JP3187649B2 - Playback method of storage type recording media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reproducing a storage type recording medium, and more particularly, to a method of reproducing a storage type recording medium while returning the pickup to a position before the jump when the pickup jumps due to vibration or the like. About.

[0002]

2. Description of the Related Art Video CDs in which compressed audio data and compressed image data are recorded in a CD-ROM format in a time-division manner and are capable of reproducing AV data for a maximum of 98 traffic have been put to practical use. FIG. 3 is a diagram showing a disk configuration of such a video CD. LIN is a lead-in area in which various TOC information is recorded, and TR1 to TRN are tracks 1 to N, L
OT is a lead-out area. Track 1 (TR
1) includes file management information PV conforming to ISO9660.
D, a karaoke information section, a video CD information section, a segment play section, and a CD-I application section. The tracks 2 to N are provided with MPEG1 (Moving Picture Image coding Experts Gr.
The audio and image data which have been highly efficiently coded (compressed) by the oup 1) method are stored. In the video CD information section of the track 1, various information, for example,
A list ID offset table (LOT) for recording moving picture and still picture IDs recorded on a disc, a playback control unit (PBC) for recording a reproduction procedure described in a list format, and the like are written. Has become.

FIG. 4 is a block diagram of a track, and FIG. 5 is a block diagram of a sector. At the beginning of the track, 150 sectors are provided as a pause margin and 15 sectors as a front and rear margin, respectively, assuming that a search is performed by a track number, as in a CD player, and the rest is an MP.
This is the EG data section. As shown in FIG. 5, the sector format of MPEG data includes a pack header PHD and pack data PDT, and one sector (2324 bytes) of a CD-ROM forms one pack. The pack data PDT is composed of a plurality of packets, and each packet is composed of a packet header PCH and packet data PCD.

[0004] One packet contains at least one screen of compressed image data, one frame of compressed audio data, or other data.
Since about 1.2 Mb / sec is assigned to image data and 0.2 Mb / sec to audio data, one audio sector appears every 5 to 6 sectors. A start code, a reference clock (SC) are included in the pack header PHD.
R: System Clock Reference), a transfer rate, etc. are entered, and in the packet header PCH, a start code, a stream type (for video / audio / data), a reproduction start time (PTS: Presentation Time Stamp), and a decode start time (DTS). : DecodingTime Stamp).

FIG. 6 shows an example of a hierarchical structure of compressed image data, which is composed of a sequence layer, a GOP layer, and a picture layer. GOP (Group Of Picture)
Are recommended), and each picture has three types of I, P, and B. The I picture is an intra-frame coded image and can be decoded independently, but has the largest data amount. The P picture is an inter-frame predictive coded image, and is predictively coded based on a past I or P picture. The B picture is a picture peculiar to MPEG, and is inter-frame predictive coded from both directions of a past I or P picture and a future I or P picture, and has a small data amount. The P picture is an intermediate data amount between the I picture and the B picture.

In order to reduce the frame memory capacity of the decoder as much as possible, the original picture order (playback order) of each picture and the recording order on a video CD are different as shown in FIG. B ₁ , B ₂ , I ₃ , B ₄ , B ₅ , P ₆ , B ₇ , B ₈ , P ₉ ,
_{B 10, B 11, P 12} , B 13, B 14, P 15 is on the recording medium (video CD) _{is, I 3, B 1, B} 2, P 6, B 4, B 5, P 9, B 7 , B ₈ ,
P ₁₂ , B ₁₀ , B ₁₁ , P ₁₅ , B ₁₃ , and B ₁₄ are used, and are reproduced in the same order as the original image during reproduction. P ₆
The picture is decoded using the decoded I ₃ picture, and P ₉
Picture is decoded using the P ₆ picture after decoding, and so Pi picture is decoded using the Pi-1 decoded pictures. B ₁ picture P ₁₅ picture after decoding in I ₃ picture and the first forward GOP after decoding, is decoded using the interpolation picture on these groups. B ₄ pictures I ₃ picture and P ₆ decoded pictures, these are decoded using an interpolation picture based on, it is similarly decoded below.

The video sequence layer is composed of one or more GOPs having the same image size, screen aspect ratio, etc. (FIG. 6), and the GOP layer is composed of 15 picture layers divided for each picture. . Following the sequence start code, the characteristics of the compressed image data required for decoding, such as the image size and the aspect ratio of the image, are recorded in the header of the sequence layer, and the GOP start code and other data are recorded in the header of the GOP layer. In the header of the picture layer, PTS, DTS, picture type, and the like are recorded together with the picture start code. After the compressed image data and the compressed audio data are individually packetized, a packet of the compressed image data and a packet of the compressed audio data are combined to be packed into a fixed data amount and recorded on a video CD.

[0008]

In a vehicle-mounted video CD player, if the pic-up jumps due to the vibration of the vehicle, images and sounds are skipped. Therefore, conventionally, when a jump occurs, the pick-up is returned to the position before the occurrence of the jump, and the image and the sound are restarted from there. However, in such a conventional method, while the pick-up is returned to the position before the occurrence of the jump, the video is monochrome and the sound is silent. For this reason, there is a problem that information provided to the viewer becomes zero and the viewer feels strange. Accordingly, an object of the present invention is to provide a method of reproducing an accumulation type recording medium in which an image displayed before a jump occurs is displayed frame-by-frame while the pic-up is returned to a position before the jump occurred.

[0009]

According to the present invention, there is provided, according to the present invention, a memory for storing several latest I pictures and P pictures read from a storage type recording medium such as a video CD during image reproduction; Jump occurrence detecting means for detecting the occurrence of a jump in the pic-up; pick-up returning means for returning the pic-up to the position before the jump when jumping; and I-pictures and P-pictures from the memory while returning the pic-up to the position before the jump. This is achieved by means for reading out and decoding in order from the oldest one, and means for displaying the decoded image frame by frame on a display screen.

[0010]

During playback of an image, the latest several I-pictures and P-pictures read from the storage type storage medium are stored in a memory, and when the pic-up jumps, the pic-up is returned to the position before the jump, and during that time, , The I picture and the P picture are read out from the memory in order from the oldest one and decoded, and the decoded image is displayed frame by frame on the display screen. By doing so, while the pic-up is returned to the position before the jump occurred, the image displayed before the jump occurred can be displayed frame by frame, and the service to the viewer can be improved.

[0011]

【Example】

(a) Configuration of Video CD Player FIG. 1 is a configuration diagram of a video CD player according to the present invention. Reference numeral 11 denotes a CD drive for reading data recorded on a video CD, and reference numeral 12 denotes an RF / servo circuit, which amplifies an RF signal read from the video CD and performs a subsequent CD operation.
While input to the signal processor, it performs various servo controls (focusing servo, tracking servo, feed servo, linear velocity constant control). A CD signal processor 13 demodulates CD format data from the RF signal and executes digital signal processing including error detection and correction processing. 14 demodulates CD-ROM format MPEG data and performs error detection and correction processing. , A CD-ROM signal processor that executes digital signal processing such as extraction of address information (time information). Reference numeral 15 denotes an SRAM, reference numeral 16 denotes a microcomputer (system controller) for controlling the entire system, and reference numeral 17 denotes an operation unit having a key unit 17a and a display unit 17b.

The microcomputer 16 has a function of detecting the occurrence of a jump in the pic-up due to the discontinuity of the current position information (time information from the beginning) of the pic-up, a function of returning the pic-up to the position before the occurrence of the jump, It has a function to enable the start of frame-by-frame drawing by I picture and P picture. Reference numeral 18 denotes a data handle controller, and reference numeral 19 denotes an image memory for storing the latest compressed image data of some I-pictures and P-pictures read from a video CD during reproduction. The data handle controller 18 has a function of separating and outputting MPEG data for each image and audio, and among the compressed image data input from the CD-ROM signal processor 14 during reproduction, some of the latest I pictures, P
A function to write a picture into the image memory 19, an I picture from the image memory 19 when a jump of a pick-up occurs,
The image data of the P picture is sequentially read at a predetermined cycle, and M
It has a function of outputting to the PEG video decoder side and the like.

Reference numeral 20 denotes an input of the compressed image data,
An MPEG video decoder for decoding an image according to the G1 system, a DRAM 21 for decoding image data,
Reference numeral 22 denotes an MPEG audio decoder to which compressed audio data is input and decodes audio data in accordance with the MPEG1 system; 23, a DRAM used for decoding audio data; 24, a DA converter for converting image data from DA to DA; This is a DA converter for conversion.

(C) Image Display Control When Jump Occurs FIG. 2 is a flowchart of image reproduction control when a jump occurs according to the present invention. The microcomputer 16 controls the CD-R during image reproduction.
With reference to the time information input from the OM signal processor 14, it is monitored whether the pickup jumps (step 101). If no jump has occurred, the data handle controller 18 checks whether the compressed image data included in the MPEG data input from the CD-ROM signal processor 14 is an I picture or a P picture (step 102). If the picture is an I or P picture, the I or P picture is stored in the image memory 19 (step 103). Note that the image memory 19 stores some of the latest I (or N) I or P pictures. Thereafter, or if it is not an I or P picture in step 102, the compressed image data contained in the MPEG data is
Output to the G video decoder 20,
To decode the moving image and display it on the display screen (step 104). Thereafter, the process returns to the beginning and repeats the processing from step 101.

On the other hand, when a jump occurs in the pick-up, the microcomputer 16 instructs the data handle controller 18 to perform frame-by-frame drawing and executes return control for returning the pick-up to the jump start position (step 10).
5). The data handle controller 18 reads out the I and P pictures stored in the image memory 19 from the oldest one at a predetermined cycle and outputs the I and P pictures to the MPEG video decoder 20 in response to the frame advance drawing instruction (step 106). The MPEG video decoder 20 decodes image data based on the input I and P pictures, and displays an image on a display screen based on the decoded image data. In this case, MPEG
Since the I and P pictures are input to the video decoder 20 at a speed of 1 / n of the normal input speed, frame display is performed on the display screen at a speed of 1 / n (step 107).

Next, the microcomputer 16 checks whether or not the pick-up has returned to the jump start position (step 10).
8) If not recovered, the frame-by-frame drawing process from step 106 is continued. On the other hand, when the pick-up returns to the jump start position, the microcomputer 16
Is instructed to stop frame-feed drawing (step 109). Thereafter, the processing returns to the beginning, and the reproduction of the image is restarted from the position before the jump. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0017]

As described above, according to the present invention, during image reproduction, some of the latest I-pictures and P-pictures read from the storage type storage medium are stored in the memory, and when the pic-up jumps, At the same time, the I-picture and the P-picture are read out from the memory in order from the oldest one and decoded, and the decoded image is displayed frame-by-frame on the display screen. While the image is being returned, the image displayed before the jump occurred can be displayed frame by frame, and the service to the viewer can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video CD player of the present invention.

FIG. 2 is a flowchart of image display control when a jump occurs.

FIG. 3 is a diagram illustrating a disk configuration of a video CD.

FIG. 4 is a configuration diagram of a track.

FIG. 5 is a configuration diagram of a sector.

FIG. 6 is an explanatory diagram of a hierarchical structure of MPEG video data.

FIG. 7 is an explanatory diagram of a recording position on a medium of a picture constituting a GPO.

[Explanation of symbols]

 11, CD drive 13, CD signal processor 14, CD-ROM signal processor 16, microcomputer (system controller) 18, data handle controller 20, MPEG video decoder 22, MPEG audio decoder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/76-5/956 G11B 19/02 501 G11B 20/10-20/18 H04N 7/24-7 / 68

Claims (1)

(57) [Claims] 1. A method for reproducing a storage type recording medium in which compressed image data composed of three types of pictures of I, P, and B are recorded in accordance with an MPEG format, wherein the latest image read from the storage type recording medium during image reproduction. Stores some I-pictures and P-pictures in the memory, and when the pic-up jumps, returns the pic-up to the position before the jump, while the I-picture,
A method for reproducing a storage-type recording medium, wherein P-pictures are read out in order from the oldest one, decoded, and the decoded images are displayed frame-by-frame on a display screen.