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Code Issues Releases Activity

avcodec/mlpenc: increase compression ratio when input is of lower bit depth

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This commit is contained in:
Paul B Mahol 2023-10-02 18:52:35 +02:00
parent b36f3d5330
commit 0be5da9cfa
1 changed files with 3 additions and 11 deletions
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14
libavcodec/mlpenc.c
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@ -1259,16 +1259,9 @@ static void input_to_sample_buffer(MLPEncodeContext *ctx)
****************************************************************************/ ****************************************************************************/
/** Counts the number of trailing zeroes in a value */ /** Counts the number of trailing zeroes in a value */
static int number_trailing_zeroes(int32_t sample, const int wordlength) static int number_trailing_zeroes(int32_t sample)
{ {
int bits = ff_ctz(sample); return FFMIN(15, ff_ctz(sample));
/* All samples are 0. TODO Return previous quant_step_size to avoid
* writing a new header. */
if (bits >= wordlength)
return 0;
return bits;
} }
/** Determines how many bits are zero at the end of all samples so they can be /** Determines how many bits are zero at the end of all samples so they can be
@ -1279,7 +1272,6 @@ static void determine_quant_step_size(MLPEncodeContext *ctx)
DecodingParams *dp = ctx->cur_decoding_params; DecodingParams *dp = ctx->cur_decoding_params;
RestartHeader *rh = ctx->cur_restart_header; RestartHeader *rh = ctx->cur_restart_header;
MatrixParams *mp = &dp->matrix_params; MatrixParams *mp = &dp->matrix_params;
const int wordlength = ctx->wordlength;
int32_t *sample_buffer = ctx->sample_buffer; int32_t *sample_buffer = ctx->sample_buffer;
int32_t sample_mask[MAX_CHANNELS]; int32_t sample_mask[MAX_CHANNELS];
@ -1293,7 +1285,7 @@ static void determine_quant_step_size(MLPEncodeContext *ctx)
} }
for (unsigned int channel = 0; channel <= rh->max_channel; channel++) for (unsigned int channel = 0; channel <= rh->max_channel; channel++)
dp->quant_step_size[channel] = number_trailing_zeroes(sample_mask[channel], wordlength) - mp->shift[channel]; dp->quant_step_size[channel] = number_trailing_zeroes(sample_mask[channel]) - mp->shift[channel];
} }
/** Determines the smallest number of bits needed to encode the filter /** Determines the smallest number of bits needed to encode the filter