Revision 39ded680 libavcodec/qcelpdec.c
libavcodec/qcelpdec.c | ||
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} |
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/** |
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* Initialize the speech codec according to the specification. |
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* |
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* TIA/EIA/IS-733 2.4.9 |
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*/ |
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static av_cold int qcelp_decode_init(AVCodecContext *avctx) { |
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QCELPContext *q = avctx->priv_data; |
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int i; |
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avctx->sample_fmt = SAMPLE_FMT_FLT; |
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for (i = 0; i < 10; i++) |
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q->prev_lspf[i] = (i + 1) / 11.; |
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return 0; |
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} |
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/** |
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* Computes the scaled codebook vector Cdn From INDEX and GAIN |
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* for all rates. |
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* |
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* The specification lacks some information here. |
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* |
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* TIA/EIA/IS-733 has an omission on the codebook index determination |
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* formula for RATE_FULL and RATE_HALF frames at section 2.4.8.1.1. It says |
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* you have to subtract the decoded index parameter from the given scaled |
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* codebook vector index 'n' to get the desired circular codebook index, but |
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* it does not mention that you have to clamp 'n' to [0-9] in order to get |
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* RI-compliant results. |
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* |
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* The reason for this mistake seems to be the fact they forgot to mention you |
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* have to do these calculations per codebook subframe and adjust given |
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* equation values accordingly. |
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* |
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* @param q the context |
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* @param gain array holding the 4 pitch subframe gain values |
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* @param cdn_vector array for the generated scaled codebook vector |
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*/ |
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static void compute_svector(const QCELPContext *q, |
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const float *gain, |
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float *cdn_vector) { |
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int i, j, k; |
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uint16_t cbseed, cindex; |
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float *rnd, tmp_gain, fir_filter_value; |
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switch (q->framerate) { |
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case RATE_FULL: |
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for (i = 0; i < 16; i++) { |
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tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; |
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cindex = -q->cindex[i]; |
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for (j = 0; j < 10; j++) |
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*cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cindex++ & 127]; |
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} |
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break; |
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case RATE_HALF: |
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for (i = 0; i < 4; i++) { |
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tmp_gain = gain[i] * QCELP_RATE_HALF_CODEBOOK_RATIO; |
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cindex = -q->cindex[i]; |
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for (j = 0; j < 40; j++) |
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*cdn_vector++ = tmp_gain * qcelp_rate_half_codebook[cindex++ & 127]; |
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} |
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break; |
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case RATE_QUARTER: |
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cbseed = (0x0003 & q->lspv[4])<<14 | |
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(0x003F & q->lspv[3])<< 8 | |
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(0x0060 & q->lspv[2])<< 1 | |
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(0x0007 & q->lspv[1])<< 3 | |
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(0x0038 & q->lspv[0])>> 3 ; |
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rnd = q->rnd_fir_filter_mem + 20; |
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for (i = 0; i < 8; i++) { |
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tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); |
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for (k = 0; k < 20; k++) { |
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cbseed = 521 * cbseed + 259; |
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*rnd = (int16_t)cbseed; |
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// FIR filter |
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fir_filter_value = 0.0; |
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for (j = 0; j < 10; j++) |
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fir_filter_value += qcelp_rnd_fir_coefs[j ] * (rnd[-j ] + rnd[-20+j]); |
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fir_filter_value += qcelp_rnd_fir_coefs[10] * rnd[-10]; |
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*cdn_vector++ = tmp_gain * fir_filter_value; |
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rnd++; |
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} |
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} |
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memcpy(q->rnd_fir_filter_mem, q->rnd_fir_filter_mem + 160, 20 * sizeof(float)); |
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break; |
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case RATE_OCTAVE: |
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cbseed = q->first16bits; |
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for (i = 0; i < 8; i++) { |
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tmp_gain = gain[i] * (QCELP_SQRT1887 / 32768.0); |
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for (j = 0; j < 20; j++) { |
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cbseed = 521 * cbseed + 259; |
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*cdn_vector++ = tmp_gain * (int16_t)cbseed; |
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} |
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} |
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break; |
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case I_F_Q: |
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cbseed = -44; // random codebook index |
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for (i = 0; i < 4; i++) { |
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tmp_gain = gain[i] * QCELP_RATE_FULL_CODEBOOK_RATIO; |
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for (j = 0; j < 40; j++) |
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*cdn_vector++ = tmp_gain * qcelp_rate_full_codebook[cbseed++ & 127]; |
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} |
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break; |
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} |
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} |
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/** |
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* Apply generic gain control. |
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* |
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* @param v_out output vector |
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* @param v_in gain-controlled vector |
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* @param v_ref vector to control gain of |
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* |
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* FIXME: If v_ref is a zero vector, it energy is zero |
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* and the behavior of the gain control is |
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* undefined in the specs. |
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* |
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* TIA/EIA/IS-733 2.4.8.3-2/3/4/5, 2.4.8.6 |
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*/ |
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static void apply_gain_ctrl(float *v_out, |
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const float *v_ref, |
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const float *v_in) { |
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int i, j, len; |
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float scalefactor; |
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for (i = 0, j = 0; i < 4; i++) { |
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scalefactor = ff_dot_productf(v_in + j, v_in + j, 40); |
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if (scalefactor) |
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scalefactor = sqrt(ff_dot_productf(v_ref + j, v_ref + j, 40) / scalefactor); |
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else |
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av_log_missing_feature(NULL, "Zero energy for gain control", 1); |
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for (len = j + 40; j < len; j++) |
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v_out[j] = scalefactor * v_in[j]; |
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} |
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} |
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/** |
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* Apply filter in pitch-subframe steps. |
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* |
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* @param memory buffer for the previous state of the filter |
... | ... | |
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if (weight != 1.0) { |
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weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf, weight, 1.0 - weight, 10); |
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lspf2lpc(q, interpolated_lspf, lpc);
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qcelp_lspf2lpc(interpolated_lspf, lpc);
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} else if (q->framerate >= RATE_QUARTER || (q->framerate == I_F_Q && !subframe_num)) |
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lspf2lpc(q, curr_lspf, lpc);
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qcelp_lspf2lpc(curr_lspf, lpc);
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} |
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static int buf_size2framerate(const int buf_size) { |
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