mirror of https://git.ffmpeg.org/ffmpeg.git
only calculate number of exponent groups when exponents are not reused.
Originally committed as revision 13587 to svn://svn.ffmpeg.org/ffmpeg/trunk
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@ -154,6 +154,7 @@ typedef struct {
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int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin
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int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin
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AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
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AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
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int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups
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int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
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int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
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uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
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uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
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int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
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int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
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@ -907,6 +908,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
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for (ch = 1; ch <= fbw_channels; ch++) {
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for (ch = 1; ch <= fbw_channels; ch++) {
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s->start_freq[ch] = 0;
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s->start_freq[ch] = 0;
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if (s->exp_strategy[ch] != EXP_REUSE) {
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if (s->exp_strategy[ch] != EXP_REUSE) {
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int group_size;
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int prev = s->end_freq[ch];
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int prev = s->end_freq[ch];
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if (s->channel_in_cpl[ch])
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if (s->channel_in_cpl[ch])
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s->end_freq[ch] = s->start_freq[CPL_CH];
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s->end_freq[ch] = s->start_freq[CPL_CH];
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@ -918,26 +920,26 @@ static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
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}
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}
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s->end_freq[ch] = bandwidth_code * 3 + 73;
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s->end_freq[ch] = bandwidth_code * 3 + 73;
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}
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}
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group_size = 3 << (s->exp_strategy[ch] - 1);
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s->num_exp_groups[ch] = (s->end_freq[ch]+group_size-4) / group_size;
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if(blk > 0 && s->end_freq[ch] != prev)
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if(blk > 0 && s->end_freq[ch] != prev)
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memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
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memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
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}
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}
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}
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}
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s->start_freq[s->lfe_ch] = 0;
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s->start_freq[s->lfe_ch] = 0;
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s->end_freq[s->lfe_ch] = 7;
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s->end_freq[s->lfe_ch] = 7;
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s->num_exp_groups[s->lfe_ch] = 2;
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if (s->cpl_in_use && s->exp_strategy[CPL_CH] != EXP_REUSE) {
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s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
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(3 << (s->exp_strategy[CPL_CH] - 1));
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}
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/* decode exponents for each channel */
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/* decode exponents for each channel */
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for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
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for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
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if (s->exp_strategy[ch] != EXP_REUSE) {
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if (s->exp_strategy[ch] != EXP_REUSE) {
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int group_size, num_groups;
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group_size = 3 << (s->exp_strategy[ch] - 1);
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if(ch == CPL_CH)
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num_groups = (s->end_freq[ch] - s->start_freq[ch]) / group_size;
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else if(ch == s->lfe_ch)
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num_groups = 2;
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else
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num_groups = (s->end_freq[ch] + group_size - 4) / group_size;
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s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
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s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
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decode_exponents(gbc, s->exp_strategy[ch], num_groups, s->dexps[ch][0],
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decode_exponents(gbc, s->exp_strategy[ch],
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s->num_exp_groups[ch], s->dexps[ch][0],
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&s->dexps[ch][s->start_freq[ch]+!!ch]);
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&s->dexps[ch][s->start_freq[ch]+!!ch]);
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if(ch != CPL_CH && ch != s->lfe_ch)
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if(ch != CPL_CH && ch != s->lfe_ch)
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skip_bits(gbc, 2); /* skip gainrng */
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skip_bits(gbc, 2); /* skip gainrng */
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