Apparatus for simultaneously writing and outputting data stream
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTakenori Maehashi, Mitsuaki Morita, Nobuyuki Enoki
Life of this patent
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Abstract
An apparatus for simultaneously writing a data stream onto a recording medium with a low writing and reading rate such as an optical disk and outputting a data stream stored on the recording medium. In the apparatus, the first buffer retains an inputted data stream. The stream held in the first buffer is written on the recording medium. The stream recorded on the recording medium is read onto the second buffer to output the stream to an external device. The writing and the reading are controlled based on the duration to consume the stream held on the second buffer, so that the writing and reading are real-time.
Claims11
A data output apparatus for exclusively writing on a recording medium a data stream to be inputted and reading said data stream recorded on said recording medium to send said data stream to an external device,
- said data stream containing video-audio information compressed at a variable bit rate,
- said data output apparatus comprising:
- a first buffer for holding said inputted data stream;
- writing means for writing on said recording medium said data stream held in said first buffer;
- a second buffer for holding said data stream to be outputted to said external device;
- reading means for reading onto said second buffer said data stream held on said recording medium;
- predicting means for predicting duration to consume said data stream held on said second buffer on the basis of duration required for presentation of the video-audio information contained in said data stream held on said second buffer;
- and
- control means for controlling said writing means and said reading means, said control means gives a permit to said reading means to read said data stream from said recording medium onto the second buffer if the predicted duration is less than a threshold value.
A data output apparatus for writing on a recording medium a data stream to be inputted and reading and sending out said data stream recorded on said recording medium to an external device,
- said data stream containing video-audio information compressed at a variable bit rate,
- said data output apparatus comprising:
- a first buffer for holding said inputted data stream;
- writing means for writing on said recording medium said data stream held in said first buffer;
- a second buffer for holding said data stream to be outputted to said external device;
- reading means for reading onto said second buffer said data stream held on said recording medium;
- a memory holding a duration table where the offset values b01, b02, . . . , b0n of said data stream are linked to the times a01, a02, . . . , a0n for said data stream of said offset values b01, b02, . . . , b0n each to be reproduced;
- predicting means for predicting duration to consume said data stream held on said second buffer on the basis of duration required for presentation of the video-audio information contained in said data stream held on said second buffer, said predicting means measuring the amount of data sent out from said second buffer and the amount of data inputted in the second buffer, working out the top offset value b0i and the last offset value b0j of said data stream held in the second buffer on the basis of said amount of data sent out and the amount of data inputted, and acquiring the time a0i corresponding to the offset value b0i and the time a0j corresponding to the offset value b0j, thereby working out said predicted duration a0j-a0i, and
- control means for controlling said writing means and said reading means,
- said writing means and said reading means writing or reading said data stream exclusively on said recording medium, and
- said control means controlling said writing means and said reading means on the basis of the predicted duration to consume said data stream to prevent said second buffer from underflow.
A data output apparatus for writing on a recording medium a data stream to be inputted and reading and sending out said data stream recorded on said recording medium to an external device,
- said data stream containing video-audio information compressed at a variable bit rate,
- said data output apparatus comprising:
- a first buffer for holding said inputted data stream;
- writing means for writing on said recording medium said data stream held in said first buffer;
- a second buffer for holding said data stream to be outputted to said external device;
- reading means for reading onto said second buffer said data stream held on said recording medium;
- a memory having a time table on which the durations “a11-0,” “a12-a11,” “a13-a12,” . . . “a1n-a1(n−1)” are linked to the bit rates r11, r12, r13 . . . , r1n of the data stream at the respective durations;
- predicting means for predicting duration to consume said data stream held on said second buffer on the basis of duration required for presentation of the video-audio information contained in said data stream held on said second buffer, said predicting means measuring the amount of data sent out from said second buffer and the amount of data inputted in the second buffer, and working out the top offset value a1i and the last offset value a1j of said data stream held in the second buffer on the basis of said amount of data sent out and the amount of data inputted, thereby working out said predicted duration a1j-a1i, and
- control means for controlling said writing means and said reading means,
- said writing means and said reading means writing or reading said data stream exclusively on said recording medium, and
- said control means controlling said writing means and said reading means on the basis of the predicted duration to consume said data stream to prevent said second buffer from underflow.
Dependencies are inferred from the claim text.