* AAC encoder psychoacoustic model
* Copyright (C) 2008 Konstantin Shishkov
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
* constants for 3GPP AAC psychoacoustic model
* @{
*/
-#define PSY_3GPP_SPREAD_LOW 1.5f // spreading factor for ascending threshold spreading (15 dB/Bark)
-#define PSY_3GPP_SPREAD_HI 3.0f // spreading factor for descending threshold spreading (30 dB/Bark)
+#define PSY_3GPP_THR_SPREAD_HI 1.5f // spreading factor for low-to-hi threshold spreading (15 dB/Bark)
+#define PSY_3GPP_THR_SPREAD_LOW 3.0f // spreading factor for hi-to-low threshold spreading (30 dB/Bark)
#define PSY_3GPP_RPEMIN 0.01f
#define PSY_3GPP_RPELEV 2.0f
*/
typedef struct AacPsyBand{
float energy; ///< band energy
- float ffac; ///< form factor
float thr; ///< energy threshold
- float min_snr; ///< minimal SNR
float thr_quiet; ///< threshold in quiet
}AacPsyBand;
* psychoacoustic model frame type-dependent coefficients
*/
typedef struct AacPsyCoeffs{
- float ath [64]; ///< absolute threshold of hearing per bands
- float barks [64]; ///< Bark value for each spectral band in long frame
- float spread_low[64]; ///< spreading factor for low-to-high threshold spreading in long frame
- float spread_hi [64]; ///< spreading factor for high-to-low threshold spreading in long frame
+ float ath; ///< absolute threshold of hearing per bands
+ float barks; ///< Bark value for each spectral band in long frame
+ float spread_low[2]; ///< spreading factor for low-to-high threshold spreading in long frame
+ float spread_hi [2]; ///< spreading factor for high-to-low threshold spreading in long frame
+ float min_snr; ///< minimal SNR
}AacPsyCoeffs;
/**
* 3GPP TS26.403-inspired psychoacoustic model specific data
*/
typedef struct AacPsyContext{
- AacPsyCoeffs psy_coef[2];
+ AacPsyCoeffs psy_coef[2][64];
AacPsyChannel *ch;
}AacPsyContext;
minath = ath(3410, ATH_ADD);
for (j = 0; j < 2; j++) {
- AacPsyCoeffs *coeffs = &pctx->psy_coef[j];
+ AacPsyCoeffs *coeffs = pctx->psy_coef[j];
+ const uint8_t *band_sizes = ctx->bands[j];
float line_to_frequency = ctx->avctx->sample_rate / (j ? 256.f : 2048.0f);
i = 0;
prev = 0.0;
for (g = 0; g < ctx->num_bands[j]; g++) {
- i += ctx->bands[j][g];
+ i += band_sizes[g];
bark = calc_bark((i-1) * line_to_frequency);
- coeffs->barks[g] = (bark + prev) / 2.0;
+ coeffs[g].barks = (bark + prev) / 2.0;
prev = bark;
}
for (g = 0; g < ctx->num_bands[j] - 1; g++) {
- coeffs->spread_low[g] = pow(10.0, -(coeffs->barks[g+1] - coeffs->barks[g]) * PSY_3GPP_SPREAD_LOW);
- coeffs->spread_hi [g] = pow(10.0, -(coeffs->barks[g+1] - coeffs->barks[g]) * PSY_3GPP_SPREAD_HI);
+ AacPsyCoeffs *coeff = &coeffs[g];
+ float bark_width = coeffs[g+1].barks - coeffs->barks;
+ coeff->spread_low[0] = pow(10.0, -bark_width * PSY_3GPP_THR_SPREAD_LOW);
+ coeff->spread_hi [0] = pow(10.0, -bark_width * PSY_3GPP_THR_SPREAD_HI);
}
start = 0;
for (g = 0; g < ctx->num_bands[j]; g++) {
minscale = ath(start * line_to_frequency, ATH_ADD);
- for (i = 1; i < ctx->bands[j][g]; i++)
+ for (i = 1; i < band_sizes[g]; i++)
minscale = FFMIN(minscale, ath((start + i) * line_to_frequency, ATH_ADD));
- coeffs->ath[g] = minscale - minath;
- start += ctx->bands[j][g];
+ coeffs[g].ath = minscale - minath;
+ start += band_sizes[g];
}
}
AacPsyChannel *pch = &pctx->ch[channel];
int start = 0;
int i, w, g;
- const int num_bands = ctx->num_bands[wi->num_windows == 8];
- const uint8_t* band_sizes = ctx->bands[wi->num_windows == 8];
- AacPsyCoeffs *coeffs = &pctx->psy_coef[wi->num_windows == 8];
+ const int num_bands = ctx->num_bands[wi->num_windows == 8];
+ const uint8_t *band_sizes = ctx->bands[wi->num_windows == 8];
+ AacPsyCoeffs *coeffs = pctx->psy_coef[wi->num_windows == 8];
//calculate energies, initial thresholds and related values - 5.4.2 "Threshold Calculation"
for (w = 0; w < wi->num_windows*16; w += 16) {
band->energy = 0.0f;
for (i = 0; i < band_sizes[g]; i++)
band->energy += coefs[start+i] * coefs[start+i];
- band->energy *= 1.0f / (512*512);
band->thr = band->energy * 0.001258925f;
start += band_sizes[g];
-
- ctx->psy_bands[channel*PSY_MAX_BANDS+w+g].energy = band->energy;
}
}
- //modify thresholds - spread, threshold in quiet - 5.4.3 "Spreaded Energy Calculation"
+ //modify thresholds and energies - spread, threshold in quiet, pre-echo control
for (w = 0; w < wi->num_windows*16; w += 16) {
- AacPsyBand *band = &pch->band[w];
+ AacPsyBand *bands = &pch->band[w];
+ //5.4.2.3 "Spreading" & 5.4.3 "Spreaded Energy Calculation"
for (g = 1; g < num_bands; g++)
- band[g].thr = FFMAX(band[g].thr, band[g-1].thr * coeffs->spread_low[g-1]);
+ bands[g].thr = FFMAX(bands[g].thr, bands[g-1].thr * coeffs[g].spread_hi[0]);
for (g = num_bands - 2; g >= 0; g--)
- band[g].thr = FFMAX(band[g].thr, band[g+1].thr * coeffs->spread_hi [g]);
+ bands[g].thr = FFMAX(bands[g].thr, bands[g+1].thr * coeffs[g].spread_low[0]);
+ //5.4.2.4 "Threshold in quiet"
for (g = 0; g < num_bands; g++) {
- band[g].thr_quiet = band[g].thr = FFMAX(band[g].thr, coeffs->ath[g]);
+ AacPsyBand *band = &bands[g];
+ band->thr_quiet = band->thr = FFMAX(band->thr, coeffs[g].ath);
+ //5.4.2.5 "Pre-echo control"
if (!(wi->window_type[0] == LONG_STOP_SEQUENCE || (wi->window_type[1] == LONG_START_SEQUENCE && !w)))
- band[g].thr = FFMAX(PSY_3GPP_RPEMIN*band[g].thr, FFMIN(band[g].thr,
- PSY_3GPP_RPELEV*pch->prev_band[w+g].thr_quiet));
+ band->thr = FFMAX(PSY_3GPP_RPEMIN*band->thr, FFMIN(band->thr,
+ PSY_3GPP_RPELEV*pch->prev_band[w+g].thr_quiet));
+ }
+ }
+
+ for (w = 0; w < wi->num_windows*16; w += 16) {
+ for (g = 0; g < num_bands; g++) {
+ AacPsyBand *band = &pch->band[w+g];
+ FFPsyBand *psy_band = &ctx->psy_bands[channel*PSY_MAX_BANDS+w+g];
- ctx->psy_bands[channel*PSY_MAX_BANDS+w+g].threshold = band[g].thr;
+ psy_band->threshold = band->thr;
+ psy_band->energy = band->energy;
}
}
+
memcpy(pch->prev_band, pch->band, sizeof(pch->band));
}
if (pch->prev_attack == 3 || att_sum) {
uselongblock = 0;
- if (attacks[1] && attacks[0])
- attacks[1] = 0;
- if (attacks[2] && attacks[1])
- attacks[2] = 0;
- if (attacks[3] && attacks[2])
- attacks[3] = 0;
- if (attacks[4] && attacks[3])
- attacks[4] = 0;
- if (attacks[5] && attacks[4])
- attacks[5] = 0;
- if (attacks[6] && attacks[5])
- attacks[6] = 0;
- if (attacks[7] && attacks[6])
- attacks[7] = 0;
- if (attacks[8] && attacks[7])
- attacks[8] = 0;
+ for (i = 1; i < AAC_NUM_BLOCKS_SHORT + 1; i++)
+ if (attacks[i] && attacks[i-1])
+ attacks[i] = 0;
}
} else {
/* We have no lookahead info, so just use same type as the previous sequence. */
projects / ffmpeg / blobdiff