown in FIG. 4.)
In MPEG, it is necessary to pay attention to the VBV delay value at the vertex position of the graph as shown in FIG.

  Next, the second method will be described. This is the case with a variable transfer rate instead of a fixed transfer rate. According to the MPEG standard, in the case of VBR (variable bit rate), the VBV delay values indicating the buffer occupancy of the VBV buffer in the picture layer of the MPEG video are all 1 (0xffff because all 16 bits are 1). It becomes. Therefore, the first method cannot be used.

  Therefore, the following calculation is performed from information obtained by observing the MPEG image bit stream. First, it is assumed that the VBV buffer is occupied from the beginning of the bit stream up to the maximum value defined by MPEG (for example, 1.75 Mbit in the main profile main level). Next, the code amount of the first picture is subtracted. Next, using the transmission rate information of the peak rate in variable transfer rate coding, the transmission amount when the time between display pictures has elapsed is added, and the code amount of the next picture is subtracted. By repeating such a series of processes of addition and subtraction up to the position of the bit stream desired to be obtained, the picture corresponding to the predetermined position of the MPEG image data can be obtained by simulating the graph shown in FIG. The VBV buffer occupancy value at the start (or end) of the MPEG encoding can be determined. The peak rate at the time of the variable transfer rate is defined in the syntax part called bit rate of the sequence header in MPEG, and can be obtained by referring to it.

For example, this is realized by giving the above-described MPEG image bit stream to the VBV buffer information detector 33 shown in FIG. (In the case of the second method, it is necessary to observe and calculate the amount of generated codes of each picture from the beginning of the MPEG image bit stream. However, as in the first method, the information of the VBV buffer is stored in advance as side information. There is no need to prepare.)
Next, a brief description will be given of generation of the re-encoded data of the connection section when the first and second methods are used. Note that the splicing reproduction operation using the spliced section re-encoded data is the same as the case of using spliced section re-encoded data generated based on information of a VBV buffer recorded in advance as side information. Description is omitted.

  In the case where re-encoded MPEG image data of a connection section is obtained based on only the first MPEG image data side shown in FIG. 9A, the connection point (connection specification position) b in the first MPEG image data is used. A section having a position a that is a predetermined time earlier by 1 as a start position and a designated connection position b in the first MPEG image data as an end position is defined as a first connection section (connection section A). There is no need to limit the boundary of the first predetermined section as in the case where side information is used to specify the start position a of the connection section A. Similarly, the specification of the connection point (connection specification position) d in the second MPEG image data does not require the restriction such as the boundary of the second predetermined section as when side information is used.

The data in the ab section (connection section A) of the first MPEG image data is once decoded to obtain decoded image data, and the decoded image data (the first connection section decoded image data) is reproduced by the MPEG encoding method. Encoding is performed to obtain re-encoded MPEG image data of the connection section A (first connection section re-encoded data). In this re-encoding, the transition of the VBV buffer occupancy value is calculated by the first or second method, and the MPEG encoding of the picture corresponding to the position a (the MPEG code at the time of generating the first MPEG image data) is performed. ) Starts from the VBV buffer occupation value at the start time (or end time). Then, the transition of the VBV buffer occupancy value is calculated by the above-described first or second method, and starts at the time of MPEG encoding of the picture corresponding to the position of d (MPEG encoding at the time of generating the second MPEG image data). Rate control is performed so as to end the processing up to the VBV buffer occupation value at the (or end time), and re-encoding is performed by the MPEG encoding method. The obtained re-encoded MPEG image data of the connection section A (first connection section re-encoded data) is recorded on a recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
Next, a case where re-encoded MPEG image data of a connected section is obtained based on only the second MPEG image data shown in FIG. 9B will be described. In FIG. 9B, the connection point (connection specified position) in the first MPEG image data is set to the position i, and the connection point (connection specified position) in the second MPEG image data is set to the position k. A section of the second MPEG image data, in which a connection point k is set as a start position, and a position 1 which is a position after a second predetermined time from the connection point (connection specified position) k is set as an end position, a connection section B ( (Second connecting section). There is no need to limit the boundary of the second predetermined section, such as when side information is used to specify the end position 1 of the connection section B. Similarly, the specification of the connection point (connection specified position) i in the first MPEG image data does not require the restriction such as the boundary of the first predetermined section as when side information is used.

The data in the connection section B (k-1 section) of the second MPEG image data is once decoded to obtain decoded image data, and the decoded image data (second connection section decoded image data) is MPEG-encoded. In this way, re-encoding is performed by the method, and re-encoded MPEG image data of the connection section B (second re-encoding data of the connection section) is obtained. In this re-encoding, the transition of the VBV buffer occupancy value is calculated based on the VBV buffer occupancy at the MPEG encoding start (or end) time of the picture corresponding to the position i calculated by the first or second method. Start with value. Then, the transition of the VBV buffer occupancy value ends with the VBV buffer occupancy value at the MPEG encoding start (or end) time of the picture corresponding to the position 1 calculated by the first or second method. In such a way, re-encoding is performed by the MPEG encoding method by performing the rate control. The obtained re-encoded MPEG image data of the connection section B (second re-encoding data of the connection section) is recorded on a recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
Next, a case will be described in which the re-encoded MPEG image data of the connected section is obtained based on the first and second MPEG image data before and after the connection point shown in FIG. 9 (3).

In FIG. 9C, the connection point (connection specified position) in the first MPEG image data is set to the position n, and the connection point (connection specified position) in the second MPEG image data is set to the position p.
The position of the first MPEG image data before the connection point (connection specified position) n by the first predetermined time is defined as m. A section of the first MPEG image data having the position of m as the start position and the position of the connection point n as the end position is referred to as a connection section A (first connection section). The position after a second predetermined time from the connection point (connection specified position) p in the second MPEG image data is q. A section of the second MPEG image data having the connection point p as a start position and the position of q as an end position is referred to as a connection section B (second connection section).

  There is no need to limit the boundary of the first predetermined section as in the case where side information is used to specify the start position m of the connection section A. Similarly, there is no need to limit the boundary of the second predetermined section such as when side information is used to specify the end position q of the connection section B.

  The data of the connection section A (mn section) of the first MPEG image data is once decoded to obtain decoded image data (connection section A decoded image data: first connection section decoded image data). Further, the data of the connection section B (pq section) of the second MPEG image data is once decoded to obtain decoded image data (connection section B decoded image data: second connection section decoded image data). .

Then, re-encoding is performed on the connected section A + B decoded image data (third connected section decoded image data) obtained by combining the connected section A decoded image data and the connected section B decoded image data by the MPEG encoding method. The re-encoded data thus created is defined as re-encoded MPEG image data of the connection section A + B (third connection-section re-encoded data). In this re-encoding, the transition of the VBV buffer occupancy value is calculated by the first or second method, and the VBV buffer occupancy at the MPEG encoding start time (or end time) of the picture corresponding to the position m is calculated. Start with value. Then, the transition of the VBV buffer occupancy value ends with the VBV buffer occupancy value at the MPEG encoding start time (or end time) of the picture corresponding to the position q calculated by the first or second method. In such a manner, the data is re-encoded by the MPEG encoding method by performing the rate control. The obtained re-encoded MPEG image data of the connection section A + B (third connection section re-encoded data) is recorded on a recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
In the example shown in FIG. 10, it is of course possible to obtain the VBV buffer occupancy value at a required position by the above-described calculation method, and to obtain desired joint section re-encoded data).

  Next, according to an embodiment of the recording / reproducing apparatus to which the present invention is applied, the VBV buffer information to be recorded on the recording medium (at the time of starting or ending the MPEG encoding of the last picture of the section in each predetermined section of the MPEG image data). Buffer occupancy value-related information indicating an information value regarding the VBV buffer occupancy value, and address information indicating at which position in the MPEG image data the information value regarding the VBV buffer occupancy value is an information value regarding the VBV buffer occupancy value. , And the recording structure for MPEG image data will be described in detail. The recording medium records MPEG image data, which is image data compressed by the MPEG encoding method. The MPEG image data is recorded as a bit stream in which a plurality of continuously reproducible data encoded and generated in one recording unit are continuously connected.

  Apart from these encoded MPEG image data bit streams, the VBV buffer value (occupation value) at the end of picture encoding one frame before the I picture in the MPEG image data bit stream and the P picture 1 The VBV buffer value (occupation value) at the end of the picture encoding before the frame and address information indicating at which position in the MPEG image data each VBV buffer value is the VBV buffer occupation value (in this example, the MPEG image The relative address from the beginning of the data file) is recorded. FIG. 1 shows the data structure of VBV buffer information including these data.

  VBV buffer information has a hierarchical structure. First there is an entry point information structure, followed by a VBV information structure. In the entry point information structure, the number of entry point (EP) addresses is first described in 32 bits, and the EPn (n is a natural number of 1 or more) address is described in 32 bits in order. The EPn address indicates a position where EPn information (n is a natural number of 1 or more) of the VBV information structure is described, and describes a relative address from the head of the VBV buffer information. On the other hand, the VBV information structure is described in order from the EP1 information, and the content of the EP1 information describes a relative address, a PTM value, and a VBV value in order.

  The relative address in the EPn information of the VBV information structure is, as shown in FIG. 2, the end point of the picture encoding one frame before the I picture and the end point of the picture encoding one frame before the P picture in the bit stream of the MPEG image data. The relative address from the beginning of the MPEG image data at the time and at the end of recording, for example, the unit is a byte. When recorded on a disk medium, a sector or the like is used as a relative address.

  The PTM value in the EPn information of the VBV information structure is a time stamp recorded with a clock of 90 kHz or 27 MHz in the MPEG system standard (multiplexing standard). In the MPEG standard, it is called PTS (Presentation Time Stamp) or DTS (Decoding Time Stamp). Here, the DTS is recorded as time information at the end of picture encoding one frame before the I picture in the bit stream of the MPEG image data, at the end of picture encoding one frame before the P picture, and at the end of recording. . One DTS is recorded in one picture, and in the case of an NTSC video signal, it is recorded at 90 KHz clocks at an interval of 3003 clocks per picture. Therefore, when an I picture or a P picture is present for every three pictures as in the present invention and the beginning starts from 0, the PTM information is provided at intervals of 9009, 18018. Will be described.

  The VBV value in the EPn information of the VBV information structure is a virtual buffer occupancy value of a decoder specified by MPEG. It can be derived by calculation from the generated code amount for each picture of MPEG image data and the value of the transfer rate. As shown in FIG. 3, the picture code of the I-picture and the P-picture one frame before the P-picture of the compressed bit stream information Describe the VBV occupation value at the position of circle in the figure at the end of the conversion. Alternatively, a VBV delay value specified in MPEG is described. This value is a value converted into a time that indicates how long it takes at the transfer rate at that time up to the VBV occupation value. In the present invention, any information may be used as long as the information is related to the VBV buffer occupancy value. FIG. 17 shows the relationship between the VBV buffer occupancy value and the VBV delay value. The occupancy value OCC of the VBV buffer has a relationship of VBV delay = 90000 * OCC / R, where R is the coding rate, and 90000 is a value indicated by a count number of 90 kHz.

  In MPEG compression, encoding is basically performed using an I or P picture type in units of three frames, such as IBB and PBB. In MPEG compression, a B picture may be predicted from both directions, so in the order of the coded bit stream, data is added only at the end of picture coding one frame before the I picture and P picture of the bit stream. Is not easy. Therefore, the present invention has been described on the assumption that VBV information is described at the end of picture coding one frame before the I picture and P picture of the bit stream.

  However, the information value regarding the VBV occupation value may essentially have each picture. Also, instead of the picture coding end point, the picture coding start point may be used. FIG. 16A is a conceptual diagram in the case where the value of the encoding end point is included in the list. In this case, since there is no information value relating to the first VBV occupation value, the virtual value is assumed before the first frame. , The information value regarding the VBV occupation value at the end of the encoding of the virtual frame is calculated as an initial value. The calculation is performed by adding the first picture code amount to the information value relating to the first VBV occupation value, and from the added value, from the slope according to the coding rate, how much code is required in (1 / picture rate) time. When the value calculated for the transmission amount is subtracted, the initial value of the black circle in FIG. 16A is obtained. FIG. 16 (2) is a conceptual diagram in the case where the value of the encoding start point is included in the list. In this case, since there is no information value regarding the last VBV occupation value, the virtual value is placed behind the last frame. Assuming that there is a specific frame, the information value relating to the VBV occupation value at the start of encoding of the virtual frame is calculated as the final value. The calculation is performed by subtracting the last picture code amount from the information value related to the last VBV occupation value, and from the subtracted value, from the slope according to the coding rate, how much code transmission amount in (1 / picture rate) time. When the calculated values are added, the final value of the black circle in FIG. 16B is obtained.

Next, the configuration of an embodiment of a recording / reproducing apparatus to which the present invention is applied is shown in FIG. 4, and an operation for creating VBV buffer information while encoding image data by the MPEG encoding method will be described.
When there is no encoded data on the recording medium 31, that is, when encoding is performed for the first time, the data reading unit 32 from the recording medium 31 does not have any data. Transmit to the detector 33. Since no data exists in the VBV buffer information detector 33, the initial value set in advance in the parameter setting unit 34, that is, the VBV value is, for example, a value of 80% of the maximum value of VBV specified by MPEG, and the PTM Time stamp information is set to 0. These initial setting values are transmitted to the image encoder 35.

  In the image encoder 35, encoding is started from an initial set value. In the image encoder 35, while performing the encoding, the generated code amount, the PTM value, and the VBV value at the end of the picture encoding one frame before the I picture of the bit stream and one frame before the P picture are calculated every time. This is transmitted to the VBV buffer information generator 36. At the same time, the encoded data is transmitted to the data writing unit 37. Further, the image encoder 35 transmits the generated code amount, the PTM value, and the VBV value when the user temporarily stops or ends the image compression recording to the VBV buffer information generator 36.

  The VBV buffer information generator 36 generates VBV buffer information data having the structure shown in FIG. 1 from the input generated code amount value, PTM value, and VBV value. Alternatively, data necessary for creating the data structure is stored in a memory and stored in a predetermined format. The information created by the VBV buffer information creating unit 36 may be written in a burst at the same time that the encoded data (MPEG image data) is written to the recording medium 31 by the data writing unit 37. The information created by the VBV buffer information creating unit 36 is recorded and held in a predetermined format when the encoded data (MPEG image data) has been written, that is, after the user has temporarily stopped or ended the image compression recording. The written data may be converted into the structure of FIG. 1 and written by the data writing unit 37.

  Next, when re-encoding the first and second two pieces of MPEG image data recorded on the recording medium 31 in the section A to enable the joint reproduction from a predetermined position Will be described with reference to FIG.

First, a user interface (not shown) is used to specify from which point of the first and second two pieces of MPEG image data that have already been recorded, the point from which to connect and reproduce.
The recording medium 31 has already recorded the first and second two MPEG image data (compression-encoded stream) and the VBV buffer information generated by the recording / reproducing apparatus shown in FIG. Therefore, the data reading unit 32 shown in FIG. 4 reads the VBV buffer information and obtains the VBV value, the PTM value, and the relative position of the position a in FIG. Get the address.

  When the connection playback position is specified from the user interface, for example, when the specification method is the position information of the relative address of the data, the value of the value closest to the relative address information in the EPn information of the structure of the VBV buffer information is used. Use the VBV and PTM values linked to the data. Also, if the designation method is the time from the start time of the data or the time stamp information of the point to be connected and reproduced, similarly, using the PTM value in the EPn information of the structure of the VBV buffer information, When this value is recorded with a clock of 90 KHz, the time can be obtained by multiplying the value by 1 / 90,000 second, and the connection reproduction position (relative address), VBV value, PTM Value can be obtained.

  These values are input to the parameter setting unit 34, and the image encoding unit 35 starts encoding from the set values. On the other hand, the coded data search unit 38 searches for the head position of the section A to be re-encoded with respect to the already recorded bit stream. The search uses a relative address of data to set a pointer to a position from the beginning of the bit stream file.

  In the image encoder 35, the first MPEG image data corresponding to the section A is decoded, and the transition of the VBV buffer occupancy value is started again from the VBV value at the position a using the decoded image, and The rate control is performed so that the processing ends up to the VBV value at the position, and re-encoding is performed by the MPEG encoding method. For the re-encoding, a completely decoded image may be used as described above, but a technique for controlling the amount of code on a bit stream as disclosed in Japanese Patent Application Laid-Open No. H11-234677 may be used.

  If the section A to be re-encoded is longer than the minimum unit of the VBV buffer information, the re-encoding is performed at the end of the picture encoding of the I-picture and the P-picture of the bit stream one frame before. The code amount, the PTM value, and the VBV value are transmitted to the VBV buffer information generator 36 every time. At the same time, the re-encoded data is transmitted to the data writing unit 37.

  The VBV buffer information creator 36 creates data having the structure shown in FIG. 1 from the input generated code amount value, PTM value, and VBV value. Alternatively, data necessary for creating the data structure is stored in a memory and stored in a predetermined format. The information in the VBV buffer information generator 36 may be written in a burst at the same time as the encoded data is written, or when the encoded data has been written, When the recording is temporarily stopped or completed, the data recorded and held in a predetermined format may be converted into the structure shown in FIG. 1 and written.

  The re-encoded image data of section A (joint section A re-encoded data) is recorded as a separate file separated from the first and second MPEG image data. Alternatively, it is connected to the head of the recording second MPEG image data and recorded.

  The first MPEG image data, the second MPEG image data, the information on the VBV buffer occupancy value and its data address information, the re-encoded image data of the section A (or the re-encoded image data of the section B, Alternatively, the re-encoded image data of the section A + B) may be recorded on the same recording medium, may be recorded on a plurality of recording media in an arbitrary combination, or may be recorded on different recording media. I don't care. When the recording is performed by being divided into a plurality of recording media, the recording media indicate the same information group so that the recording media are linked to each other (each data and information are linked). Information, for example, an ID is preferably recorded on each recording medium. The first MPEG image data, the second MPEG image data, and the re-encoded image data of the section A (or the re-encoded image data of the section B or the re-encoded image data of the section A + B) When recorded on the same recording medium, a single recording medium can control the connected reproduction on the reproducing apparatus side.

  In addition, when the information on the VBV buffer occupancy value for obtaining the re-encoded image data is not read out from the side information recorded on the medium but is calculated, the information on the VBV buffer occupancy value and the It is not necessary to record the data address information.

  In the above embodiment, the recording medium has been described as a recording medium in the recording / reproducing apparatus. However, a recording medium detachable from the recording / reproducing apparatus or a recording medium (database) via a network may be used.

  Also, in the above embodiment, an example in which image data is connected by focusing on a single MPEG image data has been described.However, in an MPEG transport stream which is MPEG multiplexed data packet-multiplexed with the MPEG method together with audio data and the like. It may be applied when connecting MPEG image data.

  In many cases, the transport stream is multiplexed with variable-length-encoded MPEG image data and fixed-length-encoded MPEG1 layer 2 audio or AC3. Therefore, when connecting MPEG image data, which is one of the element coded data in the multiplexed data, a connection method in consideration of the consistency of the STD buffer (VBV buffer for video) specified by MPEG at the connection point The method of the embodiment described above may be applied.

  For example, first and second MPEG image data to be connected are extracted from the first and second MPEG transport streams, respectively, and connected in the same manner as in the above-described embodiment. The connection section re-encoded data (the re-encoded image data of the section A, the re-encoded image data of the section B, and the re-encoded image data of the section A + B) used for the connection reproduction are packet-multiplexed by the MPEG method. May be generated and recorded as MPEG multiplexed data.

  FIG. 14A shows the state of packet-multiplexed data of the MPEG transport stream. Packets described as V are video packets, packets described as A are audio packets, and packets described as S are information packets such as PAT and PMT used in the system. Each is recorded in a form that complies with the rules of the MPEG2 system. The video packets have a light gray color. FIG. 2B shows the state of the whole of these. The state where only the video packets are collected is shown in FIG. A typical example of the contents of this video packet is that an I picture starts at the beginning, then two B pictures and one P picture follow, as shown in FIG. is there.

  The code amount of one or more of these pictures is adjusted by re-encoding. For example, FIG. 5 (5) shows a state in which the code amount is reduced. The code amount of each picture is small. FIG. 6 (6) shows a packetized state in this state. The reduced area is black. This packet reduces the overall amount of video. Then rebuild the TS. FIG. 7 (7) shows this state as a whole. FIG. 8 is an enlarged view of FIG. 7. As a result, a part of the V packet is reduced, and the other element data packets are multiplexed as they are.

  According to the rules of the MPEG system, PCR clock information must be recorded once every 100 msec. Further, since the data length has been changed, the PCR clock information described in each element packet is changed as necessary. In a video packet, a PTS or DTS is described in a packet in which a PES header at the head of an access unit (frame or field picture unit) exists. In an audio packet, a PTS is described in a packet in which one or a plurality of audio frames are packed with a PES and a leading PES header is present. These time stamp information does not need to be changed if the number of pictures is not increased or decreased in the image, and the audio does not need to be changed unless the playback time length is increased or decreased. Add and correct appropriate PTS and DTS.

  Furthermore, in the case of simple re-encoding, the GOP unit from the I picture which is the reset timing of the predictive encoding is easy to handle, but when the GOPs are not independent, that is, when the B picture at the boundary is In the case where prediction is performed over (closed gop = 0 of the GOP), the last reference picture of the immediately preceding GOP is decoded and stored in an image recoding memory (not shown) or the like. May need to be placed.

  First MPEG multiplexed data (first MPEG transport stream), second MPEG image data (second MPEG transport stream), information on VBV buffer occupancy value, its data address information, A re-encoded image data of A (or the re-encoded image data of the section B, or the re-encoded image data of the section A + B) is included as elementary encoded data, and a connection section generated by packet multiplexing according to the MPEG method. The MPEG multiplexed data may be recorded on the same recording medium, may be recorded on a plurality of recording media in an arbitrary combination, or may be recorded on different recording media. When the recording is performed by being divided into a plurality of recording media, the recording media indicate the same information group so that the recording media are linked to each other (each data and information are linked). Information, for example, an ID is preferably recorded on each recording medium. The first MPEG multiplexed image data, the second MPEG multiplexed image data, the re-encoded image data of the section A (or the re-encoded image data of the section B, or the re-encoded image of the section A + B) In the case where the MPEG-multiplexed data and the connection section of the data are recorded on the same recording medium, a single recording medium can control the connection reproduction on the reproduction apparatus side.

FIG. 3 is a diagram showing a VBV buffer information structure based on one embodiment of a recording / reproducing device to which the present invention is applied. FIG. 3 is a diagram illustrating a relationship between MPEG image data and relative addresses according to one embodiment. FIG. 4 is an explanatory diagram illustrating a VBV value in one embodiment. FIG. 1 is a block diagram illustrating an embodiment of a recording / reproducing apparatus to which the present invention has been applied. FIG. 11 is a diagram illustrating an example of a conventional MPEG encoder. FIG. 15 is a diagram illustrating an example of a conventional MPEG decoder. FIG. 3 is a diagram for explaining the concept of a VBV buffer in MPEG. FIG. 4 is a diagram for explaining a concept of connection reproduction that can be realized by the present invention. FIG. 4 is a diagram for explaining a concept of connection reproduction that can be realized by the present invention. FIG. 4 is a diagram for explaining a concept of connection reproduction that can be realized by the present invention. FIG. 11 is an explanatory diagram showing a conventional MPEG multiplexing system. FIG. 4 is an explanatory diagram showing the relationship between MPEGTS and PS and PES. [Fig. 4] Fig. 4 is an explanatory diagram showing a usage example of MPEGTS PSI. FIG. 4 is an explanatory diagram showing an MPEGTS packet arrangement. FIG. 4 is a diagram for explaining a concept of connection reproduction that can be realized by the present invention. FIG. 9 is a diagram for explaining information values relating to VBV buffer occupancy values in one embodiment. FIG. 4 is a diagram illustrating a relationship between a VBV buffer occupation value and a VBV delay value.

Explanation of reference numerals

REFERENCE SIGNS LIST 31 recording medium 32 data reading unit 33 VBV buffer information detector 34 parameter setting unit 35 image encoder 36 VBV buffer information creator 37 data writing unit 38 encoded data search unit

Claims (1)

The first and second two MPEG image data, which are image data encoded by the MPEG encoding method, are converted from the first MPEG image data to the second MPEG image data at the designated joint designated positions in the respective MPEG image data. An MPEG data reproducing method comprising a splicing reproduction step of connecting to and reproducing the MPEG image data of No. 2
The connection reproduction step includes:
Obtaining the first MPEG image data from the first MPEG multiplexed data generated by performing packet multiplexing according to the MPEG method by including the first MPEG image data as elementary encoded data, and obtaining the second MPEG image data Is obtained as the second MPEG image data from the second MPEG multiplexed data generated by performing packet multiplexing according to the MPEG method by including as a component coded data, and a connection section recoding which is data for connection and reproduction. To obtain the connection section re-encoded data from the connection section MPEG multiplexed data generated by packet multiplexing in the MPEG method, including encoded data as elemental encoded data,
After reproducing the first MPEG image data up to the start position of the first connection section set in the first MPEG image data, the connection section re-encoded data is converted from the start position of the first connection section. The second MPEG image data is reproduced up to the end position of the second connection section set in the second MPEG image data, and then the second MPEG image data is reproduced from the end position of the second connection section in the second MPEG image data. Is a splicing playback step of playing back
The connection section re-encoded data has a start position that is a first predetermined time before the connection specification position in the first MPEG image data, and ends the connection specification position in the first MPEG image data. A section to be a position is set as the first connection section, the connection specified position in the second MPEG image data is set as a start position, and a second predetermined time from the connection specified position in the second MPEG image data is set. A section in which the position after the minute is the end position is the second connection section, and a section obtained by combining the first connection section and the second connection section is a third connection section, and the first connection section is used. First connected section decoded image data which is image data obtained by decoding the first MPEG image data of the section, and image obtained by decoding the second MPEG image data of the second connected section The second is the data A third connecting section decoded image data to be more and formic section decoded image data, a re-encoded data obtained by re-encoding by the MPEG encoding method,
The connection section re-encoded data is obtained by encoding the first MPEG image data at a position corresponding to a start position of the first connection section, wherein a transition of an information value relating to a VBV buffer occupancy value at the time of the re-encoding is performed. Starting from the information value regarding the VBV buffer occupancy value at the time and ending with the information value regarding the VBV buffer occupancy value at the time of encoding the second MPEG image data at the position corresponding to the end position of the second connection section. Code amount control is performed so that
A method for reproducing MPEG data, comprising:

Images