| 摘要 |
A block transform-based digital media codec more efficiently encodes transform coefficients by jointly-coding non-zero coefficients along with succeeding runs of zero-value coefficients. When a non-zero coefficient is the last in its block, a last indicator is substituted for the run value in the symbol for that coefficient. Initial non-zero coefficients are indicated in a special symbol which jointly-codes the non-zero coefficient along with initial and subsequent runs of zeroes. The codec allows for multiple coding contexts by recognizing breaks in runs of non-zero coefficients and coding non-zero coefficients on either side of such a break separately. The codec also reduces code table size by indicating in each symbol whether a non-zero coefficient has absolute value greater than 1 and whether runs of zeros have positive value, and separately encodes the level of the coefficients and the length of the runs outside of the symbols.
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