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Code Issues Releases Activity

avcodec/aacenc: add bitrate threshold for PNS

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This commit is contained in:
Agent45
2025-11-01 19:49:05 +00:00
committed by Lynne
parent d479a4926a
commit 9bded2145f
1 changed files with 7 additions and 2 deletions
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9
libavcodec/aaccoder.c
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@@ -58,6 +58,9 @@
* replace low energy non zero bands */
#define NOISE_LAMBDA_REPLACE 1.948f
/* Bitrate threshold (in bits/sec/channel) above which PNS is disabled. */
#define PNS_BITRATE_LIMIT 64000.0f
#include "libavcodec/aaccoder_trellis.h"
typedef float (*quantize_and_encode_band_func)(struct AACEncContext *s, PutBitContext *pb,
@@ -513,6 +516,7 @@ static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChanne
? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
: (avctx->bit_rate / avctx->ch_layout.nb_channels);
int pns_at_low_bitrate = frame_bit_rate < PNS_BITRATE_LIMIT;
frame_bit_rate *= 1.15f;
if (avctx->cutoff > 0) {
@@ -536,7 +540,7 @@ static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChanne
const int start = wstart+sce->ics.swb_offset[g];
const float freq = (start-wstart)*freq_mult;
const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
if (freq < NOISE_LOW_LIMIT || (start-wstart) >= cutoff) {
if (!pns_at_low_bitrate || freq < NOISE_LOW_LIMIT || (start-wstart) >= cutoff) {
if (!sce->zeroes[w*16+g])
prev_sf = sce->sf_idx[w*16+g];
continue;
@@ -649,6 +653,7 @@ static void mark_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelEleme
? (refbits * rate_bandwidth_multiplier * avctx->sample_rate / 1024)
: (avctx->bit_rate / avctx->ch_layout.nb_channels);
int pns_at_low_bitrate = frame_bit_rate < PNS_BITRATE_LIMIT;
frame_bit_rate *= 1.15f;
if (avctx->cutoff > 0) {
@@ -667,7 +672,7 @@ static void mark_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelEleme
const int start = sce->ics.swb_offset[g];
const float freq = start*freq_mult;
const float freq_boost = FFMAX(0.88f*freq/NOISE_LOW_LIMIT, 1.0f);
if (freq < NOISE_LOW_LIMIT || start >= cutoff) {
if (!pns_at_low_bitrate || freq < NOISE_LOW_LIMIT || start >= cutoff) {
sce->can_pns[w*16+g] = 0;
continue;
}