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Simplified logic of parsing sizes of rice-partitions

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> if the partition order is zero, n = frame's blocksize - predictor order
> else if this is not the first partition of the subframe,
>   n = (frame's blocksize / (2^partition order))
> else n = (frame's blocksize / (2^partition order)) - predictor order

if the partition order is zero, then partition_number can only be zero
if the partition order is zero, then
  (frame's blocksize / (2^partition order))
  is (frame's blocksize / 1) == frame's blocksize
This commit is contained in:
Ulrik Mikaelsson 2020-02-02 21:03:37 +01:00 committed by Erik de Castro Lopo
parent 4fbb6d4f2e
commit 37e675b777
2 changed files with 9 additions and 9 deletions
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12
doc/html/format.html
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@ -1737,13 +1737,13 @@
Encoded residual. The number of samples (n) in the partition is determined as follows:<br />
<ul>
<li>
if the partition order is zero, n = frame's blocksize - predictor order
partition size = (frame's blocksize / (2^partition order))
</li>
<li>
else if this is not the first partition of the subframe, n = (frame's blocksize / (2^partition order))
for first partition of the subframe, n = partition size - predictor
</li>
<li>
else n = (frame's blocksize / (2^partition order)) - predictor order
for remaining partitions, n = partition size
</li>
</ul>
</td>
@ -1816,13 +1816,13 @@
Encoded residual. The number of samples (n) in the partition is determined as follows:<br />
<ul>
<li>
if the partition order is zero, n = frame's blocksize - predictor order
partition size = (frame's blocksize / (2^partition order))
</li>
<li>
else if this is not the first partition of the subframe, n = (frame's blocksize / (2^partition order))
for first partition of the subframe, n = partition size - predictor
</li>
<li>
else n = (frame's blocksize / (2^partition order)) - predictor order
for remaining partitions, n = partition size
</li>
</ul>
</td>

6
src/libFLAC/stream_decoder.c
View File

@ -2752,7 +2752,7 @@ FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, uint32_
int i;
uint32_t partition, sample, u;
const uint32_t partitions = 1u << partition_order;
const uint32_t partition_samples = partition_order > 0? decoder->private_->frame.header.blocksize >> partition_order : decoder->private_->frame.header.blocksize - predictor_order;
const uint32_t partition_samples = decoder->private_->frame.header.blocksize >> partition_order;
const uint32_t plen = is_extended? FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_PARAMETER_LEN : FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
const uint32_t pesc = is_extended? FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_ESCAPE_PARAMETER : FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;
@ -2771,7 +2771,7 @@ FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, uint32_
partitioned_rice_contents->parameters[partition] = rice_parameter;
if(rice_parameter < pesc) {
partitioned_rice_contents->raw_bits[partition] = 0;
u = (partition_order == 0 || partition > 0)? partition_samples : partition_samples - predictor_order;
u = (partition == 0) ? partition_samples - predictor_order : partition_samples;
if(!FLAC__bitreader_read_rice_signed_block(decoder->private_->input, residual + sample, u, rice_parameter))
return false; /* read_callback_ sets the state for us */
sample += u;
@ -2780,7 +2780,7 @@ FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, uint32_
if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN))
return false; /* read_callback_ sets the state for us */
partitioned_rice_contents->raw_bits[partition] = rice_parameter;
for(u = (partition_order == 0 || partition > 0)? 0 : predictor_order; u < partition_samples; u++, sample++) {
for(u = (partition == 0)? predictor_order : 0; u < partition_samples; u++, sample++) {
if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &i, rice_parameter))
return false; /* read_callback_ sets the state for us */
residual[sample] = i;