diff options
Diffstat (limited to 'libavcodec/aac.c')
| -rw-r--r-- | libavcodec/aac.c | 130 |
1 files changed, 128 insertions, 2 deletions
diff --git a/libavcodec/aac.c b/libavcodec/aac.c index 36742ba..9b94b8b 100644 --- a/libavcodec/aac.c +++ b/libavcodec/aac.c @@ -41,7 +41,7 @@ * N (code in SoC repo) Long Term Prediction * Y intensity stereo * Y channel coupling - * N frequency domain prediction + * Y frequency domain prediction * Y Perceptual Noise Substitution * Y Mid/Side stereo * N Scalable Inverse AAC Quantization @@ -331,6 +331,7 @@ static int decode_audio_specific_config(AACContext * ac, void *data, int data_si skip_bits_long(&gb, i); switch (ac->m4ac.object_type) { + case AOT_AAC_MAIN: case AOT_AAC_LC: if (decode_ga_specific_config(ac, &gb, ac->m4ac.chan_config)) return -1; @@ -354,6 +355,27 @@ static av_always_inline int lcg_random(int previous_val) { return previous_val * 1664525 + 1013904223; } +static void reset_predict_state(PredictorState * ps) { + ps->r0 = 0.0f; + ps->r1 = 0.0f; + ps->cor0 = 0.0f; + ps->cor1 = 0.0f; + ps->var0 = 1.0f; + ps->var1 = 1.0f; +} + +static void reset_all_predictors(PredictorState * ps) { + int i; + for (i = 0; i < MAX_PREDICTORS; i++) + reset_predict_state(&ps[i]); +} + +static void reset_predictor_group(PredictorState * ps, int group_num) { + int i; + for (i = group_num-1; i < MAX_PREDICTORS; i+=30) + reset_predict_state(&ps[i]); +} + static av_cold int aac_decode_init(AVCodecContext * avccontext) { AACContext * ac = avccontext->priv_data; int i; @@ -432,6 +454,21 @@ static void skip_data_stream_element(GetBitContext * gb) { skip_bits_long(gb, 8 * count); } +static int decode_prediction(AACContext * ac, IndividualChannelStream * ics, GetBitContext * gb) { + int sfb; + if (get_bits1(gb)) { + ics->predictor_reset_group = get_bits(gb, 5); + if (ics->predictor_reset_group == 0 || ics->predictor_reset_group > 30) { + av_log(ac->avccontext, AV_LOG_ERROR, "Invalid Predictor Reset Group.\n"); + return -1; + } + } + for (sfb = 0; sfb < FFMIN(ics->max_sfb, ff_aac_pred_sfb_max[ac->m4ac.sampling_index]); sfb++) { + ics->prediction_used[sfb] = get_bits1(gb); + } + return 0; +} + /** * Decode Individual Channel Stream info; reference: table 4.6. * @@ -464,16 +501,30 @@ static int decode_ics_info(AACContext * ac, IndividualChannelStream * ics, GetBi ics->swb_offset = swb_offset_128[ac->m4ac.sampling_index]; ics->num_swb = ff_aac_num_swb_128[ac->m4ac.sampling_index]; ics->tns_max_bands = tns_max_bands_128[ac->m4ac.sampling_index]; + ics->predictor_present = 0; } else { ics->max_sfb = get_bits(gb, 6); ics->num_windows = 1; ics->swb_offset = swb_offset_1024[ac->m4ac.sampling_index]; ics->num_swb = ff_aac_num_swb_1024[ac->m4ac.sampling_index]; ics->tns_max_bands = tns_max_bands_1024[ac->m4ac.sampling_index]; - if (get_bits1(gb)) { + ics->predictor_present = get_bits1(gb); + ics->predictor_reset_group = 0; + if (ics->predictor_present) { + if (ac->m4ac.object_type == AOT_AAC_MAIN) { + if (decode_prediction(ac, ics, gb)) { + memset(ics, 0, sizeof(IndividualChannelStream)); + return -1; + } + } else if (ac->m4ac.object_type == AOT_AAC_LC) { + av_log(ac->avccontext, AV_LOG_ERROR, "Prediction is not allowed in AAC-LC.\n"); + memset(ics, 0, sizeof(IndividualChannelStream)); + return -1; + } else { av_log_missing_feature(ac->avccontext, "Predictor bit set but LTP is", 1); memset(ics, 0, sizeof(IndividualChannelStream)); return -1; + } } } @@ -786,6 +837,77 @@ static int decode_spectrum_and_dequant(AACContext * ac, float coef[1024], GetBit return 0; } +static av_always_inline float flt16_round(float pf) { + int exp; + pf = frexpf(pf, &exp); + pf = ldexpf(roundf(ldexpf(pf, 8)), exp-8); + return pf; +} + +static av_always_inline float flt16_even(float pf) { + int exp; + pf = frexpf(pf, &exp); + pf = ldexpf(rintf(ldexpf(pf, 8)), exp-8); + return pf; +} + +static av_always_inline float flt16_trunc(float pf) { + int exp; + pf = frexpf(pf, &exp); + pf = ldexpf(truncf(ldexpf(pf, 8)), exp-8); + return pf; +} + +static void predict(AACContext * ac, PredictorState * ps, float* coef, int output_enable) { + const float a = 0.953125; // 61.0/64 + const float alpha = 0.90625; // 29.0/32 + float e0, e1; + float pv; + float k1, k2; + + k1 = ps->var0 > 1 ? ps->cor0 * flt16_even(a / ps->var0) : 0; + k2 = ps->var1 > 1 ? ps->cor1 * flt16_even(a / ps->var1) : 0; + + pv = flt16_round(k1 * ps->r0 + k2 * ps->r1); + if (output_enable) + *coef += pv * ac->sf_scale; + + e0 = *coef / ac->sf_scale; + e1 = e0 - k1 * ps->r0; + + ps->cor1 = flt16_trunc(alpha * ps->cor1 + ps->r1 * e1); + ps->var1 = flt16_trunc(alpha * ps->var1 + 0.5 * (ps->r1 * ps->r1 + e1 * e1)); + ps->cor0 = flt16_trunc(alpha * ps->cor0 + ps->r0 * e0); + ps->var0 = flt16_trunc(alpha * ps->var0 + 0.5 * (ps->r0 * ps->r0 + e0 * e0)); + + ps->r1 = flt16_trunc(a * (ps->r0 - k1 * e0)); + ps->r0 = flt16_trunc(a * e0); +} + +/** + * Apply AAC-Main style frequency domain prediction. + */ +static void apply_prediction(AACContext * ac, SingleChannelElement * sce) { + int sfb, k; + + if (!sce->ics.predictor_initialized) { + reset_all_predictors(sce->ics.predictor_state); + sce->ics.predictor_initialized = 1; + } + + if (sce->ics.window_sequence[0] != EIGHT_SHORT_SEQUENCE) { + for (sfb = 0; sfb < ff_aac_pred_sfb_max[ac->m4ac.sampling_index]; sfb++) { + for (k = sce->ics.swb_offset[sfb]; k < sce->ics.swb_offset[sfb + 1]; k++) { + predict(ac, &sce->ics.predictor_state[k], &sce->coeffs[k], + sce->ics.predictor_present && sce->ics.prediction_used[sfb]); + } + } + if (sce->ics.predictor_reset_group) + reset_predictor_group(sce->ics.predictor_state, sce->ics.predictor_reset_group); + } else + reset_all_predictors(sce->ics.predictor_state); +} + /** * Decode an individual_channel_stream payload; reference: table 4.44. * @@ -840,6 +962,10 @@ static int decode_ics(AACContext * ac, SingleChannelElement * sce, GetBitContext if (decode_spectrum_and_dequant(ac, out, gb, sce->sf, pulse_present, &pulse, ics, sce->band_type) < 0) return -1; + + if(ac->m4ac.object_type == AOT_AAC_MAIN) + apply_prediction(ac, sce); + return 0; } |
