Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Control of information signal processing channel
Reexamination Certificate
1999-04-01
2001-08-14
Hindi, Nabil (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Control of information signal processing channel
C369S047250, C369S275300
Reexamination Certificate
active
06275457
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a recording medium in which data can be recorded in terms of headers, main data and sub-data as plural unit blocks and in which the recording capacity for the sub-data can be varied without decreasing the recording capacity of the main data. This invention also relates to a reproducing apparatus for reproducing the recording medium.
2. Description of the Related Art
In a conventional recording medium, there is provided, separate from a region for recording main data signals, a recording region for sub-data signals read out simultaneously with the main data signals. These sub-data signals, also termed sub-data or sub-codes, are used for recording the ancillary information, such as graphics information or text data.
In a compact disc (CD, registered trade mark), for example, there is provided, separate from the region for recording audio signal data, a region for recording sub-data that can be reproduced simultaneously as the audio signals are reproduced. These sub-data include letters, graphics, etc in addition to the information such as the numbers of musical numbers, indexes or playing time. In CD-G (CD-graphics), for example, the graphics information is recorded in six bits termed user bits of the sub-data so that a picture or a lyric is displayed simultaneously with the accompaniment (karaoke).
Meanwhile, since the data transfer speed of sub-data is of the order of several kBps, such as 5.4 kBps (kilobyte per second), the graphics information that can be recorded as sub-data cannot be expected to be of a high quality. This is far below the 64 kBps required for so-called streaming reproduction on the Internet now in popular use world-wide. Insofar as the still picture is concerned, the data transfer rate for displaying the high-quality still picture, encoded by the JPEG (Joint Photographic Experts Group) format or the GIF (graphics interchange format) now in popular use, cannot be met.
In order to cope with the streaming reproduction or high-quality still picture, a high transfer rate exceeding 64 kBps for ancillary data is required. However, for realizing the high transfer rate, it is necessary to provide a region for a large amount of the ancillary information needs, as a result of which the main data region is decreased. If the main data region is decreased, the net result is the decreased music reproducing time or the lowered sound quality.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a recording medium in which a transfer rate at least higher than the transfer rate for sub-data of a conventional compact disc is assured and a higher transfer rate can be variably assured, and a reproducing apparatus in which the sub-data transfer rate can be variably switched when reproducing this recording medium.
In one aspect, the present invention provides a recording medium including a program area in which digital data made up of a header, main data and sub-data is blocked and recorded with a variable number of sectors, with a unit sector being of a pre-set data length, and a management area in which there is recorded an identifier for discriminating the variable number of sectors in order to render the data volume of the sub-data variable with the volume of main data in the packet remaining fixed.
In another aspect, the present invention provides a recording/reproducing apparatus for reproducing a recording medium having a program area in which digital data made up of a header, main data and sub-data is blocked and recorded with a variable number of sectors, with a unit sector being of a pre-set data length, and a management area having recorded therein an identifier for discriminating the variable number of sectors in order to render the data volume of the sub-data variable with the volume of main data in the packet remaining fixed. Specifically, the recording/reproducing apparatus includes reproducing means for reproducing the digital data recorded in the program area and the identifier recorded in the management area, separating means for separating the main data and the sub-data from the digital data reproduced by the reproducing means from the program area of the recording medium, and control means for controlling the separating means based on the identifier that is reproduced from the management area of the recording medium by the reproducing means and which is used for identifying the variable number of sectors.
The recording medium of the present invention, as described above, has a transfer rate at least higher than the sub-data transfer rate of the conventional compact disc and is able to secure a higher variable transfer rate. Moreover, the reproducing device according to the present invention is able to variably switch the sub-rate transfer rate at the time of reproducing this recording medium.
REFERENCES:
patent: 5745454 (1998-04-01), Yokota
Hindi Nabil
Maioli Jay H.
Sony Corporation
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