JP2007109329A - Picture data recording apparatus, picture data reproducing apparatus, picture data recording method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To record and reproduce a MPEG (Moving Picture Experts Group) file to/from a recording medium without using a memory storing a header requiring large capacity. <P>SOLUTION: The apparatus is a picture data recording apparatus having an input means of picture data, an encoding means generating stream picture data by encoding input picture data for each encoding unit, a recording mode setting means , a maximum code quantity setting means setting the maximum code quantity of an encoding unit in stream picture data conforming to a control signal from the recording mode setting means, a code quantity control means controlling the encoding means so that code quantity of the encoding unit of the stream picture data is within the maximum code quantity based on the maximum code quantity setting means, and a recording means recording the stream picture data generated by the encoding means and additional information indicating the maximum code quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image data recording apparatus, an image data reproducing apparatus, an image data recording method, a program, and a recording medium, and in particular, an image data recording apparatus that records and / or reproduces moving image data in MPEG format using interframe coding, The present invention relates to an image data reproducing device, an image data recording method, a program, and a recording medium.

  2. Description of the Related Art In recent years, apparatuses for recording and reproducing moving image data encoded using inter-frame encoding such as MPEG (Moving Picture Experts Group) in a digital video camera, a digital still camera, or the like have become widespread. The MP4 (MPEG-4) file format is used as a general-purpose format for recording MPEG (MPEG-2 or MPEG-4 format) image data shot by a digital video camera, a digital still camera, etc., and is recorded as an MP4 file. Therefore, compatibility such as playback on other digital devices is guaranteed.

The MP4 file basically consists of an mdat box containing encoded stream image data and a moov box containing information related to stream image data, as shown in FIG. 5 (a). ing. The mdat box is further composed of a plurality of chunks (chunk cN) as shown in FIG. 5 (b), and each chunk is composed of a plurality of samples (sample sM) as shown in FIG. 5 (d). . For example, as shown in FIG. 5 (e), each sample has a sign of I ₀ , B ₋₂ , B ₋₁ , P ₃ ,... For samples s1, sample s2, samples s3, samples4,. Corresponding to the converted MPEG image data.

_{Here, I 0, I 1, I} 2, ···, I n is the frame image data that has been intra-coded (intra-frame _{coding), B 0, B 1,} B 2, ···, B _n is frame image data that is encoded (inter-frame encoding) with reference from both directions, and P ₀ , P ₁ , P ₂ ,..., P _n are referenced from one direction (forward direction). This is frame image data to be encoded (inter-frame encoding), both of which are variable length code data.

  As shown in FIG. 5C, the moov box is composed of an mvhd box composed of header information in which the creation date and time are recorded and a trak box into which information relating to stream image data stored in the mdat box is entered. The information stored in the trak box includes the stco box that stores the offset value information for each chunk in the mdat box as shown in FIG. 5 (h), and the information in each chunk as shown in FIG. 5 (g). There is an stsc box for storing information on the number of samples, and an stsz box for storing information on the size of each sample as shown in FIG.

  Therefore, the amount of data stored in the stco box, stsc box, and stsz box increases with the amount of recorded image data, that is, the recording time. For example, when an image of 30 frames per second is recorded as an MP4 file so that it is stored in one chunk every 15 frames, the data becomes about 1 Mbytes in 2 hours, and a moov box having a capacity of 1 Mbytes is required.

  When playing this MP4 file, read the moov box of the MP4 file from the recording medium, analyze the above stco box, stsc box, and stsz box from the moov box so that each chunk in the mdat box can be accessed. become.

  However, the amount of data in the moov box increases with the recording time, and in order to read all the moov box data, which is access information to stream image data, into the main body of a portable device such as a digital video camera or digital camera. Requires a large amount of memory.

  In order to cope with such a problem, in Patent Document 1, information for accessing stream image data is selected separately from the data in the moov box and is recorded as another data, and recorded as a separate file together with the information linked to the MP4 file. Keep it. It has been proposed to reduce the capacity of a memory for developing access information to stream image data during playback by accessing the MP4 stream image data from the separate file during playback.

However, in the above case, the access information to the stream image data in the mdat box is selected to reduce the access information. However, the access information does not change as the recording time increases. Since it is recorded as a separate file, it cannot be used even if the MP4 file is copied on the recording medium.
JP 2004-128938 A

  When the MP4 file recorded on the recording medium is reproduced as described above, there is a problem that a large memory capacity is required in the reproducing apparatus main body in order to store access information to the stream image data. Even if the access information to the stream image data is selected and the access information is reduced, it does not change as the recording time increases, and if the access data is recorded as a separate file, Even if the MP4 file is copied, there is a problem that the MP4 file created by copying cannot be played back on the playback apparatus main body. Accordingly, an object of the present invention is to enable playback of an MP4 file recorded on a recording medium with a small memory capacity.

  In one embodiment of the present invention, image data input means, encoding means for encoding input image data for each encoding unit to generate stream image data, recording mode setting means, and recording mode setting Maximum code amount setting means for setting the maximum code amount of the encoding unit in the stream image data in accordance with the control signal from the means, and the code amount of the encoding unit of the stream image data based on the maximum code amount setting means within the maximum code amount An image data recording apparatus comprising: a code amount control unit that controls the encoding unit, and a recording unit that records the stream image data generated by the encoding unit and the additional information indicating the maximum code amount on a recording medium. I will provide a.

  In another embodiment of the present invention, in the above-described embodiment of the present invention, reproduction means for reproducing stream image data and additional information recorded on a recording medium, and maximum code in the additional information reproduced by the reproduction means There is provided an image data recording apparatus further comprising: a reproduction control means for controlling the reproduction operation of the stream image data by the reproduction means based on the amount information.

  In another embodiment of the present invention, the recording medium on which the stream image data in which the encoding amount of the encoding unit of the stream image data is within a predetermined maximum code amount and the additional information indicating the maximum code amount is recorded Reproduction means for reproducing the stream image data and the additional information, and reproduction control for controlling the reproduction operation of the stream image data by the reproduction means based on the information of the maximum code amount in the additional information reproduced by the reproduction means. And an image data reproducing apparatus.

  In still another embodiment of the present invention, an image data input step, an encoding step for encoding the input image data for each encoding unit to generate stream image data, a recording mode setting step, and a recording A maximum code amount setting step for setting the maximum code amount of the encoding unit in the stream image data according to the control signal from the mode setting step, and a code amount of the encoding unit of the stream image data based on the maximum code amount setting step Image data comprising: a code amount control step for controlling the encoding step so as to be within, and a recording step for recording the stream image data generated by the encoding step and additional information indicating the maximum code amount on a recording medium Provide a recording method.

  In still another embodiment of the present invention, in the above-described embodiment, a reproduction step of reproducing the stream image data and additional information recorded on the recording medium, and a maximum code amount in the additional information reproduced by the reproducing means. There is provided an image data recording method further comprising: a reproduction control step for controlling a reproduction operation of stream image data by a reproduction step based on information.

  In still another embodiment of the present invention, there is provided a program in which a procedure for causing a computer to execute each step of the image data recording method in the above embodiment is provided.

  In still another embodiment of the present invention, a computer-readable recording medium on which the program code of the above-described embodiment is recorded is provided.

  According to the image data recording apparatus in one embodiment of the present invention, a memory for storing a header that requires a large capacity is no longer necessary for reproducing stream image data recorded on a recording medium.

  A first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a block circuit during recording of an image signal recording apparatus according to an embodiment of the present application. In FIG. 1, reference numeral 101 denotes a video signal input terminal to which a captured video signal from, for example, a camera head unit is input. Further, 102 is a camera signal processing circuit, 103 is a rearrangement circuit for rearranging frames in order for encoding, 104 is an adder circuit, 105 is a switch circuit, 106 is a DCT circuit, 107 is a quantization circuit, 108 Denotes an inverse quantization circuit. Further, 109 is an inverse DCT circuit, 110 is an adder circuit, 111 is a memory, 112 is a motion compensation circuit, 113 is a switch circuit, 114 is a variable length coding circuit, 115 is a frame buffer circuit, 116 is a code amount control circuit, 117 Indicates a recording circuit. Furthermore, 118 is a recording medium, 119 is a stream parameter addition circuit, 120 is a buffer control circuit, 121 is a header information generation circuit, 122 is a maximum code amount setting circuit, 123 is a recording control circuit, and 124 is a control to the recording control circuit 123. Data input terminal.

  Prior to the start of recording, image size information Sz (pixels), average recording rate information Rt (bits / second), and the like are set as parameters relating to the recording mode from the control data input terminal 124. The parameters relating to recording are linked with the settings relating to the image size and image quality set by the operator using touch panel type input means presented on a screen such as an LCD (Liquid Crystal Display), although not shown. . The recording control circuit 123 supplies the set average recording rate information Rt to the maximum code amount setting circuit 122.

The maximum code amount setting circuit 122 calculates a maximum encoding amount (Vmax) per encoding unit, for example, 1 GOP (Group Of Picture), from the average recording rate information Rt set by the recording control circuit 123. For example, if 1 GOP is composed of 15 frames, and the signal is 30 frames / second,
Vmax = Rtx 0.5xa (bit)
And the result is set in the code amount control circuit 116, the stream parameter addition circuit 119, and the buffer control circuit 120. Here, a is a predetermined constant for determining Vmax in consideration of a variation in the data rate per 1 GOP, and is an arbitrary value of 1 or more. Here, 1.2 is assumed.

A video signal picked up by an image pickup device incorporated in the camera head unit is input from the input terminal 101 and converted into a general image signal from the camera signal by the camera signal processing circuit 102 and separated into a luminance signal and a color difference signal. And output to the rearrangement circuit 103. Rearrangement circuit 103 in the camera signal processing circuit 102 each frame image _F -2 coming output from the respect to the time axis t as shown in FIG. _{4, F -1, F 0,} F 1, F 2, F 3, F 4 , F ₅ , F ₆ ,... Are rearranged in the order of F ₀ , F ₋₂ , F ₋₁ , F ₃ , F ₁ , F ₂ , F ₆ , F 4, F ₅ ,. The image data is divided into small blocks of coding units, and output to the adder circuit 104 and the switch circuit 105.

  At the start of recording, the recording control circuit 123 controls the switch circuit 105 so that the movable terminal c first selects the fixed terminal a, and supplies the frame image F0 from the rearrangement circuit 103 to the DCT circuit 106. The DCT circuit 106 performs a discrete cosine transform (hereinafter referred to as DCT) transformation on the frame image F 0 and supplies the result to the quantization circuit 107.

  The quantization circuit 107 quantizes the DCT image data supplied from the DCT circuit 106 in the quantization step set by the code amount control circuit 116 and supplies the quantized circuit to the variable length encoding circuit 114 and the inverse quantization circuit 108.

The variable length coding circuit 114 performs variable length coding on the image data quantized and supplied from the quantization circuit 107 using a Huffman code or the like, and encodes the frame image F ₀ as shown in FIG. The data I ₀ is supplied to the frame buffer circuit 115.

  The inverse quantization circuit 108 inversely quantizes the image data that is quantized and supplied from the quantization circuit 107 and supplies the image data to the inverse DCT circuit 109. The inverse DCT circuit 109 performs inverse discrete cosine transform (inverse DCT) on the image data inversely quantized by the inverse quantization circuit 108 and supplies the result to the adder circuit 110.

  The adder circuit 110 adds the data supplied from the switch circuit 113 to the inverse DCT image data supplied from the inverse DCT circuit 109 and supplies the result to the memory 111. Here, the switch circuit 113 supplies the input “0” data to the adder circuit 110 with the movable terminal c connected to the fixed terminal a under the control of the recording control circuit 1223. Therefore, the adder circuit 110 supplies the image data supplied from the inverse DCT circuit 109 to the memory 111 with the same value as it is, and the memory 111 stores the supplied image data.

When the processing of the frame image F ₀ is completed, the image data of the frame image F- ₂ is continuously input from the rearrangement circuit 103 to the addition circuit 104 and the motion compensation circuit 112. At this time, the switch circuit 105 is connected to the fixed terminal b by the control of the recording control circuit 123.

Further recording control circuit 123 controls the motion compensation circuit 112, the motion compensation circuit 112, a frame in this case, the reference to prediction error only frame image F ₀ as shown in FIG. 4 so immediately after the start of the recording is minimized A block of the image F ₀ is read from the memory 111 and supplied to the adder circuit 104.

  The adder circuit 104 subtracts the image data of the frame image F-2 supplied from the rearrangement circuit 103 and the data supplied from the motion compensation circuit 112, and supplies the result to the switch circuit 105 as prediction error data. The switch circuit 105 supplies the subtracted prediction error data supplied from the adder circuit 104 to the DCT circuit 106. The DCT circuit 106 DCTs the prediction error data supplied from the adder circuit 104 and supplies it to the quantization circuit 107.

  The quantization circuit 107 quantizes the DCT prediction error data supplied from the DCT circuit 106 in the quantization step set by the code amount control circuit 116 and supplies the quantized data to the variable length encoding circuit 114.

The variable-length encoding circuit 114 is supplied from the quantization circuit 107 and variable-length-encodes the quantized DCT prediction error data. As shown in FIG. 4, the frame image F- ₂ is used as interframe encoded data _B-2. This is supplied to the frame buffer circuit 115.

The next frame image F- ₁ is processed in the same manner as the frame image F- _2, and is supplied from the variable length coding circuit 114 to the frame buffer circuit 115 as interframe coding (bidirectional predictive coding) data B- _1. Is done.

Next, the frame image F ₃ is input from the rearrangement circuit 103 to the addition circuit 104 and the motion compensation circuit 112. At this time, the switch circuit 105 is connected to the fixed terminal b under the control of the recording control circuit 123. The motion compensation circuit 112 supplies the block of the frame image F ₀ to the prediction error by referring to the frame image F ₀ is minimum from the memory 111 to read the adder circuit 104.

The adder circuit 104 subtracts the image data of the frame image F ₃ supplied from the rearrangement circuit 103 and the data of the frame image F ₀ subjected to motion compensation supplied from the motion compensation circuit 112 to the switch circuit 105 as prediction error data. Supply. The switch circuit 105 supplies the subtracted prediction error data supplied from the adder circuit 104 to the DCT circuit 106. The DCT circuit 106 DCTs the prediction error data supplied from the adder circuit 104 and supplies it to the quantization circuit 107.

  The quantization circuit 107 quantizes the DCT prediction error data supplied from the DCT circuit 106 in a quantization step set by the code amount control circuit 116 and supplies the quantized data to the variable length encoding circuit 114 and the inverse quantization circuit 108.

Variable-length coding circuit 114 is supplied from the quantization circuit 107, the prediction error data quantized by variable-length coding, inter-frame coding frame image F ₃ as shown in FIG. 4 (unidirectional predictive coding) supplied to the frame buffer circuit 115 as the data _{P 3.}

  The inverse quantization circuit 108 inversely quantizes the quantized prediction error data supplied from the quantization circuit 107 and supplies the quantized prediction error data to the inverse DCT circuit 109. The inverse DCT circuit 109 performs inverse DCT on the prediction error data inversely quantized by the inverse quantization circuit 108 and supplies it to the adder circuit 110.

The adder circuit 110 adds the data supplied from the switch circuit 113 to the inverse DCT prediction error data supplied from the inverse DCT circuit 109 and supplies the result to the memory 111. Here, the switch circuit 113 is connected to the fixed terminal b under the control of the recording control circuit 123, and supplies the motion compensated frame image F ₀ data supplied from the motion compensation circuit 112 to the adder circuit 110. To do. Therefore, the adder circuit 110 adds the motion compensation data supplied from the motion compensation circuit 112 to the DCT prediction error data supplied from the inverse DCT circuit 109 and supplies it to the memory 111. The memory 111 stores the supplied image data. .

Next, the frame images F ₁ and F ₂ are processed. F ₋₂ and F ₋₁ described above except that the frame images F ₀ and F ₃ locally decoded by the motion compensation circuit are predicted from both directions. The variable length encoding circuit 114 performs variable length encoding, and the frame images F ₁ and F ₂ are stored in the frame buffer circuit 115 as interframe encoded data B ₁ and B ₂ as shown in FIG. Supplied.

Hereinafter, the frame images F ₆ , F ₄ , F ₅ , F ₉ , F ₇ , F ₈ , F ₁₂ , F ₁₀ , F ₁₁ are processed, and P ₆ , B ₄ , B ₅ , P ₁₁ are processed as shown in FIG. ₉ , B ₇ , B ₈ , P ₁₂ , B ₁₀ , B ₁₁ are obtained and sequentially stored in the frame buffer circuit 115. As shown in FIG. _{4, F -2, F -1,} F 0, F 1, ···, until _{F 12} become one of the coding unit, as encoded _data, I _{0, B} -2, B ₋₁ , P ₃ , B ₁ ,..., P ₁₂ , B ₁₀ , B ₁₁ are obtained as one GOP (GOP ₀ ).

  The code amount control circuit 116 controls the quantization circuit 107 according to the maximum code amount (Vmax) set by the maximum code amount setting circuit 122 so that the code amount of 1 GOP does not exceed Vmax. The state of the encoding unit stored in the frame buffer circuit 115 is shown in FIG.

Code amount of GOP ₀ under control of the code amount control circuit 116 is _{L 0,} and the frame buffer circuit 115, is stored until L0 position shown in FIG. When the capture of GOP _{0 into} the frame buffer circuit 115 is completed, the buffer control circuit 120 shifts the pointer for capturing the next GOP data to a position P 0 shifted by Vmax from the beginning of GOP ₀ shown in FIG. Dummy data is arranged in the area.

The storage start position of the next GOP ₁ (encoded data of I ₁₅ , B ₁₃ , B ₁₄ , P ₁₈ ,..., P ₂₇ ) in the frame buffer circuit 115 is from the position of P 0 shown in FIG. As described above, GOP ₁ is generated with the code amount L ₁ under the control of the code amount control circuit 116, and GOP ₁ is taken into the frame buffer circuit 115 so as to be stored in the frame buffer circuit 115. Then, the buffer control circuit 120 shifts the next GOP data fetch pointer to the position P1 shifted by Vmax from the head of GOP ₁ shown in FIG. 3, and arranges dummy data in the empty area.

Similarly, as shown in FIG. 3, it is encoded so that the code amount _L n (<Vmax) in GOP _n, that next fetching position starts from the position Pn offset by Vmax content from the storage start position of GOP _n Repeat that.

  The data stored in the frame buffer circuit 115 is supplied to the recording circuit 117 in accordance with an instruction from the recording control circuit 123 at a predetermined timing, for example, a timing when a predetermined number of GOPs are stored in the frame buffer circuit 115. The recording circuit 117 records data on the recording medium 118 by performing error correction for recording on the recording medium, modulation for recording, and the like.

The encoded data described above is stored and recorded in the MP4 file, but the header information generation circuit 121 generates header information to be stored in the moov box. In this case, the number of samples cn_num of each chunk is cn_num = 15, and the size sn_size of each sample is the picture data I _n , B _n−2 , B _n−1 , P _{n + 3} ,..., P _{n + 12} of each GOP _n. It becomes the size. The offset cn_offset of each chunk is cn_offset = Vmax × n. The above is described in the file as parameters of a normal MP4 file.

  Further, the header information generation circuit 121 generates a free box F-box for recording user data indicating the recording mode separately from the moov box, and describes the value of Vmax that is the basis of the offset to each chunk. .

Alternatively, the header information generation circuit 121 generates user information indicating that the offset value of the chunk is recorded so as to be an integral multiple of a constant value, and describes the user information in the moov box or the free box F-box. In addition circuit 119, user data may be added at the beginning of each GOP _n or for each picture, and the value of Vmax may be inserted. Keep further first or intraframe coded picture I _n is added as the user data indicating the recording mode coding size I _{n (size)} of the I _n recording each GOP _n. It is recorded by adding the user data to a further picture I _n the length L _n of the GOP _n First or intraframe coding of each GOP _n.

  At the end of recording, as shown in FIG. 6, the MP4 file recorded on the recording medium 118 is a free box F in which user data indicating the recording mode is stored, a moov box, and chunks arranged at Vmax × n. Consists of boxes. However, the free box F may be arranged in the moov box.

  Next, a case where the MP4 file generated as described above is reproduced will be described with reference to FIG.

  FIG. 2 shows a block circuit during reproduction of the image signal recording apparatus of one embodiment of the present application. In FIG. 2, 201 is a recording medium, 202 is a reproducing circuit for reproducing data from the recording medium, 203 is a buffer circuit, 204 is a variable length decoding circuit, 205 is an inverse quantization circuit, 206 is an inverse DCT circuit, and 207 is an addition. The device 208 is a memory. Furthermore, 209 is a motion compensation circuit, 210 is a switch circuit, 211 is a rearrangement circuit, 212 is an output terminal, 213 is a header information analysis circuit, 214 is a stream user data analysis circuit, 215 is a reproduction control circuit, 216 is a control signal Input terminal.

  Upon receiving an instruction from the reproduction control circuit 215, the reproduction circuit 202 reproduces the MP4 file recorded on the recording medium 201 and starts supplying it to the buffer circuit 203. At the same time, the header information analysis circuit 213 searches for the free box F, and free There is a box F, and it is confirmed that there is user data indicating the recording mode, which describes the MP4 file structure described above, that is, that the chunk is arranged at Vmax × n.

  If it is confirmed here, the reproduction control circuit 215 reproduces the stream image data in the mdat box without immediately reproducing the stco box, stsc box, and stsz box indicating the storage status in the mdat of the moov box from the recording medium 201. The playback circuit 202 is controlled to start.

  The reproduction circuit 202 reproduces the stream image data in the mdat box of the file recorded on the recording medium 201 from the head address and supplies it to the buffer circuit 203. The stream image data stored in the buffer circuit 203 is read out in view of the occupation state of the buffer circuit 203 and the like, and the stream image data is supplied to the variable length coding circuit 204. The variable length decoding circuit 204 performs variable length decoding on the reproduced stream image data supplied from the buffer circuit 203 and supplies the decoded stream image data to the inverse quantization circuit 205.

  The inverse quantization circuit 205 inversely quantizes the variable-length-decoded stream image data supplied from the variable-length decoding circuit 204 and supplies it to the inverse DCT circuit 206. The inverse DCT circuit 206 performs inverse DCT on the inversely quantized data supplied from the inverse quantization circuit 205 and supplies it to the adder circuit 207. The adder circuit 207 adds the inverse DCT data supplied from the inverse DCT circuit 206 and the data supplied from the switch circuit 210.

Stream image data reproduced from the recording medium 201 in this case, FIG. 3, the intra-frame coded I ₀ of first GOP ₀ as shown in FIG. 4 is reproduced, the reproduction control circuit 215 of the switch circuit 210 Control is performed to select the terminal a, and the switch circuit 210 supplies data “0” to the adder circuit 207. Adding circuit 207 supplies adds the inverse DCT data supplied from the "0" data and the inverse DCT circuit 206 is supplied from the switch circuit 210, the memory 208 and rearrangement circuit 211 as a frame _{F 0} regenerated . The memory 208 stores the addition data supplied from the addition circuit 207.

Next to the intra-frame encoded data I ₀ of GOP ₀ , the picture data B ₋₂ and B ₋₁ that have been bi-predictively encoded are reproduced, and the reproduction procedure up to the inverse DCT circuit 206 is the above intra-frame code. Since this is the same as the reproduction procedure described in the data ₁₀ , the description is omitted.

  The inverse DCT circuit 206 supplies the inverse DCT bidirectional predictive encoded image data to the adder circuit 207. At this time, the reproduction control circuit 215 controls the switch circuit 210 so that the movable terminal c of the switch circuit 210 selects the fixed terminal b, and supplies data from the motion compensation circuit 209 to the adder circuit 207.

The motion compensation circuit 209 detects the motion vector generated at the time of encoding from the reproduced stream image data and recorded in the stream image data, and reproduces the reference block data (in this case, since it is the recording start time. supplied to the movable terminal c of the switch circuit 210 to data only) from the intra-frame coded data F _0, which is read out from the memory 208.

The adder circuit 207 adds the inverse DCT data supplied from the inverse DCT circuit 206 and the motion compensated data supplied from the switch circuit 210, and reorders the regenerated frames F- ₂ and F- ₁ as the rearrangement circuit 211. To supply.

Then omitted unidirectional forward prediction coded picture data P ₃ is played, playback procedure to inverse DCT circuit 206 is the same as the playback procedure described above intra-frame coded data I _0.

  The inverse DCT circuit 206 supplies the inversely DCT-encoded picture data to the adder circuit 207. At this time, the reproduction control circuit 215 controls the switch circuit 210 so that the movable terminal c of the switch circuit 210 selects the fixed terminal b, and supplies data from the motion compensation circuit 209 to the adder circuit 207.

The motion compensation circuit 209 detects the motion vector generated at the time of encoding and recorded in the stream image data from the reproduced stream image data, and the reference block data (from the reproduced intra-frame encoded data F _0). ) From the memory 208 and supplied to the movable terminal c of the switch circuit 210.

Adding circuit 207 adds the motion compensated data supplied from the inverse DCT data and the switching circuit 210 supplied from the inverse DCT circuit 206 is supplied to the rearrangement circuit 211 and the memory 208 as a frame _{F 3} regenerated. The memory 208 stores the addition data supplied from the addition circuit 207.

Next, pictures B ₁ and B ₂ are reproduced, but the difference from B ₋₂ and B ₋₁ is not the frame at the start of recording, so it is reproduced from frames F ₀ and F ₃ as bidirectional prediction. Except for this, the same procedure as described in B- ₂ and B- ₁ is used for reproduction. Thus, as described above, P ₆ , B ₄ , B ₅ ,.

The rearrangement circuit 211 converts the frames F ₀ , F ₋₂ , F ₋₁ , F ₃ , F ₁ , F ₂ , F ₆ , F ₄ , F _{5 ,. −1} , F ₀ , F ₁ , F ₂ , F ₃ , F ₄ , F ₅ , F ₆ ,..., And outputs to the output terminal 212.

The header information analysis circuit 213 obtains the maximum code amount (Vmax) from the user data in the free box F of the MP4 file when the file reproduction is started. The stream user data analysis circuit 214 can also acquire Vmax from the stream GOP _n to be reproduced. Furthermore stream user data analyzing circuit 214 acquires the data amount _{L n} of GOP _n from the stream GOP _n to be reproduced.

As described above, after reproducing GOP ₀ from the recording medium, the recording medium contains dummy data as shown in FIG. 3 until the next GOP _1, so the difference between Vmax and L ₀ is the decoding side. in it is not necessary to send, playback control circuit 215 works from the GOP ₁ skip to GOP ₁ to begin the next play.

  Although normal playback has been described above, high speed playback (special playback) will be described next. In this embodiment, only I picture data is selected from the recorded MPEG data and reproduced. Since the data of the I picture is recorded at the head of each GOP, 15 × speed playback can be realized by detecting the head position of each GOP and playing back the I picture.

  As shown in FIG. 3, the playback control circuit 215 holds the playback position from the beginning of the recorded stream image data as an offset Sc while updating the playback as shown in FIG.

Here, when an instruction signal for fast forward reproduction in the forward direction is input from the input terminal 216 in FIG. 2 during reproduction of the data GOP _n , the reproduction control circuit 215 activates decoding circuits such as the buffer 203 and the variable length coding circuit 204. Initialize and record position (bit) as the next playback data of GOP _n
Pn = Sc + Vmax− (Sc mod (Vmax)) (1)
(Where mod is the remainder when Sc is divided by Vmax)
The playback circuit 202 is controlled to play back I _{n + 1} of GOP _{n + 1} at the position.

Reproduction circuit 202 reproduces from the recording medium I _{n + 1,} the stream user data analyzing circuit 214 encodes the I _{n + 1,} which is added as the user data to the picture I _{n + 1} which is intraframe coded coming reproduced size I _{n + 1 (size} ).

The reproduction control circuit 215 controls the reproduction circuit 202 so as to read GOP _{n + 1} data from the recording medium 201 by the encoded size I _{n + 1} (size) acquired by the stream user data analysis circuit 214.

The reproduced intra-frame encoded data I _{n + 1} is decoded in the same manner as the decoding procedure of the intra-frame encoded data I ₀ described above, supplied to the rearrangement circuit 211 and immediately output to the output terminal. When the reproduction of the intra-frame encoded data I _{n + 1} of GOP _{n + 1} is completed, the reproduction control circuit 215 sets the reproduction position Sc to Sc = P _n + I _{n + 1} (size)
And the next forward reproduction data position Pn + 1 = Sc + Vmax− (Sc mod (Vmax))
And the reproduction circuit 202 is instructed to repeat the reproduction.

When a special reproduction instruction in the reverse direction is input from the input terminal 216, the reproduction control circuit 215 obtains the next intra-frame encoded data I _{n-1 to be} reproduced,
Pn-1 = Sc-Vmax- (Sc mod (In _{+ 1} )) (2)
The reproduction circuit 202 is instructed to reproduce the position of, and the reproduction circuit 202 reproduces the intra _- frame encoded data I _n-1 of GOP _n-1 . Continue to reproduce only intraframe coded picture data I _m while updating the same manner playback position Sc and forward below.

As described above, the encoding unit (for example, the maximum code amount (Vmax) of (GOP)) is determined at the time of recording, and each encoding unit (GOP) is encoded within the maximum code amount (Vmax) and recorded. The encoded stream image data is recorded on the medium for each encoding unit (GOP) by the maximum code amount (Vmax), and the maximum code amount (Vmax) as the user data indicating the recording mode is recorded in the stream image data. recording the actual amount of data L _n, the size of the picture data I _n, which is the frame coding of the coding unit (GOP) of.

  Then, a free box is provided in the MP4 file to be stored, and information regarding the stream image data and the maximum code amount (Vmax) are recorded as user data in the free box.

  When recognizing that it is stream image data from the free box during playback, the stco box is operated by performing normal playback and special playback from the user data indicating the recording mode of the free box and the user data recorded in the stream image data. Since the header information such as the stsc box and the stsz box can be reproduced without being read, a memory for storing header information requiring a large capacity becomes unnecessary.

  Also, since the file is a normal MP4 file, it can be played back on other devices. Furthermore, since it can be realized by a single file, even when copying between media, even if it is played back by the image data recording or playback device of this embodiment, it can be played back in the same manner as in the above playback embodiment.

  In addition, since it is not necessary to read and analyze the above stco box, stsc box, stsz box and other parameters related to the encoding included in the header information, the stream image data can be accessed quickly and the reproduction waiting time is reduced. Can be reduced.

  Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in the.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

  Examples of storage media for supplying the program code include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, nonvolatile semiconductor memory cards, and other various ROMs. Can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

It is a block diagram for demonstrating the recording circuit of embodiment of this invention. It is a block diagram for demonstrating the reproducing circuit of embodiment of this invention. It is a figure for demonstrating arrangement | positioning of the stream image data in embodiment of this invention. It is a figure for demonstrating the frame order of the encoding in embodiment of this invention. It is a figure for demonstrating the structure of MP4 file. It is a figure for demonstrating the structure of the MP4 file in embodiment of this invention.

Explanation of symbols

116 Code amount control circuit 117 Recording circuit 119 Stream parameter addition circuit 122 Maximum code amount setting circuit 123 Recording control circuit 202 Reproduction circuit 213 Header information analysis circuit 214 Stream user data analysis circuit 215 Reproduction control circuit

Claims (13)

Image data input means;
Encoding means for encoding the input image data for each encoding unit to generate stream image data;
Recording mode setting means;
Maximum code amount setting means for setting a maximum code amount of the coding unit in the stream image data in accordance with a control signal from the recording mode setting means;
Code amount control means for controlling the encoding means so that the code amount of the encoding unit of the stream image data is within the maximum code amount based on the maximum code amount setting means;
An image data recording apparatus comprising: recording means for recording the stream image data generated by the encoding means and additional information indicating the maximum code amount on a recording medium.   2. The image data recording apparatus according to claim 1, wherein the stream image data is MPEG2 or MPEG4 image data.   The image data recording apparatus according to claim 1, wherein the encoding unit is GOP. The encoding means performs encoding using intraframe encoding and interframe predictive encoding,
2. The image data recording apparatus according to claim 1, wherein the additional information further includes information on a code amount of each encoding unit and a data amount of intra-frame encoded data in each encoding unit. Reproducing means for reproducing the stream image data and the additional information recorded on the recording medium;
The reproduction control means for controlling the reproduction operation of the stream image data by the reproduction means based on the information of the maximum code amount in the additional information reproduced by the reproduction means. The image data recording device described in 1.   The reproduction control means controls the reproduction means to reproduce the stream image data of a predetermined frame from a position determined based on the maximum code amount information in response to a fast-forward reproduction instruction. The image data recording apparatus according to claim 5. The stream image data and the additional information are recorded from the recording medium on which the stream image data in which the coding amount of the encoding unit of the stream image data is within a predetermined maximum code amount and the additional information indicating the maximum code amount are recorded. Playback means for playing
Reproduction control means for controlling the reproduction operation of the stream image data by the reproduction means based on the information on the maximum code amount in the additional information reproduced by the reproduction means. Playback device. The stream image data is encoded using intraframe encoding and interframe predictive encoding,
6. The image data recording apparatus according to claim 5, wherein the reproduction control unit controls the reproduction unit to reproduce only the image data encoded in the frame during the fast-forward reproduction. Each of the encoding units includes the image data encoded in the frame,
The additional information further includes information on a data amount of the intra-frame encoded data in each encoding unit,
The reproduction control unit controls the reproduction unit to reproduce only the image data encoded in the frame based on the information on the data amount of the encoded data in the frame during the fast-forward reproduction. The image data recording apparatus according to claim 8. An image data input process;
An encoding step of generating stream image data by encoding the input image data for each encoding unit;
A recording mode setting process;
A maximum code amount setting step of setting a maximum code amount of the encoding unit in the stream image data in accordance with a control signal from the recording mode setting step;
A code amount control step of controlling the encoding step so that the code amount of the encoding unit of the stream image data is within the maximum code amount based on the maximum code amount setting step;
An image data recording method comprising: a recording step of recording the stream image data generated by the encoding step and additional information indicating the maximum code amount on a recording medium. A reproduction step of reproducing the stream image data and the additional information recorded on the recording medium;
The reproduction control step of controlling the reproduction operation of the stream image data by the reproduction step based on the information of the maximum code amount in the additional information reproduced by the reproduction step. The image data recording method described in 1.   A program in which codes for causing a computer to execute each step of the image data recording method according to claim 10 or 11 are described.   A computer-readable recording medium on which the code of the program according to claim 12 is recorded.

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