diff options
| -rw-r--r-- | libavcodec/aaccoder.c | 52 | ||||
| -rw-r--r-- | libavcodec/aacenc.c | 6 | ||||
| -rw-r--r-- | libavcodec/aacenc.h | 1 |
3 files changed, 58 insertions, 1 deletions
diff --git a/libavcodec/aaccoder.c b/libavcodec/aaccoder.c index 8695a88..95782fc 100644 --- a/libavcodec/aaccoder.c +++ b/libavcodec/aaccoder.c @@ -41,7 +41,16 @@ #include "aactab.h" /** Frequency in Hz for lower limit of noise substitution **/ -#define NOISE_LOW_LIMIT 4000 +#define NOISE_LOW_LIMIT 4500 + +/* Energy spread threshold value below which no PNS is used, this corresponds to + * typically around 17Khz, after which PNS usage decays ending at 19Khz */ +#define NOISE_SPREAD_THRESHOLD 0.5f + +/* This constant gets divided by lambda to return ~1.65 which when multiplied + * by the band->threshold and compared to band->energy is the boundary between + * excessive PNS and little PNS usage. */ +#define NOISE_LAMBDA_NUMERATOR 252.1f /** Total number of usable codebooks **/ #define CB_TOT 12 @@ -1132,6 +1141,43 @@ static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s, sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g]; } +static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce, + const float lambda) +{ + int start = 0, w, w2, g; + const float freq_mult = avctx->sample_rate/(1024.0f/sce->ics.num_windows)/2.0f; + const float spread_threshold = NOISE_SPREAD_THRESHOLD*(lambda/120.f); + const float thr_mult = NOISE_LAMBDA_NUMERATOR/lambda; + + /* Coders !twoloop don't reset the band_types */ + for (w = 0; w < 128; w++) + if (sce->band_type[w] == NOISE_BT) + sce->band_type[w] = 0; + + for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) { + start = 0; + for (g = 0; g < sce->ics.num_swb; g++) { + if (start*freq_mult > NOISE_LOW_LIMIT*(lambda/170.0f)) { + float energy = 0.0f, threshold = 0.0f, spread = 0.0f; + for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) { + FFPsyBand *band = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g]; + energy += band->energy; + threshold += band->threshold; + spread += band->spread; + } + if (spread > spread_threshold*sce->ics.group_len[w] && + ((sce->zeroes[w*16+g] && energy >= threshold) || + energy < threshold*thr_mult*sce->ics.group_len[w])) { + sce->band_type[w*16+g] = NOISE_BT; + sce->pns_ener[w*16+g] = energy / sce->ics.group_len[w]; + sce->zeroes[w*16+g] = 0; + } + } + start += sce->ics.swb_sizes[g]; + } + } +} + static void search_for_ms(AACEncContext *s, ChannelElement *cpe, const float lambda) { @@ -1200,6 +1246,7 @@ AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = { encode_window_bands_info, quantize_and_encode_band, set_special_band_scalefactors, + search_for_pns, search_for_ms, }, [AAC_CODER_ANMR] = { @@ -1207,6 +1254,7 @@ AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = { encode_window_bands_info, quantize_and_encode_band, set_special_band_scalefactors, + search_for_pns, search_for_ms, }, [AAC_CODER_TWOLOOP] = { @@ -1214,6 +1262,7 @@ AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = { codebook_trellis_rate, quantize_and_encode_band, set_special_band_scalefactors, + search_for_pns, search_for_ms, }, [AAC_CODER_FAST] = { @@ -1221,6 +1270,7 @@ AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = { encode_window_bands_info, quantize_and_encode_band, set_special_band_scalefactors, + search_for_pns, search_for_ms, }, }; diff --git a/libavcodec/aacenc.c b/libavcodec/aacenc.c index 3854066..f7325d4 100644 --- a/libavcodec/aacenc.c +++ b/libavcodec/aacenc.c @@ -641,6 +641,12 @@ static int aac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, } } } + if (s->options.pns && s->coder->search_for_pns) { + for (ch = 0; ch < chans; ch++) { + s->cur_channel = start_ch + ch; + s->coder->search_for_pns(s, avctx, &cpe->ch[ch], s->lambda); + } + } s->cur_channel = start_ch; if (s->options.stereo_mode && cpe->common_window) { if (s->options.stereo_mode > 0) { diff --git a/libavcodec/aacenc.h b/libavcodec/aacenc.h index cc1b06a..8ba5817 100644 --- a/libavcodec/aacenc.h +++ b/libavcodec/aacenc.h @@ -55,6 +55,7 @@ typedef struct AACCoefficientsEncoder { void (*quantize_and_encode_band)(struct AACEncContext *s, PutBitContext *pb, const float *in, int size, int scale_idx, int cb, const float lambda); void (*set_special_band_scalefactors)(struct AACEncContext *s, SingleChannelElement *sce); + void (*search_for_pns)(struct AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce, const float lambda); void (*search_for_ms)(struct AACEncContext *s, ChannelElement *cpe, const float lambda); } AACCoefficientsEncoder; |
