JP3412567B2 - Moving image data recording / reproducing device, moving image data recording / reproducing method, moving image data reproducing device, moving image data reproducing method, moving image data recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In a device such as a digital VTR for recording or reproducing moving image data on a recording medium, a moving image data recording / reproducing device and a moving image corresponding to special reproduction such as high speed image search. Image data recording / reproducing method,
The present invention relates to a moving image data reproducing device, a moving image data reproducing method, and a moving image data recording medium.

[0002]

2. Description of the Related Art A conventional moving picture data recording apparatus, a moving picture data reproducing apparatus, and a moving picture data recording medium will be described by taking a high-speed search by a digital VTR as an example. A digital VTR that records or reproduces moving image information (hereinafter also referred to as moving image data) in which a moving image signal is digitized by high-efficiency encoding or the like requires a special reproduction function such as high-speed search. A high-speed image search (hereinafter also referred to as a high-speed search) for reproducing an image at a high speed of 5 to 50 times the original reproduction speed is an essential function.
In the case of this high-speed search, the helical scan recording track is read diagonally, and a part of the image is obtained in a finely cut state. As a result, one screen is divided into several parts and displayed in the analog VTR. High-efficiency coding is used in consumer digital VTRs, where variable-length coding is used to compress information. In this case, since the recording position on the tape and the position of the image signal on the screen are not synchronized, the data obtained by the search is such that the position on the screen deviates from the normal position. Will be difficult to obtain.

Therefore, a method of separately recording information dedicated to high-speed search (hereinafter also referred to as special reproduction image data or search data) at a predetermined position on the tape has been considered. For example, a predetermined number of positions in the information track direction are set as recording positions for high-speed search information, and the same information is repeatedly recorded there over 10 tracks. in this case,
In a high-speed search up to 10 times, any of the 10 tracks is always read, so all the information (image data for special reproduction) dedicated to high-speed search can be obtained. A high-speed search image of a frame) is obtained. At this time, the information for high-speed search, which is recorded at a predetermined position on the track, cannot record one frame in only one place.
One frame is divided into several parts and recorded.

For example, if it is divided into 10 and the same data is repeatedly recorded over 10 tracks as described above, the information dedicated to the high speed search for one frame is recorded over 100 tracks. FIG. 3 is a diagram showing a configuration example of a conventional moving image data recording apparatus. In FIG. 3, the moving image data given from the data input 1 is data compressed by high-efficiency coding using inter-frame prediction.
Given to. Here, in the moving image data, one frame out of 10 to 30 frames is independently coded in each frame, which is called an intra frame or an I frame and serves as special reproduction image data.

In the search data former 31, only this intra frame (I frame) is separated, and when it is difficult to record all the data of one frame according to the amount of recordable information, 4 × 4. Only the low-frequency information of the image such as the average value of pixels is processed and provided to the search data memory 32 as special reproduction image data. Search data memory 3
Reference numeral 2 stores information for one track, and outputs search data to the multiplexer 33 in order to record the same data across a plurality of tracks.

On the other hand, general moving image data used in normal reproduction is given from the data input 1 to the buffer 5. The buffer 5 intermittently outputs the moving image data according to the multiplexing, and supplies it to the multiplexer 33. The multiplexer 33 converts the moving image data and the special reproduction image data into a number 10 to a number 1
A data string is created by switching it in units of sectors of about 00 bytes and given to the signal recorder 7. Here, the multiplexing process is performed so that the special reproduction image data is recorded in a specific portion of a predetermined track. In addition, the same information is used for several to several tens of tracks in the special reproduction image data according to the highest search speed.

If the transfer rate of the moving image data to be recorded is lower than the recording transfer rate, the stuff data (invalid data) is inserted to make the apparent transfer rate the same as the recording transfer rate. The signal recorder 7 adds an error correction code to a data string for recording on the recording medium 8, modulates a signal suitable for recording on the recording medium 8, and records the signal on the recording medium 8. . The recording medium 8 is, for example, a video tape, and search data is recorded in a specific portion of the track, and general moving image data is recorded in the other portion.

FIG. 4 is a diagram showing a configuration example of a conventional moving image data reproducing apparatus. In FIG. 4, in the signal regenerator 21,
The signal read from the recording medium 8 is demodulated and subjected to error correction processing, and the obtained data string is given to the demultiplexer 41. The demultiplexer 41 determines the type of data of the sector from the sector number or the like inserted in the header of the sector, separates and outputs the special reproduction image data during special reproduction, and outputs the moving image data during normal reproduction. And output.

The respective output data are supplied to the buffer 24. Then, the discontinuity of the data string due to the separation of the respective data is absorbed by the buffer 24, and is output from the data output 25 as reproduction data. Here, in special reproduction (high-speed search), if the search speed is n, only 1 / n of information can be read, but since the same search information is repeatedly recorded, all search speeds up to the number of repetitions can be read. The search information will be obtained.

When recording on a tape with two heads having different azimuth angles, the information cannot be read unless the azimuth of the track and the azimuth of the head match, so the recording method must correspond to that. Specifically, information is divided for each track of each azimuth angle, and repetitive recording is performed on the same azimuth track. Also, record search information only on one azimuth angle track,
Reading may be performed by only one head.

[0011]

In the method of recording high-speed search information as shown in the conventional example, the area for recording moving image data and the area for recording special reproduction (search) data are fixed. Each recording transfer rate is determined, and when the transfer rate of moving image data to be recorded is low, blank (stuff) data is inserted and recorded. The special reproduction image data is recorded at a constant transfer rate regardless of the transfer rate of the moving image data.

On the other hand, since the special reproduction image data needs to be repeatedly recorded at the same rate as the search speed, it is difficult to secure a sufficient transfer rate. As a result, the resolution of the special reproduction image data and The number of frames tended to decrease. The present invention has been made in view of the above points, and when reproducing a recording medium on which moving image data is recorded,
The purpose is to increase the image resolution during special playback and smooth the movement.

[0013]

According to the present invention, when recording moving image data for normal reproduction and image data for special reproduction,
The transfer rate of moving image data to be recorded and the special playback image data corresponding to it is set, and the ratio of moving image data and special playback image data is changed based on the recording format. In this case, the transfer rate of the special reproduction image data can be increased accordingly. Here, the recording format means a recording form on a recording medium, and is a structure (logical format) of recorded digital information. As described above, the present invention sets the transfer rate of the special reproduction image data corresponding to the moving image data to be recorded when recording the moving image data on the recording medium, and at the set transfer rate, Generating special reproduction image data from moving image data, and
The recording format is set from the transfer rate of the special reproduction image data, and based on this recording format, according to the format information indicating the ratio mode of the moving image data sector and the special reproduction image data sector on the track of the recording medium. The moving image data, the special reproduction image data and the format information are multiplexed, the obtained data string is recorded at a predetermined position on the track of the recording medium, and then the data string recorded on the recording medium is read, A moving image in which a recording format is identified from the data string, moving image data and special reproduction image data are separated from the read data based on the identified recording format, and either one of the image data is output. An image data recording / reproducing apparatus and a moving image data recording / reproducing method.

Further, according to the present invention, when the data recorded by the moving image data recording / reproducing apparatus is reproduced from the recording medium, the data string is read from the recording medium, the recording format is identified from the data string, and the data is read. A moving image data reproducing apparatus and a moving image data reproducing method, in which moving image data and special reproduction image data are separated from the obtained data based on the identified recording format, and either one of the image data is output. is there. Further, the present invention provides
A moving image data recording medium in which moving image data and special reproduction image data generated from this moving image data are separately recorded near a predetermined position on a track of a magnetic tape, and are recorded on one track. The ratio between the code amount of the moving image data and the code amount of the special reproduction image data is variable according to the transfer rate of the moving image data, and the special reproduction image data is distributed in a plurality of areas on one track. It is a moving image data recording medium recorded in approximately equal parts.

[0015]

According to the present invention, when the moving image data for normal reproduction and the special reproduction image data are recorded, the moving image data and the special reproduction image data are recorded according to the transfer rate of the recording target moving image data. When the transfer rate of moving image data is low and the ratio of the code amount of is changed by changing the recording format, the transfer rate of image data for special playback increases accordingly, so that conventional blank (stuff) data is inserted. The special reproduction image data is entered in the portion that has been recorded, the resolution of the special reproduction image is increased, and the frame rate is increased to obtain a smooth special reproduction image.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing one embodiment of a moving image data recording device in a moving image data recording / reproducing device according to the present invention. In FIG. 1, parts corresponding to those of the conventional example of FIG. 3 are denoted by the same reference numerals, and the difference in configuration from the conventional example of FIG. 3 is the rate information separator 2, the search rate setting device. 9 and the format setting device 10 is provided. Also, the search data former 3 and the multiplexer 6
Is performed by the search data former 31 and the multiplexer 33 shown in FIG.
Behavior is different. The basic processing flow is the same in both devices, but the transfer rate of the special reproduction image data and the multiplexing method are different. The flow of recording signal formation will be described below with reference to FIG. The moving image data input from the data input 1 is input to the buffer 5, the search data former 3, and the rate information separator 2. General moving image data for normal reproduction is stored in the buffer 5 in order to deal with discontinuous reading when multiplexing. That is, in the multiplexer 6, the reading from the buffer 5 is stopped while the data is being read from the search memory 4, and the moving image data is accumulated in the buffer 5.

The rate information separator 2 analyzes the moving image data to be recorded, separates the transfer rate information of the data string from the header portion, and the search rate setter 9
Given to. In the search rate setting device 9, the transfer rate of moving image data is subtracted from the total recordable transfer rate,
A free transfer rate that can be used for search data is calculated. The total recordable transfer rate refers to the maximum total transfer rate that can be recorded on the recording medium. The free data transfer rate is divided by the number of times the search data is repeatedly recorded to obtain the search data transfer rate, which is given from the search data forming unit 3 to the format setting unit 10.

Here, the number of repeated recordings is preset according to the maximum speed of the high speed search. For example, if the maximum speed is 5 times, the number of repeated recordings is 5. The value of the transfer rate set for the special reproduction image data does not change continuously because the recording format is changed on a sector-by-sector basis as will be described later, and the sector to which the search data is assigned within one track. It changes by a constant multiple of the number. The search data former 3 analyzes the moving image data and detects only the independent image coded by the image data in the frame. The independent image is not limited to the independent image (I frame) for each frame,
In coding using inter-frame prediction, only a part of an image may be coded independently within a frame, and that part may be moved for each frame, which is also included.

Even in the case of such an independent image, one frame of independent image information can be obtained by synthesizing a partial independent image for one period of its movement, and can be handled in the same manner as an intra frame. Since the time varies depending on the partial portion of the image, the partial portion becomes discontinuous when the image moves, but the intra frame created in this way will also be described as one I frame. Search data is
From all the information of the intra frame, only the amount of information corresponding to the transfer rate of the search data given from the search rate setting unit 9 is extracted. The intra frame is usually inserted about once every 0.5 seconds, but not all of them are used, and they are thinned out according to the transfer rate. It also reduces information spatially,
Only the 8 × 8 DCT DC component or only the AC coefficient corresponding to a low frequency is used according to the transfer rate.

The search data thus formed is applied to the search data memory 4. The search data memory 4 stores search data recorded for one track. Therefore, the capacity corresponding to the maximum value is
It is necessary for the controller memory 4. On the other hand, the format setter 10 sets the format of which sector is to be used as search data according to the transfer rate of the search data given from the search rate setter 9, and gives the information to the multiplexer 6. Here, the format information, which is the information for which the format is set, indicates the ratio mode of the moving image data sector and the special reproduction image data sector on the track of the recording medium.

The multiplexer 6 time-division-multiplexes the moving image data stored in the buffer 5 and the search data recorded in the search data memory 4 on a sector-by-sector basis in accordance with the format given by the format setter 10.
The created recording data string is given to the signal recorder 7. Here, if the search data corresponds to 5 × speed, the same data is read and multiplexed five times. The data string thus formed is subjected to error correction code addition and modulation by the signal recorder 7 as in the conventional example, and is recorded on the recording medium 8.

Next, a specific recording arrangement (format) on the tape will be described with reference to FIG. FIG. 5 is a diagram showing a recording format of the moving image data recording medium according to the present invention. In FIG. 5, each track is finely divided in the vertical (vertical) direction by a thin line, and a search data recording position is enclosed by a thick line. In the case of helical scan, the actual track is oblique to the tape, but it is shown vertically in FIG. 5 for convenience. Further, the diagonal line indicates head scanning during special reproduction (5 × speed search), which is diagonal to the track.

FIG. 5A shows the case where the moving image transfer rate is high and the search data transfer rate is low, and FIG. 5B shows the case where the moving image transfer rate is low and the search data transfer rate is high. The recording position of the search data on the tape is 1
There are two predetermined areas on the track. Compared to (a), (b) has more search data. However, the continuous recording length of each search data on one track is set so that all tracks can be continuously read even if the tracks are obliquely read in the high speed search.

FIG. 6 is a diagram showing a state of a sector in one track of the moving image data recording medium according to the present invention. In the figure, one track is shown in an enlarged manner, and one division is one.
Represents a sector. The respective recording areas of the moving image data and the search data are changed in units of sectors, and the areas of the search data indicated by diagonal lines are increased or decreased with the center positions being substantially the same. Figure 6
In this case, if one track has 28 sectors and the total transfer rate of moving image data and search data is 28 Mbps, 4 sectors are used for search data in the upper stage, and moving image data is searched at 24 Mbps. The data becomes 4 Mbps. Similarly, the middle row is 20/8 Mbp each
s, the lower tier is 16/12 Mbps, respectively. For example, if the moving image data to be encoded is 18 Mbps, the recording format in the middle stage is selected, and the moving image data is 2
Staff data of Mbps is inserted. When the number of sectors per track is larger, the transfer rate can be switched more finely, and the amount of stuff data to be inserted becomes smaller. Although FIG. 5 and FIG. 6 show two search data recording areas on one track, even if the recording position is three or more, the purpose of the moving image data recording medium of the present invention will be described. It does not deviate.

FIG. 2 is a diagram showing an embodiment of the moving picture data reproducing apparatus side in the moving picture data recording / reproducing apparatus according to the present invention. The parts corresponding to those of the conventional example in FIG. 4 are designated by the same reference numerals. It differs from FIG. 4 in that a format discriminator 22 is provided. In the signal regenerator 21, the signal read from the recording medium 8 becomes a data string, and the format discriminator 2
2 and the demultiplexer 23. The format discriminator 22 detects the format information multiplexed in the data string and recognizes to which sector the moving image data and search data of the data string are allocated. In other words, the format discriminator 22 separates the format information, and discriminates the ratio mode of the moving image data sector and the special reproduction image data sector on each track which can be changed according to the transfer rate based on the format information. is doing. The demultiplexer 23 discriminates the moving image data and the search data from the format information, separates only one of the data and outputs it as in the conventional example. Each data is given to the buffer 24, the discontinuity of the data string due to the above-described separation of the data is absorbed, and the data is output from the data output 25 as reproduction data.

[0026]

According to the invention described in claim 1 or 2, when recording the moving image data for normal reproduction and the image data for special reproduction, the special image corresponding to the moving image data to be recorded is recorded. The transfer rate of the reproduction image data is set, the special reproduction image data is generated from the moving image data at the set transfer rate, and the recording format is set from the transfer rate of the special reproduction image data. Based on the format, the ratio of moving image data and special reproduction image data is changed according to the format information indicating the ratio mode of the moving image data sector and the special reproduction image data sector on the track of the recording medium. Multiplex image data, image data for special playback, and format information,
Since the obtained data string is recorded at a predetermined position on the track of the recording medium, if the transfer rate of moving image data is low, by increasing the transfer rate of special reproduction image data by that amount, it is possible to use the conventional blank. (Staff) The special reproduction image data is inserted into the portion where the data has been inserted, and the resolution and frame rate of the special reproduction image can be increased. As a result, a search image with smoother movement and higher resolution can be obtained without increasing the recording / transfer rate.

According to the third or fourth aspect of the present invention, by identifying the recording format information of the moving image data for normal reproduction and the image data for special reproduction during reproduction, the image data for special reproduction can be obtained. Even when the transfer rate is changed, it is possible to obtain all the special reproduction image data, the resolution of the reproduced image at the time of high-speed search is high, and the movement is smooth.

According to the invention described in claim 5, in the recording tape, the special reproduction image data is divided substantially evenly and recorded in a plurality of areas on the track, and the moving image data on the recording format and the special reproduction image data are recorded. By changing the area length of the special playback image data depending on the ratio of the image data,
The invalid data portion is small, and the moving image data for normal reproduction and the image data for special reproduction are effectively recorded, and the resolution and smoothness of movement of the reproduced image are improved.

[Brief description of drawings]

FIG. 1 is a diagram showing one embodiment of a moving image data recording device side in a moving image data recording / reproducing device according to the present invention.

FIG. 2 is a diagram showing one embodiment of the moving image data reproducing device side in the moving image data recording / reproducing device according to the present invention.

FIG. 3 is a diagram showing a configuration example of a conventional moving image data recording apparatus.

FIG. 4 is a diagram showing a configuration example of a conventional moving image data reproducing apparatus.

FIG. 5 is a diagram showing a recording format of a moving image data recording medium according to the present invention.

FIG. 6 is a diagram showing a state of a sector in one track of a moving image data recording medium according to the present invention.

[Explanation of symbols]

2 transfer rate detecting means (rate information separator) 3 special reproduction data forming means (search data forming device) 4 search data memory 6 multiplexing means (multiplexer) 7 signal recording means (signal recording device) 8 recording medium 9 Rate setting means (search rate setting device) 10 Format setting means (format setting device) 21 Signal reproducing means (signal reproducing device) 22 Format identifying means (format identifying device) 23 Demultiplexing means (demultiplexer)

Claims (5)

(57) [Claims] 1. A moving image data recording apparatus for recording moving image data on a recording medium, comprising rate setting means for setting a transfer rate of special reproduction image data corresponding to the moving image data, and the rate setting means. At the transfer rate set in step 1, a special reproduction data forming means for generating the special reproduction image data from the moving image data, and a recording format is set from the transfer rate of the special reproduction image data. Format setting means for outputting format information indicating a ratio mode of the moving image data sector and the special reproduction image data sector on the track of the recording medium, based on the moving image data, the special reproduction image data, and the special reproduction image data. Multiplexing means for multiplexing format information according to the format information, and the multiplexed data Signal recording means for recording a row at a predetermined position on a track of the recording medium, and the moving image data, the special reproduction image data, and the format information are multiplexed from the recording medium recorded by the signal recording means. And a format for separating the format information from the data sequence and a ratio between the moving image data sector and the special reproduction image data sector on each track based on the format information. And a demultiplexing unit that separates the moving image data and the special reproduction image data from the read data according to the format information and outputs either one of the data. A moving image data recording / reproducing apparatus characterized by the above. 2. A moving image data recording method for recording moving image data on a recording medium, the step of setting a transfer rate of special reproduction image data corresponding to the moving image data, and the set transfer rate. Then, a step of generating the special reproduction image data from the moving image data, a recording format is set from a transfer rate of the special reproduction image data, and a moving image on a track of the recording medium is set based on the recording format. Outputting format information indicating a ratio mode of the image data sector and the special reproduction image data sector; and multiplexing the moving image data, the special reproduction image data, and the format information according to the format information. Recording the multiplexed data string at a predetermined position on the track of the recording medium. A step of reading a data string in which the moving image data, the special reproduction image data, and the format information are multiplexed from the recorded recording medium, and separating the format information from the data string. A step of identifying a ratio mode of the moving image data sector and the special reproduction image data sector on each track based on this format information, and the moving image data and the special reproduction image from the read data And a step of separating the data from the data according to the format information and outputting either one of the data. 3. Moving image data and special reproduction image data corresponding to the moving image data are separately recorded near a predetermined position on a track, and the moving image data recorded on one track is recorded. A reproducing apparatus for a moving image data recording medium in which the ratio of the code amount and the code amount of the special reproduction image data is not constant, wherein the moving image data and the special reproduction image data are multiplexed from the recording medium. Signal reproducing means for reading a data stream that has been encoded, and format information from the data stream, and moving image data sectors on each track that can be changed according to the transfer rate of the moving image data based on the format information Format identifying means for identifying a ratio mode of the image data sector for special reproduction, and the moving image data and the special reproduction for reading from the read data. They separated in accordance with the image data to the format information, moving picture data reproducing apparatus, characterized in that it comprises a demultiplexing means for outputting one of the data. 4. Moving image data and special reproduction image data corresponding to this moving image data are separately recorded near a predetermined position on a track, and the moving image data recorded on one track is recorded. A method of reproducing a moving image data recording medium in which the ratio of the code amount and the code amount of the special reproduction image data is not constant, wherein the moving image data and the special reproduction image data are multiplexed from the recording medium. A step of reading the encoded data sequence, separating the format information from the data sequence, and changing the moving image data sector on each track and the special information which can be changed according to the transfer rate of the moving image data based on the format information. A step of identifying a ratio mode with the image data sector for reproduction, and the moving image data and the image data for special reproduction are preceded from the read data. Video data reproducing method characterized by a step of separating depending on the format information, and outputs either of the data. 5. A moving image data recording medium in which moving image data and special reproduction image data generated from this moving image data are separately recorded in the vicinity of a predetermined position on a track of a magnetic tape. The ratio between the code amount of the moving image data recorded on the track and the code amount of the special reproduction image data is variable according to the transfer rate of the moving image data, and the special reproduction image data is on one track. A moving image data recording medium, which is recorded in a plurality of areas in a substantially equal area.