JPH11225309A - Acoustic signal processing unit and audio high speed reproduction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce an audio signal at a high speed in matching with a reproduction speed of a video signal. SOLUTION: An input stream processing means 2 separates an audio signal and a video signal from an input stream. An audio stream buffer 3 stores an audio signal and a video stream buffer 4 stores a video signal temporarily. When a control means 6 instructs high speed reproduction, an audio processor 7 reads a signal in the audio stream buffer 3 at a usual speed and converts it into an audio output signal. A video processor 8 converts the video signal into a video output signal at a prescribed magnification. In this case, a buffer controller 5C monitors an idle capacity of the audio stream broadcast 3 and a residual capacity of the video stream buffer 4. When the idle capacity or the residual capacity is a prescribed capacity or below, part of audio data is aborted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal processing device and an audio high-speed reproduction method for controlling the reproduction speed of an audio signal in accordance with the reproduction speed of an image in an AV (audio, visual) device.

[0002]

2. Description of the Related Art In recent years, systems for reproducing media in which video data and audio data are compressed, such as DVDs, have been rapidly increasing. In these systems, video and audio input data is divided into packets and multiplexed. Video data (also referred to as a video signal) and audio data (also referred to as an audio signal) are separated from such input data, and video and audio are reproduced by decoding these data. Here, the digital video disk (D
VD) is taken as an example, and the prior art is described.

[0003] Video data is compressed according to the MPEG2 specification, and is composed of three pictures of I picture, P picture and B picture.
It consists of different types of picture data. In the NTSC standard, each picture is compressed and recorded in 1/30 second units in the case of a field structure, and each picture in the case of a frame structure.

[0004] One of the audio standards for DVD is AC-3 or MPEG-2MC. here,
The audio data is composed of 1536 audio samples as one frame, the sampling frequency is 48 kHz,
It is compressed on a 32 ms basis and recorded on a DVD.

As described above, when the unit times constituting the audio data and the video data are different, it is necessary to synchronize them in order to reproduce these data. In DVD, the synchronization of video and audio outputs is controlled by the program time stamp (PT) attached to each packet.
It is executed by the management of S). That is, synchronization is established by independently adjusting the reproduction timing of video data and audio data.

In such a system, consider the case of performing high-speed reproduction. The following method is generally used when playing back video at high speed. (1-1): Only I picture is reproduced (about 6 to 7 times)
Times). (1-2); Only I and P pictures are reproduced (about 1.5 to 3 times). (1-3): Reproduce a part of I and P pictures and B pictures (about 1 to 1.5 times).

The number of pictures varies depending on the encoding method, bit rate, etc.
In the method (3), the reproduction speed may not be constant at the time of high-speed reproduction, and may have a width of about 1.5 to about 7 times.

[0008] In the case of audio, the following method can be considered as a method for realizing a high-speed reproduction that has been conventionally achieved. (2-1): Thinning out output data and smoothing discontinuous points. (2-2): Delete silent sections.

However, in the method (2-1), since the magnification is fixed, the sound is continuous when the high-speed reproduction of the video is higher than the audio, but the video cannot be reproduced faster than the high-speed reproduction of the audio. . If the magnification of the high-speed reproduction of the video is lower than that of the audio, the sound is interrupted. The method (2-2) has a problem that it is difficult to increase the high-speed playback magnification of audio to the fastest playback magnification (maximum double speed) when the video is the fastest, and the processing for detecting a silent portion is heavy. Yes, difficult to achieve.

On the other hand, generally, a high-speed reproduction of a recording medium is mostly performed when a viewer searches a certain scene. In this case, in many DVDs currently on the market, the output of audio is stopped at the time of high-speed reproduction, and only the video is reproduced in many cases.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, has a simple signal processing, and performs high-speed reproduction of audio according to a video reproduction speed. It is another object of the present invention to realize an audio signal processing apparatus and an audio high-speed reproduction method with less sound interruption.

[0012]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application comprises a control means for instructing a reproduction speed, and a processing means for processing an input signal in which an audio signal and a video signal are multiplexed. Input signal processing means for outputting an audio signal and a video signal, an audio stream buffer for temporarily storing the audio signal output from the input signal processing means, and temporarily storing the video signal output from the input signal processing means. A video stream buffer that accumulates in the audio stream buffer, extracts an audio signal from the audio stream buffer to perform signal processing, and generates an audio output signal; an audio processor that extracts a video signal from the video stream buffer to perform signal processing; When receiving a high-speed playback instruction from
A video processor for generating a video output signal by reproducing a video signal at a high speed; and monitoring the state of the audio stream buffer, and when the free space becomes smaller than a predetermined amount A, the audio processor reproduces the audio signal at a high speed. And a buffer controller for controlling the input / output of data so as to perform the above operation.

According to a second aspect of the present invention, there is provided a control means for instructing a reproduction speed, and an input signal processing means for processing an input signal in which an audio signal and a video signal are multiplexed and outputting an audio signal and a video signal. An audio stream buffer for temporarily storing an audio signal output from the input signal processing unit; a video stream buffer for temporarily storing a video signal output from the input signal processing unit; An audio processor that extracts a signal and performs signal processing to generate an audio output signal; and an audio processor that extracts a video signal from the video stream buffer and performs signal processing. A video player that plays back video at high speed and generates a video output signal A buffer controller for monitoring the state of the video trim buffer and controlling the input and output of data so that the audio processor performs high-speed reproduction of an audio signal when the remaining amount is smaller than a predetermined amount V. , Are provided.

According to a third aspect of the present invention, there is provided a control means for instructing a reproduction speed, and an input signal processing means for processing an input signal in which an audio signal and a video signal are multiplexed and outputting an audio signal and a video signal. An audio stream buffer for temporarily storing an audio signal output from the input signal processing unit; a video stream buffer for temporarily storing a video signal output from the input signal processing unit; An audio processor that extracts a signal and performs signal processing to generate an audio output signal; and an audio processor that extracts a video signal from the video stream buffer and performs signal processing. A video player that plays back video at high speed and generates a video output signal Monitor the status of the audio stream buffer and the video stream buffer when the free space of the audio stream buffer is less than a predetermined amount A, or the remaining amount of the video stream buffer is less than a predetermined amount V. A buffer controller for controlling the input and output of data so that the audio processor performs high-speed reproduction of the audio signal when the audio processor performs a high-speed reproduction of the audio signal.

The invention described in claim 4 of the present application is based on claim 1,
An audio high-speed reproduction method in the audio signal processing device according to item 2 or 3, wherein when reproducing a video signal at a high speed, the content of the audio stream buffer is intermittently flushed to thin out the audio signal, thereby reducing the amount of audio reproduction data. And performs high-speed reproduction.

The invention described in claim 5 of the present application is based on claim 1,
A high-speed audio reproduction method in the audio signal processing device according to the second or third aspect, wherein when the video signal is reproduced at a high speed, the transfer of the audio signal output from the input signal processing means to the audio stream buffer is interrupted by a predetermined amount. By doing so, the amount of audio reproduction data is reduced, and the audio signal is reproduced at high speed.

The invention described in claim 6 of the present application provides claim 1,
2. A high-speed audio reproduction method in the audio signal processing device according to 2 or 3, wherein when reproducing a video signal at high speed, the audio processor skips a predetermined data amount of input data from the audio stream buffer, It is characterized in that an audio signal is reproduced at high speed by reducing the amount of audio reproduction data.

The invention according to claim 7 of the present application is based on claim 1,
An audio high-speed reproduction method in the audio signal processing device according to 2 or 3, wherein when the video signal is reproduced at high speed, the audio processor stops outputting the audio signal for a predetermined time to reduce the amount of audio reproduction data. It is characterized in that the audio signal is reproduced at a high speed with the reduction.

[0019]

(Embodiment 1) Hereinafter, an audio signal processing apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of the audio signal processing device according to the present embodiment. This audio signal processing device is configured to include an input stream processing means 2, an audio stream buffer 3, a video stream buffer 4, a buffer controller 5A, a control means 6, an audio processor 7, and a video processor 8.

The input stream 1 input to the input stream processing means 2 is DVD output data or data equivalent thereto. That is, the input stream data is data obtained by compressing and multiplexing a video signal and an audio signal. In this embodiment, for simplicity of description, the input stream 1 is assumed to be DVD stream data, video data conforms to MPEG2, and audio data conforms to AC-3. However, the same applies to other stream formats.

When the input stream 1 is input, the input stream processing means 2 extracts video data and audio data to be reproduced from the input stream, stores the video data in the video stream buffer 4, and stores the audio data in the audio stream buffer 3. To be stored. At this time, the buffer controller 5A monitors the free space of the audio stream buffer 3.

In a normal state, when video data is input to the video processor 8, the video processor 8 performs a decoding process and converts it into a video output signal 10. When audio data is input to the audio processor 7, the audio processor 7 performs a decoding process and converts the audio data into an audio output signal 9.

At the time of high-speed reproduction, first, the video processor 8
Performs high-speed reproduction at a predetermined magnification according to an instruction from the control means 6. At this time, the audio processor 7 makes the pitch of the sound the same as during normal reproduction, and performs high-speed reproduction of audio by discarding some audio data. For high-speed reproduction at a predetermined magnification, in the case of MPEG2 video, the following method is used. (1-1); Only I picture is reproduced (about 6 to 7 times)
Times). (1-2); Only I and P pictures are reproduced (about 1.5 to 3 times). (1-3); Reproduce a part of I and P pictures and B pictures (about 1 to 1.5 times). In addition, (1-1)-
High-speed reproduction other than (1-3) may be used.

At the same time, the buffer controller 5A monitors the free space of the audio stream buffer 3. Then, the normal reproduction is performed until the free space of the audio stream buffer 3 becomes smaller than the predetermined value A.
To inform the remaining amount information. The predetermined value A can be set variously depending on the system. In this embodiment, a case where the free space is 0 (A = 0) will be described. Of course, the same applies to the case where control is performed using a free capacity value other than zero.

When the free space of the audio stream buffer 3 becomes 0, the audio processor 7 performs high-speed reproduction of audio by deleting a part of the audio output data. This will be described with reference to FIG. FIG. 8 is an explanatory diagram showing the state of the audio stream buffer 3 and the video stream buffer 4 during reproduction. In this figure, the remaining data amount is indicated by a halftone dot portion, and the empty area is indicated by a non-halftone dot portion.

In the case where the video is being reproduced at a high speed, the state becomes state 2 while the free space of the audio stream buffer 3 does not become zero. At this time, since the remaining amount of the video stream buffer 4 is not 0, the video processor 8 reproduces only the video at high speed. Since the audio stream is input according to the video playback speed, the decoding amount of the audio data that is normally reproduced is smaller than the input data amount. Eventually, the state becomes the state 1 in FIG. 8, and the free space of the audio stream buffer 3 becomes zero.

When the free space of the audio stream buffer 3 becomes 0, the buffer controller 5A transmits this information to the audio processor 7. Then, the audio data is discarded (flashed) by a predetermined amount, and the audio processor 7 resumes decoding the audio data at the normal speed from the continuation of the discarded data.

Next, a predetermined amount of data to be discarded and a discarding method will be described for each method. (i) Clearing (flashing) the audio stream buffer A part or all of the data in the audio stream buffer 3 is discarded by flashing, and a part of the stream that is not decoded is thinned out, thereby reducing the audio data to be reproduced and performing high-speed reproduction. The predetermined amount of audio data to be discarded is an arbitrary amount equal to or smaller than the audio stream buffer size in the system. Thus, the audio data to be reproduced is as shown in FIG.

FIG. 4 shows an audio output stream. Stream 1 is for normal reproduction, and stream 2 is for buffer clear. The example in FIG. 4 shows a case where during the high-speed reproduction, a portion from the middle of the frame 4 to the middle of the frame 7 in the stream 1 is deleted by clearing the audio stream buffer. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this example, the number of frames that can be decoded can be reduced from 12 in the case of normal reproduction to 8 by buffer clear, and the reproduction magnification is 12/8 = 1.5.

This method is easy to implement because the processing is simple. However, since processing cannot be performed in units of frames of audio data, a stream error may occur in some cases. Audio stream buffer 3
Has disappeared, so that there is a problem that audio data cannot be output until the data of the next frame is input.

(Ii) Restriction of audio stream input By stopping (not transferring) the input from the input stream processing means 2 to the audio stream buffer 3 for a predetermined time, audio data to be reproduced is reduced and high-speed reproduction is performed. The predetermined amount of data to be discarded is determined by the video playback speed supported by the system. If the video playback speed is n times faster than normal playback,
(n-1) It is necessary to discard audio data of an audio frame or more.

FIG. 5 shows audio data to be reproduced. FIG. 5 shows an audio input stream. Stream 1 is for normal reproduction, and stream 2 is for input restriction. The example in FIG. 5 is a case where audio data from the middle of the frame 4 to the middle of the frame 7 in the stream 1 is deleted due to non-transfer during high-speed playback. As a result, the stream to be decoded during the high-speed playback is the stream 2 from which the section A of the stream 1 has been deleted.
become that way. In this example, the number of frames that can be decoded can be reduced from 12 in the case of normal reproduction to 8, and the reproduction magnification is 12/8 = 1.5.

This method is easy to implement because the processing is simple. However, since processing cannot be performed in units of frames of audio data, a stream error may occur in some cases. Another problem is that audio data cannot be output until the next frame of data is input.

(Iii) Skipping of audio stream The audio processor 7 skips (discards) audio data by one to several frames in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The data to be discarded is determined by the playback speed of the video supported by the system. If the video playback speed is n times the normal playback speed, (n
-1) Audio frames must be discarded.

FIG. 6 shows audio data to be reproduced. In FIG. 6, stream 1 is for normal reproduction, and stream 2 is for frame skipping. The example in FIG. 6 is a case where frames 4 to 7 in the stream 1 have been deleted by frame skip during high-speed playback. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this case,
By frame skipping, the number of frames that can be decoded can be reduced from 12 in normal playback to 8, and the playback magnification is
12/8 = 1.5 times. This method is easy to realize because the processing is simple. In addition, since the audio data is processed in units of frames, no stream error occurs.

(Iv) Stopping audio output The audio processor 7 stops outputting audio data for one to several frames in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The minimum value of the predetermined amount of data to be stopped is determined by the playback speed of the video supported by the system. If the video playback speed is n times the normal playback speed, it is necessary to discard (n-1) audio frames or more every time the output is stopped.

The audio data to be reproduced is as shown in FIG. FIG. 7 shows an audio output stream. Stream 1 is for normal playback, and stream 2 is for output stop. The example in FIG. 7 is a case where the frames 4 to 7 in the stream 1 are deleted due to the stop of the output during the high-speed reproduction. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this case,
By stopping the output, the number of frames that can be decoded can be reduced from 12 in normal playback to 8, and the playback magnification is 12/8 = 1.
5 times. This method is easy to realize because the processing is simple. In addition, since processing is performed in units of frames of audio data, no stream error occurs.

As described above, every time the free space of the audio stream buffer 3 becomes zero, a predetermined amount of the audio stream is discarded by any one of the methods (i) to (iv), so that the video can be reproduced at a high speed. It is possible to realize high-speed reproduction of audio that matches the reproduction speed of video without changing the speed. Also, by adopting the above-described audio stream discarding method, it is possible to realize high-speed audio reproduction with little sound interruption. As a result, it is possible to realize an acoustic signal processing device that is simple in processing and realizes high-speed reproduction in accordance with the video reproduction speed and has few interruptions in sound.

(Embodiment 2) Next, an audio signal processing apparatus according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing a configuration of the audio signal processing device according to the present embodiment. This audio signal processing device is configured to include an input stream processing means 2, an audio stream buffer 3, a video stream buffer 4, a buffer controller 5B, a control means 6, an audio processor 7, and a video processor 8, as in the first embodiment. You.

The input stream 1 inputted to the input stream processing means 2 is stream data obtained by compressing and multiplexing a video signal and an audio signal as DVD output data or data equivalent thereto.
In this embodiment, for simplicity of description, the input stream 1 is DVD stream data, and the video data is M
The description is based on the assumption that the audio data conforms to PEG2 and the audio data conforms to AC-3. However, the same applies to other stream formats.

The input stream processing means 2 extracts video data and audio data to be reproduced from the input stream 1, stores the video data in the video stream buffer 4, and stores the audio data in the audio stream buffer 3. At this time, the remaining amount of the video stream buffer 4 is monitored by the buffer controller 5B.

In a normal state, video data is input to the video processor 8. The video processor 8 decodes the video data and converts it into a video output signal 10.
The audio data is input to the audio processor 7. The audio processor 7 decodes the audio data and converts it into an audio output signal 9.

At the time of high-speed reproduction, first, the video processor 8
Performs a predetermined high-speed reproduction according to an instruction from the control means 6. At this time, the audio processor 7 performs normal reproduction. The predetermined high-speed reproduction uses the following method in the case of MPEG2 video. (1-1); Only I picture is reproduced (about 6 to 7 times)
Times). (1-2); Only I and P pictures are reproduced (about 1.5 to 3 times). (1-3); Reproduce a part of I and P pictures and B pictures (about 1 to 1.5 times). In addition, (1-1)-
High-speed reproduction other than (1-3) may be used.

At the same time, the buffer controller 5B monitors the remaining amount of the video stream buffer 4, and performs normal reproduction until the remaining amount of the video stream buffer 4 becomes smaller than a predetermined value V. The remaining amount information is transmitted to the audio processor 7. Predetermined value V
Can be set variously depending on the system. In the present embodiment, the case where the remaining amount is 0 (V = 0) will be described. Of course, the same applies to the case where control is performed using a remaining value other than 0.

When the remaining amount of the video stream buffer 4 becomes zero, high-speed reproduction of audio is performed by partially deleting audio data. This will be described with reference to FIG. FIG. 9 is an explanatory diagram showing the state of the audio stream buffer 3 and the video stream buffer 4 during reproduction. In this figure, the remaining data amount is indicated by a halftone dot portion, and the empty area is indicated by a non-halftone dot portion.

When video data is being reproduced at high speed and the remaining amount of the video stream buffer 4 does not become 0, the state is as shown in state 2 in FIG. That is, the video stream buffer 4 and the audio stream buffer 3
The remaining amount is not 0, and only the video is reproduced at high speed. Since the data of the audio stream is input according to the video playback speed, the decoding amount of the audio data that is normally reproduced is smaller than the input data amount. Thus, the audio stream buffer 3
9, the video stream cannot be newly extracted from the input stream 1 and the remaining amount of the video stream buffer 4 becomes 0 as in state 1 in FIG.

When the remaining amount of the video stream buffer 4 becomes 0, the buffer controller 5B transmits this information to the audio processor 7. The audio processor 7 receiving this information sets the audio stream buffer 3
Are discarded by a predetermined amount, and then decoding is resumed at the normal speed from the continuation of the discarded data.

A predetermined amount of data to be discarded and a discarding method will be described for each method. (i) Clearing audio stream buffer A part or all of the data in the audio stream buffer 3 is discarded, and a part of the stream that has not been decoded is thinned out, thereby reducing audio data to be reproduced and performing high-speed reproduction. The predetermined amount A of audio data to be discarded is
It is an arbitrary amount equal to or less than the audio stream buffer size 3 in the system. The reproduced audio data is as shown in FIG.

FIG. 4 shows an audio output stream. Stream 1 is for normal playback, and stream 2 is for buffer clear. The example in FIG. 4 is a case where during the high-speed reproduction, a portion from the middle of the frame 4 to the middle of the frame 7 in the stream 1 is deleted by clearing the buffer of the audio stream. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this example, the number of frames that can be decoded can be reduced from 12 in the case of normal reproduction to 8 by buffer clear, and the reproduction magnification is 12/8 = 1.5.

This method is easy to implement because the processing is simple. However, since processing cannot be performed in units of frames of audio data, a stream error may occur in some cases. Further, since all the contents of the audio stream buffer disappear, there is a problem that audio data cannot be output until data of the next frame is input.

(Ii) Restriction of Audio Stream Input By stopping input from the input stream processing means 2 to the audio stream buffer 3 for a predetermined time, audio data to be reproduced is reduced and high-speed reproduction is performed. The predetermined amount A of data to be discarded is determined by the playback speed of the video supported by the system. If the video playback speed is n times that of normal playback, it is necessary to discard audio data of (n-1) audio frames or more for each input limitation.

The audio data to be reproduced is as shown in FIG. FIG. 5 shows an audio output stream. Stream 1 is for normal reproduction, and stream 2 is for audio data not transferred. The example in FIG. 5 is a case where a portion from the middle of frame 4 to the middle of frame 7 in stream 1 is deleted during high-speed playback.
As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In the case of this example, the number of frames that can be decoded is 1 in the case of normal reproduction due to data input restriction (untransferred).
It can be reduced from 2 to 8, and the reproduction magnification becomes 12/8 = 1.5 times.

This method is easy to implement because the processing is simple. However, since processing cannot be performed in units of frames of audio data, a stream error may occur in some cases. In addition, since data in the audio stream buffer is lost, there is a problem that audio data cannot be output until data of the next frame is input.

(Iii) Skipping of audio stream The audio processor 7 skips one to several frames of audio data in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The predetermined amount of data to be skipped is determined by the playback speed of the video supported by the system.
If the playback speed of the video is n times that of the normal playback, it is necessary to discard (n-1) audio frames or more for each skip.

FIG. 6 shows audio data to be reproduced. FIG. 6 shows an audio output stream. Stream 1 is for normal playback, and stream 2 is for frame skipping. The example in FIG. 6 is a case where frames 4 to 7 in the stream 1 have been deleted by frame skip during high-speed playback. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In the case of this example, the number of frames that can be decoded by buffer clear can be reduced from 12 in normal reproduction to 8, and the reproduction magnification is 12/8 = 1.5. This method is easy to realize because the processing is simple. In addition, since processing is performed in units of frames of audio data, no stream error occurs.

(Iv) Stopping audio output The audio processor 7 stops outputting audio data for one to several frames in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The predetermined amount of data to stop outputting is determined by the playback speed of the video supported by the system.
If the playback speed of the video is n times that of the normal playback, it is necessary to discard (n-1) audio frames or more every time the output is stopped.

FIG. 7 shows audio data to be reproduced. FIG. 7 shows an audio output stream. Stream 1 is for normal playback, and stream 2 is for output stop. The example in FIG. 7 is a case where the frames 4 to 7 in the stream 1 are deleted due to the stop of the output during the high-speed reproduction. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this case,
The number of frames that can be decoded by stopping the output can be reduced from 12 in the case of normal reproduction to 8, and the reproduction magnification is 12/8 = 1.5. This method is easy to realize because the processing is simple. Moreover, since the audio data is processed in frame units, no stream error occurs.

As described above, every time the remaining amount of the video stream buffer 4 becomes zero, a predetermined amount of the audio stream is discarded, so that the speed of the high-speed reproduction of the video is not changed and the speed of the video is adjusted to the reproduction speed of the video. High-speed reproduction of audio can be realized. Also, by adopting the above-described audio stream discarding method, it is possible to realize high-speed audio reproduction with little sound interruption. This allows
It is possible to realize an audio signal processing apparatus which is simple in processing, realizes high-speed reproduction in accordance with the video reproduction speed, and has few interruptions in sound.

(Embodiment 3) Next, an acoustic signal processing apparatus according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram illustrating a configuration of the acoustic signal processing device according to the present embodiment. This audio signal processing apparatus is configured to include an input stream processing unit 2, an audio stream buffer 3, a video stream buffer 4, a buffer controller 5C, a control unit 6, an audio processor 7, and a video processor 8, as in the first embodiment. You.

The input stream 1 input to the input stream processing means 2 is DVD output data or data equivalent thereto. That is, the input stream data is data obtained by compressing and multiplexing a video signal and an audio signal. In this embodiment, for simplicity of description, the input stream 1 is assumed to be DVD stream data, video data conforms to MPEG2, and audio data conforms to AC-3. However, the same applies to other stream formats.

The input stream processing means 2 extracts video data and audio data to be reproduced from the input stream 1. Then, the video data is stored in the video stream buffer 4 and the audio data is stored in the audio stream buffer 3. At this time, the remaining amount of the video stream buffer 4 and the free space of the audio stream buffer 3 are monitored by the buffer controller 5C.

In a normal state, the video data is input to the video processor 8, where the video data is decoded and converted into a video output signal 10. The audio data is input to the audio processor 7 and, after being decoded,
It is converted to an audio output signal 9.

At the time of high-speed reproduction, first, the video processor 8
Performs a predetermined high-speed reproduction according to an instruction from the control means 6. At this time, the audio processor 7 performs normal reproduction. The predetermined high-speed reproduction uses the following method in the case of MPEG2 video. (1-1); Only I picture is reproduced (about 6 to 7 times)
Times). (1-2); Only I and P pictures are reproduced (about 1.5 to 3 times). (1-3); Reproduce a part of I and P pictures and B pictures (about 1 to 1.5 times). In addition, (1-1)-
High-speed reproduction other than (1-3) may be used.

At the same time, the buffer controller 5C monitors the remaining capacity of the video stream buffer 4 and the free capacity of the audio stream buffer 3. Then, the normal reproduction is performed until the remaining amount of the video stream buffer becomes smaller than the predetermined value V or the free space of the audio stream buffer 3 becomes smaller than the predetermined value A. When the remaining amount of the video stream buffer 4 becomes smaller than the predetermined value V, or when the free space of the audio stream buffer 3 becomes smaller than the predetermined value A, the remaining amount information is transmitted to the audio processor 7. Although the predetermined values V and A can be set variously depending on the system, in the present embodiment, a case where the predetermined values V and A are 0 will be described. Of course, the same applies to the case where control is performed using a value other than 0.

When the remaining amount of the video stream buffer 4 becomes zero or when the free space of the audio stream buffer 3 becomes zero, high-speed reproduction of audio is performed by partially deleting audio data. This will be described with reference to FIGS. FIGS. 8 and 9 show examples of the remaining data state of the audio stream buffer 3 and the video stream buffer 4 during reproduction.

In the case where the video data is reproduced at a high speed, while the remaining amount of the video stream buffer 4 does not become 0, a state 2 shown in FIGS. 8 and 9 is obtained. That is, although the remaining amounts of the video stream buffer 4 and the audio stream buffer 3 are not 0, only the video data is reproduced at a high speed, and the data stream is input in accordance with the reproduction speed of the video. The decoding amount is smaller than the input data amount. Therefore, the free space of the audio stream buffer 3 becomes 0 as in state 1 in FIG. Alternatively, the remaining amount of the video stream buffer 4 becomes 0 as in the state 1 in FIG.

When the free space of the audio stream buffer 3 becomes 0 or the remaining amount of the video stream buffer 4 becomes 0, the buffer controller 5C transmits this information to the audio processor 7. Then, a predetermined amount of data in the audio stream buffer 3 is discarded, and the audio processor 7 resumes decoding at the normal speed from the continuation of the discarded data.

The data discarding amount and the discarding method will be described for each method. (i) Clearing the audio stream buffer A part of the data in the audio stream buffer 3 is discarded, and a part of the stream that has not been decoded is thinned out, thereby reducing the audio data to be reproduced and performing high-speed reproduction. The predetermined amount of audio data to be discarded is an arbitrary amount equal to or smaller than the audio stream buffer size in the system. Thus, the audio data to be reproduced is as shown in FIG.

FIG. 4 shows an audio output stream. Stream 1 is for normal reproduction, and stream 2 is for buffer clear. The example in FIG. 4 is a case where during the high-speed reproduction, a part of the stream 1 from the middle of the frame 4 to a half of the frame 7 is deleted by clearing the buffer of the audio stream. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this example, the number of frames that can be decoded can be reduced from 12 in the case of normal reproduction to 8 by buffer clear, and the reproduction magnification is 12/8 = 1.5.

This method is easy to implement because the processing is simple. However, since audio data cannot be processed on a frame basis, a stream error may occur in some cases. Audio stream buffer 3
Has disappeared, so that there is a problem that audio data cannot be output until the data of the next frame is input.

(Ii) Restriction of Audio Stream Input By stopping (not transferring) the input from the input stream processing means 2 to the audio stream buffer 3 for a predetermined time, audio data to be reproduced is reduced and high-speed reproduction is performed. The predetermined amount of data to be discarded is determined by the video playback speed supported by the system. If the video playback speed is n times faster than normal playback,
(n-1) It is necessary to discard audio data of an audio frame or more.

The audio data to be reproduced is as shown in FIG. FIG. 5 shows an audio input stream. Stream 1 is for normal playback, and stream 2 is for buffer clear. The example in FIG. 5 is a case where a part from the middle of the frame 4 to the middle of the frame 7 in the stream 1 is deleted by the audio data input restriction during the high-speed reproduction. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In the case of this example, the number of frames that can be decoded can be reduced from 12 in the case of normal reproduction to 8 by buffer clear, and the reproduction magnification is 12/8 = 1.
5 times.

This method is easy to implement because the processing is simple. However, since audio data cannot be processed on a frame basis, a stream error may occur in some cases. Audio stream buffer 3
Has disappeared, so that there is a problem that audio data cannot be output until the data of the next frame is input.

(Iii) Skipping of audio stream The audio processor skips one to several frames of audio data in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The predetermined amount of data to be discarded is determined by the video playback speed supported by the system. If the video playback speed is n times the normal playback speed, (n
-1) Audio frames must be discarded.

The audio data to be reproduced is as shown in FIG. FIG. 6 shows an audio output stream. Stream 1 is for normal playback, and stream 2 is for frame skipping. In the example in FIG. 6, frames 4 to 7 in stream 1 during high-speed playback
Is the case where the audio stream is deleted by skipping the audio stream. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In this example, the number of decodable frames can be reduced from 12 in normal reproduction to 8 by frame skipping, and the reproduction magnification is 12/8 = 1.5. This method is easy to realize because the processing is simple. In addition, since processing is performed in units of frames of audio data, no stream error occurs.

(Iv) Stopping audio output The audio processor 7 stops outputting audio data for one to several frames in frame units, thereby reducing audio data to be reproduced and performing high-speed reproduction. The predetermined amount of data to stop outputting is determined by the playback speed of the video supported by the system.
If the playback speed of the video is n times that of the normal playback, it is necessary to discard (n-1) audio frames or more every time the output is stopped.

The audio data to be reproduced is as shown in FIG. FIG. 7 shows an output stream of audio, where stream 1 is for normal playback and stream 2 is for output stop. The example in FIG.
This is a case where frames 4 to 7 in the stream 1 are deleted due to the stop of the output of the audio stream. As a result, the stream to be decoded at the time of the high-speed reproduction is like the stream 2 from which the section A of the stream 1 is deleted. In the case of this example, the number of frames that can be decoded is reduced from 12 to 8 in the case of normal reproduction due to the output stop.
The playback magnification is 12/8 = 1.5 times. This method is easy to realize because the processing is simple. In addition, since processing is performed in units of frames of audio data, no stream error occurs.

As described above, every time the free space of the audio stream buffer 3 becomes zero or the remaining amount of the video stream buffer 4 becomes zero, a predetermined amount of the audio stream is discarded. In this manner, high-speed reproduction of audio that matches the video reproduction speed can be realized without changing the high-speed reproduction speed of the video.

In the data stream of the MPEG standard, audio data and video data are generally often decoded by independently chipped LSIs. Even in the same chip, each core is often formed in an independent block. In such a case, the buffer controller 5 cannot always monitor the contents of both the audio stream buffer 3 and the video stream buffer 4. In such a situation, the buffer controller 5 refers only to the stream buffer that can be monitored. When audio data and video data are decoded by the LSI of the same chip, both stream buffers can be referred to via the data bus.

As described above, by adopting the above-mentioned methods (i) to (iv) for the audio stream discarding method, high-speed audio reproduction with few interruptions in sound can be realized. As a result, it is possible to realize an acoustic signal processing device that is simple in processing and realizes high-speed reproduction in accordance with the video reproduction speed, and has few sound interruptions.

In the above embodiment, when audio data is deleted on a frame basis, for example, frame 0 to frame i, frame i + 1,... Frame k-1
, Frame k, and frame k + 1, and input frame i + 1
,... When deleting frame k-1, frame i
, Frame k is cross-fade.

[0082]

According to the first aspect of the present invention, the free space of the audio stream buffer is monitored, and when the amount of the audio stream buffer becomes smaller than a predetermined amount, the audio stream is discarded by a predetermined amount, thereby achieving a high-speed playback speed of the video. It is possible to realize high-speed reproduction of audio with few interruptions in line with the reproduction speed of a video without changing the video.

According to the second aspect of the present invention, the remaining amount of the video stream buffer is monitored, and when the remaining amount becomes smaller than the predetermined amount, the audio stream is discarded by the predetermined amount, thereby changing the speed of the high-speed reproduction of the video. Thus, it is possible to realize high-speed reproduction of audio with few interruptions, which matches the reproduction speed of the video.

According to the third aspect of the present invention, the free space in the audio stream buffer is monitored, and when the free space is less than a predetermined amount, or when the remaining amount in the video stream buffer is monitored, the free space is monitored. In this case, by discarding a predetermined amount of the audio stream, it is possible to realize high-speed reproduction of audio with little interruption of sound, which matches the video reproduction speed, without changing the video high-speed reproduction speed.

According to the fourth aspect of the present invention, the audio signal is thinned out intermittently by flashing the contents of the audio stream buffer, the amount of audio data to be reproduced is reduced, and high-speed reproduction is performed. It is possible to realize high-speed reproduction of audio with few interruptions in line with the reproduction speed of a video without changing the speed of the video.

According to the fifth aspect of the present invention, the transfer of the audio signal output from the input signal processing means to the audio stream buffer is interrupted by a predetermined amount, thereby reducing the audio reproduction data amount and By playing back the signal at high speed, it is possible to realize high-speed playback of audio with few interruptions that matches the video playback speed without changing the speed of video playback at high speed.

According to the sixth aspect of the present invention, in the audio processor, the input data from the audio stream buffer is skipped by a predetermined data amount, thereby reducing the audio reproduction data amount and reproducing the audio signal at high speed. This makes it possible to realize high-speed reproduction of audio with few interruptions that matches the video reproduction speed without changing the high-speed reproduction speed of the video.

According to the seventh aspect of the present invention, in the audio processor, the output of the audio signal is stopped for a predetermined period of time, thereby reducing the amount of audio data to be reproduced and reproducing the audio signal at a high speed. It is possible to realize high-speed reproduction of audio with little interruption, which matches the video reproduction speed, without changing the high-speed reproduction speed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an acoustic signal processing device according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of an audio signal processing device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an audio signal processing device according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an audio stream deletion method (i) in the audio signal processing devices according to the first to third embodiments of the present invention.

FIG. 5 is a diagram illustrating the acoustic signal processing device according to the first to third embodiments;
FIG. 3 is an explanatory diagram showing an audio stream deletion method (ii).

FIG. 6 shows an acoustic signal processing device according to the first to third embodiments;
It is an explanatory view showing an audio stream deletion method (iii).

FIG. 7 is a diagram illustrating the acoustic signal processing apparatus according to the first to third embodiments;
FIG. 9 is an explanatory diagram showing an audio stream deletion method (iv).

FIG. 8 is an explanatory diagram showing a remaining state of data in an audio stream buffer and a video stream buffer in the audio signal processing devices according to the first and third embodiments.

FIG. 9 is an explanatory diagram showing a remaining state of data in an audio stream buffer and a video stream buffer in the audio signal processing devices according to the second and third embodiments.

[Explanation of symbols]

 Reference Signs List 1 input stream 2 input stream processing means (input signal processing means) 3 audio stream buffer 4 video stream buffer 5A, 5B, 5C buffer controller 6 control means 7 audio processor 8 video processor 9 audio output signal 10 video output signal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihisa Kawamura 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Takeshi Fujita 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Tsuyoshi Nakamura 1006 Odaka Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 1006 Kadoma Kadoma Matsushita Electric Industrial Co., Ltd. (72) Eiji Otomura Inventor 1006 Kadoma Kadoma Osaka Kadoma City Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] A control means for instructing a reproduction speed; an input signal processing means for processing an input signal in which an audio signal and a video signal are multiplexed to output an audio signal and a video signal; An audio stream buffer for temporarily storing an audio signal to be output, a video stream buffer for temporarily storing a video signal output from the input signal processing unit, and an audio signal extracted from the audio stream buffer to perform signal processing. An audio processor for generating an audio output signal; extracting a video signal from the video stream buffer, performing signal processing, and receiving a high-speed reproduction instruction from the control unit, reproducing the video signal at a high speed, and outputting a video output signal. A video processor for generating the audio data; A buffer controller that monitors the state of the audio stream buffer and controls the input / output of data so that the audio processor performs high-speed reproduction of the audio signal when the free space becomes smaller than a predetermined amount A. A sound signal processing device characterized by the above-mentioned. A control means for instructing a reproduction speed; an input signal processing means for processing an input signal in which an audio signal and a video signal are multiplexed to output an audio signal and a video signal; An audio stream buffer for temporarily storing an audio signal to be output; a video stream buffer for temporarily storing a video signal output from the input signal processing means; an audio signal from the audio stream buffer; An audio processor for generating an audio output signal; extracting a video signal from the video stream buffer to perform signal processing; and receiving a high-speed reproduction instruction from the control unit, reproducing the video signal at a high speed and outputting a video output signal. A video processor for generating A buffer controller that monitors a state of the stream buffer and controls input / output of data so that the audio processor performs high-speed reproduction of an audio signal when the remaining amount becomes smaller than a predetermined amount V. A sound signal processing device characterized by the above-mentioned. Control means for instructing a reproduction speed; input signal processing means for processing an input signal in which an audio signal and a video signal are multiplexed to output an audio signal and a video signal; An audio stream buffer for temporarily storing an audio signal to be output, a video stream buffer for temporarily storing a video signal output from the input signal processing unit, and an audio signal extracted from the audio stream buffer to perform signal processing. An audio processor for generating an audio output signal; extracting a video signal from the video stream buffer, performing signal processing, and receiving a high-speed reproduction instruction from the control unit, reproducing the video signal at a high speed, and outputting a video output signal. A video processor for generating the audio data; The state of the audio stream buffer and the video stream buffer is monitored, and when the free space of the audio stream buffer becomes smaller than a predetermined amount A, or when the remaining amount of the video trim buffer becomes a predetermined amount V
An audio signal processing device, comprising: a buffer controller that controls input and output of data so that the audio processor performs high-speed reproduction of an audio signal when the number becomes smaller. 4. The high-speed audio reproduction method in the audio signal processing apparatus according to claim 1, wherein, when a video signal is reproduced at high speed, the contents of the audio stream buffer are intermittently flushed to thereby reproduce the audio. A high-speed audio reproduction method characterized by thinning out signals and reducing the amount of audio reproduction data to perform high-speed reproduction. 5. The high-speed audio reproduction method in the audio signal processing device according to claim 1, wherein when reproducing a video signal at a high speed, an audio stream buffer output from the input signal processing means is used as an audio stream buffer. An audio high-speed reproduction method characterized by reducing the amount of audio reproduction data by reproducing the audio signal at a high speed by interrupting the transfer of the audio signal by a predetermined amount. 6. The high-speed audio reproduction method in the audio signal processing device according to claim 1, 2 or 3, wherein when the video signal is reproduced at high speed, the audio processor determines input data from the audio stream buffer in a predetermined manner. A high-speed audio reproduction method characterized in that an audio signal is reproduced at a high speed by reducing the amount of reproduced data of audio by skipping the data amount of the audio signal. 7. The high-speed audio reproduction method in the audio signal processing device according to claim 1, 2 or 3, wherein when the video signal is reproduced at high speed, the audio processor stops outputting the audio signal for a predetermined time. An audio high-speed reproduction method characterized by reducing the amount of audio reproduction data and reproducing the audio signal at high speed.