JP2001128119A - Encoded data recording and reproducing device, encoded data reproducing device, and encoded data recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoded data recording and reproducing device, an encoded data reproducing device and an encoded data recording medium which prevent discontinuity of sounds at a connection point without muting when reproducing programs recorded on the recording medium while partially connecting them. SOLUTION: When video frames V1 and V3 are connected and reproduced, a sound data block B0 is outputted after the end of reproducing and output of a sound frame A1, and thereafter, a sound frame A4 and following frames are reproduced and outputted. The sound data block B0 is generated by cross fading of non-compressed sound frame data obtained by decoding sound frames A1 and A3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoded data recording / reproducing apparatus for recording / reproducing data obtained by encoding moving images and audio, an encoded data reproducing apparatus for reproducing encoded data, and recording encoded data. Coded data recording medium. The present invention provides an encoded data recording / reproducing apparatus, an encoded data reproducing apparatus, and a method suitable for reproducing a program recorded on a medium while partially connecting the program.
And an encoded data recording medium.

[0002]

2. Description of the Related Art With the recent development of information processing technology, digital audiovisual information is being compressed and recorded on an information recording medium. In particular, recordable disk media to which these compression techniques are applied are considered to become mainstream as digital audio / video recording media in the future due to their good random access properties.

[0003] In general, since a moving image has a huge amount of information with respect to sound, an advanced compression technique is used to effectively use a limited amount of information recorded on a medium. A typical example of this method is not only data compression using a correlation in a video frame as a video unit but also compression using a correlation between a plurality of temporally close video frames.
As a result of this data compression, one video frame (first
It is well known that the amount of data per image data unit of a predetermined time unit greatly varies according to the complexity of the intra-frame video and the degree of correlation between video frames. In this way, the state where the amount of code generated during a certain period fluctuates due to data compression is referred to as "compression coding at a variable bit rate"
Alternatively, it is called "VBR (Variable Bit Rate) compression encoding." On the other hand, for voice, because of the relatively small amount of information, compression coding at a fixed bit rate, where the amount of code generated during a certain period is constant, so-called CBR (Constant Bit Rat
The compression encoding in e) is often employed. In general, audio is divided into audio frames corresponding to a certain output period, similarly to a moving image, and compression-encoded in units of audio frames (audio data units of a second predetermined time unit).

A conventional recording / reproducing apparatus for recording / reproducing coded video / audio data on a medium has a configuration shown in FIG. The moving image is compression-encoded by the moving image encoding unit 1, and the audio is similarly compression-encoded by the audio encoding unit 2. The coded data generated independently from these becomes a single coded data string in the multiplexing unit 3 so as to be suitable for recording. In the moving image encoding unit 1, encoding is performed by VBR as described above. However, encoded data strings are continuously arranged on a recording medium without any space in order to use the data capacity efficiently. A write buffer 4 is provided for this purpose, and when the output rate of the multiplexing unit 3 is high or when writing to the recording medium is in a rotation waiting state,
The write buffer 4 is configured to store encoded data. The output of the write buffer 4 is recorded in a continuous arrangement on a recording medium 6 through an information writing section 5 composed of an optical head or the like.

[0005] On the recording medium 6, a small amount and a fixed data amount section called a sector are continuously arranged, and encoded data of moving image / audio is divided into sectors and recorded. Further, writing / reading to / from a recording medium by a recording / reproducing apparatus is generally performed in sector units, and it is not preferable to record different types of data in the same sector from the viewpoint of easy access. Accordingly, the encoded data of the moving image and the audio data are recorded in different sectors as shown in FIG. FIG. 6 shows an example in which encoded data for forming each video frame (each image data unit) is V1 to V4, and encoded data for forming each audio frame (each audio data unit) is A0 to A5. It is shown. In the example shown in FIG. 6, the encoded data of each video frame is 3
The data is recorded over one sector, and the encoded data of each audio frame is recorded in one sector. A video frame V1 as one image unit is constituted by the encoded data of three sectors indicated by V1 in the figure.

When reproducing moving picture / audio encoded data on the recording medium 6, a reverse process corresponding to the recording is performed. That is, as shown in FIG. 5, each encoded data is read out intermittently by an information reading unit 7 composed of an optical head and the like, temporarily stored in a reading buffer 8, and then supplied to a demultiplexing unit 9. Is done. The encoded data of the moving image and the audio are separated by the multiplexing / demultiplexing unit 9 and decoded and output by the moving image decoding unit 10 and the audio decoding unit 11, respectively.

FIG. 7 shows a temporal relationship between a video frame and an audio frame which are output when the sector row on the recording medium shown in FIG. 6 is read and reproduced. That is, it is a state in which the encoded video data V1 to V4 and the encoded audio data A0 to A5 shown in FIG. 6 are output. Temporal period of video frame (video frame period)
Is about 33.4 msec for the NTSC system and 40 msec for the PAL system, and the definition is clear, but the temporal period of the audio frame (audio frame period) is determined by the compression method used, and the audio frame period is video It often does not match the frame period. Therefore, as shown in FIG. 7, it can be understood that the boundary between the video frame and the boundary between the audio frames has an asynchronous relationship.

[0008]

Here, it is assumed that the reproduction of a video frame (hereinafter referred to as a video frame V2) corresponding to the encoded video data V2 is skipped by editing. That is, this is a case where the video frame V1 and the video frame V3 are reproduced as a continuous frame (the video frame V1 and the video frame V3, which are two image data units that are not temporally continuous, are reproduced continuously). If you do). At this time, the encoded data shown in FIG.
The purpose is achieved by skipping reading of the encoded data V2, instead of actually deleting V2.

[0009] However, regarding audio, audio frame A2 (audio encoded data A2) related to video frame V2.
The objective is not achieved only by skipping the reproduction of the audio frame (equivalent to the above) (skipping the reading of the encoded audio data A2). This is because audio is compression-encoded in audio frame units, and the boundaries of audio frames do not match the boundaries of video frames as shown in FIG.

This will be described in more detail with reference to FIG. In the case of normal playback, the audio frame temporally related to the video frame V2 is not only the audio frame A2,
As shown in FIG. 7, audio frames A1 and A3 are also related. Therefore, when the video frame V1 and the video frame V3 are played back continuously, the skipping of the playback of the audio frame A2 alone causes the temporal overlap of the playback of the audio frames A1 and A3 as shown in FIG. Will occur. Therefore, in order not to cause overlap, the reproduction of not only the audio frame A2 but also the audio frame A3 (or the audio frame A1) must be skipped. The reproduction output after performing such editing is as shown in FIG.

After the audio frame A1 shown in FIG.
Since there is a period during which no sound exists for a maximum of one sound frame period, it is necessary to mute the output in the playback device. Further, when the sound pressure level of the recorded sound is high including before and after this period, noise is likely to be output due to a large change in the output level in a simple output mute, and the gain as shown in FIG. I needed to do a precise mute with a curve.

The present invention relates to a case where a program recorded on a recording medium is reproduced while being partially connected (the first image data which is two image data units which are not temporally continuous in the recorded image data). Coded data recording / reproducing apparatus capable of preventing discontinuity of sound at a connection point without performing sound mute processing, in a case where a unit and a second image data unit are reproduced continuously. It is an object of the present invention to provide a playback device and an encoded data recording medium.

[0013]

Therefore, in order to solve the above problems, the present invention provides the following coded data recording / reproducing apparatus:
An encoded data reproducing apparatus and an encoded data recording medium are provided. (1) Image data compressed and encoded for each first predetermined time unit of image data, and audio data related to the image data and compression encoded for each second predetermined time unit of audio data unit An encoded data recording / reproducing apparatus for recording / reproducing the recorded audio data on / from a recording medium, wherein the first image data unit and the second When two image data units are successively reproduced, the first audio data associated with the first image data unit is two audio data units that temporally overlap when reproduced together with the image data. Decoding a unit and a second audio data unit associated with the second image data unit;
Means for performing cross-fade processing on the overlapped portion of the uncompressed audio data obtained by the decoding and recording the block as one block of uncompressed audio data on the recording medium. Recording and playback device. (2) Image data compressed and coded for each first predetermined time unit of image data, and audio data related to the image data and compression coded for each second predetermined time unit of audio data unit 2. An encoded data reproducing apparatus for reproducing encoded audio data from a recording medium, wherein an image recorded on the recording medium on which the one-block uncompressed audio data according to claim 1 is recorded. 2. When the first image data unit and the second image data unit, which are the two image data units according to claim 1, which are not temporally continuous in the data, are continuously reproduced together with the image data. A first audio data unit related to the first image data unit and a second audio data related to the second image data unit, which are two audio data units that overlap each other. The period corresponding to the over data unit, the encoded data reproducing apparatus characterized by comprising output means for outputting the non-compressed audio data of the one block reproduced from the recording medium. (3) Image data compressed and encoded for each first predetermined time unit of image data is recorded, and audio data related to the image data is stored for each second predetermined time unit of audio data unit. In an encoded data recording medium on which compression-encoded audio data is recorded, a first image data unit and a second image data unit, which are two image data units that are not temporally continuous in the image data, are defined as: In the case of continuous reproduction, a first audio data unit related to the first image data unit and a second audio data unit, which are two audio data units that temporally overlap when reproduced together with image data. An encoded data recording medium on which uncompressed audio data corresponding to a second audio data unit related to a data unit is recorded.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The coded data recording / reproducing apparatus of the present invention is capable of connecting image data units which are not adjacent to each other in a program on a recording medium (in terms of time in the image data recorded on the recording medium). A first image data unit (for example, video frame V1), which is two discontinuous image data units, and a second image data unit (for example, video frame V1)
3) and two consecutive audio frames (first audio data unit (audio frame) related to the first image data unit)
A1) and a second audio data unit (audio frame A3) related to the second image data unit) are decoded by the decoding means, and the obtained two uncompressed audio frame data are overlapped. After performing cross-fade processing by the audio data processing means, the audio data is recorded as one block of audio data B0 on a recording medium.

The coded data reproducing apparatus according to the present invention, when connecting and reproducing image data units (program portions which are not adjacently arranged) on a medium (for example, continuously connects the video frame V1 and the video frame V3) Before playing back the connected portion, one block of audio data B0 corresponding to the above-described connected portion is read from the recording medium into the memory, and two audio frame periods (audio frame A1 and A3)
The audio data B0 stored in the memory is output.

In the coded data recording medium of the present invention, when connecting and reproducing program parts which are not arranged adjacently on the recording medium (when reproducing video frame V1 and video frame V3 continuously), the Uncompressed audio data B0 corresponding to two audio frame periods in which a lap occurs (the period between audio frames A1 and A3) is separately recorded.

For example, one period of the compressed voice frame is 32 ms
In the case of ec and the audio overlap is very small, almost 2 audio frames of uncompressed audio data will be recorded.If this data format is used, 48 kHz sampling, 16 bit / sample linear PCM is used. , One block is about 12 kByte and occupies only a small area on the medium.

At the connection point (the connection point between the video frame V1 and the video frame V3), which has conventionally required complicated audio mute processing in reproducing the recording medium, the reproduction device is previously set to be in a period in which the audio is discontinuous. The read audio data block B0 is output instead of the output of the audio decoding unit, so that discontinuity does not occur in the final audio output. Further, in creating the audio data block B0, a cross-fade process is performed to prevent a sudden level change at a connection point.

Next, one embodiment of the encoded data recording / reproducing apparatus is shown in FIG. A major difference from FIG. 5 which is a conventional example is that a memory unit 21, an audio data processing unit 22, and an output switching unit 23 are added. Hereinafter, description will be made focusing on this additional portion.

First, on the premise that the program shown in FIG. 6 is recorded on the recording medium 16, the reproduction of the video frame V2 (the video frame composed of the encoded data V2) is skipped by editing during reproduction. Consider the case. In this case, as shown in FIG. 4, the reproduction of the video frame V2 is skipped and the video frames V1 and V3 are connected and reproduced,
After the reproduction and output of the audio frame A0 (the audio frame composed of the encoded audio data A0) is completed, the audio data block B0 described below is output, and then the editing is instructed to perform the reproduction and output from the audio frame A4. Since the period of the audio frame A2 shown in FIG. 7 is included in the period of the video frame V2, it is not output at all after editing.
A3 is used to create the audio data block B0 for connection.

In FIG. 1, encoded data A1 and A3 corresponding to audio frames A1 and A3 are sequentially decoded from a recording medium 16 via an information reading unit 17, a reading buffer 8, a demultiplexing unit 9, and an audio decoding unit 11. Then, it is stored in the memory unit 21 as uncompressed audio frame data. Memory part 2
The content of the uncompressed audio frame data stored in 1 is
The audio data is processed by the audio data processing unit 22 and recorded on the medium 16 through the information writing unit 15 as an audio data block B0 for connection.

FIG. 2 shows, as an example of the recording medium 16, a case where a connection audio data block is stored in an area having a small sector address. When there are a plurality of connection points, a plurality of connection audio data blocks B0, B1,... Corresponding to each connection point are stored in this area.

The processing contents of the audio data processing unit 22 are shown in FIG.
As shown in (2), a so-called cross-fade process of mixing a part of two uncompressed audio frame data (data obtained by decoding the audio frames A1 and A3) while changing the audio level is performed. The output period of the audio block data B0 for connection created in this way is from A1 to A3.
The cross-fade period of the audio data processing unit 22 is adjusted so that there is a difference between the three audio frame periods and one video frame period of V2.

As described above, after the connection audio data block B0 is newly recorded, continuous audio can be output at the connection point (the connection point between the video frame V1 and the video frame V3). In FIG. 1, prior to reproduction of a program including a connection point, an audio data block B0 for connection is stored in the memory unit 21 from the recording medium 16 through the information reading unit 17. At the same time, the output switching unit 23 is set so that the input from the audio decoding unit 11 is supplied to an external output to which a D / A converter or the like is connected.

Thereafter, reproduction of the program is started. That is, encoded data is sequentially supplied from the medium to the information reading unit 17, the reading buffer 8, the demultiplexing unit 9, the moving image decoding unit 10, and the audio decoding unit 11. When the external output of the audio frame A0 ends, the output switching unit 23 is set so that the input from the memory unit 21 is output to the outside, and the audio data block for connection stored in advance is stored.
B0 is output. After that, the output switching unit 23 is set to output the input from the audio decoding unit 11 again, and outputs the audio data after the audio frame A4 output from the audio decoding unit 11 to the outside. The output state before and after the connection point in the encoded data recording / reproducing apparatus is as shown in FIG.

[0026]

As described above, according to the present invention, when a program recorded on a recording medium is reproduced while partially connected (two image data that are not temporally continuous in the recorded image data) When the first image data unit and the second image data unit, which are units, are played back continuously.
In addition, since uncompressed audio data blocks are used, it is possible to prevent discontinuous audio at the connection point without performing audio mute processing. Further, according to the present invention, when the audio data block is created, a cross-fade process is performed to prevent a sudden level change at the connection point, so that noise is not generated at the connection point and good reproduction is performed. I can do it. Further, an area on a recording medium for recording the audio data block,
Alternatively, the amount of memory for temporarily storing this in the device is small, and the feasibility is very high.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an encoded data recording / reproducing apparatus.

FIG. 2 is a diagram showing a data arrangement of an embodiment of an encoded data recording medium.

FIG. 3 is a diagram illustrating a cross-fade process of an embodiment of an encoded data recording / reproducing apparatus.

FIG. 4 is a diagram showing a reproduction output of an embodiment of an encoded data recording / reproduction device.

FIG. 5 is a diagram showing a conventional encoded data recording / reproducing apparatus.

FIG. 6 is a diagram showing a conventional coded data arrangement.

FIG. 7 is a diagram showing a temporal relationship between a video frame and an audio frame during reproduction.

FIG. 8 is a diagram showing a reproduction output after performing a conventional editing operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 moving image encoding unit 2 audio encoding unit 3 multiplexing unit 4 write buffer 8 read buffer 9 demultiplexing unit 10 moving image decoding unit 11 audio decoding unit 15 information writing unit 16 recording medium 17 information reading unit 21 memory unit 22 audio Data processing unit 23 Output switching unit

Claims (3)

[Claims] An image data compressed and encoded for each first predetermined time unit of image data, and audio data related to the image data and compressed for each second predetermined time unit of audio data unit. An encoded data recording / reproducing apparatus for recording / reproducing encoded audio data on / from a recording medium, comprising: a first image data unit which is two temporally non-continuous image data units in the image data recorded on the recording medium And the second image data unit are successively reproduced, the first audio data unit associated with the first image data unit, which is two audio data units that temporally overlap when reproduced together with the image data. Decoding an audio data unit and a second audio data unit related to the second image data unit, and converting the uncompressed audio data obtained by the decoding to the overlap unit; A coded data recording / reproducing apparatus, further comprising means for performing a cross-fade process on the minutes and recording the blocks as uncompressed audio data of one block on the recording medium. 2. An image data compression-encoded for each first predetermined time unit of image data, and audio data related to the image data and compressed for each second predetermined time unit of audio data unit. 2. An encoded data reproducing apparatus for reproducing encoded audio data from a recording medium, wherein the one block of the uncompressed audio data according to claim 1 is recorded on the recording medium. 2. When the first image data unit and the second image data unit, which are two image data units, which are not temporally continuous in the present image data, are reproduced together with the image data. A first audio data unit associated with the first image data unit and a second audio data unit associated with the second image data unit, which are two audio data units in which temporal overlap occurs. An output means for outputting the one block of uncompressed audio data reproduced from the recording medium during a period corresponding to the audio data unit. 3. An image data compressed and encoded for each first predetermined time unit of image data, and audio data related to the image data and a second predetermined time unit of audio data. A first image data unit and a second image data unit, which are two image data units that are not temporally continuous in the image data, on an encoded data recording medium on which compression-encoded audio data is recorded. Are continuously reproduced, the first audio data unit and the second audio data unit related to the first image data unit are two audio data units that temporally overlap when reproduced together with the image data. A non-compressed audio data corresponding to a second audio data unit related to the image data unit is recorded.