diff options
| -rw-r--r-- | libavcodec/aacenc_tns.c | 75 | ||||
| -rw-r--r-- | libavcodec/aacenc_tns.h | 18 |
2 files changed, 40 insertions, 53 deletions
diff --git a/libavcodec/aacenc_tns.c b/libavcodec/aacenc_tns.c index f08b31eb62..694fbb99e0 100644 --- a/libavcodec/aacenc_tns.c +++ b/libavcodec/aacenc_tns.c @@ -31,10 +31,22 @@ #include "aacenc_utils.h" #include "aacenc_quantization.h" +/* Could be set to 3 to save an additional bit at the cost of little quality */ +#define TNS_Q_BITS 4 + +/* Coefficient resolution in short windows */ +#define TNS_Q_BITS_IS8 4 + /* Define this to save a bit, be warned decoders can't deal with it * so it is not lossless despite what the specifications say */ // #define TNS_ENABLE_COEF_COMPRESSION +/* TNS will only be used if the LPC gain is within these margins */ +#define TNS_GAIN_THRESHOLD_LOW 1.477f +#define TNS_GAIN_THRESHOLD_HIGH 7.0f +#define TNS_GAIN_THRESHOLD_LOW_IS8 0.16f*TNS_GAIN_THRESHOLD_LOW +#define TNS_GAIN_THRESHOLD_HIGH_IS8 0.26f*TNS_GAIN_THRESHOLD_HIGH + static inline int compress_coeffs(int *coef, int order, int c_bits) { int i; @@ -160,21 +172,22 @@ static inline void quantize_coefs(double *coef, int *idx, float *lpc, int order, void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) { TemporalNoiseShaping *tns = &sce->tns; + double gain, coefs[MAX_LPC_ORDER]; int w, w2, g, count = 0; const int mmm = FFMIN(sce->ics.tns_max_bands, sce->ics.max_sfb); const int is8 = sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE; - const int c_bits = is8 ? TNS_Q_BITS_SHORT == 4 : TNS_Q_BITS == 4; + const int c_bits = is8 ? TNS_Q_BITS_IS8 == 4 : TNS_Q_BITS == 4; + const int slant = sce->ics.window_sequence[0] == LONG_STOP_SEQUENCE ? 1 : + sce->ics.window_sequence[0] == LONG_START_SEQUENCE ? 0 : 2; int sfb_start = av_clip(tns_min_sfb[is8][s->samplerate_index], 0, mmm); int sfb_end = av_clip(sce->ics.num_swb, 0, mmm); + int order = is8 ? 5 : s->profile == FF_PROFILE_AAC_LOW ? 12 : TNS_MAX_ORDER; for (w = 0; w < sce->ics.num_windows; w++) { - int use_tns; - int order = is8 ? 5 : s->profile == FF_PROFILE_AAC_LOW ? 12 : TNS_MAX_ORDER; + float en[2] = {0.0f, 0.0f}; int coef_start = w*sce->ics.num_swb + sce->ics.swb_offset[sfb_start]; int coef_len = sce->ics.swb_offset[sfb_end] - sce->ics.swb_offset[sfb_start]; - float e_ratio = 0.0f, threshold = 0.0f, spread = 0.0f, en[2] = {0.0, 0.0f}; - double gain = 0.0f, coefs[MAX_LPC_ORDER] = {0}; for (g = 0; g < sce->ics.num_swb; g++) { if (w*16+g < sfb_start || w*16+g > sfb_end) @@ -185,8 +198,6 @@ void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) en[1] += band->energy; else en[0] += band->energy; - threshold += band->threshold; - spread += band->spread; } } @@ -198,37 +209,31 @@ void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce) coef_len, order, coefs); if (!order || gain < TNS_GAIN_THRESHOLD_LOW || gain > TNS_GAIN_THRESHOLD_HIGH) - use_tns = 0; - else if ((en[0]+en[1]) < TNS_GAIN_THRESHOLD_LOW*threshold || spread < TNS_SPREAD_THRESHOLD) - use_tns = 0; - else - use_tns = 1; - - if (use_tns) { - e_ratio = en[0]/en[1]; - if (is8 || order < 2 || (e_ratio > TNS_E_RATIO_LOW && e_ratio < TNS_E_RATIO_HIGH)) { - tns->n_filt[w] = 1; - for (g = 0; g < tns->n_filt[w]; g++) { - tns->length[w][g] = sfb_end - sfb_start; - tns->direction[w][g] = en[0] < en[1]; - tns->order[w][g] = order; - quantize_coefs(coefs, tns->coef_idx[w][g], tns->coef[w][g], - order, c_bits); - } - } else { /* 2 filters due to energy disbalance */ - tns->n_filt[w] = 2; - for (g = 0; g < tns->n_filt[w]; g++) { - tns->direction[w][g] = en[g] < en[!g]; - tns->order[w][g] = !g ? order/2 : order - tns->order[w][g-1]; - tns->length[w][g] = !g ? (sfb_end - sfb_start)/2 : \ + continue; + if (is8 && (gain < TNS_GAIN_THRESHOLD_LOW_IS8 || gain > TNS_GAIN_THRESHOLD_HIGH_IS8)) + continue; + if (is8 || order < 2) { + tns->n_filt[w] = 1; + for (g = 0; g < tns->n_filt[w]; g++) { + tns->length[w][g] = sfb_end - sfb_start; + tns->direction[w][g] = slant != 2 ? slant : en[0] < en[1]; + tns->order[w][g] = order; + quantize_coefs(coefs, tns->coef_idx[w][g], tns->coef[w][g], + order, c_bits); + } + } else { /* 2 filters due to energy disbalance */ + tns->n_filt[w] = 2; + for (g = 0; g < tns->n_filt[w]; g++) { + tns->direction[w][g] = slant != 2 ? slant : en[g] < en[!g]; + tns->order[w][g] = !g ? order/2 : order - tns->order[w][g-1]; + tns->length[w][g] = !g ? (sfb_end - sfb_start)/2 : \ (sfb_end - sfb_start) - tns->length[w][g-1]; - quantize_coefs(&coefs[!g ? 0 : order - tns->order[w][g-1]], - tns->coef_idx[w][g], tns->coef[w][g], - tns->order[w][g], c_bits); - } + quantize_coefs(&coefs[!g ? 0 : order - tns->order[w][g-1]], + tns->coef_idx[w][g], tns->coef[w][g], + tns->order[w][g], c_bits); } - count++; } + count += tns->n_filt[w]; } sce->tns.present = !!count; } diff --git a/libavcodec/aacenc_tns.h b/libavcodec/aacenc_tns.h index a7c119f368..466738dd16 100644 --- a/libavcodec/aacenc_tns.h +++ b/libavcodec/aacenc_tns.h @@ -30,24 +30,6 @@ #include "aacenc.h" -/* Could be set to 3 to save an additional bit at the cost of little quality */ -#define TNS_Q_BITS 4 - -/* Coefficient resolution in short windows */ -#define TNS_Q_BITS_SHORT 3 - -/* TNS will only be used if the LPC gain is within these margins */ -#define TNS_GAIN_THRESHOLD_LOW 1.437f -#define TNS_GAIN_THRESHOLD_HIGH 21.19f - -/* If the energy ratio between the low SFBs vs the high SFBs is not between - * those two values, use 2 filters instead */ -#define TNS_E_RATIO_LOW 0.77 -#define TNS_E_RATIO_HIGH 1.23 - -/* Do not use TNS if the psy band spread is below this value */ -#define TNS_SPREAD_THRESHOLD 0.5f - void ff_aac_encode_tns_info(AACEncContext *s, SingleChannelElement *sce); void ff_aac_apply_tns(AACEncContext *s, SingleChannelElement *sce); void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce); |