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ac3dec: Split spx-specific code from decode_audio_block()
Signed-off-by: Diego Biurrun <diego@biurrun.de>
This commit is contained in:
Luca Barbato
Diego Biurrun
parent
2ac00d2d1d
commit
a5ebe5d121
@ -746,6 +746,109 @@ static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
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memcpy(band_sizes, bnd_sz, n_bands);
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}
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static inline int spx_strategy(AC3DecodeContext *s, int blk)
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{
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GetBitContext *bc = &s->gbc;
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int fbw_channels = s->fbw_channels;
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int dst_start_freq, dst_end_freq, src_start_freq,
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start_subband, end_subband, ch;
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/* determine which channels use spx */
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if (s->channel_mode == AC3_CHMODE_MONO) {
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s->channel_uses_spx[1] = 1;
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} else {
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for (ch = 1; ch <= fbw_channels; ch++)
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s->channel_uses_spx[ch] = get_bits1(bc);
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}
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/* get the frequency bins of the spx copy region and the spx start
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and end subbands */
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dst_start_freq = get_bits(bc, 2);
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start_subband = get_bits(bc, 3) + 2;
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if (start_subband > 7)
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start_subband += start_subband - 7;
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end_subband = get_bits(bc, 3) + 5;
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if (end_subband > 7)
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end_subband += end_subband - 7;
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dst_start_freq = dst_start_freq * 12 + 25;
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src_start_freq = start_subband * 12 + 25;
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dst_end_freq = end_subband * 12 + 25;
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/* check validity of spx ranges */
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if (start_subband >= end_subband) {
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av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
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"range (%d >= %d)\n", start_subband, end_subband);
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return AVERROR_INVALIDDATA;
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}
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if (dst_start_freq >= src_start_freq) {
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av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
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"copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
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return AVERROR_INVALIDDATA;
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}
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s->spx_dst_start_freq = dst_start_freq;
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s->spx_src_start_freq = src_start_freq;
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s->spx_dst_end_freq = dst_end_freq;
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decode_band_structure(bc, blk, s->eac3, 0,
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start_subband, end_subband,
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ff_eac3_default_spx_band_struct,
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&s->num_spx_bands,
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s->spx_band_sizes);
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return 0;
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}
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static inline void spx_coordinates(AC3DecodeContext *s)
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{
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GetBitContext *bc = &s->gbc;
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int fbw_channels = s->fbw_channels;
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int ch, bnd;
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for (ch = 1; ch <= fbw_channels; ch++) {
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if (s->channel_uses_spx[ch]) {
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if (s->first_spx_coords[ch] || get_bits1(bc)) {
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float spx_blend;
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int bin, master_spx_coord;
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s->first_spx_coords[ch] = 0;
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spx_blend = get_bits(bc, 5) * (1.0f / 32);
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master_spx_coord = get_bits(bc, 2) * 3;
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bin = s->spx_src_start_freq;
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for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
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int bandsize;
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int spx_coord_exp, spx_coord_mant;
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float nratio, sblend, nblend, spx_coord;
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/* calculate blending factors */
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bandsize = s->spx_band_sizes[bnd];
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nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
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nratio = av_clipf(nratio, 0.0f, 1.0f);
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nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
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// to give unity variance
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sblend = sqrtf(1.0f - nratio);
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bin += bandsize;
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/* decode spx coordinates */
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spx_coord_exp = get_bits(bc, 4);
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spx_coord_mant = get_bits(bc, 2);
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if (spx_coord_exp == 15) spx_coord_mant <<= 1;
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else spx_coord_mant += 4;
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spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
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spx_coord = spx_coord_mant * (1.0f / (1 << 23));
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/* multiply noise and signal blending factors by spx coordinate */
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s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
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s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
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}
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}
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} else {
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s->first_spx_coords[ch] = 1;
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}
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}
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}
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/**
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* Decode a single audio block from the AC-3 bitstream.
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*/
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@ -753,7 +856,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
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{
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int fbw_channels = s->fbw_channels;
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int channel_mode = s->channel_mode;
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int i, bnd, seg, ch;
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int i, bnd, seg, ch, ret;
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int different_transforms;
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int downmix_output;
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int cpl_in_use;
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@ -797,51 +900,8 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
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if (s->eac3 && (!blk || get_bits1(gbc))) {
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s->spx_in_use = get_bits1(gbc);
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if (s->spx_in_use) {
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int dst_start_freq, dst_end_freq, src_start_freq,
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start_subband, end_subband;
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/* determine which channels use spx */
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if (s->channel_mode == AC3_CHMODE_MONO) {
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s->channel_uses_spx[1] = 1;
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} else {
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for (ch = 1; ch <= fbw_channels; ch++)
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s->channel_uses_spx[ch] = get_bits1(gbc);
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}
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/* get the frequency bins of the spx copy region and the spx start
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and end subbands */
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dst_start_freq = get_bits(gbc, 2);
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start_subband = get_bits(gbc, 3) + 2;
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if (start_subband > 7)
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start_subband += start_subband - 7;
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end_subband = get_bits(gbc, 3) + 5;
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if (end_subband > 7)
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end_subband += end_subband - 7;
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dst_start_freq = dst_start_freq * 12 + 25;
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src_start_freq = start_subband * 12 + 25;
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dst_end_freq = end_subband * 12 + 25;
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/* check validity of spx ranges */
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if (start_subband >= end_subband) {
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av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
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"range (%d >= %d)\n", start_subband, end_subband);
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return AVERROR_INVALIDDATA;
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}
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if (dst_start_freq >= src_start_freq) {
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av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
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"copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
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return AVERROR_INVALIDDATA;
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}
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s->spx_dst_start_freq = dst_start_freq;
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s->spx_src_start_freq = src_start_freq;
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s->spx_dst_end_freq = dst_end_freq;
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decode_band_structure(gbc, blk, s->eac3, 0,
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start_subband, end_subband,
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ff_eac3_default_spx_band_struct,
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&s->num_spx_bands,
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s->spx_band_sizes);
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if ((ret = spx_strategy(s, blk)) < 0)
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return ret;
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} else {
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for (ch = 1; ch <= fbw_channels; ch++) {
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s->channel_uses_spx[ch] = 0;
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@ -851,50 +911,8 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
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}
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/* spectral extension coordinates */
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if (s->spx_in_use) {
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for (ch = 1; ch <= fbw_channels; ch++) {
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if (s->channel_uses_spx[ch]) {
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if (s->first_spx_coords[ch] || get_bits1(gbc)) {
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float spx_blend;
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int bin, master_spx_coord;
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s->first_spx_coords[ch] = 0;
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spx_blend = get_bits(gbc, 5) * (1.0f/32);
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master_spx_coord = get_bits(gbc, 2) * 3;
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bin = s->spx_src_start_freq;
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for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
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int bandsize;
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int spx_coord_exp, spx_coord_mant;
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float nratio, sblend, nblend, spx_coord;
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/* calculate blending factors */
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bandsize = s->spx_band_sizes[bnd];
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nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
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nratio = av_clipf(nratio, 0.0f, 1.0f);
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nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
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// to give unity variance
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sblend = sqrtf(1.0f - nratio);
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bin += bandsize;
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/* decode spx coordinates */
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spx_coord_exp = get_bits(gbc, 4);
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spx_coord_mant = get_bits(gbc, 2);
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if (spx_coord_exp == 15) spx_coord_mant <<= 1;
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else spx_coord_mant += 4;
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spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
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spx_coord = spx_coord_mant * (1.0f / (1 << 23));
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/* multiply noise and signal blending factors by spx coordinate */
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s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
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s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
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}
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}
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} else {
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s->first_spx_coords[ch] = 1;
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}
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}
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}
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if (s->spx_in_use)
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spx_coordinates(s);
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/* coupling strategy */
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if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
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