JP2001211420A - Edit method and edit device for compression coded stream in recording disk medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an edit method and an edit device that can joint streams at a desired location while suppressing deterioration in image quality. SOLUTION: The edit device is provided with a 1st decoder 15 that decodes a stream read from a 1st location of a recording disk medium, a 2nd decoder 16 that decodes the stream read from a 2nd location of the recording disk medium, and a changeover switch 17 that selects an output of the 1st decoder 15 or an output of the 2nd decoder 16 at an edit point. In the case that outputs from the two decoders 15, 16 are given through the changeover switch 17 without interruption, the output of the changeover switch 17 is used for the edit and in the case that the output is interrupted, after decoding the stream and encoded again for the edit. Limiting a re-encoded length can suppress deterioration in the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a DVD (Digital)
The present invention relates to an editing method and an editing apparatus for editing a compression-encoded stream recorded on a disk recording medium such as a Video Disc, and more particularly to an editing method and an editing apparatus capable of minimizing deterioration of image quality.

[0002]

2. Description of the Related Art When video data and audio data are recorded on a disk recording medium such as a DVD, compression encoding is performed to reduce the amount of data. In the MPEG (Moving Picture Experts Group) system, which is a typical compression coding system for video data and audio data, when a moving image is compression-coded, DCT (Discrete) is used.
The amount of data is reduced using Cosine Transform) or predictive coding.

FIG. 13 shows predictive coding in MPEG. In MPEG, the input frame may be an I-picture containing only intra (intra-frame) macroblocks, a P-picture containing intra and forward interframe predictive coding macroblocks, or intra, forward, interframe predictive coding and It is encoded as a B picture including a macroblock of backward interframe prediction encoding.

FIG. 14 is a diagram showing the rearrangement of pictures in MPEG bidirectional prediction. As shown in FIG. 13, since the B picture is subjected to backward prediction encoding, the order of the pictures of the original image is rearranged in the encoding process and recorded on the recording medium. Then, the image is read from the recording medium, restored to the order of the original image after decoding, and becomes a reproduced image.

FIG. 15 shows a process from the time when audio data is multiplexed to the video data encoded as shown in FIG. 13 until a compressed encoded stream conforming to the format of the recording medium is generated. I have.

[0006] The input moving image is rearranged in an order different from the frame order at the time of input, and is encoded into I, P, and B pictures, and the video ES (elementary stream).
Is generated. The audio data is, for example, 24
ms, compression encoding is performed, and the E
S is generated. These ESs are divided into appropriate sizes, and a packet is formed with a header. This header includes a PTS (Pres
entation Time Stamp). These packets are multiplexed as a pack with a header attached to complete a compressed encoded stream.

[0007] This compression-encoded stream is recorded on a disk recording medium such as a DVD. And during playback,
The compression-encoded stream is read from the disk recording medium, each packet data is decoded, and the PTS is decoded.
It is played back at the time specified in.

[0008]

SUMMARY OF THE INVENTION When a compressed encoded stream of desired content is created from a plurality of compressed encoded streams recorded on a disk recording medium, the recorded compressed encoded stream is read and reconnected. Is edited.

Conventionally, when a compressed coded stream # 3 is generated by connecting another compressed coded stream # 2 in the middle of one compressed coded stream # 1, the compressed coded stream # 1 is switched , And re-encodes it to create the first half of the compressed coded stream # 3. Then, decodes the portion after the switching of the compressed coded stream # 2 and decodes the second half of the compressed coded stream # 3. The compressed encoded stream # 3 is edited by re-encoding.

In this editing method, there is a problem that the image quality of the edited image is deteriorated by the re-encoding.

The present invention has been made to solve such a conventional problem, and minimizes deterioration of image quality when editing a compression-encoded stream recorded on a disk recording medium. It is an object of the present invention to provide an editing method and an editing device that can perform the editing.

It is another object of the present invention to provide an editing method and an editing apparatus that eliminate the deterioration of image quality and reduce the number of audio encoders to reduce the cost.

Further, the present invention provides an editing method and an editing apparatus capable of eliminating deterioration in image quality and performing post-recording without causing a time lag to an audio stream of an edited compression-encoded stream. The purpose is to do.

[0014]

An editing method according to the present invention comprises a first decoder for decoding a compression-encoded stream read from a first location on a disk recording medium, and a second location on the recording medium. A second decoder for decoding the compression-encoded stream read from the first decoder, and switching means for switching and outputting the output of the first decoder and the output of the second decoder at an editing point, 1
When the output of the second decoder and the output of the second decoder are continuously output from the switching means,
When editing is performed using the output of the switching means, and the output between the first decoder and the output of the second decoder is interrupted, the compression code read from the first location is output. After decoding the encoded stream and the compressed encoded stream read from the second location, the encoded stream is encoded again and edited.
With this configuration, when editing can be performed by switching the outputs of the two decoders, editing is performed without re-encoding, thereby minimizing deterioration in image quality.

[0015] The editing apparatus of the present invention further comprises a first decoder for decoding a compression-encoded stream read from a first location on the disk recording medium, and a second decoder read from a second location on the recording medium. A second decoder for decoding the compressed and coded stream, switching means for switching and outputting the output of the first decoder or the output of the second decoder at an editing point, and an output of the first decoder. Determining means for determining whether or not the output of the second decoder is continuously output from the switching means. With this configuration, it is possible to determine whether or not editing is possible by switching the outputs of the two decoders, and if possible, perform editing without re-encoding, thereby minimizing deterioration in image quality.

Further, according to the editing method of the present invention, there is provided a first video decoder for decoding a compression-encoded video stream read from a first location on a disk recording medium, and a video decoder for reading from a second location on the recording medium. A second video decoder for decoding the output compression-encoded video stream, first switching means for switching and outputting between the output of the first video decoder and the output of the second video decoder, and the recording A second switching means for switching and outputting a compressed and encoded audio stream read from a first location of the medium and a compressed and encoded audio stream read from a second location of the recording medium; And an audio decoder that decodes the output of the second switching means. Performs editing of the video data is switched, and performs editing of the audio data is switched at the timing of the second audio frame of the editing point or near the output of the switching means. With this configuration, one audio decoder can be switched to decode two audio streams, so that the number of audio decoders can be reduced and cost can be reduced.

The editing apparatus of the present invention includes a first video decoder for decoding a compression-encoded video stream read from a first location on a disk recording medium, and a video decoder for reading from a second location on the recording medium. A second video decoder for decoding the output compression-encoded video stream, first switching means for switching and outputting between the output of the first video decoder and the output of the second video decoder, and the recording A second switching means for switching and outputting a compressed and encoded audio stream read from a first location of the medium and a compressed and encoded audio stream read from a second location of the recording medium; An audio decoder for decoding the output of the second switching means and the output of the first switching means at an editing point; Obtaining with, characterized in that a control means for switching at a timing of the second audio frame of the editing point or near the output of the switching means. With this configuration, one audio decoder can be switched to decode two audio streams, so that the number of audio decoders can be reduced and cost can be reduced.

[0018] The editing method of the present invention is a method for dubbing an audio stream of an edited compressed coded stream by switching at least one compressed coded stream recorded on a disk recording medium at an editing point. The dubbing audio signal of the first location is encoded in synchronization with an audio frame recorded in a first location of the recording medium, and the audio signal is encoded in synchronization with an audio frame recorded in a second location of the recording medium. An audio signal for dubbing at a second location is encoded, and the same audio signal is duplicatedly recorded on the first location and the second location for a predetermined period before and after the editing point. I do. With this configuration, after-recording can be performed continuously from the first scene to the second scene without causing a time lag with respect to the original audio frame.

The editing apparatus of the present invention is a device for dubbing an audio stream of a compressed encoded stream edited by switching one or more compressed encoded streams recorded on a disk recording medium at an editing point.
A first audio encoder that encodes an after-recording audio signal at the first location in synchronization with an audio frame recorded at a first location on the recording medium; and a second audio encoder recorded at a second location on the recording medium. A second audio encoder that encodes the audio signal for dubbing at the second location in synchronization with an audio frame; and a predetermined period before and after the edit point is relative to the first location and the second location. Control means for duplicating recording of the same audio signal. With this configuration, after-recording can be performed continuously from the first scene to the second scene without causing a time lag with respect to the original audio frame.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) In the first embodiment, a DVD recorder is provided with two decoders,
When editing a compression-encoded stream (hereinafter abbreviated as a stream) recorded in the RAM, the output of the two decoders is switched as much as possible, and editing is performed. Perform encoding.

FIG. 1 is a block diagram showing the configuration of the editing apparatus according to the first embodiment of the present invention. This editing device is constituted by a DVD recorder 1 having an editing function.

This DVD recorder 1 has a DVD-RAM
Drive 2, playback system 3, recording system 4, control block 5, interface 6, operation switch 7
And an operation display unit 8. A monitor 9 and a speaker 10 are connected to the reproduction system 3, and a camera 11 and a microphone 12 are connected to the recording system 4.

The DVD-RAM drive 2 has a drive mechanism for a DVD and a drive mechanism for an optical pickup, and can write / read a stream to / from a set DVD-RAM.

The reproducing system 3 reads out the first and second buffer memories 13 and 14 in which the streams read from the DVD-RAM are temporarily stored, and reads out the streams from the first and second buffer memories 13 and 14. And second audio and video data for decoding video data and audio data from the stream
The outputs of the video decoders 15 and 16 and the first and second audio / video decoders 15 and 16 are switched to output video data to the D / A converter 18 and to output audio data to the D / A
A changeover switch 17 for outputting to a converter 19, a D / A converter 18 for converting video data into an analog video signal and outputting it to an external monitor 9, and an external speaker 10 for converting audio data to an analog audio signal. Output to D /
An A converter 19 is provided. Here, each of the first and second audio / video decoders 15 and 16 is a system decoder for separating an input stream into a video stream and an audio stream, and a video decoder for decoding the separated video stream. And an audio decoder that decodes the separated audio stream.

The recording system 4 includes an A / D converter 20 for digitizing an analog video signal input from an external camera 11.
An A / D converter 21 for digitizing an analog audio signal input from an external microphone 12;
A video encoder 22 for compressing and encoding the output of the converter 20 to generate a video packet, an audio encoder 23 for compressing and encoding the output of the A / D converter 21 to generate an audio packet, and packing the video packet and the audio packet. And a third buffer memory 25 for temporarily accumulating the output of the system encoder 24 and sending it to the DVD-RAM drive 2 via the interface 6.

The control block 5 comprises a CPU and hardware.
Control, buffer memory control, control of each encoder, control of each decoder, switch control, and re-encoding processing. Details of these controls and processes will be described later.

The interface 6 is, for example, a SCSI (Sm
All Computer System Interface), and transfers data transmitted and received between the DVD-RAM drive 2, the reproduction system 3, the recording system 4, and the control block 5.

The operation switch 7 is a user interface for inputting various operation commands to the DVD recorder 1, and the device display section 8 is a user interface for displaying an operation state of the operation switch 7 and the like.

FIG. 2 is a diagram for explaining an example of the operation of the editing apparatus. Here, scene # 1 and scene #
2 is switched at the edit point Se to generate an edit output. The out point of scene # 1 is S1o, and the in point of scene # 2 is S2i. And scene # 2 is the in-point S2i
The scene # 1 is played back from tpr before
It is reproduced until tpo after 1o. As described with reference to FIGS. 6 and 7, in the MPEG system, video data is composed of one I picture, a plurality of P pictures, and B pictures.
A group of pictures is grouped in units of a GOP (Group of Pictures) including pictures, and one GOP usually includes 15 pictures (0.5 seconds). Further, the order of the images on the recording medium is different from the order of the original images. Therefore, if the out point S1o or the in point S2i is a P picture or B
If the picture is a picture, the picture cannot be decoded by itself, and an I-picture or P-picture that is temporally earlier on the recording medium but temporally later on the decoder output is required. Therefore, tpr and tpo are set.

First, a stream corresponding to scene # 1 is read from the DVD-RAM and stored in the first buffer memory 13 via the interface 6. This reading and storage is performed at a higher speed than the stream rate. When the storage amount of the first buffer memory 13 reaches a predetermined decoding start buffer amount, a stream is read from the first buffer memory 13 and transferred to the first audio / video decoder 15 to start decoding. . The video data and audio data decoded by the first audio / video decoder 15 are output to a D / A converter 18 for video data and a D / A converter 19 for audio data by a changeover switch 17, respectively. Converted to analog video signals and analog audio signals,
It is output to the monitor device 9 and the speaker 10.

In the graph of time versus buffer accumulation amount in the lower part of FIG.
, And the characteristic of the solid line indicates a change in the accumulation amount of the second buffer memory 14. In this figure,
Until time T1, reading and decoding of scene # 1 from the DVD-RAM are performed in parallel. At time T1, the pickup of the DVD-RAM drive 2 is sought to read scene # 2. The seek is completed at time T2, and reading of scene # 2 is started. The read stream of scene # 2 is stored in the second buffer memory 14. Then, at time T3, when a predetermined decoding start buffer amount Bc is reached, the stream is read out from the second buffer memory 14 and the second audio
The data is transferred to the video decoder 16 and decoding is started.
Decoding of scene # 1 continues for time t1 after time T1. That is, from time T3 to time T1 + t1 (T1 + t1
Until> T3), both the first audio / video decoder 15 and the second audio / video decoder 16 perform decoding. Then, the edit point Se (time T3 + t
In pr), the changeover switch 17 switches from the output of the first audio / video decoder 15 to the output of the second audio / video decoder 16. After the edit point Se, the decoding of the scene # 2 is continued. At this time, decoding is performed in parallel with reading of scene # 2 from the DVD-RAM until time T5. In the present embodiment, scene #
2 is divided and recorded at different positions on the disk, seek is performed between times T5 and T6, and after time T6, reading and decoding of scene # 2 are performed in parallel.

As described above, the control block 5
DVD-RAM drive 2, first and second buffer memories 13, 14, first and second audio / video decoder 1
By controlling 5, 16, and the changeover switch 17,
The edited output is reproduced from the monitor 9 and the speaker 10 without interruption.

However, as can be seen from FIG. 2, if the seek time ts + the read time tr + the time tpr + the time tpo is longer than the time t1, the out point S1o of the scene # 1 is decoded and output. Therefore, since the in-point S2i of the scene # 2 is not output, the editing output is interrupted.

Therefore, in the present embodiment, when editing, the control block 5 sets the above-mentioned t1 with respect to the out point S1o of scene # 1 and the in point S2i of scene # 2.
And ts + tr + tpr + tpo are calculated. Where ts
Is calculated from the end position of scene # 1 and the start position of scene # 2 on the DVD-RAM. tr is the time required for the stream of the decoding start buffer amount Bc to be stored in the second buffer memory 14. Here, the decoding start buffer amount Bc is such that the scene # 2 is DVD-RA
The value is small when recorded continuously on M, and large when discontinuous. However, since the control block 5 knows the recording position of each scene,
In any case, it can be calculated. tpo is determined by the type of picture at the in point S2i of scene # 2, and tpr
Is determined by the type of picture at the out point S1o of scene # 1. t1 can be calculated from the amount of data stored in the first buffer memory 13 at the end of reading of scene # 1 and the data rate of scene # 1.

As a result of the calculation, if t1 ≧ ts + tr + tpr + tpo (1) is satisfied, the DVD-RA is generated at the timing described above.
By controlling the M drive 2, the first and second buffer memories 13 and 14, the first and second audio / video decoders 15 and 16, and the changeover switch 17, the editing output can be output from the monitor 9 and the speaker 10. Reproduce.

On the other hand, if t1 <ts + tr + tpr + tpo (2) is satisfied, the scene # 1 and the scene # 2 are re-encoded and edited. The above processing flow is shown in FIG.
Shown in

Here, re-encoding will be described.
In the present embodiment, re-encoding is performed offline using the control block 5. FIG. 4 is a timing chart for explaining re-encoding. Here, the edit output is generated by combining the sections A and B of the scene # 1 with the sections C and D of the scene # 2. There is an edit point between section B and section C. Equally spaced sections in the stream of each scene represent a GOP unit, and an I picture exists at the head of each GOP. Here, the edit point is in the middle of the GOP, and does not match the beginning of the GOP. Section B is G of scene # 1 including the edit point.
The section from the beginning of the OP to the edit point is indicated, and section A
Represents the previous section. In addition, the section C is defined as a GO from the edit point of the GOP of scene # 2 including the edit point.
A section up to the end of P is shown, and section D represents a section thereafter.

The control block 5 of the DVD recorder 1 transmits a stream read from the DVD-RAM set in the DVD-RAM drive 2 to the internal RAM via the interface 6 at the time of re-encoding and editing.
(Not shown). And in section A, DVD
-Use the data of scene # 1 read from the RAM as it is. In the section B, the scene # 2 is decoded by software and further re-encoded. In section C, scene # 2 is decoded by software and re-encoded. In the section D, the data of the scene # 2 read from the DVD-RAM is used as it is. Therefore,
In the generated edited stream, the portions to be re-encoded are only the section B and the section C. Therefore, the deterioration of the image quality due to the re-encoding is small.

The edited stream may be recorded in a place different from the original image on the DVD-RAM, or may be output to the outside via the reproduction system 3.

In the DVD recorder 1 shown in FIG. 1, the control block 5 performs off-line re-encoding by software, but between the A / D converter 20 and the video encoder 22 in the recording system 4 and the A / D converter
A changeover switch is provided between the audio encoder 23 and the audio encoder 23 so that the output of the changeover switch 17 in the reproduction system 3 can be input to the changeover switch provided in the recording system. It can also be used to re-encode in real time. The above description relates to the case where two streams are edited. However, the same applies to the case where editing is performed so as to delete the middle part of one stream.

As described above, according to the first embodiment of the present invention, the first audio / video decoder and the second
As long as the output of those decoders can be switched without interruption at the edit point, edit them by switching their outputs, and re-encode and edit only if the output is interrupted Therefore, deterioration of image quality can be minimized. Further, even if re-encoding is performed, the section is only the GOP including the editing point, so that the deterioration of the image quality due to the re-encoding is minimal.

(Second Embodiment) The configuration of an editing device according to a second embodiment of the present invention is the same as that of FIG. 1, and the operation executed by the control block 5 is different.
In the second embodiment of the present invention, by storing the stream of scene # 2 in the second buffer memory 14 in advance, after the reading of scene # 1 is completed, until the decoding of scene # 2 becomes possible. To shorten the time.

FIG. 5 is a diagram for explaining the operation of the present embodiment. In this figure, the characteristic of the dashed line is the first line.
The characteristic indicated by a solid line indicates a change in the storage amount of the second buffer memory 14. As shown in this figure, until time T1 ', the DVD-RA
Reading of scene # 1 from M and decoding are performed in parallel. At time T1 ', reading of scene # 1 is temporarily interrupted to read scene # 2, and the DVD-R
The seek of the AM drive 2 is made to seek. Time T
The seek is completed at 2 ', and reading of scene # 2 starts. After reading the minimum read unit amount of data from scene # 2,
In order to read scene # 1 again, seek is performed from time T3 ', and reading of scene # 1 is restarted from time T4'. As a result, the minimum read unit amount Bm is stored in the second buffer memory 14.
Are accumulated. During this time, since the decoding of scene # 1 is continued, the monitor 9 and the speaker 10
The video and audio are not interrupted. When the scene # 1 is long, the cycle of “temporary suspension of reading of the scene # 1 → reading of the minimum read unit amount of the scene # 2 → resuming reading of the scene # 1” is repeated in this manner, thereby setting the first 2
The stream can be gradually accumulated in the buffer memory 14 of FIG.

Here, "temporary suspension of reading of scene # 1 →
Reading the minimum unit of scene # 2 → restarting reading of scene # 1 ”
The conditions under which this cycle is possible will be described. At an arbitrary time t in FIG. 5, the accumulated amount of the first buffer
f1, the decoding start buffer amount is Bc, the data rate of scene # 1 is B1, the seek time is tS, and the read time of the minimum read unit is trm. During this time, it is only necessary that the accumulation amount of the first buffer memory 13 does not fall below Bc. Therefore, if (Bf1−Bc) / B1 ≧ 2tS + trm (3) holds, then “temporary suspension of reading of scene # 1 → scene” Reading of minimum reading unit amount of # 2 → Resuming reading of scene # 1 ”
1 cycle can be executed. Expression [3]
If the value on the left side is sufficiently larger than the value on the right side, more data than the minimum read unit amount may be read.

Then, as described above, the second buffer memory
If the stream of scene # 2 is stored in advance in 14, the time from completion of reading of scene # 1 to start of decoding of scene # 2 can be reduced. That is, as indicated by the two-dot chain line in the graph of the time vs. buffer accumulation amount in FIG. 2, when the reading of the scene # 2 is performed at the time T2, since the data has already been accumulated in the second buffer memory 14, The time required for the accumulated amount to reach the decoding start buffer amount Bc is reduced. If scene # 1 is sufficiently long and if data equal to or greater than the decoding start buffer amount Bc has already been accumulated at time T2, decoding can be performed in parallel with reading from time T2. In other words, according to the present embodiment, even if Expression (1) is not satisfied (that is, Expression (2) is satisfied), the DVD-
RAM drive 2, first and second buffer memories 13, 1
4, the first and second audio / video decoders 15, 16,
By controlling the changeover switch 17 and the
The editing output can be reproduced from the speaker 10 and the speaker 10 without interruption.

In the above description, when the scene # 1 is long, the reading thereof is temporarily interrupted, and a part of the scene # 2 is read. However, when the scene # 1 is short, the scene # 1 is short. Before starting the reading of scene # 1, a part of the data of scene # 2 may be read and stored in the second buffer memory 14. Further, the editing apparatus according to the present embodiment may be configured to first determine whether or not Expression [1] is satisfied, and to execute the editing method according to the present embodiment if not, 1] without determining whether or not
The editing method of the present embodiment may be executed from the beginning.

As described above, in the second embodiment of the present invention, by storing a part of the stream of scene # 2 in advance, from the end of reading of scene # 1 to the start of decoding of scene # 2. By reducing the time, the number of scenes requiring re-encoding can be further reduced as compared with the first embodiment.

(Third Embodiment) FIG. 6 is a block diagram showing a configuration of an editing apparatus according to a third embodiment of the present invention. In this figure, the same components as those in FIG. 1 or corresponding components are denoted by the same reference numerals as those used in FIG. 1, and descriptions of those components are omitted to avoid duplication.

The editing apparatus according to the present embodiment is different from FIG. 1 in the configuration of the reproduction system 3. The reproduction system 3 includes first and second buffer memories 13 and 14 for temporarily storing a stream read from the DVD-RAM, and first and second buffer memories 1 and 2.
First and second system decoders 26 and 27 for separating a stream read from 3 and 14 into a video stream and an audio stream, and decoding video data from the video stream separated by the first system decoder 26 The output of the first video decoder 28, the second video decoder 29 for decoding video data from the video stream separated by the second system decoder 27, and the output of the first and second video decoders 28 and 29 are switched. D / A converter
A second switch 32 for switching the audio stream separated by the first and second system decoders 26 and 27; and an audio output from the second switch 32. And an audio decoder 30 for decoding data.

That is, in the first embodiment shown in FIG. 1, each of the first and second audio / video decoders 15 and 16 includes a system decoder, a video decoder, and an audio decoder. In this embodiment,
The same function is realized by one audio decoder 30 and the changeover switch 32.

The operation of the editing apparatus configured as described above will be described. First, a stream # 1 corresponding to scene # 1 is read from the DVD-RAM and stored in the first buffer memory 13 via the interface 6. This reading and storage is performed at a higher speed than the stream rate. When the accumulated amount of the first buffer memory 13 reaches a predetermined decoding start buffer amount, a stream is read from the first buffer memory 13 and sent to the first system decoder 26. Then, the video stream is separated into a video stream and an audio stream, the video stream is transferred to the first video decoder 28, and the audio stream is transferred to the audio decoder 30 through the second switch 32. The switching operation of the second switch 32 will be described later. The video data decoded by the first video decoder 28 and the audio data decoded by the audio decoder 30 are output to a D / A converter 18 for video data and a D / A converter 19 for audio data, respectively. The signals are converted into analog video signals and analog audio signals, respectively, and output to the monitor device 9 and the speaker 10.

FIG. 7 shows the first changeover switch 31 and the second changeover switch 31.
3 is a diagram for explaining the switching timing of the changeover switch 32 of FIG.

As described above, first, stream # 1 corresponding to scene # 1 is decoded and output to the outside. This is a state temporally before the edit point Se in FIG. At this time, the first changeover switch 31 has selected the output of the first video decoder 28. Then, at the editing point Se, the first changeover switch 31 is switched to select the output of the second video decoder 29, so that the decoded output of the stream # 2 corresponding to the scene # 2 is output to the external monitor device 9. You. Where stream #
The video frame of No. 1 and the video frame of stream # 2 are synchronized, and the edit point Se also coincides with the timing of the break of the video frame.

Next, the timing of switching from the audio data of stream # 1 to the audio data of stream # 2 will be described. Since audio data is also processed on a frame-by-frame basis, it is necessary to switch at the timing of audio frame delimitation. However, the length of an audio frame is usually different from the length of a video frame, and their timing is not synchronized.

Therefore, in the present embodiment, the stream is switched from stream # 1 to stream # 1 at the end of the audio frame immediately before or after the edit point Se. Edit point Se
7, the second changeover switch 32 selects the output of the first system decoder 26 until time Tc, as shown in Example 1 of FIG. Therefore, the time Tc
Up to this point, the audio stream of stream # 1 passes through the second changeover switch 32, is decoded by the audio decoder 30, is converted into an analog audio signal by the D / A converter 19 for audio data, and is output to the speaker 10. . Then, after time Tc, time Td, which is the timing of the first break of the audio frame of stream # 2
Therefore, the second changeover switch 32 is connected to the second system decoder.
Switch to select 27 outputs. Therefore, after time Td, the audio stream of stream # 2 is decoded and output to speaker 10. From time Tc to time Td, the audio decoder 30 stops operating.

When switching just before the edit point Se,
As shown in Example 2 of FIG. 7, the second changeover switch 32 selects the output of the first system decoder 26 until time Ta.
Therefore, the audio stream of stream # 1 is decoded and output to the speaker 10 until time Tc. Then, after time Ta, time Tb, which is the timing of the first delimiter of the audio frame of stream # 2
Therefore, the second changeover switch 32 is connected to the second system decoder.
Switch to select 27 outputs. Therefore, after time Td, the audio stream of stream # 2 is decoded and output to speaker 10.

The above-described editing operation is performed only when the editing output of the video data is output from the first changeover switch 31 without interruption.

As described above, according to the third embodiment of the present invention, by switching one audio decoder, the audio streams of two scenes can be decoded, thereby reducing the number of audio recorders. Thus, cost reduction can be realized.

(Fourth Embodiment) In a fourth embodiment of the present invention, an audio stream is dubbed on a stream edited by switching between a video decoder and an audio decoder. As described with reference to FIG. 7, the switching of the scene (editing point) is performed at the timing of the break of the video frame. And
Since the video frame and the audio frame do not match, the switching of the audio stream from scene # 1 to scene # 2 is performed at the timing of the delimitation of the audio frame immediately before or immediately after the edit point. Post-recording such as BGM or narration is continuously performed on the stream edited in this manner from scene # 1 to scene # 2.

FIG. 8 is a diagram for explaining the principle of the fourth embodiment of the present invention. In this figure, the shading of the audio frame indicates that the post-recording has been performed on the frame. The after-recording of scene # 1 is encoded and recorded in synchronization with the original audio frame of scene # 1, and the after-recording of scene # 2 is encoded and recorded in synchronization with the original audio frame of scene # 2. Also, audio frames # 5, 6, 7 of scene # 1 and audio frames # 2 of scene # 2
The same audio signal is dubbed on 1, 2, and 3.

As shown in FIG. 8, the editing point is set at the timing of the separation between video frame # 4 and video frame # 5 of scene # 1. Therefore, the audio frame switches from the beginning or end of frame # 6 of scene # 1 to the beginning or end of frame # 2 of scene # 2. Here, audio frame # of scene # 1
6 and the audio frame # 2 of the scene # 2, the same audio signal is dubbed duplicatively. Therefore, when the scene is switched, the dubbed audio signal is decoded without discontinuity and output from the speaker. Further, audio frame # 6 of scene # 1 and scene # 2
Since the same audio signal is recorded in the audio frame # 2, if the editing apparatus has two audio decoders, the decoding is performed in parallel to switch at a timing other than the delimitation of the audio frame. , The audio signal is continuously reproduced.
Since the post-recording of the scene # 2 is encoded and recorded in synchronization with the original audio frame of the scene # 2, the end of the post-recorded audio frame has a time lag from the original audio frame of the scene # 2. It does not occur.

FIG. 9 is a block diagram showing a configuration of an editing apparatus according to the fourth embodiment of the present invention. In this figure, the same components as those in FIG. 6 or the corresponding components are denoted by the same reference numerals as those used in FIG. 6, and descriptions of those components are omitted to avoid duplication.

The editing apparatus according to the present embodiment includes the reproduction system 3 having two audio decoders 33 and 34,
, The first and second video decoders
28, 29, that the outputs of the first and second audio decoders 33, 34 are switched, and that one channel (L or R) of audio data output from the second switch 35
Is supplied to the first changeover switch 36 of the recording system 4, and the synchronization signal of the audio frame is transmitted from the first and second audio decoders 33 and 34 to the first and second audio encoders 37 and 6 differs from FIG. 6 shows that the recording system 4 includes a first switching switch 36, two audio encoders 37 and 38, and two buffer memories 25 and 39, and the above-described signal is input from the reproduction system 3 to FIG. Different.

The operation of the editing apparatus having the above-described structure at the time of post-recording will be described with reference to the timing chart of FIG. Here, a case will be described in which eight frames of scene # 1 (frames # 2 to # 9) and eight frames of scene # 2 (frames # 1 to # 8) are dubbed, as shown in FIG.

First, from the beginning of frame # 2 of scene # 1 in FIG.
Of the changeover switch 35 is selected. At this time, the second
Switch 35 selects the output of the first audio decoder 33, so that the first switch 36 outputs the decoded output of the audio stream of scene # 1, which is the output of the first audio decoder 33, to the first. , To the second audio encoders 37 and 38. The audio data input to the first audio encoder 37 is
Encoded in synchronization with the frame synchronization signal supplied from the first audio decoder 33, the system encoder
24, third buffer memory 25, and interface 6
Through the DVD-RAM drive 2. Second
Audio encoder 38 has not yet begun operation. Therefore, during this time, the audio stream of scene # 1 recorded on the DVD-RAM is recorded as it is at the original recording position.

Next, when the after-recording section starts, the output of the first changeover switch 36 is switched to the output of the microphone 12. As a result, the output of the microphone 12 is overwritten on the DVD-RAM in synchronization with the original audio frame of the scene # 1. In FIG. 10, the first audio encoder
Since 37 operates for 8 frame periods, Micron
Is overwritten on the original recording position for a total of eight frames (frames # 2 to # 9).

On the other hand, at the sixth frame after the start of the dubbing of scene # 1, the second audio encoder
38 also starts operating. The audio data input to the second audio encoder 38 is encoded in synchronization with the frame synchronization signal supplied from the second audio decoder 34, and is encoded via the fourth buffer memory 39 and the interface 6 in the DVD-RAM. Supplied to drive 2. As a result, the output of the microphone 12 is overwritten on the DVD-RAM in synchronization with the original audio frame of the scene # 2.

When the post-recording section ends, the first
Is switched from the output of the microphone 12 to the output of the second switch 35 again. Since the output of the second changeover switch 35 has been switched to the output of the second audio decoder 34 at the editing point, the rest of frame # 8 is the audio stream of scene # 2 recorded on the DVD-RAM. Encoded,
It is recorded again in the original position.

In the audio stream dubbed as described above, the last three frames of scene # 1 (frames # 7 to # 9) and the first three frames of scene # 2 (frames # 1 to # 3) are the same. Content.

As described above, according to the fourth embodiment of the present invention, after-recording of scene # 1 is performed in synchronization with the audio frame of scene # 1, and scene # 1 is synchronized with the audio frame of scene # 2. 2, the post-recording audio signal is decoded without discontinuity when switching scenes, and the end of the post-recording audio frame is temporally shifted from the original audio frame of scene # 2. Nor. Further, by using two audio encoders and operating in parallel for a predetermined period before and after the edit point, encoding of the overlap period can be performed in real time.

(Fifth Embodiment) In a fifth embodiment of the present invention, the same post-recording as that of the fourth embodiment is performed by using one audio encoder, an audio buffer memory, and a changeover switch. It is realized.

FIG. 11 is a block diagram showing a configuration of an editing apparatus according to the fifth embodiment of the present invention. In this figure, the same components as those in FIG. 9 or corresponding components are denoted by the same reference numerals as those used in FIG.
The description of those components will be omitted to avoid duplication.

The editing apparatus according to the fifth embodiment of the present invention
The audio encoder of the recording system 4 is a single unit, and an audio buffer memory 37 for temporarily storing an audio signal for dubbing during an overlap period, and an output of the first changeover switch 36 or an output of the audio buffer memory 37 are selectively provided. Third switch to be supplied to the audio encoder 39
This is a difference from FIG. The audio frame synchronization signals output from the first and second audio decoders 33 and 34 of the reproduction system 3 are both supplied to the third switch 41.

The operation of the editing apparatus having the above-described structure during dubbing will be described with reference to the timing chart of FIG. Here, a case will be described in which eight frames of scene # 1 (frames # 2 to # 9) and eight frames of scene # 2 (frames # 1 to # 8) are dubbed, as shown in FIG.

First, from the beginning of frame # 2 of scene # 1 in FIG.
Of the changeover switch 35 is selected. At this time, the second
Switch 35 selects the output of the first audio decoder 33, so that the first switch 36 outputs the decode output of the audio stream of scene # 1, which is the output of the first audio decoder 33, to the third output. Changeover switch 41
Output to The third changeover switch 41 selects the output of the first changeover switch 36 and outputs the first audio decoder
Since the frame synchronization signal is supplied from 33, the decoded output of the audio stream of scene # 1 is supplied to the audio encoder 39. Audio encoder
The audio data input to 39 is scene # 1
And is supplied to the DVD-RAM drive 2 via the system encoder 24, the third buffer memory 25, and the interface 6. Therefore, during this time, the audio stream of scene # 1 recorded on the DVD-RAM is recorded as it is at the original recording position.

Next, when the after-recording section starts, the output of the first changeover switch 36 is switched to the output of the microphone 12. As a result, the output of the microphone 12 is overwritten on the DVD-RAM in synchronization with the original audio frame of the scene # 1. In FIG. 12, the audio encoder 39 has 8
Since the operation is performed during the frame period, the output of the microphone 12 is overwritten on the original recording position for a total of eight frames (frames # 2 to # 9).

At the sixth frame after the start of post-recording of scene # 1, the audio buffer memory 40 starts writing, and the post-recording audio signal output from the first changeover switch 36 is output for three frames (frames). # 1
# 3) Store.

At the editing point, the output of the second changeover switch 35 is switched to the output of the second audio decoder 34. After that, after the end of the audio stream of the scene # 1, the frame synchronization signal supplied to the third changeover switch 36 is output to the second audio decoder.
Switches to 34 output. As a result, after-recording of the audio stream of scene # 2 starts from frame # 4 of scene # 2. Then, post-recording is completed in the middle of frame # 8.

At the end of the after-recording section, the output of the first switch 36 switches from the output of the microphone 12 to the output of the second switch 35 again. Since the output of the second changeover switch 35 has been switched to the output of the second audio decoder 34 at the editing point, the rest of frame # 8 is the scene # recorded on the DVD-RAM.
The second audio stream is encoded and recorded again at the original position.

Further, when the encoding of the frame # 8 is completed, the third changeover switch 36 selects the output of the audio buffer memory 40, and the audio signals for the after-recording of the frames # 1 to # 3 are sequentially transmitted from the audio buffer memory 40. Is read. Therefore, frames # 1 to
The audio signal for audio dubbing of # 3 is encoded and D
Recorded in the VD-RAM. At this time, frame # 1
The # 3 post-recording audio signal is overwritten on the original positions of frames # 1 to # 3 on the DVD-RAM.

As described above, according to the fifth embodiment of the present invention, after-recording of scene # 1 is performed in synchronization with the audio frame of scene # 1, and scene # 1 is synchronized with the audio frame of scene # 2. 2, the post-recording audio signal is decoded without discontinuity when switching scenes, and the end of the post-recording audio frame is temporally shifted from the original audio frame of scene # 2. Nor. In addition, by performing the post-recording encoding of the overlap period, the same post-recording as in the fourth embodiment can be performed without using two audio encoders.

[0083]

As is apparent from the above description, according to the editing method and the editing apparatus of the present invention, when the output is switched by switching between the two decoders as much as possible and the output from the two decoders is switched. Since re-encoding is performed only when reproduction output is interrupted, deterioration of image quality due to re-encoding can be minimized.

According to the editing method and the editing apparatus of the present invention, two audio streams can be decoded by switching one audio decoder. And the cost can be reduced.

Further, according to the editing method and the editing apparatus of the present invention, it is possible to eliminate the deterioration of the image quality due to the re-encoding and to reduce the time lag with respect to the original audio frame from the first scene to the second scene. Recording can be performed continuously without occurrence.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an editing device according to a first embodiment of the present invention;

FIG. 2 is a diagram for explaining an operation of the editing device according to the first embodiment of the present invention;

FIG. 3 is a diagram showing an editing operation of the editing device according to the first embodiment of the present invention;

FIG. 4 is a diagram for explaining re-encoding;

FIG. 5 is a diagram for explaining the operation of the editing device according to the second embodiment of the present invention;

FIG. 6 is a block diagram showing a configuration of an editing device according to a third embodiment of the present invention;

FIG. 7 is a diagram for explaining switching timings of a first switch and a second switch of the editing apparatus according to the third embodiment of the present invention;

FIG. 8 is a diagram for explaining the principle of a fourth embodiment of the present invention;

FIG. 9 is a block diagram showing a configuration of an editing device according to a fourth embodiment of the present invention;

FIG. 10 is a diagram for explaining an operation at the time of after-recording of the editing apparatus according to the fourth embodiment of the present invention;

FIG. 11 is a block diagram showing a configuration of an editing device according to a fifth embodiment of the present invention;

FIG. 12 is a diagram for explaining the operation of the editing apparatus at the time of after-recording according to the fifth embodiment of the present invention;

FIG. 13 is a diagram showing predictive encoding in MPEG.

FIG. 14 is a diagram showing rearrangement of pictures in MPEG bidirectional prediction;

FIG. 15 is a diagram illustrating a multiplexing process of video data and audio data in MPEG.

[Explanation of symbols]

 Reference Signs List 1 DVD recorder 2 DVD-RAM drive 5 Control block 13, 14, 25, 39 Buffer memory 15, 16 Audio / video decoder 17, 31, 32, 35, 36, 41 Switch 28, 29 Video decoder 30, 33, 34 Audio decoder 23, 37, 38, 39 Audio encoder 40 Audio buffer memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 27/02 B F-term (Reference) 5C052 AA01 AB02 CC11 DD04 EE03 5C053 FA14 FA24 GA11 GB08 GB21 GB29 JA22 KA01 KA08 LA01 5D044 AB05 AB07 BC06 CC04 DE03 EF03 FG10 FG21 GK08 HL14 5D110 CA05 CA06 CA42 CB04 CD15 CF21 CK02 CK28

Claims (18)

[Claims] 1. An editing method for editing one or more streams recorded on a disk recording medium, comprising: a first decoder for decoding a compression-encoded stream read from a first location on the recording medium; A second decoder for decoding a compression-encoded stream read from a second location on the recording medium, and switching between an output of the first decoder and an output of the second decoder at an editing point for output When the output of the first decoder and the output of the second decoder are continuously output from the switching unit, the output of the switching unit is switched to perform editing. If the output between the first decoder and the output of the second decoder is interrupted, the compression encoding unit read from the first location is used. After decoding the compression encoded stream read from the stream and the second location, modifying the compression coded stream of the disk recording medium and performing edit encoded again. 2. The method according to claim 1, wherein after the reading of the compressed coded stream recorded in the first location is completed, the reading of the compressed coded stream recorded in the second location is started. A method for editing a compression-encoded stream in the disk recording medium described in the above. 3. A part of the compressed coded stream recorded in the second location is read before reading of the compressed coded stream recorded in the first location is completed. 2. The method for editing a compression-encoded stream in the disk recording medium according to 1. 4. Temporarily interrupting reading of a compression-encoded stream recorded in the first location, while the second
2. The method for editing a compressed encoded stream on a disk recording medium according to claim 1, wherein a part of the compressed encoded stream recorded at the location is read. 5. The method according to claim 1, wherein a part of the compressed coded stream recorded in the second location is read before starting to read the compressed coded stream recorded in the first location. 2. The method for editing a compression-encoded stream in the disk recording medium according to 1. 6. An editing apparatus for editing one or more compressed coded streams recorded on a disk recording medium, wherein the first device decodes a compressed coded stream read from a first location on the recording medium. , A second decoder for decoding a compressed coded stream read from a second location on the recording medium, and switching between the output of the first decoder or the output of the second decoder at an editing point And a determination unit for determining whether or not the output of the first decoder and the output of the second decoder are continuously output from the switching unit. For editing a compression-encoded stream in a disc recording medium to be compressed. 7. A control means for controlling to start reading of the compressed coded stream recorded in the second location after reading of the compressed coded stream recorded in the first location is completed. 7. The apparatus for editing a compression-encoded stream on a disk recording medium according to claim 6, wherein: 8. A control means for controlling to read a part of the compressed coded stream recorded in the second location before the reading of the compressed coded stream recorded in the first location is completed. 7. The apparatus for editing a compression-encoded stream on a disk recording medium according to claim 6, further comprising: 9. Temporarily interrupting reading of a compression-encoded stream recorded in the first location, during which the second
7. The apparatus for editing a compressed encoded stream on a disk recording medium according to claim 6, further comprising control means for controlling to read a part of the compressed encoded stream recorded at the location. 10. A control means for controlling so as to read a part of the compressed coded stream recorded in the second location before starting to read the compressed coded stream recorded in the first location. 7. The apparatus for editing a compression-encoded stream on a disk recording medium according to claim 6, further comprising: 11. An editing method in which one or more compression-encoded streams recorded on a disk recording medium are switched and synthesized at an editing point, wherein the compression-encoded video read from a first location on the recording medium is provided. A first video decoder for decoding a stream; a second video decoder for decoding a compression-encoded video stream read from a second location on the recording medium; an output of the first video decoder; A first switching means for switching and outputting the output of the second video decoder, a compression-encoded audio stream read from a first location on the recording medium, and a second encoding means read from a second location on the recording medium. A second switching means for switching and outputting the compressed and encoded audio stream, and an output of the second switching means. And an audio decoder for coding, the output of the first switching means is switched at an editing point to edit video data, and the output of the second switching means is adjusted to the timing of an audio frame at or near the editing point. 3. A method for editing a compressed coded stream in a disk recording medium, wherein audio data is edited by switching over. 12. An editing apparatus for switching one or more compressed encoded streams recorded on a disk recording medium at an editing point and synthesizing the compressed encoded video stream read from a first location of the recording medium. A first video decoder for decoding a stream; a second video decoder for decoding a compression-encoded video stream read from a second location on the recording medium; an output of the first video decoder; A first switching means for switching and outputting the output of the second video decoder, a compression-encoded audio stream read from a first location on the recording medium, and a second encoding means read from a second location on the recording medium. Switching means for switching and outputting the compressed and encoded audio stream, and an output of the second switching means. An audio decoder to be coded, and control means for switching the output of the first switching means at an edit point and switching the output of the second switching means at the timing of an audio frame at or near the edit point. An apparatus for editing a compression-encoded stream in a disk recording medium. 13. A method for dubbing an audio stream of an edited compressed coded stream by switching one or more compressed coded streams recorded on a disk recording medium at an editing point, wherein The audio signal for dubbing at the first location is encoded in synchronization with the audio frame recorded at the first location, and the audio signal for dubbing at the second location is encoded in synchronization with the audio frame recorded at the second location on the recording medium. An editing method for a disk recording medium, wherein an audio signal is encoded and the same audio signal is redundantly recorded in the first location and the second location for a predetermined period before and after the editing point. . 14. A dubbing audio signal at the first location is encoded by a first audio encoder, and a dubbing audio signal at the second location is encoded by a second audio encoder. Item 14. An editing method for a disk recording medium according to Item 13. 15. A dubbing audio signal at said first location and a dubbing audio signal at said second location are encoded by a single audio encoder,
14. The method according to claim 13, wherein the audio signal during the predetermined period is encoded after encoding of the audio signal for dubbing in the second location is completed. 16. An apparatus for dubbing an audio stream of an edited compressed coded stream by switching one or more compressed coded streams recorded on a disk recording medium at an editing point, wherein the first location of the recording medium is A first audio encoder that encodes the audio signal for post-recording at the first location in synchronization with an audio frame recorded in the recording medium; and the first audio encoder in synchronization with an audio frame recorded in a second location on the recording medium. A second audio encoder that encodes the audio signal for post-recording at the second location, and duplicates the same audio signal for the first location and the second location for a predetermined period before and after the edit point. An editing apparatus for a disk recording medium, comprising: a control unit. 17. The method according to claim 17, wherein the first encoder and the second encoder are separate encoders, and the two encoders are operated in parallel during the predetermined period, and their encoded outputs are recorded. An editing device for a disk recording medium according to claim 16. 18. A post-recording audio signal in the second location, wherein the first encoder and the second encoder are a common encoder, and a buffer memory for temporarily storing the post-recording audio signal for the predetermined period is provided. 17. The editing apparatus according to claim 16, wherein after the encoding of the audio signal is completed, the audio signal for the predetermined period output from the buffer memory is encoded.