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Commit 304dc455 authored by Jean-Baptiste Kempf's avatar Jean-Baptiste Kempf
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Provide the E-AC3 Spectral FFmpeg patch, made by Justin. 

Thanks a lot, French CSA for using it with almost noone able to decode it...
parent 36b4ced9
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extras/contrib/src/Makefile
View file @ 304dc455
......@@ -1111,6 +1111,7 @@ ifdef NO_TEXT_RELOCATION
echo "Broken LD. Fix your tools."
exit -1
endif
patch -p0 < Patches/eac3_spectral.patch
else
ffmpeg-$(FFMPEG_VERSION).tar.gz:
echo "ffmpeg snapshot is too old, you MUST use subversion !"
......
extras/contrib/src/Patches/eac3_spectral.patch 0 → 100644
View file @ 304dc455
Index: ffmpeg/libavcodec/ac3dec.c
===================================================================
--- ffmpeg/libavcodec/ac3dec.c (révision 19328)
+++ ffmpeg/libavcodec/ac3dec.c (copie de travail)
@@ -819,15 +819,99 @@
/* spectral extension strategy */
if (s->eac3 && (!blk || get_bits1(gbc))) {
+ s->spx_in_use = get_bits1(gbc);
+ if (s->spx_in_use) {
+ int begf, endf;
+ int spx_end_subband;
+
+ /* determine which channels use spx */
+ if (s->channel_mode == AC3_CHMODE_MONO) {
+ s->channel_in_spx[1] = 1;
+ } else {
+ for (ch = 1; ch <= fbw_channels; ch++)
+ s->channel_in_spx[ch] = get_bits1(gbc);
+ }
+
+ s->spx_copy_start_freq = get_bits(gbc, 2) * 12 + 25;
+ begf = get_bits(gbc, 3);
+ endf = get_bits(gbc, 3);
+ s->spx_start_subband = begf < 6 ? begf+2 : 2*begf-3;
+ spx_end_subband = endf < 4 ? endf+5 : 2*endf+3;
+ if (s->spx_start_subband >= spx_end_subband) {
+ av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension range (%d >= %d)\n",
+ s->spx_start_subband, spx_end_subband);
+ return -1;
+ }
+ s->spx_start_freq = s->spx_start_subband * 12 + 25;
+ s->spx_end_freq = spx_end_subband * 12 + 25;
+ if (s->spx_copy_start_freq >= s->spx_start_freq) {
+ av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension copy start bin (%d >= %d)\n",
+ s->spx_copy_start_freq, s->spx_start_freq);
+ return -1;
+ }
+ decode_band_structure(gbc, blk, s->eac3, 0,
+ s->spx_start_subband, spx_end_subband,
+ ff_eac3_default_spx_band_struct,
+ s->spx_band_struct, &s->num_spx_bands,
+ s->spx_band_sizes);
+ } else {
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->channel_in_spx[ch] = 0;
+ s->first_spx_coords[ch] = 1;
+ }
if (get_bits1(gbc)) {
av_log_missing_feature(s->avctx, "Spectral extension", 1);
return -1;
}
- /* TODO: parse spectral extension strategy info */
}
- /* TODO: spectral extension coordinates */
+ /* spectral extension coordinates */
+ if (s->spx_in_use) {
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ if (s->channel_in_spx[ch]) {
+ if (s->first_spx_coords[ch] || get_bits1(gbc)) {
+ float spx_blend;
+ int bin, master_spx_coord;
+ s->first_spx_coords[ch] = 0;
+ spx_blend = get_bits(gbc, 5) * (1.0f/32);
+ master_spx_coord = get_bits(gbc, 2) * 3;
+
+ bin = s->spx_start_freq;
+ for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
+ int bandsize;
+ int spx_coord_exp, spx_coord_mant;
+ float nratio, sblend, nblend, spx_coord;
+
+ /* calculate blending factors */
+ bandsize = s->spx_band_sizes[bnd];
+ nratio = ((float)((bin + (bandsize >> 1))) / s->spx_end_freq) - spx_blend;
+ nratio = av_clipf(nratio, 0.0f, 1.0f);
+ nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3) to give unity variance
+ sblend = sqrtf(1.0f - nratio);
+ bin += bandsize;
+
+ /* decode spx coordinates */
+ spx_coord_exp = get_bits(gbc, 4);
+ spx_coord_mant = get_bits(gbc, 2);
+ if (spx_coord_exp == 15)
+ spx_coord_mant <<= 1;
+ else
+ spx_coord_mant += 4;
+ spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
+ spx_coord = spx_coord_mant * (1.0f/(1<<23));
+
+ /* multiply noise and signal blending factors by spx coordinate */
+ s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
+ s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
+ }
+ }
+ } else {
+ s->first_spx_coords[ch] = 1;
+ }
+ }
+ }
+
/* coupling strategy */
if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
@@ -863,9 +947,9 @@
s->phase_flags_in_use = get_bits1(gbc);
/* coupling frequency range */
- /* TODO: modify coupling end freq if spectral extension is used */
cpl_start_subband = get_bits(gbc, 4);
- cpl_end_subband = get_bits(gbc, 4) + 3;
+ cpl_end_subband = s->spx_in_use ? s->spx_start_subband - 1 :
+ get_bits(gbc, 4) + 3;
if (cpl_start_subband >= cpl_end_subband) {
av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
cpl_start_subband, cpl_end_subband);
@@ -938,8 +1022,11 @@
if (channel_mode == AC3_CHMODE_STEREO) {
if ((s->eac3 && !blk) || get_bits1(gbc)) {
s->num_rematrixing_bands = 4;
- if(cpl_in_use && s->start_freq[CPL_CH] <= 61)
+ if (cpl_in_use && s->start_freq[CPL_CH] <= 61) {
s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
+ } else if (s->spx_in_use && s->spx_start_freq <= 61) {
+ s->num_rematrixing_bands -= 1;
+ }
for(bnd=0; bnd<s->num_rematrixing_bands; bnd++)
s->rematrixing_flags[bnd] = get_bits1(gbc);
} else if (!blk) {
@@ -964,6 +1051,8 @@
int prev = s->end_freq[ch];
if (s->channel_in_cpl[ch])
s->end_freq[ch] = s->start_freq[CPL_CH];
+ else if (s->channel_in_spx[ch])
+ s->end_freq[ch] = s->spx_start_freq;
else {
int bandwidth_code = get_bits(gbc, 6);
if (bandwidth_code > 60) {
@@ -1160,8 +1249,6 @@
/* TODO: generate enhanced coupling coordinates and uncouple */
- /* TODO: apply spectral extension */
-
/* recover coefficients if rematrixing is in use */
if(s->channel_mode == AC3_CHMODE_STEREO)
do_rematrixing(s);
@@ -1177,6 +1264,10 @@
s->dsp.int32_to_float_fmul_scalar(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
}
+ /* apply spectral extension to high frequency bins */
+ if (s->spx_in_use)
+ ff_eac3_apply_spectral_extension(s);
+
/* downmix and MDCT. order depends on whether block switching is used for
any channel in this block. this is because coefficients for the long
and short transforms cannot be mixed. */
Index: ffmpeg/libavcodec/ac3dec.h
===================================================================
--- ffmpeg/libavcodec/ac3dec.h (révision 19328)
+++ ffmpeg/libavcodec/ac3dec.h (copie de travail)
@@ -42,6 +42,7 @@
#define AC3_MAX_COEFS 256
#define AC3_BLOCK_SIZE 256
#define MAX_BLOCKS 6
+#define SPX_MAX_BANDS 17
typedef struct {
AVCodecContext *avctx; ///< parent context
@@ -88,6 +89,23 @@
int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco)
///@}
+///@defgroup spx spectral extension
+///@{
+ int spx_in_use; ///< spectral extension in use (spxinu)
+ uint8_t channel_in_spx[AC3_MAX_CHANNELS]; ///< channel in spectral extension (chinspx)
+ int8_t spx_atten_code[AC3_MAX_CHANNELS]; ///< spx attenuation code (spxattencod)
+ int spx_start_subband; ///< spx beginning frequency band (spxbegf)
+ int spx_start_freq; ///< spx start frequency bin
+ int spx_end_freq; ///< spx end frequency bin
+ int spx_copy_start_freq; ///< spx starting frequency for copying (copystartmant)
+ int num_spx_bands; ///< number of spx bands (nspxbnds)
+ uint8_t spx_band_struct[SPX_MAX_BANDS]; ///< spectral extension band structure (spxbndstrc)
+ uint8_t spx_band_sizes[SPX_MAX_BANDS]; ///< number of bins in each band (spxbndsztab)
+ uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states (firstspxcos)
+ float spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor (nblendfact)
+ float spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
+///@}
+
///@defgroup aht adaptive hybrid transform
int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu)
int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS]; ///< pre-IDCT mantissas
@@ -179,4 +197,11 @@
*/
void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
+/**
+ * Apply spectral extension to each channel by copying lower frequency
+ * coefficients to higher frequency bins and applying side information to
+ * approximate the original high frequency signal.
+ */
+void ff_eac3_apply_spectral_extension(AC3DecodeContext *s);
+
#endif /* AVCODEC_AC3DEC_H */
Index: ffmpeg/libavcodec/eac3dec.c
===================================================================
--- ffmpeg/libavcodec/eac3dec.c (révision 19328)
+++ ffmpeg/libavcodec/eac3dec.c (copie de travail)
@@ -23,10 +23,6 @@
/*
* There are several features of E-AC-3 that this decoder does not yet support.
*
- * Spectral Extension
- * There is a patch to get this working for the two samples we have that
- * use it, but it needs some minor changes in order to be accepted.
- *
* Enhanced Coupling
* No known samples exist. If any ever surface, this feature should not be
* too difficult to implement.
@@ -66,6 +62,95 @@
#define EAC3_SR_CODE_REDUCED 3
+void ff_eac3_apply_spectral_extension(AC3DecodeContext *s)
+{
+ int bin, bnd, ch, i;
+ uint8_t wrapflag[SPX_MAX_BANDS]={1,0,}, num_copy_sections, copy_sizes[SPX_MAX_BANDS];
+ float rms_energy[SPX_MAX_BANDS];
+
+ /* Set copy index mapping table. Set wrap flags to apply a notch filter at
+ wrap points later on. */
+ bin = s->spx_copy_start_freq;
+ num_copy_sections = 0;
+ for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
+ int copysize;
+ int bandsize = s->spx_band_sizes[bnd];
+ if (bin + bandsize > s->spx_start_freq) {
+ copy_sizes[num_copy_sections++] = bin - s->spx_copy_start_freq;
+ bin = s->spx_copy_start_freq;
+ wrapflag[bnd] = 1;
+ }
+ for (i = 0; i < bandsize; i += copysize) {
+ if (bin == s->spx_start_freq) {
+ copy_sizes[num_copy_sections++] = bin - s->spx_copy_start_freq;
+ bin = s->spx_copy_start_freq;
+ }
+ copysize = FFMIN(bandsize - i, s->spx_start_freq - bin);
+ bin += copysize;
+ }
+ }
+ copy_sizes[num_copy_sections++] = bin - s->spx_copy_start_freq;
+
+ for (ch = 1; ch <= s->fbw_channels; ch++) {
+ if (!s->channel_in_spx[ch])
+ continue;
+
+ /* Copy coeffs from normal bands to extension bands */
+ bin = s->spx_start_freq;
+ for (i = 0; i < num_copy_sections; i++) {
+ memcpy(&s->transform_coeffs[ch][bin],
+ &s->transform_coeffs[ch][s->spx_copy_start_freq],
+ copy_sizes[i]*sizeof(float));
+ bin += copy_sizes[i];
+ }
+
+ /* Calculate RMS energy for each SPX band. */
+ bin = s->spx_start_freq;
+ for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
+ int bandsize = s->spx_band_sizes[bnd];
+ float accum = 0.0f;
+ for (i = 0; i < bandsize; i++) {
+ float coeff = s->transform_coeffs[ch][bin++];
+ accum += coeff * coeff;
+ }
+ rms_energy[bnd] = sqrtf(accum / bandsize);
+ }
+
+ /* Apply a notch filter at transitions between normal and extension
+ bands and at all wrap points. */
+ if (s->spx_atten_code[ch] >= 0) {
+ const float *atten_tab = ff_eac3_spx_atten_tab[s->spx_atten_code[ch]];
+ bin = s->spx_start_freq - 2;
+ for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
+ if (wrapflag[bnd]) {
+ float *coeffs = &s->transform_coeffs[ch][bin];
+ coeffs[0] *= atten_tab[0];
+ coeffs[1] *= atten_tab[1];
+ coeffs[2] *= atten_tab[2];
+ coeffs[3] *= atten_tab[1];
+ coeffs[4] *= atten_tab[0];
+ }
+ bin += s->spx_band_sizes[bnd];
+ }
+ }
+
+ /* Apply noise-blended coefficient scaling based on previously
+ calculated RMS energy, blending factors, and SPX coordinates for
+ each band. */
+ bin = s->spx_start_freq;
+ for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
+ float nscale = s->spx_noise_blend[ch][bnd] * rms_energy[bnd] * (1.0f/(1<<31));
+ float sscale = s->spx_signal_blend[ch][bnd];
+ for (i = 0; i < s->spx_band_sizes[bnd]; i++) {
+ float noise = nscale * (int)av_lfg_get(&s->dith_state);
+ s->transform_coeffs[ch][bin] *= sscale;
+ s->transform_coeffs[ch][bin++] += noise;
+ }
+ }
+ }
+}
+
+
/** lrint(M_SQRT2*cos(2*M_PI/12)*(1<<23)) */
#define COEFF_0 10273905LL
@@ -494,9 +579,10 @@
if (parse_spx_atten_data) {
av_log_missing_feature(s->avctx, "Spectral extension attenuation", 1);
for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (get_bits1(gbc)) { // channel has spx attenuation
- skip_bits(gbc, 5); // skip spx attenuation code
- }
+ if (parse_spx_atten_data && get_bits1(gbc))
+ s->spx_atten_code[ch] = get_bits(gbc, 5);
+ else
+ s->spx_atten_code[ch] = -1;
}
}
@@ -513,6 +599,7 @@
/* syntax state initialization */
for (ch = 1; ch <= s->fbw_channels; ch++) {
+ s->first_spx_coords[ch] = 1;
s->first_cpl_coords[ch] = 1;
}
s->first_cpl_leak = 1;
Index: ffmpeg/libavcodec/ac3dec_data.c
===================================================================
--- ffmpeg/libavcodec/ac3dec_data.c (révision 19328)
+++ ffmpeg/libavcodec/ac3dec_data.c (copie de travail)
@@ -1127,6 +1127,51 @@
{ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1 };
/**
+ * Table E2.15 Default Spectral Extension Banding Structure
+ */
+const uint8_t ff_eac3_default_spx_band_struct[17] =
+{ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };
+
+/**
+ * Table E.25: Spectral Extension Attenuation Table
+ * ff_eac3_spx_atten_tab[code][bin]=pow(2.0,(bin+1)*(code+1)/-15.0);
+ */
+const float ff_eac3_spx_atten_tab[32][3] = {
+ { 0.954841603910416503f, 0.911722488558216804f, 0.870550563296124125f },
+ { 0.911722488558216804f, 0.831237896142787758f, 0.757858283255198995f },
+ { 0.870550563296124125f, 0.757858283255198995f, 0.659753955386447100f },
+ { 0.831237896142787758f, 0.690956439983888004f, 0.574349177498517438f },
+ { 0.793700525984099792f, 0.629960524947436595f, 0.500000000000000000f },
+ { 0.757858283255198995f, 0.574349177498517438f, 0.435275281648062062f },
+ { 0.723634618720189082f, 0.523647061410313364f, 0.378929141627599553f },
+ { 0.690956439983888004f, 0.477420801955208307f, 0.329876977693223550f },
+ { 0.659753955386447100f, 0.435275281648062062f, 0.287174588749258719f },
+ { 0.629960524947436595f, 0.396850262992049896f, 0.250000000000000000f },
+ { 0.601512518041058319f, 0.361817309360094541f, 0.217637640824031003f },
+ { 0.574349177498517438f, 0.329876977693223550f, 0.189464570813799776f },
+ { 0.548412489847312945f, 0.300756259020529160f, 0.164938488846611775f },
+ { 0.523647061410313364f, 0.274206244923656473f, 0.143587294374629387f },
+ { 0.500000000000000000f, 0.250000000000000000f, 0.125000000000000000f },
+ { 0.477420801955208307f, 0.227930622139554201f, 0.108818820412015502f },
+ { 0.455861244279108402f, 0.207809474035696939f, 0.094732285406899888f },
+ { 0.435275281648062062f, 0.189464570813799776f, 0.082469244423305887f },
+ { 0.415618948071393879f, 0.172739109995972029f, 0.071793647187314694f },
+ { 0.396850262992049896f, 0.157490131236859149f, 0.062500000000000000f },
+ { 0.378929141627599553f, 0.143587294374629387f, 0.054409410206007751f },
+ { 0.361817309360094541f, 0.130911765352578369f, 0.047366142703449930f },
+ { 0.345478219991944002f, 0.119355200488802049f, 0.041234622211652958f },
+ { 0.329876977693223550f, 0.108818820412015502f, 0.035896823593657347f },
+ { 0.314980262473718298f, 0.099212565748012460f, 0.031250000000000000f },
+ { 0.300756259020529160f, 0.090454327340023621f, 0.027204705103003875f },
+ { 0.287174588749258719f, 0.082469244423305887f, 0.023683071351724965f },
+ { 0.274206244923656473f, 0.075189064755132290f, 0.020617311105826479f },
+ { 0.261823530705156682f, 0.068551561230914118f, 0.017948411796828673f },
+ { 0.250000000000000000f, 0.062500000000000000f, 0.015625000000000000f },
+ { 0.238710400977604098f, 0.056982655534888536f, 0.013602352551501938f },
+ { 0.227930622139554201f, 0.051952368508924235f, 0.011841535675862483f }
+};
+
+/**
* Table of bin locations for rematrixing bands
* reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
*/
Index: ffmpeg/libavcodec/ac3dec_data.h
===================================================================
--- ffmpeg/libavcodec/ac3dec_data.h (révision 19328)
+++ ffmpeg/libavcodec/ac3dec_data.h (copie de travail)
@@ -34,6 +34,8 @@
extern const int16_t (* const ff_eac3_mantissa_vq[8])[6];
extern const uint8_t ff_eac3_frm_expstr[32][6];
extern const uint8_t ff_eac3_default_cpl_band_struct[18];
+extern const uint8_t ff_eac3_default_spx_band_struct[17];
+extern const float ff_eac3_spx_atten_tab[32][3];
extern const uint8_t ff_ac3_rematrix_band_tab[5];
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