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fix bug where LP was tried even if autoc[0]==0.0

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This commit is contained in:
Josh Coalson
2001-02-28 23:45:15 +00:00
parent fe9ba6f44f
commit f4ce50b9b9
1 changed files with 32 additions and 29 deletions
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61
src/libFLAC/encoder.c
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@@ -871,35 +871,38 @@ bool encoder_process_subframe_(FLAC__Encoder *encoder, unsigned max_partition_or
max_lpc_order = encoder->max_lpc_order;
if(max_lpc_order > 0) {
FLAC__lpc_compute_autocorrelation(real_signal, frame_header->blocksize, max_lpc_order+1, autoc);
FLAC__lpc_compute_lp_coefficients(autoc, max_lpc_order, lp_coeff, lpc_error);
if(encoder->do_exhaustive_model_search) {
min_lpc_order = 1;
}
else {
unsigned guess_lpc_order = FLAC__lpc_compute_best_order(lpc_error, max_lpc_order, frame_header->blocksize, bits_per_sample);
min_lpc_order = max_lpc_order = guess_lpc_order;
}
if(encoder->do_qlp_coeff_prec_search) {
min_qlp_coeff_precision = FLAC__MIN_QLP_COEFF_PRECISION;
max_qlp_coeff_precision = min(32 - bits_per_sample - 1, (1u<<FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN)-1);
}
else {
min_qlp_coeff_precision = max_qlp_coeff_precision = encoder->qlp_coeff_precision;
}
for(lpc_order = min_lpc_order; lpc_order <= max_lpc_order; lpc_order++) {
lpc_residual_bits_per_sample = FLAC__lpc_compute_expected_bits_per_residual_sample(lpc_error[lpc_order-1], frame_header->blocksize-lpc_order);
if(lpc_residual_bits_per_sample >= (real)bits_per_sample)
continue; /* don't even try */
rice_parameter = (lpc_residual_bits_per_sample > 0.0)? (unsigned)(lpc_residual_bits_per_sample+0.5) : 0; /* 0.5 is for rounding */
rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
for(qlp_coeff_precision = min_qlp_coeff_precision; qlp_coeff_precision <= max_qlp_coeff_precision; qlp_coeff_precision++) {
_candidate_bits = encoder_evaluate_lpc_subframe_(integer_signal, residual[!_best_subframe], encoder->guts->abs_residual, lp_coeff[lpc_order-1], frame_header->blocksize, bits_per_sample, lpc_order, qlp_coeff_precision, rice_parameter, max_partition_order, subframe[!_best_subframe]);
if(_candidate_bits > 0) { /* if == 0, there was a problem quantizing the lpcoeffs */
if(_candidate_bits < _best_bits) {
_best_subframe = !_best_subframe;
_best_bits = _candidate_bits;
/* if autoc[0] == 0.0, the signal is constant and we usually won't get here, but it can happen */
if(autoc[0] != 0.0) {
FLAC__lpc_compute_lp_coefficients(autoc, max_lpc_order, lp_coeff, lpc_error);
if(encoder->do_exhaustive_model_search) {
min_lpc_order = 1;
}
else {
unsigned guess_lpc_order = FLAC__lpc_compute_best_order(lpc_error, max_lpc_order, frame_header->blocksize, bits_per_sample);
min_lpc_order = max_lpc_order = guess_lpc_order;
}
if(encoder->do_qlp_coeff_prec_search) {
min_qlp_coeff_precision = FLAC__MIN_QLP_COEFF_PRECISION;
max_qlp_coeff_precision = min(32 - bits_per_sample - 1, (1u<<FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN)-1);
}
else {
min_qlp_coeff_precision = max_qlp_coeff_precision = encoder->qlp_coeff_precision;
}
for(lpc_order = min_lpc_order; lpc_order <= max_lpc_order; lpc_order++) {
lpc_residual_bits_per_sample = FLAC__lpc_compute_expected_bits_per_residual_sample(lpc_error[lpc_order-1], frame_header->blocksize-lpc_order);
if(lpc_residual_bits_per_sample >= (real)bits_per_sample)
continue; /* don't even try */
rice_parameter = (lpc_residual_bits_per_sample > 0.0)? (unsigned)(lpc_residual_bits_per_sample+0.5) : 0; /* 0.5 is for rounding */
rice_parameter++; /* to account for the signed->unsigned conversion during rice coding */
if(rice_parameter >= (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN))
rice_parameter = (1u << FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN) - 1;
for(qlp_coeff_precision = min_qlp_coeff_precision; qlp_coeff_precision <= max_qlp_coeff_precision; qlp_coeff_precision++) {
_candidate_bits = encoder_evaluate_lpc_subframe_(integer_signal, residual[!_best_subframe], encoder->guts->abs_residual, lp_coeff[lpc_order-1], frame_header->blocksize, bits_per_sample, lpc_order, qlp_coeff_precision, rice_parameter, max_partition_order, subframe[!_best_subframe]);
if(_candidate_bits > 0) { /* if == 0, there was a problem quantizing the lpcoeffs */
if(_candidate_bits < _best_bits) {
_best_subframe = !_best_subframe;
_best_bits = _candidate_bits;
}
}
}
}