JPH07123357A - Compressed picture reproducing method - Google Patents

Abstract

PURPOSE:To provide a compressed picture reproducing method for reducing the reproducing time of unnecessary data in the selective reproduction of intra- frame encoded pictures and improving sensation at the time of reproduction such as fast forwarding or the like. CONSTITUTION:A header detection means 13 monitors a header which is the starting information of pictures in a picture bit stream and transmits a monitored result to a control means 16. When the header detection means 13 detects the header, the control means 16 instructs the header detection means 13 to output the picture bit stream from the head of the intra-frame encoded pictures to a FIFO means 14 and when the header is consecutively detected, lets output to the FIFO means 14 stop. Simultaneously, the control means 16 instructs a disk read means 11 the read of data from a new optional position. A bit stream decoding means 15 successively decodes the picture bit streams buffered in the FIFO means 14, successively completes the intra-frame encoded pictures and outputs them as video information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing method for a compressed image reproducing apparatus.

[0002]

2. Description of the Related Art As a conventional compressed image reproducing apparatus, there is, for example, a karaoke apparatus using a CD-ROM as a recording medium.

A conventional compressed image reproducing apparatus will be described below. FIG. 2 shows a block diagram of this conventional compressed image reproducing apparatus. In FIG. 2, 21 is a CD-ROM
A disc reading means for reading the recorded data from a designated physical address on the disc, and a structure 22 for decoding the CD-ROM structured data read by the disc reading means 21 and selectively outputting an image bit stream included therein. Data decoding means, 24 is a bit stream decoding means for decoding the image bit stream and outputting it as video information, 23 is a FIFO means for storing the image bit stream and absorbing the fluctuation of the decoding processing speed of the bit stream decoding means 24, 25 Is a control means for managing and controlling the disk reading means 21, the structured data decoding means 22, the FIFO means 23, and the bit stream decoding means 24.

A reproducing method of the compressed image reproducing apparatus having the above-mentioned structure will be described below.

First, the disk reading means 21 receives an instruction from the control means 25 and reads the recorded data from an arbitrary position on the disk. The structured decoding means 22 recognizes that the read data is in the sector unit of the CD-ROM structure, selectively extracts the image bit stream from the sectors, and outputs it to the FIFO means 23. The bit stream decoding means 24 sequentially decodes the image bit stream buffered by the FIFO means 23 and outputs it as image information.

When performing special reproduction such as fast-forwarding using the above basic operation, the control means 25 first instructs the disc reading means 21 to perform reproduction from an arbitrary position,
The header of the intra-frame coded image is detected from the reproduced image bit stream by the header detecting unit in the bit stream decoding unit 24. As a result, the decoding of the intra-frame coded image is started, and when the decoding is completed, the reproduction from a new arbitrary position is continuously repeated, and the intra-frame coded image is selectively reproduced for fast-forward reproduction. To be realized.

[0007]

However, in the above-mentioned conventional configuration, in order to shift to the reproduction of a new intra-frame coded image, the bit stream decoding means 24 decodes the bit stream of this intra-frame coded image. I have to wait for completion. However, the disk reading means 21 continues to read even during decoding, and there is a problem that a time required for reading unnecessary data other than the intra-frame encoded image data occurs. Further, this unnecessary data is stored in the FIFO means 2
It is stored in 3 and the reproduction from a new arbitrary position is
It is necessary to wait for the completion of decoding of the bit stream of the intra-frame coded image and to discard the contents held by the FIFO means 23, which makes it impossible to obtain a good usability during special reproduction such as fast-forwarding. Had a point.

The present invention solves the above problems of the prior art by reducing the reproduction time of unnecessary data in the selective reproduction of intra-frame coded images and improving the usability during special reproduction such as fast-forwarding. It is an object to provide a compressed image reproducing method.

[0009]

In order to achieve this object, a compressed image reproducing method of the present invention provides a bit stream of a compressed image in which image information is encoded in a frame unit or in a frame. In a compressed image reproducing device for reproducing the recorded recording medium and reproducing the image information,
After detecting the header of the first intra-frame coded image data from the bit stream read from the recording medium, a frame that immediately follows the first intra-frame coded image data from the bit stream that continues. By detecting the header of the encoded data, it is determined that the reading of the first intra-frame encoded data is completed, and the reading of new second and third intra-frame encoded image data from a new position is repeated, and The intraframe-coded images are selectively reproduced by measuring the appearance intervals of the intraframe-coded images in the bitstream read in advance and predicting the positions of the preceding and following intraframe-coded images.

[0010]

According to the present invention, after the header of the first intra-frame encoded image data is detected from the bit stream recorded on the recording medium by the above method, the first intra-frame encoded image data is detected from the continuous bit stream. By detecting the header of the inter-frame coded data that immediately follows
By determining that the reading of the intra-frame coded data of 1 has been completed, the process quickly searches for new new second and third intra-frame coded image data to be reproduced from the recording medium. Also, the appearance interval of the intra-frame coded image data in the bit stream read in this way on the recording medium, that is, the header recording interval of the intra-frame coded image data is measured, By predicting the recording position of the encoded image data, it is possible to reduce the time required to search the recording medium for the new intra-frame encoded image data described above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a compressed image reproducing apparatus which realizes a compressed image reproducing method in a first embodiment of the present invention. In FIG. 1, 11 is a disk reading means for reading data recorded from a designated physical address on a CD-ROM disk, 12 is a CD-ROM structured sector decoded from the data read by the disk reading means 11, and a CD -Structured data decoding means for extracting the sector address of the ROM structured sector and selectively outputting the included image bit stream, 13 detects the header of the intra-frame encoded and inter-frame encoded image from the image bit stream , Header detection means for determining whether the image is intra-frame encoded or inter-frame encoded image, 15
Is a bitstream decoding means for decoding the image bitstream and outputting it as video information, 14 is a FIFO means for accumulating the image bitstream and absorbing fluctuations in the decoding processing speed of the bitstream decoding means 15, 16 is a disk reading means 11, Structured data decoding means 12, header detection means 13, FIFO means 1
4 is a control means for managing and controlling each of the bitstream decoding means 15.

The operation of the compressed image reproducing method of the compressed image reproducing system of the above embodiment will be described below.

First, the disc reading means 11 receives an instruction from the control means 16 and starts reading the recorded data from an arbitrary position on the disc. The read data is transferred to the CD-RO by the structured decoding means 12.
Recognizing that it is a sector unit of M structure, the image bit stream is extracted and selected from the sector, and the header detecting means 1 is selected.
Output to 3. The header detection unit 13 monitors the header which is the start information of the intra-frame coding and inter-frame coding image in the image bit stream, and the monitoring result is the control unit 1.
Sent to 6. When the header detection unit 13 detects the header of the intra-frame encoded image, the control unit 16 receives the image bit stream from the beginning of the intra-frame encoded image as a FIF.
The header detecting means 13 is instructed to output to the O means 14. Subsequently, when the header of the inter-frame coded image is detected in the image bit stream, the output to the FIFO means 14 is stopped, and the sending of data other than the intra-frame coded image to the FIFO means 14 is blocked. At the same time as the sending out is blocked, the control means 16 instructs the disk reading means 11 to read data from a new arbitrary position, and the same operation is repeated thereafter.

In the bit stream decoding means 15, F
The buffered image bit stream is sequentially decoded by the IFO means 14 to sequentially complete the intra-frame encoded image and output it as video information.

As described above, according to the present embodiment, before the bit stream decoding means 15 actually decodes the image bit stream read from the disk reading means 11, the intra-frame coding and the inter-frame coding picture are carried out. Since it can be determined by the header detecting means 13, the time for reading unnecessary data can be reduced, and the read position of the disk reading means 11 can be quickly controlled.

Further, the control means 16 includes the header detection means 1
C when 3 detects the header of the intra-frame coded image
By recording the sector address of the D-ROM structured sector and calculating how many sector addresses the detection interval of the header of the intra-frame encoded image is, the position to be read next can be predicted. By this prediction, the detection time of the intra-frame coded image is shortened, and a good operation such as fast-forward reproduction can be realized.

In the embodiment, 11 is a CD-ROM
However, the recording medium is not particularly limited.

[0019]

As described above, according to the present invention, after detecting the header of the intra-frame coded image data from the bit stream read from the recording medium, the header is detected immediately after the intra-frame coded image data from the continuous bit stream. By detecting the header of the subsequent inter-frame coded data, it is judged that the reading of the intra-frame coded data has been completed, and the process can be quickly moved to the search for new intra-frame coded image data from a new position. , Unnecessary reading of data can be eliminated as much as possible, and by measuring the header recording interval of intra-frame encoded image data and predicting the recording position of the preceding and following intra-frame encoded image data, a new intra-frame encoding is performed. By reducing the time required to retrieve image data from the recording medium and speeding up selective playback of intra-frame encoded images, It can improve the feeling at the time of special reproduction of the feed and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a compressed image reproduction device that realizes a compressed image reproduction method according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a compressed image reproducing device in a conventional example.

[Explanation of symbols]

 11 Disk Reading Means 12 Structured Data Decoding Means 13 Header Detecting Means 14 FIFO Means 15 Bit Stream Decoding Means 16 Control Means

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area H04N 7/137 Z

Claims (2)

[Claims] 1. A compressed image reproducing apparatus which reproduces image information by reproducing a recording medium recording a bit stream of a compressed image in which image information is intra-frame coded or inter-frame coded in frame units, After detecting the header of the first intra-frame encoded image data from the bit stream read from the recording medium, the inter-frame code that immediately follows the first intra-frame encoded image data from the continuing bit stream. It is determined that the reading of the first intra-frame coded data is completed by detecting the header of the coded data, and the reading of new second and third intra-frame coded image data from a new position is repeated. And compressed image playback method. 2. An intra-frame coded image is selected by measuring an appearance interval of intra-frame coded images in a bit stream read in advance and predicting positions of preceding and following intra-frame coded images. The compressed image reproducing method according to claim 1, wherein the compressed image is reproduced.