#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;
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)
en[1] += band->energy;
else
en[0] += band->energy;
- threshold += band->threshold;
- spread += band->spread;
}
}
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;
}
#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);