JP2006101533A - Image recording system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To record a still image which will not damage the image quality or search property, even when using an encoding system that is in common with moving image. <P>SOLUTION: If digital image data inputted to a terminal 201 are still image data, the data are held via a still image hold switch 202 into a still image frame memory 203. When a still image recording instruction is input, a still image recording control circuit 205 connects a switch 204 to the side of the still image frame memory 203 only for a prescribed period of time, and continuously inputs the same still image frame to an encoding loop. Furthermore, a motion compensation predicting circuit 219 is controlled to suppress the generation of motion vectors, without forcibly performing motion compensation, when recording still images. Moreover, a quantization circuit 209 is controlled to perform encoding, where quantization steps in still image recording are made more precise than that in moving image recording. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image recording method and method, and more particularly, to a still image data recording method and method in a recording method that compresses and records a moving image using interframe coding, such as MPEG-1 and MPEG-2 methods.

  Products such as D-VHS have been developed by a technique for recording MPEG data on a home digital video recorder, and a technique for recording HD (High Definition) video data on a DV standard small cassette has been disclosed in Patent Document 1 and the like. Yes.

  On the other hand, in the SD standard SD recording format, a method for recording a still image on a tape medium together with a predetermined search ID for a certain period is standardized, and a still image search technique on a tape using this is disclosed in Patent Document 2 and the like. ing.

JP 2001-275077 A JP-A-7-98965

  However, when applying a tape still image recording in the conventional SD recording format to HD video recording using MPEG data, an inter-frame encoding process similar to that for a moving image is applied to a still image sequence that should not cause an inter-frame difference due to motion. However, there is a problem that the original image quality and searchability of the still image are impaired, such as image quality deterioration at the beginning of the still image and mismatch of variable length code and ID for each track.

  The present invention has been made in view of the above points, and an object of the present invention is to enable still image recording that does not impair image quality and searchability even when an encoding method common to moving images is used. .

The image recording system according to the present invention is an image recording system that records moving image data that is inter-frame encoded and that can record still image data as video for a predetermined period using a common encoding method with moving images. And still image frame memory means for holding still image data recorded as video for the predetermined period, encoding means for encoding image data, and motion compensation prediction for inter-frame encoding Motion compensation predicting means, encoding motion picture data by performing the motion compensation prediction at the time of moving picture recording, and encoding still picture data output from the still picture frame memory means without motion compensation prediction at the time of still picture recording And a control means for controlling the encoding means.
Another image recording method according to the present invention is an image recording method that records inter-frame encoded moving image data and enables still image data to be recorded as video for a predetermined period using an encoding method common to moving images. A still image frame memory means for holding still image data recorded as video for the predetermined period, an encoding means for encoding image data according to a predetermined frame encoding unit, and an inter-frame code A motion compensation prediction means for performing motion compensation prediction for encoding, and a motion compensation prediction for encoding the frame coding unit during moving image recording, and a still image output from the still image frame memory means during still image recording When encoding image data, the encoding is performed so that the frame encoding unit is encoded without performing motion compensation prediction from the previous frame encoding unit. Characterized in that a control means for controlling the means.
The image recording method according to the present invention is an image recording method for recording moving image data that is inter-frame encoded, and enabling still image data to be recorded as a video for a predetermined period using an encoding method common to moving images. A procedure for holding still image data recorded as video for the predetermined period, a procedure for encoding image data, and a procedure for motion compensation prediction for inter-frame encoding. Is characterized in that the motion compensation prediction is performed to encode the moving image data, and the still image data that is held is encoded without the motion compensation prediction at the time of recording a still image.
Another image recording method according to the present invention is an image recording method for recording moving image data that has been inter-frame encoded, and enabling still image data to be recorded as a video for a predetermined period using an encoding method common to moving images. A procedure for holding still image data recorded as video for the predetermined period, a procedure for encoding image data according to a predetermined frame encoding unit, and motion compensation prediction for inter-frame encoding. The frame encoding unit is encoded by performing the motion compensation prediction at the time of moving image recording, and when the stored still image data is encoded at the time of still image recording, the immediately preceding frame encoding unit It is characterized in that the frame coding unit is encoded without performing motion compensated prediction from.

  According to the present invention, when still image data output from the still image frame memory means is encoded at the time of still image recording, since motion compensation prediction is not performed, it is possible to prevent an increase in code amount.

  Hereinafter, an embodiment of an image recording method of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a digital video recording apparatus according to an embodiment. The video signal input to the input terminal 101 is digitized by the A / D conversion circuit 102 and converted into digital image data.

  The image data is compression encoded by the compression encoding circuit 103 and multiplexed with the audio data and additional information by the data multiplexing circuit 104. Note that description of components other than the image data is omitted.

  For the multiplexed data, error correction coding circuit 105 adds parity information for error correction. In the recording formatting circuit 106, additional information including a subcode is added and converted into a recording format on a medium.

  In the modulation encoding circuit 107, the formatted recording data is modulated into a data string suitable for recording on a medium. The recording data is applied to the head 109 as an electric signal through the recording amplifier 108 and recorded on the recording medium 110.

  The still image recording instruction input 111 is supplied with a control signal for instructing this when performing still image recording according to the present invention. The still image recording instruction signal is supplied to the compression encoding circuit 103 and the recording formatting circuit 106, and processing for still image recording is performed. At the time of still image recording, an ID for identifying still image recording, for example, ID information called PPID in the DV format, is recorded in the subcode of the video track on which the still image is recorded. Cueing is possible.

  FIG. 2 is a diagram showing details of the compression coding circuit 103 according to the MPEG coding system of the present embodiment. The digital image data input to the terminal 201 becomes one input of the switch 204. In the case of still image data, the digital image data is held in the still image frame memory 203 via the still image hold switch 202 and becomes the other input of the switch 204. .

  The frame rearrangement circuit 206 rearranges each frame of the moving image in the order of MPEG encoding. FIG. 3 is a diagram showing the relationship between a GOP (group of pictures), which is an MPEG interframe coding unit, and an I picture, a P picture, and a B picture. (A) is the order of input of moving images. In MPEG encoding, the order of B pictures, which is bidirectional prediction, is changed as shown in (b) for encoding.

  In the frame difference circuit 207, the switch 220 obtains a difference from the inter-frame prediction data for the P picture and the B picture.

  The DCT circuit 208 converts the original image for the I picture and the prediction error image for the P picture and B picture into DCT coefficients.

  The quantization circuit 209 performs quantization by the product of the quantization matrix and the quantization characteristic value Q based on feedback from the code amount control circuit 210. The quantized coefficient is entropy-coded in the variable-length coding circuit 211, and is output from the terminal 213 via the buffer 212 for rate control.

  The inverse quantization circuit 214 inversely quantizes the quantization coefficient output from the quantization circuit 209, converts it to a pixel value by the inverse DCT circuit 215, and then controls the switch 217 to cause the frame addition circuit 216 to perform P picture and B picture. Is added to the predicted image and held in the video memory 218 as a locally decoded image.

  The image held in the video memory 218 is converted into a motion compensated predicted image with the input image to be predicted in the motion compensated prediction circuit 219, and becomes prediction data of P picture and B picture in the frame difference circuit 207.

  When a still image recording instruction is input to the terminal 221, the still image recording control circuit 205 connects the switch 204 to the still image frame memory 203 side for a predetermined period, and continuously inputs the same still image frame to the encoding loop. To do.

  Further, the still image recording control circuit 205 controls the motion compensation prediction circuit 219 to suppress the generation of a motion vector without forcibly performing motion compensation at the time of still image recording (the motion vector is set to 0). This is to prevent an unnecessary motion vector from being generated between the inter-frame prediction image and the original image due to the occurrence of a coding error even if the same frame is input, and the amount of code to increase.

  Further, the still image recording control circuit 205 controls the quantization circuit 209 to perform encoding with finer quantization steps at the time of still image recording than at the time of moving image recording.

  FIG. 4 shows an example in which a quantization characteristic value Q determined by code amount control is encoded using a fine step quantization characteristic value Q-Still when recording a still image. This is because the B picture and P picture only encode the coding error component of the I picture at the time of still picture recording, and it is considered that there is a margin in the amount of generated code compared to the moving picture recording that encodes the inter-frame difference. It is.

  Regarding the application range of Q-Still, a method of applying to a B picture or a P picture that encodes only a prediction error, or applying a predetermined period to an I picture, a P picture, and a B picture as described later is considered. It is done.

  FIG. 5 shows an example in which the quantization step is changed by the quantization matrix. (A) is a default matrix of a moving picture for an I picture, and (b) is a default matrix for a B picture and a P picture.

  On the other hand, (c) is an example of a still picture I picture quantization matrix, and (d) is an example of a still picture B picture and P picture quantization matrix. As described above, in the still picture, the B picture and the P picture represent the encoding error of the I picture. Therefore, in the I picture, a matrix storing higher frequency components is used, and the encoding error is higher in the B picture and the P picture. By encoding with high accuracy, it is possible to record still images with high image quality.

(Second Embodiment)
FIG. 6 is a diagram showing processing for setting the first GOP of still image recording as a closed GOP as the second embodiment. (A) shows the prediction direction of the first B picture in the closed GOP, and is not the bidirectional prediction from the P picture and the I picture of the preceding GOP, but the one-way prediction from the I picture.

  In the encoding method described in the first embodiment, the head GOP is closed by an instruction from the still image recording control circuit 205 at the start of still image recording, thereby preventing image degradation due to discontinuity at the start of still images. Is possible.

  In the case of MPEG2 coding, the picture structure of image data is fixed to the frame structure for still images, and the motion compensation prediction circuit 219 is set to frame prediction, thereby improving the prediction efficiency of B pictures and P pictures. It is possible to record high-quality still images.

(Third embodiment)
FIG. 7 is a diagram showing details of a compression encoding circuit according to the MPEG encoding system of the present embodiment. Digital image data input to the terminal 701 is supplied to the resolution conversion circuit 722. In the resolution conversion circuit 722, when the code amount exceeds a predetermined threshold and the image quality deterioration due to quantization becomes significant due to feedback from the code amount control circuit 710, the resolution of the input image is limited by the spatial filter, and further, the resolution by resampling Conversion is performed to limit the high frequency component of the input image and reduce the number of pixels.

  The resolution-converted image data becomes one input of the switch 704, and in the case of still image data, it is held in the still image frame memory 703 via the still image hold switch 702 and becomes the other input of the switch 704.

  The frame rearrangement circuit 706 rearranges each frame of the moving image in the order of MPEG encoding.

  In the frame difference circuit 707, a difference between the P picture and the B picture and the inter-frame prediction data is obtained by the switch 720.

  The DCT circuit 708 converts the original image for the I picture and the prediction error image for the P picture and B picture into DCT coefficients.

  The quantization circuit 709 quantizes the product of the quantization matrix and the quantization characteristic value Q based on feedback from the code amount control circuit 710. The quantized coefficient is entropy-coded in the variable-length coding circuit 711, and is output from the terminal 713 via the buffer 712 for rate control.

  In the inverse quantization circuit 714, the quantization coefficient output from the quantization circuit 709 is inversely quantized, converted into a pixel value by the inverse DCT circuit 715, and then controlled by the switch 717, in the frame addition circuit 716, P picture, B picture Is added to the predicted image and held in the video memory 718 as a locally decoded image.

  The image held in the video memory 718 is converted into a motion compensated predicted image with the input image to be predicted in the motion compensated prediction circuit 719, and becomes the prediction data of the P picture and B picture in the frame difference circuit 707.

  When a still image recording instruction is input to the terminal 721, the still image recording control circuit 705 connects the switch 704 to the still image frame memory 703 side for a predetermined period, and continuously inputs the same still image frame to the encoding loop. To do.

  The still image recording control circuit 705 controls the motion compensation prediction circuit 719 to suppress the generation of motion vectors without forcibly performing motion compensation during still image recording (the motion vector is set to 0). This is to prevent an unnecessary motion vector from being generated between the inter-frame prediction image and the original image due to the occurrence of a coding error even if the same frame is input, and the amount of code to increase.

  Further, the still image recording control circuit 705 controls the resolution conversion circuit 722, and in still image recording, the resolution conversion by the control at the time of moving images is suppressed, and processing is performed so that a predetermined resolution is maintained. As a result, even when the horizontal resolution is decimated to 1/2 when recording a moving image, the original resolution can be maintained when recording a still image, and the increase in the code amount resulting from this increases the encoding efficiency of B and P pictures. It can be expected to be offset by this.

(Fourth embodiment)
FIG. 8 is a diagram showing details of a compression encoding circuit according to the MPEG encoding system of the present embodiment. The digital image data input to the terminal 801 becomes one input of the switch 804. In the case of still image data, the digital image data is held in the still image frame memory 803 via the still image hold switch 802 and becomes the other input of the switch 804. .

  The frame rearrangement circuit 806 rearranges each frame of the moving image in the order of MPEG encoding.

  In the frame difference circuit 807, a difference between the P picture and the B picture and the inter-frame prediction data is obtained by the switch 820.

  The DCT circuit 808 converts the original image for the I picture and the prediction error image for the P picture and B picture into DCT coefficients.

  The quantization circuit 809 quantizes the product of the quantization matrix and the quantization characteristic value Q based on feedback from the code amount control circuit 810. The quantized coefficient is entropy-encoded in the variable-length encoding circuit 811 and output from a terminal 813 through a buffer 812 for rate control.

  The inverse quantization circuit 814 inversely quantizes the quantization coefficient output from the quantization circuit 809, converts it to a pixel value by the inverse DCT circuit 815, and then controls the switch 817 in the frame addition circuit 816 to perform P picture and B picture. Is added to the predicted image and held in the video memory 818 as a locally decoded image.

  The image held in the video memory 818 is converted into a motion compensated predicted image with the input image to be predicted in the motion compensated prediction circuit 819, and becomes the prediction data of P picture and B picture in the frame difference circuit 807.

  When a still image recording instruction is input to the terminal 821, the still image recording control circuit 805 connects the switch 804 to the still image frame memory 803 side for a predetermined period, and continuously inputs the same still image frame to the encoding loop. To do.

  Also, the still image recording control circuit 805 controls the motion compensation prediction circuit 819 to suppress the generation of motion vectors without forcibly performing motion compensation during still image recording (the motion vector is set to 0). This is to prevent an unnecessary motion vector from being generated between the inter-frame prediction image and the original image due to the occurrence of a coding error even if the same frame is input, and the amount of code to increase.

  Further, the still image recording control circuit 805 controls the quantization circuit 809 and the code amount control circuit 810 and uses the quantization characteristic value Q of the Q map memory 823 to change the quantization characteristic value Q during the still image recording period. Control is performed so as to be constant between frames for each picture.

  FIG. 9 is a diagram showing an operation of fixing the quantization characteristic value Q. At the start of still image recording (GOPn), first, a quantization characteristic value Q of each picture for a still image sequence is obtained for each macroblock. For this, a normal sequence in code amount control may be used, or a sequence converted into a Q value for still images as described above may be used.

  When the GOPn encoding is completed, the subsequent still image sequence is an encoding of exactly the same digital data. Therefore, the optimum quantization characteristic value Q for the same still image sequence is estimated from the encoded code amount. Is possible. Let M ′ be a macroblock unit map for each estimated Q picture.

  In the Q map memory 823, the Q map M ′ estimated for the still image is held while the same still image is being recorded, and the subsequent GOP is quantized accordingly. As a result, it is possible to prevent the problem that the image quality varies with time even though they are the same still image.

  FIG. 10 is a diagram showing a recording format for synchronizing the still image ID information added to each track and variable-length still image data. The recording track format is shown in FIG. A track is composed of a preamble part, a data area, a subcode area, a postamble part, and a margin part shown in gray. Image data is recorded in the data area, and PPID, which is an example of a still image identification ID, is recorded in the subcode area. Is done.

  FIG. 4B shows a recording format on the tape, and tracks are recorded from left to right. Here, the moving image data ends in the middle of the third track, and the next still image data is recorded from the head of the next track, not this track, and the stuff data is recorded in the rest of the third track. With the start of recording the still image on the fourth track, the PPID corresponding to the still image ID is recorded in the subcode area. Thus, even when a high-speed search is performed while reproducing only the tape subcode, the still image recording start position can be detected by PPID, and the beginning of still image data can be detected.

(Other embodiments)
A software program for realizing the functions of the above-described embodiment for an apparatus or a computer in the system connected to the various devices so as to operate the various devices to realize the functions of the above-described embodiments. What is implemented by supplying a code and operating the various devices according to a program stored in a computer (CPU or MPU) of the system or apparatus is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself constitutes the present invention. As a transmission medium for the program code, a communication medium (wired line or wireless line such as an optical fiber) in a computer network (LAN, WAN such as the Internet, wireless communication network, etc.) system for propagating and supplying program information as a carrier wave Etc.) can be used.

  Further, means for supplying the program code to the computer, for example, a recording medium storing the program code constitutes the present invention. As a recording medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer. Needless to say, such a program code is included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with the above-described embodiment.

  Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the CPU provided in the function expansion board or function expansion unit based on the instruction of the program code Needless to say, the present invention includes the case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.

  It should be noted that the shapes and structures of the respective parts shown in the above-described embodiments are merely examples of implementation in carrying out the present invention, and these limit the technical scope of the present invention. It should not be interpreted. That is, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

Examples of embodiments of the present invention are listed below.
(Embodiment 1) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as for moving images,
Still image frame memory means for holding still image data that continues for a predetermined period;
A quantization means for quantizing the image data;
An image recording system comprising: control means for controlling the quantization means during still image recording to quantize still image data in a quantization step finer than moving image data.

  (Embodiment 2) The image recording system according to embodiment 1, wherein the quantization means performs quantization by a product of a quantization matrix and a quantization characteristic value.

  (Embodiment 3) The image recording method according to embodiment 2, wherein a quantization characteristic value of a finer step than the quantization characteristic value of moving image data is used during still image recording.

  (Embodiment 4) The image recording method according to embodiment 2, wherein a quantization matrix for still image data different from the quantization matrix for moving image data is used during still image recording.

  (Embodiment 5) An image recording method according to embodiment 4, wherein the still picture quantization matrix information is recorded in encoded data.

  (Embodiment 6) Motion compensation prediction means for performing motion compensation prediction for inter-frame coding, and forcing motion vectors for motion compensation prediction for inter-frame coding by controlling the motion compensation prediction means when recording a still image 6. The image recording method according to any one of embodiments 1 to 5, further comprising a control unit that automatically sets to zero.

(Embodiment 7) An image recording system that records inter-frame encoded moving image data and enables still image data to be recorded using the same encoding method as the moving image,
Still image frame memory means for holding still image data that continues for a predetermined period;
An image recording system comprising: control means for preventing prediction from a previous frame coding unit in a frame coding unit at a still image recording start point.

  (Embodiment 8) The image recording method according to embodiment 7, wherein the frame coding unit at the still image recording start point is a closed GOP.

  (Embodiment 9) Motion compensation prediction means for performing motion compensation prediction for interframe coding, and forcing motion vectors for motion compensation prediction for interframe coding by controlling the motion compensation prediction means at the time of recording a still image The image recording method according to the embodiment 7 or 8, further comprising: a control unit that automatically sets to zero.

(Embodiment 10) An image recording method of recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
Still image frame memory means for holding still image data that continues for a predetermined period;
A quantization means for quantizing the image data;
An image recording method comprising: control means for controlling so as not to change the quantization step in the quantization means during recording of the same still image data.

  According to the image recording method of the tenth embodiment as described above, it is possible to prevent the still image from being deteriorated due to the fluctuation of the encoding distortion at the time of reproduction, and the generation of the still image continuation period by the code amount of the head GOP. By estimating the code amount, determining an optimal quantization step, and applying a fixed quantization step to subsequent GOPs, it is possible to perform optimal encoding from the point of code amount control.

  (Embodiment 11) Embodiment 10 in which the subsequent quantization step size is determined by the filling rate of the code amount control buffer before the start of still image recording and the code amount of the frame encoding unit at the still image recording start point The image recording method described in 1.

  (Embodiment 12) Motion compensation prediction means for performing motion compensation prediction for interframe coding, and forcing motion vectors for motion compensation prediction for interframe coding by controlling the motion compensation prediction means at the time of recording a still image The image recording method according to the embodiment 10 or 11, further comprising: a control unit that automatically sets to zero.

(Embodiment 13) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
Still image frame memory means for holding still image data that continues for a predetermined period;
A quantization means for quantizing the image data;
Motion compensation prediction means for performing motion compensation prediction of inter-frame coding,
An image recording method characterized in that for still image data, an image has a frame structure and prediction is frame prediction.

  (Embodiment 14) An embodiment comprising control means for controlling the motion compensation prediction means at the time of recording a still image to forcibly set a motion vector for motion compensation prediction of interframe coding to 0. The image recording system according to aspect 13.

(Embodiment 15) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
Resolution conversion means for reducing the encoding rate by reducing the resolution of the image;
Still image frame memory means for holding still image data that continues for a predetermined period;
An image recording method comprising: control means for controlling still image data so as not to use the resolution conversion means.

  (Embodiment 16) Motion compensation prediction means for performing motion compensation prediction for interframe coding, and forcing a motion vector for motion compensation prediction for interframe coding by controlling the motion compensation prediction means at the time of recording a still image 16. The image recording method according to claim 15, further comprising control means for automatically setting to zero.

(Embodiment 17) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
Still image frame memory means for holding still image data that continues for a predetermined period;
Still image start point synchronization means for resetting the encoding unit of inter-frame encoding at the still image recording start point and starting recording from the intra-frame encoded data;
A still image ID information recording means indicating a still image recording portion in the recording data,
An image recording method for recording still image data in conformity with a still image ID information recording unit.

  (Embodiment 18) The image recording system according to Embodiment 17, wherein the still image ID information recording unit is a recording track on a recording medium.

(Embodiment 19) An image recording method for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A procedure for holding still image data that continues for a predetermined period of time;
A procedure for quantizing image data;
An image recording method comprising: a step of controlling the quantization means during still image recording to quantize still image data in a quantization step finer than moving image data.

(Embodiment 20) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as the moving image,
A procedure for holding still image data that continues for a predetermined period of time;
And a procedure for preventing prediction from the immediately preceding frame coding unit in the frame coding unit of the still image recording start point.

(Embodiment 21) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as for moving images,
A procedure for holding still image data that continues for a predetermined period of time;
A procedure for quantizing image data;
An image recording method, wherein the quantization step in the quantization procedure is not changed during recording of the same still image data.

(Embodiment 22) An image recording method for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A procedure for holding still image data that continues for a predetermined period of time;
A procedure for quantizing image data;
A procedure for performing motion compensated prediction of interframe coding,
An image recording method, wherein for still image data, an image has a frame structure and prediction is frame prediction.

(Embodiment 23) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
A procedure to reduce the encoding rate by reducing the resolution of the image,
A procedure for holding still image data that continues for a predetermined period of time;
And a procedure for controlling so as not to use the resolution conversion means for still image data.

(Embodiment 24) An image recording method for recording moving image data encoded between frames and enabling recording of still image data using the same encoding method as that of moving images,
A procedure for holding still image data that continues for a predetermined period of time;
A procedure for resetting the encoding unit of interframe encoding at the still image recording start point and starting recording from the data encoded in the frame;
A procedure for recording still image ID information indicating a still image recording portion in the recording data,
An image recording method, wherein still image data is recorded in conformity with a still image ID information recording unit.

(Embodiment 25) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A process for holding still image data that continues for a predetermined period of time;
A process of quantizing the image data;
A computer program for controlling the quantization means at the time of recording a still image to perform a process of quantizing still image data in a quantization step finer than moving image data.

(Embodiment 26) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A process for holding still image data that continues for a predetermined period of time;
A computer program for executing processing for preventing prediction from a previous frame coding unit in a frame coding unit at a still image recording start point.

(Embodiment 27) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A process for holding still image data that continues for a predetermined period of time;
Processing to quantize the image data,
A computer program characterized in that the quantization step in the quantization process is not changed during recording of the same still image data.

(Embodiment 28) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A process for holding still image data that continues for a predetermined period of time;
A process of quantizing the image data;
And motion compensation prediction processing for performing motion compensation prediction of interframe coding,
A computer program characterized in that for still image data, an image has a frame structure and prediction is frame prediction.

(Embodiment 29) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
Processing to reduce the encoding rate by reducing the resolution of the image,
A process for holding still image data that continues for a predetermined period of time;
A computer program for executing processing for controlling so as not to use the resolution conversion means for still image data.

(Embodiment 30) A computer program for recording inter-frame encoded moving image data and enabling still image data to be recorded using the same encoding method as the moving image,
A process for holding still image data that continues for a predetermined period of time;
A process of resetting the encoding unit of inter-frame encoding at a still image recording start point and starting recording from the data encoded in the frame;
Recording the still image ID information indicating the still image recording portion in the recording data,
A computer program for recording still image data in conformity with a still image ID information recording unit.

  (Embodiment 31) A computer-readable storage medium characterized by storing the computer program according to any one of Embodiments 25 to 30.

  According to these embodiments, by quantizing still image data in a quantization step finer than that of moving image data, the amount of code reduction due to inter-frame encoding of the same image can be used for improving image quality. Even when a common encoding method is used, high-quality still image recording is possible.

  In addition, since the frame encoding unit at the still image recording start point is not predicted from the immediately preceding frame encoding unit, a frame predicted from both directions such as an MPEG B picture starts still image recording. It is possible to prevent the image quality from being deteriorated due to the influence of the immediately preceding image.

  In addition, for still image data, the image has a frame structure, and prediction is performed by frame prediction, so that it is possible to perform optimal encoding for still images and improve image quality while using a common encoding method with moving images. it can.

  Further, by not using the resolution conversion means for still image data, it is possible to maintain the resolution of the still image while performing processing common to the moving image.

  Also, by recording still image data consistent with the still image ID information recording unit, variable-length encoded data is recorded in a fixed track format such as a tape medium, and added to the track unit for high-speed search. Even when the still image ID information is used, it is possible to correctly search the still image start point recorded in alignment with the track unit.

It is a figure which shows schematic structure of the digital video recording device of embodiment. It is a figure which shows the detail of the compression encoding circuit by the MPEG encoding system of 1st Embodiment. It is a figure which shows the relationship between GOP which is an MPEG interframe coding unit, and an I picture, a P picture, and a B picture. It is a figure which shows an example of the quantization characteristic value at the time of still image recording. It is a figure for demonstrating the quantization matrix at the time of still image recording. It is a figure which shows the closed GOP of MPEG. It is a figure which shows the detail of the compression encoding circuit by the MPEG encoding system of 3rd Embodiment. It is a figure which shows the detail of the compression encoding circuit by the MPEG encoding system of 4th Embodiment. It is a figure which shows the operation | movement of quantization characteristic value Q fixed at the time of a still image recording. It is a figure which shows the recording format of variable-length still image data synchronized with still image ID information.

Explanation of symbols

Reference numeral 201 terminal 202 still image hold switch 203 still image frame memory 204 switch 205 still image recording control circuit 206 frame rearrangement circuit 207 frame difference circuit 208 DCT circuit 209 quantization circuit 210 code amount control circuit 211 variable length encoding circuit 212 buffer 213 Terminal 214 Inverse quantization circuit 215 Inverse DCT circuit 216 Frame addition circuit 217 Switch 218 Video memory 219 Motion compensation prediction circuit 220 Switch 221 terminal

Claims (8)

It is an image recording method that records inter-frame encoded moving image data and enables still image data to be recorded as video for a predetermined period using a common encoding method with moving images,
Still image frame memory means for holding still image data recorded as video for the predetermined period;
Encoding means for encoding image data;
Motion compensation prediction means for performing motion compensation prediction for interframe coding;
The moving image data is encoded by performing the motion compensation prediction during moving image recording, and the still image data output from the still image frame memory means is encoded without the motion compensation prediction during still image recording. An image recording method comprising: control means for controlling the converting means.   2. The image recording method according to claim 1, wherein the control unit controls the motion compensation prediction unit during still image recording to forcibly set a motion vector generated by the motion compensation prediction unit to zero. . It is an image recording method that records inter-frame encoded moving image data and enables still image data to be recorded as video for a predetermined period using a common encoding method with moving images,
Still image frame memory means for holding still image data recorded as video for the predetermined period;
Encoding means for encoding image data according to a predetermined frame encoding unit;
Motion compensation prediction means for performing motion compensation prediction for interframe coding;
When recording a moving image, the frame coding unit is encoded by performing the motion compensation prediction, and when still image data output from the still image frame memory means is encoded at the time of still image recording, the previous frame encoding unit is encoded. And a control means for controlling the encoding means so as to encode the frame encoding unit without performing motion compensation prediction from the image recording system.   The control means encodes the first frame coding unit when coding still picture data output from the still picture frame memory means without performing prediction from the immediately preceding frame coding unit. 4. The image recording system according to claim 3, wherein the encoding unit is controlled.   5. The image recording method according to claim 3, wherein the frame coding unit is GOP.   6. The image recording system according to claim 5, wherein the control means sets a GOP at a still image recording start point as a closed GOP. An image recording method for recording inter-frame encoded moving image data and enabling still image data to be recorded as video for a predetermined period using an encoding method common to moving images,
A procedure for holding still image data recorded as video for the predetermined period;
A procedure for encoding image data;
A motion compensated prediction procedure for interframe coding,
An image recording method characterized in that the motion compensation prediction is performed at the time of moving image recording to encode the moving image data, and at the time of still image recording, the retained still image data is encoded without the motion compensation prediction. An image recording method for recording inter-frame encoded moving image data and enabling still image data to be recorded as video for a predetermined period using an encoding method common to moving images,
A procedure for holding still image data recorded as video for the predetermined period;
A procedure for encoding image data according to a predetermined frame encoding unit;
A motion compensated prediction procedure for interframe coding,
When recording moving images, the motion compensation prediction is performed to encode the frame coding unit. When still image data is encoded during still image recording, the motion compensation prediction from the immediately preceding frame coding unit is performed. An image recording method, wherein the frame encoding unit is encoded without being performed.

Images