Method for adjusting the quality of a video coder
First Claim
1. A method for adjusting the quality of a video coder, comprising the steps of:
- converting an input signal into a predetermined digital format;
transferring said digital format image signal to at least one encoder processor;
applying, at said at least one encoder processor, a hierarchical compression algorithm, having a plurality of encoding levels, to said digitized image signal;
collecting a resultant encoded bit stream generated by said application of said algorithm, wherein said resultant encoded bit stream is collected in a buffer coupled to said at least one encoder processor;
providing feedback to said at least one encoder processor from said buffer, said feedback indicating fullness of said buffer;
adjusting a threshold that is applied by said at least one encoder processor, said threshold being adjusted in accordance with said feedback and the encoding level within the hierarchical compression algorithm of the at least one encoder processor; and
transferring said resultant encoded bit stream from said buffer to a host processor when a predetermined portion of said input image signal is encoded.
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Abstract
A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.
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Citations
20 Claims
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1. A method for adjusting the quality of a video coder, comprising the steps of:
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converting an input signal into a predetermined digital format; transferring said digital format image signal to at least one encoder processor; applying, at said at least one encoder processor, a hierarchical compression algorithm, having a plurality of encoding levels, to said digitized image signal; collecting a resultant encoded bit stream generated by said application of said algorithm, wherein said resultant encoded bit stream is collected in a buffer coupled to said at least one encoder processor; providing feedback to said at least one encoder processor from said buffer, said feedback indicating fullness of said buffer; adjusting a threshold that is applied by said at least one encoder processor, said threshold being adjusted in accordance with said feedback and the encoding level within the hierarchical compression algorithm of the at least one encoder processor; and transferring said resultant encoded bit stream from said buffer to a host processor when a predetermined portion of said input image signal is encoded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for adjusting the quality of a video coder, comprising the steps of:
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applying, at an encoder processor, a hierarchical compression algorithm having a plurality of encoding levels and associated image block sizes, to a digitized image signal wherein the application of the algorithm comprises; parsing the digitized image signal into an image block whose size depends upon the encoding level; and calculating a distortion measure for the image block; collecting a bit stream generated by the application of the algorithm in a buffer coupled to the encoder processor; providing feedback to the encoder processor from the buffer, the feedback indicating a measure of the fullness of the buffer; adjusting a threshold that is applied by the encoder processor, the threshold being adjusted in accordance with the image block size and the feedback from the buffer; comparing the distortion measure to the threshold; and proceeding to a lower level of the hierarchical compression algorithm when the distortion measure exceeds the threshold.
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Specification