KR100220848B1 - Audio channel inserting apparatus for a digital video camera - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an audio channel insertion apparatus for recording another digital audio signal in a digital video camera (DVC), in which a digital audio signal is already recorded. An apparatus for inserting an audio channel that matches an average value of the magnitude of an audio signal per frame.

The present invention inserts a channel using two frame memories composed of a ping-pong structure for recording and reproduction, and encodes according to the AF size (AF-SIZE) of the decoded previous frame of the channel already recorded upon insertion.

Therefore, the present invention can insert a channel without adding memory during normal recording and playback, and satisfies the difference between the cumulative average values defined in the DVC SD specification according to the AF size (AF-SIZE) of the decoded previous frame of the already recorded channel. do.

Description

Audio Channel Inserting Apparatus for Digital Video Camera

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an audio channel insertion apparatus for recording another digital audio signal in a digital video camera (DVC), in which a digital audio signal is already recorded. An apparatus for inserting an audio channel that matches an average value of the magnitude of an audio signal per frame.

In general, audio encoding modes in digital audio cameras for digital video cameras are supported in four formats: two 48-kHz, 44.1-kHz, and 32-kHz and four-channel 32-kHz modes, depending on the product.

At this time, the audio data is recorded in two or four channels without compression. In particular, in the case of two channels, tracks for recording one frame are divided into a first half and a second half to record data of one channel.

That is, in the 525/60 mode as shown in FIG. 1, since one frame consists of 10 tracks, audio data of channel 1 is recorded on five tracks corresponding to the first half, and channel 2 is recorded on five tracks corresponding to the second half. Record audio data.

In other words, audio data of channel 1 is recorded in tracks 0 through 4, and audio data of channel 2 is recorded in tracks 5 through 9.

In addition, in 625/50 mode, one frame is composed of 12 tracks, so audio data of channel 1 is recorded in tracks 0 through 5 corresponding to the first half, and audio data of channel 2 is recorded in tracks 6 through 11 corresponding to the second half. Record it.

On the other hand, in the case of mono, when audio data of channel 2 is not used, audio data of channel 1 is copied to a track for recording audio data of channel 2, and dummy data is filled in a channel without information, and a video signal and The synchronized channel is always recorded in the track on which the audio data of channel 1 is recorded.

However, when audio data of another channel is recorded while the audio signal of one channel is already recorded, it is necessary to match the average value of the size (AF-SIZE) of the audio signal per frame. That is, in the case where an audio signal is recorded in a track corresponding to one channel while the audio signal is recorded in a track corresponding to one channel, the average value of the magnitude of the audio signal per frame must be matched per frame between channels with the same playback clock. An audio signal having a different size (AF-SIZE) can be reproduced.

For example, when recording an audio signal corresponding to channel 1 from track 0 to track 4 and recording an audio signal corresponding to channel 2 from track 5 to track 9, the size of the audio signal per frame between channels (AF-SIZE) Can be played with different frames at the same playback clock.

Accordingly, the present invention provides an audio channel insertion apparatus for simultaneously performing recording and playback with the same playback clock by matching an average value of the audio signal per frame of a channel to be inserted with an already recorded channel in a digital video camera. The purpose is.

1 is a structural diagram of a general track and channel

2 is a block diagram of an audio channel insertion apparatus according to the present invention

FIG. 3 is a diagram for describing a memory control operation when a channel is inserted in FIG. 2.

4 is a diagram for determining an AF size at the time of inserting a channel of FIG. 2;

5 is a diagram for explaining a playback operation after channel insertion;

* Explanation of symbols for main parts of the drawings

100: A / D converter 110: encoder

120: recording memory 121,122,141,142: frame memory

130: ECC and recording and playback system 140: Memory for playback

150: decoder 1 60: size determination unit

170: D / A Converter

In order to achieve the above object, an audio channel insertion apparatus of a digital video camera according to the present invention comprises: an encoder for encoding audio data of a channel to be recorded; A recording memory for storing audio data output from the encoder in units of frames, respectively; A recording / playback system for recording audio data output from the recording memory in units of frames in one channel and reproducing audio data recorded in another channel; A reproducing memory for storing audio data reproduced by the recording and reproducing system in units of frames, respectively; A decoder for decoding audio data in units of frames output from the reproduction memory; And a size for determining the size of audio data per frame of the one channel according to the size per frame of audio data output from the decoder and outputting the encoded data to the encoder to reduce the cumulative difference of the average value of the size of audio data per frame between channels. It is characterized by consisting of a decision unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

An audio channel insertion apparatus of a digital video camera according to the present invention includes an analog / digital converter (100), an encoder (110), a recording memory (120), an error correction code (ECC), and a recording. The playback system 130, the playback memory 140, the decoder 150, the size determiner 160, and the D / A converter 170 are provided.

The A / D converter 100 converts the audio data of the channel to be recorded by A / D conversion and outputs it to the encoder 110, and the encoder 110 records the A / D converted by the A / D converter 100. Encodes the audio data of the channel.

The recording memory 120 stores the audio data output from the encoder 110 in units of frames, and includes two frame memories 121 and 122 having a ping pong structure. .

That is, the recording memory 120 includes two frame memories 121 and 122 that alternately store audio data output from the encoder 110 in units of frames.

The ECC and the recording / reproducing system 130 perform error correction coding on audio data output from the two frame memories 121 and 122 of the recording memory 120 in units of frames, respectively, and record the audio data in one channel, and in another channel. The audio data recorded in " 1 " is reproduced and output to the reproducing memory 140.

The reproducing memory 140 stores audio data reproduced by the recording and reproducing system 130 in units of frames, and includes two frame memories 121 and 122 having a ping pong structure.

That is, the reproduction memory 140 is composed of two frame memories 141 and 142 which alternately store audio data reproduced by the recording and reproduction system 130 in units of frames.

The decoder 150 decodes audio data output in units of frames output from the two frame memories 141 and 142 of the reproduction memory 140.

The size determiner 160 determines the size of the audio data per frame of the one channel according to the size of the frame of audio data output from the decoder 150 and outputs the size to the encoder 110 to inter-channel frames. Reduce the cumulative difference in the mean value of the size of the audio data per sugar.

That is, the size determiner 160 outputs 1601, which is an average value of the size of audio data per frame in the 48K mode when the initial frame is encoded, to the encoder 110 to output the audio data per frame when the encoder 110 is encoded. Determine the size.

The operation of the audio channel insertion apparatus of the digital video camera according to the present invention configured as described above will be described.

First, audio data to be inserted into one channel is A / D-converted by the A / D converter 100 and then encoded by the encoder 110. In this case, since there is no audio data that is already recorded and reproduced and output from the ECC and recording / reproducing system 130, the size of the audio data per frame (AF-SIZE) cannot be known. The average value of the size AF-size is output by the size determining unit 160, and the encoder 110 outputs audio data of the first one frame to be inserted per frame output from the size determining unit 160. The encoding is performed by determining the average value of the audio data.

Audio data of one frame encoded by the encoder 110 is stored in one of the frame memories 121 and 122 of the recording memory 120. In other words, it is recorded in one of the frame memories 121 and 122 consisting of eight bytes and then recorded in one channel of the audio track of the tape in the ECC and the recording / reproducing system 130.

At this time, the audio data already recorded in the track of the other channel is reproduced by the ECC and the recording / reproducing system 130, stored in one of the frame memories 141 and 142 of the memory 140 for reproduction, and decoded by the decoder 150. The D / A converter 170 converts the D / A and outputs the reproduced audio data.

As described above, the encoder 110 encodes data to be recorded on another channel, stores the data in the memories 121 and 122, and records the data. The frame memories 141 and 142 operate in a ping-pong structure, which will be described with reference to FIG. 3.

FIG. 3A is a waveform diagram of a frame synchronizing signal, and FIG. 3B is a signal waveform diagram showing an operation state of the frame memories 141 and 142 for playback, and FIG. 121 and 122 are signal waveform diagrams showing an operating state, and FIG. 3 (d) is a signal waveform diagram showing an operating state of the encoder 110, and FIG. 3 (e) is a signal showing an operating state of the decoder 150. It is a waveform diagram.

When the frame synchronizing signal is generated as shown in Fig. 3 (a), the A / D converter (at the encoder 110) as shown in Fig. 3 (d) during one frame synchronizing, i.e., until the next rising edge is generated. The inserted channel audio data converted at 100 is encoded and stored in the frame memory 121. At this time, since the encoded data is the first frame, the ECC and the recording / reproducing system 130 cannot reproduce audio data of one frame that has already been recorded, and thus the average value of the size (AF-SIZE) of audio data per frame is determined. ) Is output to the encoder 110.

In addition, as shown in FIG. 3B, when the frame synchronizing signal becomes the rising edge during the first frame synchronizing, audio data of one frame already recorded is reproduced by the ECC and the recording / reproducing system 130 and stored in the memory 141. do.

Subsequently, when a second frame synchronization signal is generated as shown in FIG. 3 (a), the encoder 110 may perform A / A during one frame synchronization, that is, until the next rising edge is generated. The inserted channel audio data of the next frame converted by the D converter 100 is encoded and stored in the frame memory 122.

In addition, as shown in FIG. 3 (C), audio data of one frame already stored in the frame memory 121 is read and output from the ECC and recording / reproducing system 130 to the ECC and recording / reproducing system 130.

3, audio data stored in the frame memory 141 is encoded by the decoder 150 and output to the D / A converter 170 during the first frame synchronization.

In addition, as shown in FIG. 3 (b), when the frame synchronizing signal is the rising edge of the second frame synchronizing, the audio data of the next second frame already recorded is reproduced by the ECC and the recording / reproducing system 130 to the memory 142. Stored.

After that, when the third frame synchronization signal is generated as shown in FIG. 3 (a), the next frame converted by the A / D converter 100 at the encoder 110 as shown at 3 (d) during one frame synchronization. The embedded channel audio data is encoded and stored in the frame memory 121.

In addition, as shown in FIG. 3 (c), audio data of one frame already stored in the frame memory 122 is read and output from the ECC and recording / reproducing system 130 to the ECC and recording / reproducing system 130.

3, audio data stored in the frame memory 142 is encoded by the decoder 150 and output to the D / A converter 170 during the second frame synchronization.

As shown in Fig. 3B, when the frame synchronizing signal is the rising edge of the third frame synchronizing, the audio data of the next third frame which has already been recorded is reproduced by the ECC and the recording / reproducing system 130 to be stored in the memory 141. Stored.

Subsequently, when the fourth frame synchronization signal is generated as shown in FIG. 3 (a), the next frame converted by the A / D converter 100 at the encoder 110 as shown at 3 (d) during one frame synchronization. The embedded channel audio data is encoded and stored in the frame memory 122.

In addition, as shown in FIG. 3 (C), audio data of one frame already stored in the frame memory 121 is read and output from the ECC and recording / reproducing system 130 to the ECC and recording / reproducing system 130.

3, audio data stored in the frame memory 141 is encoded by the decoder 150 and output to the D / A converter 170 during the third frame synchronization.

As shown in Fig. 3B, when the frame synchronizing signal is the rising edge of the fourth frame synchronizing, the audio data of the next fourth frame already recorded is reproduced by the ECC and the recording / reproducing system 130 to be stored in the memory 142. Stored.

Decoded and encoded in this manner, stored and read in each frame memory 121, 122, 141, 142.

In other words, the already recorded audio data is transmitted to the frame memories 141 and 142, which are ping ponged by the frame memories 141 and 142 during transmission to be read in the memory 142 while being written to the memory 141. Repeat In addition, the embedded audio data to be recorded is encoded and transmitted to the frame memories 121 and 122. In transmission, the frame audio 121 and 122 is ping-ponged to perform a ping-pong operation to be recorded in the memory 121 and simultaneously recorded in the memory 122. Repeat reading.

On the other hand, the audio data decoded by the decoder 150 is input to the size determiner 160 to determine the size (AF-SIZE) of the audio data per frame of the audio data to be inserted, which will be described with reference to FIG. do.

4A is a waveform diagram of a frame synchronization signal, FIG. 4B is an AF size (AF-SIZE) of audio data of a decoded already recorded channel, and FIG. 4 (C) is audio data of an insertion channel. Is an AF size (AF-SIZE), and FIG. 4 (D) is a cumulative difference of average values between channels of the AF size (AF-SIZE).

Since there is no decoded AF size (AF-SIZE) at the beginning of operation, i.e., insertion of audio data of the first frame, the average value of the AF size (AF-SIZE) presented in the specification is determined and encoded as the AF size (AF-SIZE).

For example, in the 48K mode of the 525/60 system, the average value of the AF size (AF-SIZE) is 3203 bytes and 1601 samples, so 1601 is determined as the AF size (AF-SIZE) of the first frame.

That is, as shown in FIG. 3 (a), during the first frame synchronization, audio data of the insertion channel is encoded with an initial average AF size (AF-SIZE), that is, 1601, as shown in FIG. 3 (c).

Next, when the audio data of the second frame is inserted, there is a decoded AF size (AF-SIZE), so the AF size (AF-SIZE) of audio data of another decoded already recorded channel is determined as the AF size (AF-SIZE). To encode.

That is, as shown in FIG. 3 (a), during the second frame synchronization, 1600 samples are inserted because the AF size (AF-SIZE) of the first frame of another channel already recorded as shown in FIG. 3 (b) is 1600. The audio data is encoded by determining the AF size (AF-SIZE) of the audio data.

In this way, the audio data of the insertion channel is continuously encoded according to the AF size (AF-SIZE) of the audio data of the already recorded channel. Therefore, as shown in FIG. 3 (d), the cumulative value of the difference between the AF size (AF-SIZE) between the channels, that is, the channel already recorded and the channel to be inserted is reduced.

That is, the cumulative difference in the average value between the channels of the AF size AF-SIZE converges to '0' through continuous insertion as shown in FIG.

Therefore, when reproducing the inserted data, it is possible to continuously reproduce the audio signal output by controlling the address while using the same reproducing clock.

As described above, a process of recording and reproducing audio data on another channel while recording on one channel is described with reference to FIG.

FIG. 5A is a waveform diagram of a frame sync signal, FIG. 5B is a ping-pong sequence signal, FIG. 5C shows an AF size (AF-SIZE) of channel 1 that has already been recorded, and FIG. D) represents the AF size (AF-SIZE) of channel 2 to be inserted, FIG. 5 (e) is a ping-pong sequence transform value, FIG. 5 (bar) shows an address difference value, and FIG. 5 (g) shows channel 1 Shows a memory read operation, and FIG. 5 (h) shows a memory read operation of channel 2. FIG.

As shown in FIG. 5A, when the frame synchronization signal is input, as shown in FIG. 5B, the ping-pong sequence signal has a period twice that of the frame synchronization signal. At this time, the AF size (AF-SIZE) of the recorded channel 1 is encoded by determining the AF size (AF-SIZE) of the channel 2 to be inserted in the next frame sync as shown in FIG. The same as the AF size (AF-SIZE) of the next insertion channel 2, Figure 5 (e) shows the conversion value of the ping-pong sequence at this time.

On the other hand, the address is controlled using the same reproduction clock, and the difference of the addresses between the channels is as shown in Fig. 5 (bar), and the audio data of each channel 1 and 2 is shown in Fig. 5 (g) (a). As it is, it is read from memory.

As described above, the audio channel insertion apparatus of the digital video camera according to the present invention has the following effects.

First, channel insertion is possible without adding memory during normal recording and playback.

Second, according to the AF size (AF-SIZE) of the decoded previous frame of the already recorded channel, the difference between the cumulative average values defined in the DVC SD specification is satisfied.

Claims (5)

An encoder 110 for encoding audio data of a channel to be recorded; A recording memory 120 for storing audio data output from the encoder 110 in units of frames, respectively; A recording / playback system (130) for recording audio data output in units of frames from the recording memory (120) in one channel and reproducing audio data recorded in another channel; A reproducing memory 140 for storing the audio data reproduced by the recording and reproducing system 130 in units of frames, respectively; A decoder (150) for decoding audio data in units of frames output from the reproduction memory (140); And The size of the audio data per frame of the one channel is determined according to the size per frame of the audio data output from the decoder 150 and output to the encoder 110 to determine the average value of the size of the audio data per frame between the channels. Audio channel insertion apparatus of a digital video camera, characterized in that consisting of a size determiner 160 to reduce the cumulative difference. The first and second frames of claim 1, wherein the recording memory 120 stores frame-by-frame audio data output from the encoder 110 and outputs the recording data to the recording and playback system 130. Audio channel insertion apparatus of a digital video camera, characterized in that consisting of memory (121, 122). The first and second frame memories 141 of claim 1, wherein the reproducing memory 140 stores audio data reproduced by the recording and reproducing system 130 in units of frames and outputs them to the decoder 150. And an audio channel insertion device of a digital video camera. The apparatus of claim 1, wherein the size determiner (160) outputs an average value of the size of audio data per frame to the encoder (110) when encoding an initial frame. The apparatus of claim 4, wherein the size determiner (160) outputs 1601 as the size of audio data per frame to the encoder (110) when encoding an initial frame.