JP3743309B2 - Recording method and recording / reproducing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording / reproducing apparatus for recording and editing video data and audio data on a magnetic tape by a helical scan method, and particularly suitable for performing editing while reproducing recorded audio data with one apparatus. About.
[0002]
[Prior art]
Some broadcasting digital VTRs have a function of editing in real time while playing back a tape with a single VTR on a magnetic tape on which video data and audio data are recorded. For example, a pre-read editing function that mixes already recorded audio data with another audio data while recording the tape and records it again at the original location is one such editing function.
[0003]
A conventional broadcasting digital VTR having such a pre-read editing function will be described below with reference to the drawings. FIG. 8 is a schematic view showing a head arrangement on a rotary cylinder of a conventional broadcasting digital VTR, and is a view of the rotary cylinder 19 as viewed from above. In FIG. 8, the rotating cylinder 19 rotates counterclockwise. The rotary cylinder 19 is equipped with recording heads 3a and 3b and preceding reproducing heads 4a and 4b. The rotating tape 19 travels with the magnetic tape 5 being wound obliquely over an interval of approximately half a circle (180 degrees).
[0004]
FIG. 9 shows the positional relationship between the recording track pattern on the magnetic tape 5 and the head. In FIG. 9, video data and audio data are already recorded on the magnetic tape 5, and tracks are formed obliquely. Here, the magnetic tape 5 always travels at a constant speed from right to left as viewed in the drawing. Accordingly, signals are recorded on the tracks in order from right to left. The preceding reproducing head 4a is mounted on the cylinder so as to reproduce a track that precedes the recording head 3a by the time required for signal processing at the time of recording / reproducing (a signal in which a later signal is recorded). . That is, the preceding reproducing head 4a is on a track preceding N tracks (N is a natural number) with respect to the track scanned by the recording head 3a. Although not shown, similarly, when the recording head 3b is positioned on the tape, the preceding reproducing head 4b reproduces a track that is N tracks ahead of the recording head 3b.
[0005]
Next, the configuration of this conventional broadcast digital VTR and the operation in the case where the already recorded audio data and another audio data are mixed and recorded in the original location will be described. FIG. 10 shows a configuration in the case of editing audio data already recorded by a conventional broadcast digital VTR. The signal reproduced by the preceding reproducing head 4a or reproducing head 4b is supplied to the reproducing processing circuit 13 via the head switch 21. The head switch 21 is controlled by a control signal synchronized with the rotation of the rotary cylinder 19 and selects the preceding reproducing head located on the magnetic tape 5. The reproduction processing circuit 13 performs demodulation, error correction processing, and deshuffling processing on the reproduction signal selected by the head switch 21, and outputs a signal restored to the original digitized video data and audio data. The reproduced audio data is input to the mixing circuit 18 and mixed with audio data input from the outside via the audio input terminal 17 to obtain new audio data, which is output to the recording signal processing circuit 12. The recording processing circuit 12 performs shuffling processing, error correction coding, modulation, etc., is supplied to the recording head 3a or recording head 3b via the head switch 20, and is overwritten and recorded on all or part of the tracks on the magnetic tape. The head switch 20 is controlled by a control signal synchronized with the rotation of the rotary cylinder 19, and selects a recording head located on the tape.
[0006]
The processing time required for the signal processing until the signal recorded on the tape is reproduced by the preceding reproducing head, mixed with other input data, and recorded on the tape again, scans N tracks. It corresponds to the time required to do. Further, as described above, the preceding reproducing heads 4a and 4b are configured to reproduce a track that precedes the recording heads 3a and 3b by N tracks (recorded with the preceding signal in time). . As a result, the signal reproduced by the preceding reproducing head can be recorded at the original position on the magnetic tape after the reproducing, mixing and recording processes.
[0007]
As described above, in a conventional broadcast digital VTR, recording can be performed while reproducing a tape by mounting a recording head and a preceding reproducing head on a cylinder so that a track that precedes the recording head can be reproduced. An editing function is realized that mixes the recorded data and the data input from the outside and records the data again in the original location.
[0008]
[Problems to be solved by the invention]
However, in the above-described helical scan type recording / reproducing apparatus, the tape is obliquely wound around the rotating cylinder for recording / reproducing. Therefore, if the preceding reproducing head is too far from the recording head, the preceding reproducing head can Cannot be scanned. Such a limit of the preceding distance is physically determined from the configuration of the cylinder and the head, the tape width, and the like. Therefore, if the rotating cylinder is downsized to reduce the size and weight of the equipment, or if the number of tracks per time required for recording and playback is increased by increasing the recording rate, the entire track is played back to the position where playback is possible. There is a problem that it is impossible to provide a head mechanically and pre-read editing cannot be realized.
[0009]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording / reproducing apparatus having a pre-read editing function that processes already recorded audio data and records it again in the original location even when the entire track cannot be reproduced by the preceding reproducing head. It is.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a method for recording audio data on a magnetic tape in a helical scan system on a magnetic tape in a region close to the terminal end in the head scanning direction. The video data recording area is independent from the audio data recording area. In the video data recording area, data important for reproducing the outline of the recorded image data is recorded in the head scanning direction. Record on the end side of.
[0011]
Further, the preceding reproducing means reproduces at least the number of tracks corresponding to the time required for reproduction signal processing and recording signal processing with respect to the track scanned by the recording head, and the video output means is reproduced by the preceding reproducing means. The outline of the video data is reproduced, and the recording processing means overwrites and records only the audio data on the recording track.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The first invention of the present invention is a recording method for recording video data and audio data on a magnetic tape by a helical scan method, wherein the audio data is an area close to the terminal end in the head scanning direction on a recording track. The video data recording area is an area independent of the audio data recording area, and data important for reproducing the outline of the video data to be recorded is recorded in the video data recording area. Is recorded on the end side in the head scanning direction, and recording is performed by providing an audio recording area on the end side of head scanning, which is a reproducible range on the track. It becomes possible to play the outline of the video data in advance.
[0013]
According to a second aspect of the present invention, in the first aspect, the data important for reproducing the outline of the video data is pixel data near the center of the screen or low-frequency component data of the video data. The recording method is characterized by the fact that the low-frequency component in the center of the screen is recorded in the head scanning end of the video recording area, so that the outline of the video data is reproduced during the previous playback, and the video is synchronized with the external timing. It is easy to input voice from.
[0014]
Further, according to a third aspect of the present invention, in the first aspect, one frame of video data is divided into a plurality of segments in the horizontal direction, and the screen is viewed from the end side in the head scanning direction within the video data recording area. It is a recording method characterized by arranging and recording at least the low frequency component of the video data of each segment in order from the segment close to the center, and even when it can be reproduced only halfway within the recording area of each segment, always The adjacent area on the screen can be reproduced.
[0015]
According to a fourth aspect of the present invention, there is provided a recording / reproducing apparatus for recording video data and audio data on a magnetic tape by a helical scan method in the first invention, wherein the audio data is recorded on a recording track in a head scanning direction. The video data recording area is an area independent of the audio data recording area, and the outline of the video data to be recorded is reproduced in the video data recording area. Is required for at least reproduction signal processing and recording signal processing on the recording tape and the track scanned by the recording head with respect to the magnetic tape on which important data is arranged on the end side in the head scanning direction. A preceding playback means for playing back the track preceding the number of tracks corresponding to the time, and a video outline is played back by the video data played by the preceding playback means. And a video processing unit for overwriting only the audio data on the recording track, and the audio data is reproduced in advance and mixed with another signal. Recording is physically possible.
[0016]
FIG. 1 is a diagram showing a positional relationship between a recording track pattern and a head according to an embodiment of the present invention.
[0017]
In FIG. 1, 1 is an audio data recording area for recording audio data, 2 is a video data recording area for recording video data, 3 is a recording head for recording video and audio data on the magnetic tape 5, and 4 is an image from the magnetic tape 5. And a preceding reproduction head for prefetching audio data.
[0018]
As shown in FIG. 1, on the recording track of the magnetic tape 5, the area closest to the end in the head scanning direction is the audio data recording area 1, and the area independent of the audio data recording area is the video data recording area. Record as 2.
[0019]
FIG. 2 is a configuration diagram of a recording apparatus for recording with the track pattern of FIG. In FIG. 2, the same components as those in FIG.
[0020]
In FIG. 2, 6 is a video signal input terminal to which video data is input, 7 is an audio signal input terminal to which audio data is input, 8 is a video compression circuit that compresses video data input from the video signal input terminal 6, 9 is an audio shuffling circuit for rearranging audio data input from the audio signal input terminal 7 in a predetermined order, 10 is a memory for storing video data compressed by the video compression circuit 8, and 11 is compressed by the video compression circuit 8. A video data rearrangement circuit for rearranging the video data, 12 is a recording head 3 for recording the compressed video data output from the video data rearrangement circuit 11 and the audio data output from the audio shuffling circuit 9 on the magnetic tape 5. A recording processing circuit.
[0021]
In this embodiment, it is assumed that the video data is compressed by the DV compression method adopted in the home digital VTR.
[0022]
In FIG. 2, digital video data is input to the video compression circuit 8 via the video input terminal 6. The video compression circuit 8 compresses and outputs video data according to the DV compression method. FIG. 3 is a diagram showing video shuffling rules of the DV compression method in the 525/60 system in which the number of scanning lines of one frame is 525 and the field frequency is 60 Hz.
[0023]
As shown in FIG. 3, the screen of one frame is divided into super blocks of 10 rows in the vertical direction and 5 columns in the horizontal direction, and each super block is composed of 27 macro blocks. In the DV compression method, one super block is selected from each different row of each column, one macro block is taken out from each super block to form one video segment, and DCT, quantization, variable length in video segment units. A compression process such as encoding is performed. At this time, the data amount is always controlled to be equal to or smaller than a predetermined amount, and the compressed data for the video signal of each video segment is stored in a DIF group composed of five DIF blocks. One DIF block is assigned to each macroblock, and data is stored from the low-frequency data of the macroblock. The data that could not be stored is stored in free areas of the other four DIF blocks in the DIF group. That is, the low frequency data of each macro block is stored in the DIF block, and the high frequency data is also stored at least in the DIF group. Similar compression processing is performed on the 27 video segments in the super block to form one sector. That is, one sector is composed of 27 × 5 = 135 DIF blocks. For the jth DIF block of the kth DIF group in the sector, k (k = 0 to 26) corresponds to the macroblock number in the super block, and j (j = 0 to 4) is on the screen. Correspond to 5 columns. When the processing for one sector is completed, the next five super blocks are selected and the same processing is performed. One frame of video data is compressed, stored in 10 sectors, and output as a compressed data stream.
[0024]
The video data rearrangement circuit 11 performs rearrangement processing in units of DIF blocks on each input compressed data stream. The video data rearrangement circuit 11 writes 135 DIF blocks in a sector to the memory 10 in the order of input, and when reading, first reads all 27 DIF blocks with j = 2, and then j = 1, j = 3, DIF block data is read in the order of j = 0 and j = 4. That is, reading is performed from the DIF block close to the center of the screen. At this time, when j = 2, j = 3, and j = 4, data is read in the order of k = 0, 1, 2,..., 26, and when j = 0 and j = 1, conversely, k = 26 , 25, 24,..., 0 in this order. The audio shuffling circuit 9 rearranges the audio data input from the audio signal input terminal 7 in a predetermined order. The recording signal processing circuit 12 adds an error correction code to the compressed video data and shuffled audio data, performs modulation processing, and records on the magnetic tape 5. A sync block, which is a recording unit, corresponds to a DIF block, and data of one sector is recorded on one track. The data format on the tape is as shown in FIG. 1, and the audio data is located on the most end side with respect to the head scanning direction on the recording track.
[0025]
FIG. 4 is a diagram showing the data arrangement in one track. In FIG. 4, the same components as those in FIG. As shown in FIG. 4, in the recording area of the video data, from the head scanning end side, j = 2, j = 1, j = 3, j = 0, j = 4 from the super block close to the center of the screen in order. A low frequency component of video data of each super block is recorded, and a parity is recorded at the end. In the recording area of j = 2, j = 3, j = 4, data is recorded in the order of k = 0, 1,..., 26, that is, from left to right on the screen, and j = 0, j = 1. In the recording area, data is recorded in the order of k = 26, 25,..., 0, that is, in order from right to left on the screen.
[0026]
Next, a case where pre-read editing is performed on the tape recorded as described above will be described.
[0027]
FIG. 5 is a block diagram of the recording / reproducing apparatus according to the embodiment of the present invention. In FIG. 5, the same components as those in FIGS.
[0028]
In FIG. 5, 14 is a video decompression circuit which is a video output means for decompressing the compressed video data reproduced by the reproduction processing circuit 13, and 15 is an audio deshuffling circuit which converts the audio data reproduced by the reproduction processing circuit 13 from the original arrangement. , 16 is a video signal output terminal for outputting video data output from the video decompression circuit 14, 17 is an audio signal input terminal for inputting audio data, and 18 is an audio data and audio signal input terminal output from the audio deshuffling circuit 15. 17 is a mixing circuit that mixes audio data input from 17;
[0029]
Here, it is assumed that each of the recording process and the reproduction process takes a processing time of two frames. Therefore, the preceding reproducing head 4 is mounted on the rotating cylinder so as to scan 4 frames, that is, 40 tracks before the recording head 3. The scanning of each head on the tape is as shown in FIG. 1, where N = 40. As shown in FIG. 1, since only a part of the track is wound around the cylinder at the position where the preceding reproducing head 4 scans on the tape, a part of the audio data and the video data is reproduced. Data reproduced by the reproduction processing circuit 13 is subjected to reproduction processing such as demodulation and error correction processing, and separated into video data and audio data. The audio data is converted and output by the audio deshuffling circuit 15 as well as the original data. The video data is input to the video decompression circuit 14, where variable length code decoding processing, inverse quantization, and inverse DCT processing are performed in units of reproduced macroblocks. At this time, if all the data of the macro block is not stored in the reproduced sync block, the video signal is reproduced and output only by the stored low frequency data. While watching this output video, audio data such as narration or music is generated in accordance with the timing of the video and input from the audio signal input terminal 17. The mixing circuit 18 mixes and outputs the sound data input from the sound signal input terminal 17 and the sound data output from the sound deshuffling circuit 15. The data output from the mixing circuit 18 is subjected to a predetermined shuffling process in the audio shuffling circuit 9, and then the recording processing circuit 12 performs a recording process to overwrite the original audio data recording area.
[0030]
Here, for example, when about 70% of the video recording area shown in the preceding playable range in FIG. 4 is played back, the preceding playable area becomes the area shown by the shaded portion in FIG. The center of the screen can be reproduced with at least low-frequency components. In many cases, the subject of the video is in the center of the screen, and if there is a low frequency component in frequency, the outline of the image can be reproduced. For this reason, even if the entire screen cannot be reproduced, the outline of the image can be grasped.
[0031]
In this way, even when the entire track cannot be played back by the preceding playback head, by providing the audio recording area on the end side of head scanning, which is the range that can be played back on the track, the audio data is played back in advance and another signal is reproduced. It is physically possible to record with mixing. In addition, by recording the low-frequency component at the center of the screen in the head scanning end of the video recording area, it is possible to reproduce the outline of the video data at the time of preceding playback and to input audio from the outside in time with the video Can be.
[0032]
Further, by dividing the segment horizontally on the screen (5 segments in the present embodiment) and arranging and recording the data in segment units, the compatibility with the DV compression shuffling method is good, and the DV compression method Can be realized by adding a simple rearrangement circuit.
[0033]
At this time, the data arrangement of each macroblock in each segment is arranged in order from right to left toward the screen for the segment left from the center on the screen, and from the left for the segment to the right from the center. The data is arranged in order from the macroblock that touches the adjacent segment on the center side of the screen so that they are arranged in the right order. As a result, even when playback is possible only halfway within the recording area of each segment, it is possible to always play back an adjacent area on the screen.
[0034]
In this embodiment, the video compression method is the DV compression method, and one screen is divided in units of super blocks according to the DV compression shuffling method. However, the compression method and the shuffling method are not limited to this. It can be applied in various ways. When recording is performed by shuffling at random, for example, an area that can be reproduced in advance is as shown in FIG. At this time, only a rectangular area (reproduction data display area) inscribed in the reproducible area is displayed, and other areas are displayed at a fixed level (fixed data) such as a black level, so that an image that is easier to view is displayed. can get.
[0035]
Needless to say, the video data is not limited to the 525/60 format, and is effective when recording video signals having different signal formats. For example, the same recording method and recording / reproducing apparatus can be used when rearranging the pixels at the upper and lower ends of the screen to the left and right ends of the screen or when inputting and recording an image obtained by sub-sampling the screen in the horizontal and vertical directions. realizable.
[0036]
【The invention's effect】
As described above, according to the present invention, even when the entire track cannot be reproduced by the preceding reproducing head due to signal processing delay or mechanical limitations, the already recorded audio data is processed and recorded again at the original location. A recording / reproducing apparatus having a pre-read editing function can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positional relationship between a recording track pattern on a magnetic tape and a head in an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a recording apparatus in the embodiment of the present invention. FIG. 4 is a diagram showing a shuffling rule of the DV compression method. FIG. 4 is a diagram showing data arrangement on a recording track in the embodiment of the invention. FIG. 5 is a block diagram showing a configuration of a recording / reproducing apparatus in the embodiment of the invention. FIG. 6 is a diagram showing a first playback video example during pre-read editing in the embodiment of the present invention. FIG. 7 is a diagram showing a second playback video example during pre-read editing in the embodiment of the present invention. 8 is a diagram showing a head arrangement on a rotating cylinder of a conventional recording / reproducing apparatus. FIG. 9 is a diagram showing a positional relationship between a recording track on a magnetic tape and a head in a conventional recording / reproducing apparatus. Block diagram showing the configuration EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Video data recording area 2 Audio | voice data recording area 3 Recording head 4 Previous reproduction | regeneration head 5 Magnetic tape 8 Video compression circuit 9 Audio shuffling circuit 11 Video data rearrangement circuit 12 Recording processing circuit 13 Playback processing circuit 14 Video expansion circuit 15 Audio deshuffling Circuit 18 Mixing circuit

Claims (6)

A recording method for recording video data and audio data on a magnetic tape by a helical scan method, wherein the audio data is recorded on a recording track arranged in a region near a terminal end with respect to a head scanning direction. The data recording area is an area independent of the audio data recording area. In the video data recording area, data important for reproducing the outline of the video data to be recorded is placed at the end side in the head scanning direction. A recording method comprising arranging and recording. 2. The recording method according to claim 1, wherein the data important for reproducing the outline of the video data is pixel data near the center of the screen or low-frequency component data of the video data. One frame of video data is divided into a plurality of segments in the horizontal direction, and within the video data recording area, at least the video data of each segment is sequentially recorded from the end side in the head scanning direction from the segment closest to the center of the screen. 3. A recording method according to claim 2, wherein the recording is performed by arranging the band components. In the area where the segment is divided into a plurality of pixel blocks and each segment is arranged in the recording area of the video data, the boundary portion in contact with the adjacent segment on the center side of the screen in the segment from the end side in the head scanning direction 4. The recording method according to claim 3, wherein data is arranged and recorded in order from the pixel block. A recording / reproducing apparatus for recording video data and audio data on a magnetic tape by a helical scan method,
The audio data is arranged on a recording track in an area close to a terminal end with respect to the head scanning direction, and the recording area of the video data is an area independent of the recording area of the audio data, and within the recording area of the video data Is recorded on the magnetic tape recorded with the data important for reproducing the outline of the video data to be recorded arranged on the end side in the head scanning direction,
A recording head; and a preceding reproduction means for reproducing a track preceding the number of tracks corresponding to at least a time required for reproduction signal processing and recording signal processing with respect to a track scanned by the recording head;
Video output means for reproducing and outputting an outline of the video with the video data reproduced by the preceding reproduction means;
A recording / reproducing apparatus comprising recording processing means for overwriting only audio data on the recording track. 6. The recording / reproducing apparatus according to claim 5, wherein the video output means replaces the outside of the rectangular area inscribed in the area on the screen that can be displayed with the video data reproduced by the preceding reproduction means with fixed data.

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