JP2006129338A - Video recording and reproducing apparatus and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video recording and reproducing apparatus capable of arbitrarily starting reproduction even if a frame designated to start reproduction is a frame other than intra-frame encoding in the video recording and reproducing apparatus. <P>SOLUTION: A second image data stream resulting from performing intra-frame encoding on an inputted video signal is generated to be decoded separately from a first image data stream resulting from performing intra-frame encoding or inter-frame encoding on the inputted video signal, thereby obtaining an apparatus capable of starting reproduction from an arbitrarily designated frame when a user reproduces a video image in the middle of a program. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a video recording / reproducing apparatus for recording video data inputted into a recording medium, recording the image data compressed by the inter-frame coding method or the intra-frame coding method, reading the image data from the recording medium, decoding, and reproducing the data. In particular, the present invention relates to a technique for arbitrarily selecting a read head image when reproducing a video.

  A conventional video recording / reproducing apparatus compresses a video signal and records it on a recording medium by using a moving picture encoding method such as MPEG (Moving Picture Codin Experts Group). In this MPEG system, a so-called GOP (Group Of Pictures) structure is adopted. The GOP structure is an access unit in which a plurality of pictures (pictures) of video data obtained by encoding a video signal are grouped. The GOP is composed of three types: an I picture (intra-encoded image), a P picture (forward predictive encoded image), and a B picture (bidirectional predictive encoded image). Here, the I picture is image information that can be decoded independently of other types of picture data, and the P or B picture is image information that can be decoded using the difference information of the preceding and succeeding pictures. That is, a P or B picture other than an I picture cannot be decoded by itself.

  In such a video recording / playback apparatus, in order to play back video from the middle of a program, bit strings obtained by inter-frame coding and intra-frame coding of video signals are stored and stored in separate packets, respectively. The position of the packet storing the bit string by the inner encoding is stored as a search table. Thereby, data obtained by intra-frame coding is read out as a head image (see, for example, Patent Document 1).

JP-A-8-195925 (page 4, FIG. 2, FIG. 3)

  Since the conventional video recording / playback apparatus is configured as described above, when a user plays a video from the middle of a program, the video is always played back from a frame by intraframe coding. There was a problem that playback could not be started. For example, if the GOP is composed of 15 frames, it cannot be reproduced from 14 frames other than the intra-frame coding of the 15 frames, and the image resolution at the start of reproduction becomes extremely low.

  The present invention has been made to solve the above-described problems, and even when a frame for which reproduction start is designated is a frame other than intra-frame encoding, reproduction can be arbitrarily started. An object is to provide a video recording / reproducing apparatus.

  The video recording / reproducing apparatus according to the present invention includes a first encoding means for generating a first image data sequence from an input video signal by each encoding method of intraframe encoding or interframe encoding, A second encoding means for generating a second image data sequence from a video signal by an intra-frame encoding method; a write control means for packetizing the first and second image data sequences; Image information generating means for generating an image information table including each encoding method for generating the second image data sequence and packetization information when packetized, and an image for recording the packetized image data Data recording means, image information recording means for recording the image information table, and the encoding method for generating image data that is to be reproduced and that forms the first image data sequence Image information management means for reading out the equation from the image information table and selecting the image data to be reproduced based on the encoding method from the packetized first image data sequence or second image data sequence; Read control means for packet-decoding the selected image data, and decoding means having an image memory for decoding the packet-decoded image data and holding the image.

  The present invention generates a second image data sequence obtained by intra-frame coding of an input video signal separately from the first image data sequence obtained by intra-frame coding or inter-frame coding of the input video signal. By enabling decoding, it is possible to obtain an apparatus that can be played back from an arbitrarily designated frame when the user plays back video from the middle of a program.

Hereinafter, a case where the present invention is applied to a video recording / reproducing apparatus will be described as an example.
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating the overall configuration of a video recording / reproducing apparatus according to Embodiment 1 of the present invention.
In the video recording / reproducing apparatus 1, a video signal a that is a signal including video information is input to an input unit 2 that converts an analog signal into a digital signal. The video signal b converted from an analog signal to a digital signal is a first encoding means from the input unit 2 and generates a first image data string by each of intra-frame encoding or inter-frame encoding. 1 to the MPEG encoder 3. Similarly, the video signal b is output from the input unit 2 to the second MPEG encoder 4 which is the second encoding means and generates the second image data string by the intraframe encoding method.

When the video signal b is input to the first MPEG encoder 3, a first image data sequence c which is intra-frame encoded or inter-frame encoded is generated, and is a writing control means. The data is output to the write control unit 5 to be packetized. At the same time, when the first image data sequence c is generated in the first MPEG encoder 3, it is encoding information, and the encoding type of the encoded image is I picture, B picture, or P First encoded information d, which is information indicating whether it is a picture or not, is generated and output to an image information generation unit 6 that is an image information generation unit and generates an image information table i including image information. Similarly, when the video signal b is input to the second MPEG encoder 4, a second image data sequence e that is intra-frame encoded is generated and output to the write control unit 5. At the same time, the second MPEG encoder 4 outputs second encoded information f, which is encoded information when the second image data string e is generated, to the image information generating unit 6.

The first image data sequence c and the second image data sequence e input to the writing control unit 5 are converted into image data g packetized for each frame, and are image data recording means, which is an image data recording unit. It is output to the image data recording unit 7 to be recorded. At the same time, the write control unit 5 outputs the packet data h, such as the packet number and the number of packets, to the image information generation unit 6 as information when the packet data is generated. The three pieces of input data input to the image information generation unit 6, that is, the first encoded information d, the second encoded information f, and the packetized information h, store information about the image data. The image information table i is converted and output to the image information recording unit 8 which is an image information recording unit and records the image information table.

On the other hand, the position information j indicating the image reproduction start position in the image data string selected by the user is image information management means from the main control unit 10 that controls the video recording / reproducing apparatus 1, and image information for selecting an image to be reproduced. When input to the management unit 9, a necessary image information table i is read from the image information recording unit 8. Then, an image to be read is determined with reference to the image information table i, and read image selection information k indicating which image is to be read is read control means, and packet decoding is performed on the selected image data sequence. The data is output to the read control unit 11 and the MPEG decoder 12 which is decoding means and decodes the encoded data.

When the read image selection information k is input to the read control unit 11, the packetized image data m to be read is read from the image data recording unit 7 in which the packetized image data g is recorded based on the control information. It is output to the control unit 11. When the packetized image data m is input to the read control unit 11, it is output to the MPEG decoder 12 as packet-decoded image data n. The image data n input to the MPEG decoder 12 is MPEG-decoded and output as image data p to the output unit 13 that converts digital data into analog data. If necessary, the image data r MPEG-decoded by the MPEG decoder 12 is output to the image memory 14 holding the image data. The image data p input to the output unit 13 is converted into analog data and output as a video output signal q.

The image data r held in the image memory 14 is read by the MPEG decoder 12 as necessary when MPEG decoding is performed. The image information generation unit 6, the image information management unit 9, and the main control unit 10 are realized by the CPU 15 and controlled based on a program stored in a memory (not shown). Although a CPU is used in FIG. 1, a DSP or other controller may be used.

  FIG. 2 is a diagram for explaining a processing order at the time of encoding and decoding of general MPEG image data in order to help understanding of the present invention. FIG. 2A shows a reference relationship between MPEG images. In FIG. 2A, alphabet I represents an I picture, B represents a B picture, and P represents a P picture. The numbers following the alphabet indicate the time relationship of the image, and the larger the number, the newer the data. As shown in this figure, GOP is generally composed of 15 frames. As described above, an I picture can be decoded independently, and a P picture is decoded with reference to an I picture temporally preceding the P picture. A frame referred to when decoding an image in this way is called a reference frame. For example, when the encoding type of the corresponding frame is a P picture, a frame of which the encoding type preceding the corresponding frame is an I picture or a P picture is a reference frame, and the encoding type of the corresponding frame is a B picture. In this case, a frame whose encoding type precedes the corresponding frame is an I picture or P picture, and a frame whose encoding type subsequent to the corresponding frame is an I picture or P picture is a reference frame. Specifically, in FIG. 2A, for example, the reference frame of P5 is I2, and P5 is decoded with reference to the image data of I2. The reference frames of B3 are I2 and P5, and B3 is decoded with reference to I2 and P5.

  Next, (B) to (F) in FIG. 2 are diagrams showing the order of accessing each image during image processing, and (B) in FIG. 2 is an image data string indicating an original video, ) Is an encoding process, FIG. 2D is on a recording medium, FIG. 2E is a decoding process, and FIG. 2F is an image data string for reproduction. Shows the order in which they will be performed. One GOP is configured in the order of B0, B1, I2, B3, B4, and P5 as shown in FIG. Since these images have the image reference relationship as described above, it is necessary that the images to be referred to have already been decoded in order to reproduce each image. Therefore, at the time of encoding the image, the order of image processing is changed as shown in FIG. Thereby, the image to be referred to when decoding each image has already been decoded. For example, in FIG. 2C, B3 refers to I2 and P5, but since I2 and P5 are decoded before B3 is decoded, the decoded image can be referred to. When recording on the recording medium, it is recorded on the recording medium as it is in the order of access during the encoding process as shown in FIG. As a result, as shown in FIG. 2E, images can be decoded in order from the top during the decoding process. Since there is an image whose temporal relationship is shifted in the decoded image as it is, when the final reproduced image is obtained, the images are replaced as shown in FIG. In other words, the same arrangement as that shown in FIG. 2B, which is the original image, is restored.

Next, the operation of the present invention will be described with reference to FIG. First, the video signal recording operation will be described.
The video signal a is, for example, an NTSC composite signal, a YC (luminance, color difference) signal, or a component signal. The video signal a is converted into a digital signal by the input unit 2 and input to the first MPEG encoder 3 and the second MPEG encoder 4.

  The first MPEG encoder 3 performs intraframe coding or interframe coding on the input video signal b to generate a first image data string c. The first image data sequence c is an image data sequence including picture types of I picture, P picture, and B picture. The first image data string c is encoded at a designated bit rate and used for normal display. At the same time, the first encoded information d, which is information indicating whether the encoded image, that is, the encoding type of the encoded image is an I picture, a B picture, or a P picture. Output for.

On the other hand, the second MPEG encoder 4 performs only intra-frame coding on the input digital video signal b to generate a second image data string e. The second image data string e is an image data string composed of continuous image data composed of only I pictures that can be decoded (MPEG decoded) independently of other images. The second image data string e is encoded at a designated bit rate and is used as an auxiliary when reproducing a head image designated by the user.
The information at the time of encoding simultaneously, that is, the second encoded information f which is information indicating that the encoded type of the encoded image is I picture is output to the image information generating unit 6. The second MPEG encoder 4 is newly added in the present invention.

  The first image data sequence c and the second image data sequence e are converted into packet data g stored in a separate packet for each frame by the write control unit 5, and the image data recording unit 7 is output. At the same time, the packet information when the packet data is generated, that is, the data amount of the packet data and the packetization information h that is the storage position are output to the image information generation unit 6. Here, the reason for packetization is that the first image data sequence c and the second image data sequence e are variable-length data sequences because the amount of data to be encoded differs depending on the information included in the image. Therefore, the data is grouped in packets so that data processing can be easily performed later. This packetization method will be described below.

FIG. 3 is a diagram for explaining the format of the packet data e generated by the write control unit 5. In the figure, 20 is the format per packet of packet data g. 21 is a packet header of the packet, and 22 is a data area. Information for identifying each packet is written in the packet header 21. The amount of data in the packet header 21 and the data area of each packet is a fixed amount. Therefore, each packet has a certain amount of data.

  When arranging an image data string in a packet, the top data of the image data does not start from the middle of the packet data area, but is always arranged from the top of the packet data area. When the arrangement of image data ends in the middle of the packet data area, invalidation data (for example, value 0) is packed in the remaining packet data area. FIG. 4 is a diagram for explaining the operation of converting the image data string into the packet data g in the writing control unit 5. The upper diagram in FIG. 4 shows the first image data sequence c before being packetized, 30a is an I picture by intraframe coding, 30b and 30c are B pictures by interframe coding, 30d is a P picture by interframe coding. Reference numerals 31 to 41 denote packet data packetized by the write control unit 5. Each packet has the format shown in FIG. 3 and a constant data amount.

In FIG. 4, when the first image data string c is packetized, the data is cut out within a predetermined size and stored in each packet. The predetermined size is the amount of data in the data area in FIG. In the packets 31 to 34, a bit string 30a that is an I picture of intraframe coding is stored. The packets 35 and 36 store a bit string 30b which is a B picture of interframe coding. The packets 37 and 38 store a bit string 30c which is a B picture of interframe coding. Similarly, 39, 40, and 41 store a bit string 30d that is a P picture of interframe coding. For example, in the packet 34, the data to be stored ends when the bit string based on the I-picture of the intra-frame encoding 30a is stored partway, so invalidation data is stored after the bit string. Then, the bit sequence 30b of the B picture of the inter-frame coding that follows this is stored from the head data area of the next packet 35.

  On the other hand, the image information generation unit 6 generates an image information table i that stores information about each image data based on the first encoded information d, the second encoded information f, and the packetized information h. And output to the image information recording unit 8. The image information table d is recorded in the image information recording unit 8 for each image data string. The image data recording unit 7 and the image information recording unit 8 are configured by a writing / reading device using a rewritable magnetic disk such as a hard disk or a DVD, for example. The packetized image data g recorded in the image data recording unit 7 can be read out in units of packets. The contents of the image information table i will be described below.

FIG. 5 shows an example of the image information table i. As shown in FIG. 5, the image information table i has a coding type, a packet number, and an information amount as information of the first image data sequence of each image, and a packet as information of the second image data sequence. Has a number and amount of information. The encoding type is an encoding type when an image is encoded, specifically, I, P, and B. The packet number is a leading number of a packet in which each encoded image is stored. The amount of information is the number of packets constituting each encoded packet image. The parameters are recorded for each image. By using this image information table i, an image corresponding to the image number can be easily retrieved from the first image data or the second image data recorded in the image data recording unit 8. Specifically, if a file block of a recording medium for recording an image is composed of, for example, 32 packets, if the packet number of each encoded image is known from this image information table, this packet is recorded on the recording medium. The file block that is being processed is obtained. Then, the file block is read from the recording medium by a predetermined method, and data after the next packet can be obtained.

Next, the video signal playback operation will be described.
FIG. 6 is an operation flowchart showing image data read processing in the video signal reproduction operation. FIG. 7 is an operational flowchart of a subroutine of the decryption permission / inhibition determination process in step S6 in FIG.

First, step S1 is processing performed in the main control unit 10, and the main control unit 10 obtains image reproduction start position information j, which is information indicating the position (frame) of the reproduction start image in the image bit string selected by the user. Output to the image information management unit 9. The image information reproduction position information j specifically corresponds to the image number of the image information table i in FIG. Next, step S2 is processing performed in the image information management unit 9 and the image information storage unit 8, and the image information management unit 9 performs image information table i corresponding to the image reproduction start position information j acquired in step S1. Is retrieved from the image information storage unit 8 and read.

  Next, step S3 is a process performed in the image information management unit 9, and acquires the coding type of the image corresponding to the image to be reproduced in the first image data sequence c. Specifically, referring to the image information table i read in step S2, the encoding type of the first image data string c corresponding to the image number of the reproduction start image is read.

  Next, step S4 is processing performed by the image information management unit 9, and it is determined whether or not the encoding type extracted in step S3 is a B picture. If the encoding type is a B picture, the process proceeds to the next step S5. On the other hand, if the encoding type is not a B picture, the process proceeds to step S6.

Next, step S5 is a process performed by the image information management unit 9, the image data recording unit 7, the read control unit 11, the MPEG decoder 12, and the image memory 14. In the first image data sequence c, the reproduction start image is displayed. The I picture one or two before the image corresponding to or the P picture one or two before the image used as the reproduction start image in the second image data string e is decoded. The reason why Step S4 and Step S5 are performed is that when the reproduction start image is a B picture, the I picture or P picture that is temporally behind the B picture is the B picture depending on the arrangement of the image data on the recording medium. This is because the I picture or P picture needs to be decoded and reproduced because it has been recorded earlier. Specifically, in FIG. 2D, for example, when the reproduction start image is B0, I2 of an image to be reproduced later in time with respect to B0 is recorded on the recording medium. In this case, the image of I2 is lost unless this I2 is reproduced. Therefore, this I2 is decoded and reproduced first. Similarly, when the reproduction start image is B3, P5 of the image to be reproduced later in time with respect to B3 is recorded before B3 on the recording medium, so this P5 must be reproduced. The image of P5 will be lost. Therefore, this P5 is decoded and reproduced first.

  The specific operation in step S5 is as follows. The image information management unit 9 refers to the image information table i, extracts the packet number and the packet number of the I picture or P picture to be decoded, and reads the image from the read control unit 11. Control information k for reading is output to the read control unit 11. Then, the read control unit 11 reads only the corresponding packet from the image data recording unit 7, returns the image to the original image data n after packet decoding, and outputs it to the MPEG decoder 12. Then, the MPEG decoder 12 decodes the image. Then, the decoded image is output to the image memory 14 and held.

  Next, step S6 is processing performed by the image information management unit 9, and in the first image data sequence c, whether the image to be reproduced can be decoded based on the encoding type of the image corresponding to the image to be reproduced. Determine whether or not. This decoding permission / inhibition determination process will be described with reference to FIG.

  In FIG. 7, steps S <b> 61 to S <b> 63 are processes performed in the image information management unit 9. First, in step S61, it is determined whether or not the coding type of the image extracted in step S3 in FIG. 6 is an I picture. If the encoding type is an I picture, it is determined that the image to be reproduced can be decoded, and this subroutine is terminated. On the other hand, if the encoding type is not an I picture, the process proceeds to step S62. Next, in step S62, information indicating which image the decoded image held in the image memory 14 is decoded is acquired. Next, in step S63, based on the information acquired in step S62, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14. If it is determined that the frame is held, it is determined that the corresponding frame can be encoded, and this subroutine is terminated. If it is determined that the frame is not held, it is determined that the corresponding frame cannot be encoded, and this subroutine is terminated.

Next, in FIG. 6, step S7 is a process performed by the image information management unit 9, the image data recording unit 7, the read control unit 11, the MPEG decoder 12, the image memory 14, and the output unit 13, and corresponds to the step S6. Since it is determined that the frame can be encoded, the corresponding frame and subsequent images are continuously read and reproduced using the first image data string c. Specifically, the image information management unit 9 refers to the image information table i, extracts the packet number and the number of packets corresponding to the image number of the image to be read, and performs control for reading the image from the read control unit 11 The information k is output to the read control unit 11. Then, the read control unit 11 reads only the corresponding packet from the image data recording unit 7, returns the image to the original image data n after packet decoding, and outputs it to the MPEG decoder 12. Then, the MPEG decoder 12 decodes the image. At this time, if it is determined in step S63 that there is a processed reference frame, the decoded image stored in the image memory 14 is referred to for decoding. The decoded image data p is output to the output unit, converted into analog data by the output unit 13, and output as a video output signal q. Thereafter, the next image in the image information table i is read and the image reproduction process is performed in the same manner, and the image is read continuously.

  On the other hand, step S8 is processing performed by the image information management unit 9, the image data recording unit 7, the read control unit 11, the MPEG decoder 12, the image memory 14, and the output unit 13, and it is determined in step S6 that encoding is impossible. In this case, the corresponding image is read from the second image data string e, decoded, and the process proceeds to the next step S9. Specifically, it is the same as the process of reading the first image data string c in step S7, and the image information management unit 9 refers to the image information table i and the packet number corresponding to the image number of the image to be read. The number of packets is extracted, and control information k for reading the image from the read control unit 11 is output to the read control unit 11. Then, the read control unit 11 reads only the corresponding packet from the image data recording unit 7, returns the image to the original image data n after packet decoding, and outputs it to the MPEG decoder 12. Then, the MPEG decoder 12 decodes the image. The decoded image data p is output to the output unit, converted into analog data by the output unit 13, and output as a video output signal q such as an NTSC composite signal, YC (luminance, color difference) signal, component signal, or the like.

Next, step S9 is a process performed by the image information management unit 9 and the image information storage unit 8, refers to the image information table i, acquires the encoding type of the frame to be reproduced next, and proceeds to step S6. Therefore, it is determined whether or not encoding is possible in the same manner as described above. If it is determined that decoding is possible, the process proceeds to the next step S7, and the first image data sequence c is continuously reproduced in the same manner as described above and determined as impossible. If it has been done, the process proceeds to step S8 in the same manner as described above, and the second image data sequence e is read and reproduced to obtain the coding type of the next reproduction frame, and whether or not the coding is possible is determined. As described above, one GOP is composed of 15 frames, and one I picture is always included therein. Therefore, in the case where encoding is impossible in step S6, the number of times is 14 at most, and I is the 15th. The picture corresponds to this, and the process proceeds to step S7, and the first image data is read out continuously.

  As described above, the image reproduction operation has been described with reference to the flowcharts of FIGS. Next, this reproduction operation will be described in a specific example. 8 to 11 are diagrams for explaining an operation of reproducing a designated image. 8 to 11, (A) shows a first image data string corresponding to an image to be reproduced, and (B) shows a second image data string e corresponding to the image to be reproduced. (C) is a number indicating which of the first image data string c and the second image data string e is the image data string to be used during the image reproduction operation. For example, 1 indicates that the first image data string c is used. (D) shows an image frame that is selected from the first and second image data strings e. (E) and (F) show reference frames that are referred to by the image held in the image memory 14 when (D) the image is decoded. (G) indicates an image to be decoded, and (H) indicates which image is to be reproduced. In the figure, it is assumed that time advances as it goes to the right and right. The following description will be made with reference to the flowcharts of FIGS.

  FIG. 8 is a diagram for explaining the operation when the reproduction start image (frame) is an I picture. First, in step S1, information indicating the image reproduction start position in the image bit string selected by the user is set. In this case, it corresponds to I2 of the first image data string c in FIG. Next, in step S2, the image information table i for the bit string of the image to be reproduced is read. In this case, the image information table i in FIG. 5 is read. Next, in step S3, the encoding type of the image corresponding to the image to be reproduced is extracted from the first image data string with reference to the image information table i. In this case, the column of the image number P0 of the image information table i in FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to, and the content is I, so that it corresponds. It is determined that the frame coding type is an I picture. Next, in step S4, it is determined that the encoding type of the frame acquired in step S3 is not a B picture, and the process proceeds to step S6.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, since the corresponding frame is an I picture, it is determined that encoding is possible, and the process proceeds to the next step S7. In step S7, the corresponding frame and subsequent image data are continuously read and reproduced using the first image data string c. In this case, as shown in FIG. 8, the head image to be reproduced is I2, and the image I2 is selected from the first image data string c. In FIG. 8, the image to be used is a location I2. Next, the image I2 is decoded by the MPEG decoder 12. In FIG. 8, this is where the decoded image of I2 is decoded. The decoded I2 image data is stored in the image memory 14. Thereafter, the first image data is continuously read and decoded. Specifically, P5 is selected from the first image data string c ((D) in FIG. 8), and the decoded image of I2 held in the image memory 14 is used as a reference frame ((E in FIG. 8). )) Decode P5 ((D) of FIG. 8). The decoded image data of P5 is held in the image memory 14.

  Next, B3 is selected from the first image data sequence c (FIG. 8D), and the decoded images of I2 and P5 held in the image memory 14 are used as reference images (FIGS. 8E and 8F). )) Decode B3 ((G) in FIG. 8). The decoded B3 image data is held in the image memory 14. Next, B4 is selected from the first image data sequence c, and B4 is decoded using the decoded images of I2 and P5 held in the image memory 14 as reference images ((E) and (F) in FIG. 8). The decoded B4 image data is held in the image memory 14. Next, P8 is selected from the first image data sequence c ((D) in FIG. 8), and P8 is decoded using the decoded image of P5 held in the image memory 14 as a reference image ((E) in FIG. 8). (G in FIG. 8). The decoded P8 image data is held in the image memory 14. Thereafter, the image data is decoded in the same procedure. The images are reproduced while being switched in the same order as the original images by the method described with reference to FIG. Specifically, as shown in (H) of FIG. 8, the image data of the decoded image sequence (G) after the decoding process is reproduced in the same order as the original image. That is, playback is performed like I2, B3, B4, and P5. As described above, an image can be reproduced with the reproduction start frame I2 as the head.

  FIG. 9 is a diagram for explaining the operation when the reproduction start image (frame) is a B picture following the I picture. First, in step S1, information indicating the image reproduction start position (frame) in the image bit string selected by the user is set. In this case, it corresponds to the image B0 in the first image data string c in FIG. Next, in step S2, the image information table i for the bit string of the image to be reproduced is read. In this case, the image information table i in FIG. 5 is read. Next, in step S3, the encoding type of the image corresponding to the image to be reproduced is extracted from the first image data string c with reference to the image information table i. In this case, the column of the image number P1 in the image information table i in FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to in the column, and the content is B. It is determined that the encoding type is a B picture.

  Next, in step S4, it is determined that the encoding type acquired in step S3 is a B picture, and the process proceeds to step S5. Next, in step S5, the previous I picture is decoded from the first image data sequence c, and the process proceeds to the next step S6. In this case, the image I2 is selected from the first image data string c ((D) in FIG. 9) and decoded by the MPEG decoder 12 ((G) in FIG. 9). The decoded I2 image data is stored in the image memory 14.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a B picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, since I2 which is an image necessary for decoding this image is not held in the image memory 14, it is determined that it cannot be encoded, and this subroutine is terminated, and the process proceeds to the next step S8.

Next, in step S8, the corresponding image is read from the second image data e and decoded, and the process proceeds to the next step S9. In this case, the image I0 is selected from the second image data string e ((D) in FIG. 9) and decoded by the MPEG decoder 12 ((G) in FIG. 9). The decoded image data of B0 is held in the image memory 14.

Next, in step S9, the image information table i is referred to obtain the encoding type of the next frame to be reproduced, and the process proceeds to step S6. In this case, the column of the image number P2 in the image information table of FIG. 5 is selected, the column of the encoding type of the first image data information is referred to, and the content is B. It is determined that the converted frame type is a B picture.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a B picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the images necessary for decoding this image B1 are P14 and I2, but since the corresponding reference frame is not held in the image memory 14, it is determined that the encoding is impossible, and this subroutine is terminated. The process proceeds to step S8.

Next, in step S8, the corresponding image is read from the second image data string e and decoded, and the process proceeds to the next step S9. In this case, the image I1 is selected from the second image data string e ((D) in FIG. 9) and decoded by the MPEG decoder 12 ((G) in FIG. 9). The decoded I1 image data is held in the image memory 14.

Next, in step S9, the image information table i is referred to obtain the encoding type of the next frame to be reproduced, and the process proceeds to step S6. In this case, the column of the image number P3 in the image information table of FIG. 5 is selected, the column of the encoding type of the first image data information is referred to, and the content is P. It is determined that the conversion type is a P picture.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a P picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the image necessary for decoding the image P5 is I2, and since I2 is held in the image memory 14, it is determined that encoding is possible, and this subroutine is terminated, and the process proceeds to the next step S7.

  In step S7, the corresponding frame and subsequent image data are continuously read and reproduced using the first image data string c. The subsequent operation is the same as the reproduction operation after the P5 image described in FIG. That is, P5 is selected from the first image data string c ((D) of FIG. 9), and the decoded image of I2 held in the image memory 14 is used as a reference frame (FIG. 9 (E)). Decoding is performed ((G) in FIG. 9). The decoded image data of P5 is held in the image memory 14. Next, B3 is selected from the first image data string c ((D) of FIG. 9), and the decoded images of I2 and P5 held in the image memory 14 are used as reference images ((e), (FIG. 9)). F)) B3 is decoded ((G) in FIG. 9). The decoded B3 image data is held in the image memory 14. Next, B4 is selected from the first image data sequence c ((D) in FIG. 9), and the decoded images of I2 and P5 held in the image memory 14 are used as reference images ((E) and (E) in FIG. F)) B4 is decoded ((G) in FIG. 9). The decoded B4 image data is held in the image memory 14. Next, P8 is selected from the first image data sequence c ((D) of FIG. 9), and the decoded image of P5 held in the image memory 14 is used as a reference image ((E), (F) of FIG. 9). ) P8 is decoded ((G) in FIG. 9). The decoded B8 image data is held in the image memory 14. Thereafter, the image data is similarly decoded. The images are reproduced while being switched in the same order as the original images by the method described with reference to FIG. Specifically, as shown in the reproduced image sequence in FIG. 9, the image data of the decoded image sequence after the decoding process is reproduced in the same order as the original image. That is, reproduction is performed like I0, I1, I2, B3, B4, and P5. As described above, an image can be reproduced with the reproduction head frame B0 as the head.

  FIG. 10 is a diagram for explaining the operation when the reproduction start image (frame) is a P picture. First, in step S1, information indicating the image reproduction start position (frame) in the image bit string selected by the user is set. In this case, it corresponds to P5 of the first image data string c in FIG. Next, in step S2, the image information table i for the bit string of the image to be reproduced is read. In this case, the image information table i in FIG. 5 is read. Next, in step S3, the encoding type of the image corresponding to the image to be reproduced is extracted from the first image data string c with reference to the image information table i. In this case, the column of the image number P3 in the image information table i in FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to, and the content is P. It is determined that the encoding type is a P picture. Next, in step S4, it is determined that the encoding type acquired in step S3 is not a B picture, and the process proceeds to step S6.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a P picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the image necessary for decoding this image is I2, but since the corresponding reference frame is not held in the image memory 14, it is determined that encoding is impossible, and this subroutine is terminated, and the next step S8 is performed. Proceed to

Next, in step S8, the corresponding image is read from the second image data string e and decoded, and the process proceeds to the next step S9. In this case, the image I5 is selected from the second image data string e ((D) in FIG. 10) and decoded by the MPEG decoder 12 ((G) in FIG. 10). The decoded I5 image data is held in the image memory 14.

Next, in step S9, the image information table i is referred to obtain the encoding type of the next frame to be reproduced, and the process proceeds to step S6. In this case, the column of the image number P6 of the image information table i in FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to. It is determined that the encoding type is a P picture. Here, the reason for skipping B3 and B4 to P8 for the next image to be reproduced is that B3 and B4 are later in time than the reproduction head image.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a P picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the image necessary for decoding the image P8 is I5, and since the decoded image of I5 is held in the image memory 14, it is determined that encoding is possible, and the process proceeds to the next step S7.

  In step S7, the corresponding frame and subsequent image data are continuously read and reproduced using the first image data string c. The subsequent operation is the same as the reproduction operation after the P5 image described in FIG. That is, P8 is selected from the first image data string c ((D) in FIG. 10), and the decoded image of I5 held in the image memory 14 is used as a reference frame ((E) in FIG. 10). Is decoded ((G) in FIG. 10). The decoded P8 image data is held in the image memory 14.

  Next, B6 is selected from the first image data sequence c ((D) in FIG. 10), and the decoded images of I5 and P8 held in the image memory 14 are used as reference images ((E) and (E) in FIG. F)) B6 is decoded ((G) in FIG. 10). The decoded B6 image data is stored in the image memory 14. Next, B7 is selected from the first image data sequence c ((d) in FIG. 10), and the decoded images of I5 and P8 held in the image memory 14 are used as reference images ((E) and (E in FIG. 10). F)) B7 is decoded ((G) in FIG. 10). The decoded B7 image data is held in the image memory 14. Next, P11 is selected from the first image data sequence c ((d) in FIG. 10), and the decoded image of P8 stored in the image memory 14 is used as a reference image ((E) P11 in FIG. 10 is decoded). Then, the decoded image data of P11 is held in the image memory 14. Thereafter, the image data is similarly decoded, and the reproduction of the images is performed in the same order as the original images by the method described with reference to FIG. Specifically, as shown in the reproduced image sequence in Fig. 10, the image data of the decoded image sequence after the decoding process is reproduced in the same order as the original image. That is, the image is reproduced as I5, B6, B7, P8 As described above, the image can be reproduced with P5 of the reproduction head frame as the head.

  FIG. 11 is a diagram for explaining the operation when the reproduction start image is a B picture following the P picture. First, in step S1, information indicating the image reproduction start position (frame) in the image bit string selected by the user is set. In this case, it corresponds to the first image data string cB3 in FIG. Next, in step S2, the image information table i for the bit string of the image to be reproduced is read. In this case, the image information table i in FIG. 5 is read. Next, in step S3, the encoding type of the image corresponding to the image to be reproduced is extracted from the first image data string c with reference to the image information table i. In this case, the column of the image number P4 in the table of FIG. 5 is selected, the column of the encoding type of the first image data information is referred to, and the content is B. Is a B picture.

  Next, in step S4, it is determined that the encoding type acquired in step S3 is a B picture, and the process proceeds to step S5.

  Next, in step S5, the image corresponding to the previous P picture is decoded from the second image data string e, and the process proceeds to the next step S6. In this case, the image I5 is selected from the second image data string e ((D) in FIG. 11) and decoded by the MPEG decoder 12 ((G) in FIG. 11). The decoded I5 image data is held in the image memory 14.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a B picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the images necessary for decoding the image B3 are I2 and P5, but since the corresponding reference frame is not held in the image memory 14, it is determined that encoding is impossible, and the process proceeds to the next step S8. .

Next, in step S8, the corresponding image is read from the second image data and decoded, and the process proceeds to the next step S9. In this case, the image I3 is selected from the second image data string e ((D) in FIG. 11) and is decoded by the MPEG decoder 12 ((G) in FIG. 11). The decoded I3 image data is held in the image memory 14.

Next, in step S9, the image information table i is referred to obtain the encoding type of the next frame to be reproduced, and the process proceeds to step S6. In this case, the column of the image number P5 in the image information table i of FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to in the column, and the content is “B”. It is determined that the encoding type is a B picture.

  Next, in step S61, which is a lower module of step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a B picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the images necessary for decoding the image B4 are I2 and P5, but since the corresponding reference frame is not held in the image memory 14, it is determined that encoding is impossible, and the process proceeds to the next step S8. .

Next, in step S8, the corresponding image is read from the second image data string e and decoded, and the process proceeds to the next step S9. In this case, the image I4 is selected from the second image data string e ((D) in FIG. 11) and is decoded by the MPEG decoder 12 ((G) in FIG. 11). The decoded I4 image data is held in the image memory 14.

Next, in step S9, the image information table i is referred to obtain the encoding type of the next frame to be reproduced, and the process proceeds to step S6. In this case, the column of the image number P6 of the image information table i in FIG. 5 is selected, and the column of the encoding type of the first image data information is referred to. It is determined that the encoding type is a P picture.

  Next, in S61, which is a lower module in step S6, it is determined whether or not the coding type is an I picture. In this case, it is determined that the corresponding frame is a P picture and not an I picture, and the process proceeds to step S62. In step S62, information about which image is the decoded image stored in the image memory 14 is acquired. Next, in step S63, it is determined whether or not a reference frame necessary for decoding the image to be reproduced is held in the image memory 14 based on the information acquired in step S62. In this case, the image necessary for decoding the image P5 is I5, and since I5 is held in the image memory 14, it is determined that encoding is possible, and the process proceeds to the next step S7.

  In step S7, the corresponding frame and subsequent image data are continuously read and reproduced using the first image data string c. The subsequent operation is the same as the reproduction operation after the P8 image in the example of FIG. That is, P8 is selected from the first image data string c ((D) in FIG. 11), and the decoded image of I5 held in the image memory 14 is used as a reference frame ((E) in FIG. 11). Is decoded ((G) in FIG. 11). The decoded P8 image data is held in the image memory 14.

  Next, B6 is selected from the first image data sequence c ((D) in FIG. 11), and the decoded images of I5 and P8 held in the image memory 14 are used as reference images ((E), (FIG. 11)). F)) B6 is decoded ((G) in FIG. 11). The decoded B6 image data is stored in the image memory 14. Next, B7 is selected from the first image data string c ((D) in FIG. 11), and the decoded images of I5 and P8 stored in the image memory 14 are used as reference images ((E) and (E) in FIG. F)) B7 is decoded ((G) in FIG. 11). The decoded B7 image data is held in the image memory 14. Next, P11 is selected from the first image data string c ((D) in FIG. 11), and the decoded image of P8 held in the image memory 14 is used as a reference image ((E), (F) in FIG. 11). ) P11 is decoded ((G) in FIG. 11). The decoded image data of P11 is held in the image memory 14. Thereafter, the image data is similarly decoded. The images are reproduced while being switched in the same order as the original images by the method described with reference to FIG. Specifically, as shown in the reproduction image sequence of FIG. 11, the image data of the decoded image sequence after the decoding process is reproduced in the same order as the original image. That is, an image can be reproduced starting from B3 of the reproduction start frame, such as I3, I4, I5, B6, B7, and P8.

  As described above, the video recording / playback apparatus according to the first embodiment performs the intra-frame encoded second video data separately from the first video data sequence c obtained by intra-frame encoding or inter-frame encoding of the video signal. By generating the column e and making it decodable, it is possible to obtain a video recording / playback apparatus that can play back from an arbitrarily designated frame when the user plays back video from the middle of a program.

Embodiment 2. FIG.
In Embodiment 1, the image encoded by the first MPEG encoder is encoded at the same compression rate (bit rate) by the second MPEG encoder. In the second embodiment, the compression rate of the image compressed by the second MPEG encoder is increased. In this case, the MPEG decoder 12 decodes the first image and the second image having different compression rates. Therefore, information indicating the compression rate of the image decoded by the MPEG decoder 12 is included in the read image selection information k and is output from the image information management unit 9 to the MPEG decoder 12. Accordingly, when the first MPEG image and the second image are decoded in the second MPEG decoder, the image is decoded corresponding to the compression rate of each image. Other operations are the same as those described in the first embodiment.

  As described above, the video recording / playback apparatus according to the second embodiment can reduce the amount of image data by increasing the compression rate of the image generated by the second MPEG encoder, so that a certain amount of recording medium can be used. The effect of increasing the amount of video that can be recorded is obtained.

Embodiment 3 FIG.
In the first embodiment, the same number of images as the images encoded by the first MPEG encoder are generated by the second MPEG encoder. In the third embodiment, an image generated by the second MPEG encoder is a B picture and a P picture. That is, the image corresponding to the I picture of the first image is not used as the second image data. Other operations are the same as those described in the first embodiment.

  As described above, the video recording / playback apparatus according to Embodiment 3 increases the amount of video that can be recorded on a certain amount of recording medium by reducing the amount of images generated by the second MPEG encoder. Is obtained.

Embodiment 4 FIG.
The video recording / reproducing apparatus 1 according to the first embodiment records and reproduces images. The fourth embodiment is a video playback device for playing back the recording medium of the present invention recorded by the first video recording / playback device, which cannot record video. FIG. 12 is a block diagram illustrating the overall configuration of the video reproduction apparatus according to Embodiment 4 of the present invention. In FIG. 12, 7 to 14 are the same as those in FIG. The CPU 15 is obtained by deleting the function of the image information generation unit 6 in the CPU of the first embodiment. The image data recording unit 7 and the image information recording unit 8 are composed of, for example, a DVD or the like, and the DVD can be taken out from the video reproduction device 16. The DVD records image data g obtained by packetizing the first image data sequence c and the second image data sequence e recorded by the video recording / reproducing apparatus 1 of Embodiment 1, and data such as the image information table i. Has been. Thus, by reproducing this DVD by the video reproduction device 16, it is possible to perform video reproduction similar to that in the first embodiment.

  As described above, the video playback apparatus according to the fourth embodiment is provided with a function that allows playback from an arbitrarily designated image to a playback apparatus that has only a playback function, and thus adds value to an inexpensive playback-only video playback apparatus. You can have it. In addition, the DVD, which is a recording medium recorded by the video recording / playback apparatus 1 of the first embodiment, uses the playback-only video playback apparatus, so that when a user plays back video from the middle of a program, it is optional. It is possible to provide a recording medium that can be played back from a frame specified in the above.

1 is a block diagram of a video recording / reproducing apparatus in Embodiment 1 of the present invention. It is a figure for demonstrating the process order of the encoding of general MPEG image data, and decoding. It is a figure for demonstrating the format of the packet data g which the control part 5 in Embodiment 1 of this invention produces | generates. It is a figure explaining the operation | movement which produces | generates the packet data g of the write control part 5 in Embodiment 1 of this invention. It is a figure which shows an example of the image information table i in Embodiment 1 of this invention. 5 is an operation flowchart showing a reading process of image data in a video signal reproduction operation according to the first embodiment of the present invention. It is an operation | movement flowchart of the subroutine of the encoding decision | availability determination process of step S6 in FIG. 6 in Embodiment 1 of this invention. It is a figure for demonstrating the operation | movement which reproduces | regenerates the designated image in Embodiment 1 of this invention. It is a figure for demonstrating the operation | movement which reproduces | regenerates the designated image in Embodiment 1 of this invention. It is a figure for demonstrating the operation | movement which reproduces | regenerates the designated image in Embodiment 1 of this invention. It is a figure for demonstrating the operation | movement which reproduces | regenerates the designated image in Embodiment 1 of this invention. It is a block diagram of the video reproduction apparatus in Embodiment 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Video recording / reproducing apparatus, 3 1st MPEG encoder, 4 2nd MPEG encoder, 5 Write control part, 6 Image information generation part, 7 Image data recording part, 8 Image information recording part, 9 Image information management part, 10 Main control unit, 11 readout control unit, 12 MPEG decoder, 14 image memory, 15 CPU, 16 video playback device

Claims (5)

First encoding means for generating a first image data sequence from an input video signal by each encoding method of intra-frame encoding or inter-frame encoding;
Second encoding means for generating a second image data sequence from the video signal by an intra-frame encoding method;
Write control means for packetizing each of the first and second image data sequences;
Image information generating means for generating an image information table including each encoding method for generating the first and second image data sequences, and packetization information at the time of packetization;
Image data recording means for recording the packetized image data;
Image information recording means for recording the image information table;
The image data that is to be reproduced and that has generated the image data that forms the first image data sequence is read from the image information table, and the image data to be reproduced based on the encoding method is the packet Image information management means for selecting from the converted first image data string or second image data string;
Read control means for packet decoding the selected image data;
A video recording / reproducing apparatus comprising: decoding means having an image memory for decoding the packet-decoded image data and holding the image. Image information management means
Determining whether the encoding method for generating the image data forming the first image data sequence is an intra-frame encoding method or an inter-frame encoding method that is to be reproduced;
If the determined encoding method is an intra-frame encoding method, the subsequent image data is selected from the first image data sequence,
In the case of the inter-frame coding method, it is determined whether or not image data to be referred to when decoding the reproduced image data is held in the image memory,
If held, the image data to be reproduced is selected from the first image data with reference to the held image data,
2. The video recording / reproducing apparatus according to claim 1, wherein when not held, image data to be reproduced is selected from the second image data string.   3. The video recording / reproducing apparatus according to claim 1, wherein the second encoding means performs intra-frame encoding of the video signal at a compression rate higher than that of the first image data sequence.   3. The video recording / reproducing apparatus according to claim 1, wherein the second encoding means performs intra-frame encoding of the video signal only when the first image data string is a B picture and a P picture. A first image data sequence generated by intra-frame encoding or inter-frame encoding for the input video signal, and a second image data sequence generated by intra-frame encoding for the video signal And packetized image data,
A recording medium on which each encoding method for generating the first and second image data sequences and an image information table including the packetization information when packetized are recorded.

Images