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minor optimizations to precompute_partition_info_sums_()

This commit is contained in:
Josh Coalson 2007-03-31 01:01:02 +00:00
parent 2258fa8ec9
commit 0a0a10f358
1 changed files with 36 additions and 33 deletions
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69
src/libFLAC/stream_encoder.c
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@ -249,6 +249,7 @@ static unsigned find_best_partition_order_(
unsigned rice_parameter,
unsigned min_partition_order,
unsigned max_partition_order,
unsigned bps,
FLAC__bool do_escape_coding,
unsigned rice_parameter_search_dist,
FLAC__EntropyCodingMethod_PartitionedRice *best_partitioned_rice
@ -260,7 +261,8 @@ static void precompute_partition_info_sums_(
unsigned residual_samples,
unsigned predictor_order,
unsigned min_partition_order,
unsigned max_partition_order
unsigned max_partition_order,
unsigned bps
);
static void precompute_partition_info_escapes_(
@ -3741,6 +3743,7 @@ unsigned evaluate_fixed_subframe_(
rice_parameter,
min_partition_order,
max_partition_order,
subframe_bps,
do_escape_coding,
rice_parameter_search_dist,
&subframe->data.fixed.entropy_coding_method.data.partitioned_rice
@ -3821,6 +3824,7 @@ unsigned evaluate_lpc_subframe_(
rice_parameter,
min_partition_order,
max_partition_order,
subframe_bps,
do_escape_coding,
rice_parameter_search_dist,
&subframe->data.lpc.entropy_coding_method.data.partitioned_rice
@ -3878,6 +3882,7 @@ unsigned find_best_partition_order_(
unsigned rice_parameter,
unsigned min_partition_order,
unsigned max_partition_order,
unsigned bps,
FLAC__bool do_escape_coding,
unsigned rice_parameter_search_dist,
FLAC__EntropyCodingMethod_PartitionedRice *best_partitioned_rice
@ -3890,7 +3895,7 @@ unsigned find_best_partition_order_(
max_partition_order = FLAC__format_get_max_rice_partition_order_from_blocksize_limited_max_and_predictor_order(max_partition_order, blocksize, predictor_order);
min_partition_order = min(min_partition_order, max_partition_order);
precompute_partition_info_sums_(residual, abs_residual_partition_sums, residual_samples, predictor_order, min_partition_order, max_partition_order);
precompute_partition_info_sums_(residual, abs_residual_partition_sums, residual_samples, predictor_order, min_partition_order, max_partition_order, bps);
if(do_escape_coding)
precompute_partition_info_escapes_(residual, raw_bits_per_partition, residual_samples, predictor_order, min_partition_order, max_partition_order);
@ -3950,56 +3955,54 @@ void precompute_partition_info_sums_(
unsigned residual_samples,
unsigned predictor_order,
unsigned min_partition_order,
unsigned max_partition_order
unsigned max_partition_order,
unsigned bps
)
{
int partition_order;
unsigned from_partition, to_partition = 0;
const unsigned blocksize = residual_samples + predictor_order;
const unsigned partitions = 1u << max_partition_order;
const unsigned default_partition_samples = blocksize >> max_partition_order;
unsigned partition, end, residual_sample;
FLAC__ASSERT(default_partition_samples > predictor_order);
/* first do max_partition_order */
for(partition_order = (int)max_partition_order; partition_order >= 0; partition_order--) {
FLAC__uint64 abs_residual_partition_sum; /* OPT: can reasonably be FLAC__uint32 for bps <= 17 and maybe higher */
unsigned partition, partition_sample, partition_samples, residual_sample;
const unsigned partitions = 1u << partition_order;
const unsigned default_partition_samples = blocksize >> partition_order;
FLAC__ASSERT(default_partition_samples > predictor_order);
if(FLAC__bitmath_ilog2(default_partition_samples) + bps < 32) { /* very slightly pessimistic but still catches all common cases */
FLAC__uint32 abs_residual_partition_sum;
end = (unsigned)(-(int)predictor_order);
for(partition = residual_sample = 0; partition < partitions; partition++) {
partition_samples = default_partition_samples;
if(partition == 0)
partition_samples -= predictor_order;
end += default_partition_samples;
abs_residual_partition_sum = 0;
for(partition_sample = 0; partition_sample < partition_samples; partition_sample++, residual_sample++) {
#if defined _MSC_VER
/* OPT: abs() may be faster for some compilers */
for( ; residual_sample < end; residual_sample++)
abs_residual_partition_sum += abs(residual[residual_sample]); /* abs(INT_MIN) is undefined, but if the residual is INT_MIN we have bigger problems */
abs_residual_partition_sums[partition] = abs_residual_partition_sum;
}
}
else { /* have to pessimistically use 64 bits for accumulator */
FLAC__uint64 abs_residual_partition_sum;
end = (unsigned)(-(int)predictor_order);
for(partition = residual_sample = 0; partition < partitions; partition++) {
end += default_partition_samples;
abs_residual_partition_sum = 0;
for( ; residual_sample < end; residual_sample++)
abs_residual_partition_sum += abs(residual[residual_sample]); /* abs(INT_MIN) is undefined, but if the residual is INT_MIN we have bigger problems */
#else
const FLAC__int32 r = residual[residual_sample];
if(r < 0)
abs_residual_partition_sum -= r;
else
abs_residual_partition_sum += r;
#endif
}
abs_residual_partition_sums[partition] = abs_residual_partition_sum;
}
to_partition = partitions;
break;
}
/* now merge partitions for lower orders */
for(from_partition = 0, --partition_order; partition_order >= (int)min_partition_order; partition_order--) {
FLAC__uint64 s;
for(from_partition = 0, to_partition = partitions, partition_order = (int)max_partition_order - 1; partition_order >= (int)min_partition_order; partition_order--) {
unsigned i;
const unsigned partitions = 1u << partition_order;
for(i = 0; i < partitions; i++) {
s = abs_residual_partition_sums[from_partition];
from_partition++;
abs_residual_partition_sums[to_partition] = s + abs_residual_partition_sums[from_partition];
from_partition++;
to_partition++;
abs_residual_partition_sums[to_partition++] =
abs_residual_partition_sums[from_partition ] +
abs_residual_partition_sums[from_partition+1];
from_partition += 2;
}
}
}