JP3121054B2 - Information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, for example, an information recording / reproducing apparatus for recording and reproducing a still image with sound on a predetermined recording medium.

[0002]

2. Description of the Related Art A still picture program with sound having a variety of display switching effects (cut, scroll, wipe, dissolve, etc.) using a high-definition still picture and PCM sound is transmitted as a digital data packet via a satellite line or CATV. Delivery services are being considered.

FIG. 3 shows a packet format when audio-related digital data and image-related digital data of the still picture program with audio are packed into packets.

[0004] As shown in FIG. 3A, one packet is composed of 2048 bits with seven packets, and a 16-bit synchronization signal FS is provided at the head of one frame. The 16-bit synchronization signal FS is followed by the frame control signal F
C has 16 bits.

[0005] The frame control signal FC contains additional information such as mode information. Further, as shown in FIG. 3B, the structure of one packet (288 bits) is composed of a 16-bit header HA, HS, a 174-bit data part,
Consists of bit error correction. The header HA indicates the attribute of the packet, that is, the type of the delivered service (for example, the packet is a still image program with sound). The header HS indicates the type of the packet in the attribute indicated by the header HA (for example, in the case of a still picture program with sound, whether the packet is related to sound or image). Is information indicating
In the case of a still image program with audio, audio data, image data, program control data, and the like are contained in the 174-bit data portion.

Digital services such as still picture programs have several M
Since the data is transmitted through a transmission path of about bps, compression of audio data as well as compression of image data is indispensable. With regard to image compression, encoding is performed for each still image, and a synchronization signal, encoding parameters, encoded data, and the like are transmitted in packets according to the encoding format. Audio is also encoded every several ms, and a synchronization signal, encoding parameters, encoded data, and the like are transmitted in packets. In transmission, it is not necessary that the synchronization signal of the encoding format of the image data and the synchronization signal of the encoding format of the audio data be transmitted in agreement.

FIG. 2 shows an example of a configuration for recording, reproducing and retrieving a still picture program with audio transmitted by the above-mentioned packet.
Shown in The digital data sequence input from the input terminal 100 is synchronized with the synchronization signal FS by the reception demodulation circuit 102 and is received and demodulated. The received and demodulated digital data is separated into each packet by a packet separation circuit 104,
The header correction circuit 106 decodes the error correction codes of the headers HA and HS, and the error correction decoder 108 decodes the error correction codes attached to the header HS and the data part.

[0008] The packet string whose error correction code is decoded by the error correction decoder 108 is sent to a service identification circuit 110.
, The service is identified based on the header HA, and the service packet of the still image program with audio is extracted. Next, information such as an ID necessary for the search is added by the search information adding circuit 112 and sent to the recording / reproducing circuit 118 via the bus A. The recording / reproducing circuit 118 receives a recording control signal from the recording / reproducing search control circuit 116, adds a recording error correction code, and writes the recording medium 120 (for example, a magneto-optical disk). Note that the above recording process is all CP
It is under the control of U122.

During reproduction and retrieval, the CPU 12
2, the recording / reproducing circuit 118 receives the reproduction control signal from the recording / reproduction search control circuit 116, and
The data is read from the bus 20, the error correction code is decoded, and transmitted to the bus A. The search information read circuit 126 reads information necessary for search through the bus A. CPU1
Reference numeral 22 controls search and reproduction based on the search information.

[0010] Based on the search information, the packet sequence read under the control of the CPU 122 identifies a packet for audio and a packet for image by the packet identification circuit 134, and the packet for audio is sent to the audio decoder 136. Is transmitted to the image decoder 138.

Since the audio data is encoded, the audio decoder 136 decodes the audio packet and outputs it from the output terminal 140 as audio data. The image decoder 138 decodes the packet for the image, calculates the display timing of the image based on the reproduced transmission time data and the image display time data, and outputs the image data from the output 142 when the display time comes.

Thereafter, audio amplifiers, speakers, monitors, and the like (not shown) are connected to the outputs 140 and 142 to reproduce a still picture program with sound.

[0013]

However, in the above-mentioned conventional example, a problem occurs when an image is searched and a program is reproduced from the search point. For example, FIG. 4 (in the drawing, Vk (k = 1, 2,...) Represents an image packet and Al (l = 1,
2,... Indicate audio packets), and if a packet is read from the point a after the search, the audio packets A1, A2 after the point b follow the image packets V1, V2, V3. A2, .. is read out, but since the audio data is encoded and compressed, if the synchronization of the encoding of the audio data does not match the point b, the audio will not be decoded correctly, resulting in noise Problem occurs.

The present invention has been made in view of the above problems, and even when a still image is reproduced from a desired position on a recording medium, the sound corresponding to the still image can be correctly decoded and the sound without noise can be reproduced. It is intended to provide an information recording / reproducing device.

[0015]

To solve this problem, for example, an information recording / reproducing apparatus according to the present invention has the following arrangement. That is, an information recording / reproducing apparatus which records and reproduces still image information with audio in a packet format on a predetermined recording medium, wherein when a reproduction start position of a still image in the recording medium is designated, the designated reproduction start A still image reproducing unit that reproduces a still image from a position, a detecting unit that detects audio synchronization of audio data when reproducing audio data corresponding to a still image reproduced by the still image reproducing unit; Audio reproduction means for starting reproduction from audio data matching the detected audio synchronization.

[0016]

In the configuration of the present invention, when the reproduction of a still image is started by the still image reproducing means, the audio synchronization of the audio data after the start position is detected. Then, the audio data up to the coincidence with the audio synchronization is not reproduced, and the reproduction is performed from the coincident audio data.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of the information recording / reproducing apparatus of the embodiment. Those having the same functions as those of the conventional example are given the same numbers. Hereinafter, only different points from the conventional example will be described.

Now, it is assumed that the point a shown in FIG. 4 is searched based on the search information read by the search information reading circuit 126, and the reading is started. The read packet is stored in the buffer 13
Once taken into 2. Voice packet Am at point c in FIG.
In the case where the first audio synchronization exists, the synchronization detection circuit 1
28 detects voice synchronization when a packet is read up to the point c, and sends a detection signal to the packet control circuit 130.

The packet is sent from the buffer 132 to the packet identification circuit 134 with an appropriate delay amount, and the packet identification circuit 134 identifies the audio packet and the image packet and outputs them to the audio decoder 136 and the image decoder 138, respectively. However, under the control of the packet control circuit 130, the audio packets until the first audio synchronization is detected, that is, up to the point in FIG. 4c, are masked so as not to be output to the audio decoder 136. Then, the audio packet is reproduced from the point c corresponding to the audio synchronization. Here, the buffer 132 needs to have a sufficient buffer amount until the first audio synchronization is read out.

As described above, when a search and a reproduction are performed, the audio synchronization that is read first is detected, and the previously read audio packet is masked so as not to be reproduced. By reproducing from the packet for the voice that matches the detected voice synchronization, it is possible to prevent the generation of noise and to reproduce the normal voice without reproducing the erroneously decoded voice data.

Also, the position of audio synchronization (point c in FIG. 4) with respect to the image search point (point a in FIG. 4) is recorded in advance as additional information at the time of recording.
28 prefetches this additional information and sends it out to bus A,
By controlling the recording / reproduction search control circuit 116 under the control of U122, the audio packet up to the audio synchronization position (point c in FIG. 4) is not read, and the audio packet (point c in FIG. 4) matching the audio synchronization is not read. The same effect can be obtained by reading. At this time, the packet control 130 and the buffer 132 become unnecessary.

As described above, according to the present embodiment, when image data is retrieved and reproduced, audio synchronization is detected, and reproduction is started from an audio packet that matches the audio synchronization. Thus, the audio data to be decoded can be reproduced without reproducing, and thus without generating noise.

[0024]

As described above, according to the present invention, even when a still image is reproduced from a desired position on a recording medium, the sound corresponding to the still image can be correctly decoded and the noise-free sound can be reproduced. become.

[Brief description of the drawings]

FIG. 1 is a block diagram of an information recording / reproducing apparatus according to an embodiment.

FIG. 2 is a block diagram of a conventional information recording / reproducing apparatus.

FIG. 3 is a diagram showing a packet format and a transmission format of a still image broadcast with audio.

FIG. 4 is a diagram showing a temporal relationship between an image packet and an audio packet.

[Explanation of symbols]

 Reference Signs List 120 recording medium 122 CPU 126 search information readout circuit 128 synchronization detection circuit 130 packet control circuit 132 buffer 134 packet identification circuit 136 audio decoder 138 image decoder

Claims (1)

(57) [Claims] 1. An information recording / reproducing apparatus for recording and reproducing still image information with sound in a packet format on a predetermined recording medium, wherein when a reproduction start position of a still image in the recording medium is designated, the information is designated. A still image reproducing unit that reproduces a still image from the reproduction start position, and a detecting unit that detects audio synchronization of audio data when reproducing audio data corresponding to a still image reproduced by the still image reproducing unit. An information recording / reproducing apparatus, comprising: audio reproducing means for starting reproduction from audio data matching the audio synchronization detected by the detecting means.