#include "avcodec.h"
#include "ac3_parser.h"
#include "bitstream.h"
+#include "crc.h"
#include "dsputil.h"
#include "random.h"
*/
static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
-/**
- * table for exponent to scale_factor mapping
- * scale_factors[i] = 2 ^ -i
- */
-static float scale_factors[25];
-
/** table for grouping exponents */
static uint8_t exp_ungroup_tab[128][3];
/** tables for ungrouping mantissas */
-static float b1_mantissas[32][3];
-static float b2_mantissas[128][3];
-static float b3_mantissas[8];
-static float b4_mantissas[128][2];
-static float b5_mantissas[16];
+static int b1_mantissas[32][3];
+static int b2_mantissas[128][3];
+static int b3_mantissas[8];
+static int b4_mantissas[128][2];
+static int b5_mantissas[16];
/**
* Quantization table: levels for symmetric. bits for asymmetric.
* reference: Table 7.18 Mapping of bap to Quantizer
*/
-static const uint8_t qntztab[16] = {
+static const uint8_t quantization_tab[16] = {
0, 3, 5, 7, 11, 15,
5, 6, 7, 8, 9, 10, 11, 12, 14, 16
};
/** dynamic range table. converts codes to scale factors. */
-static float dynrng_tab[256];
-
-/** dialog normalization table */
-static float dialnorm_tab[32];
+static float dynamic_range_tab[256];
/** Adjustments in dB gain */
#define LEVEL_MINUS_3DB 0.7071067811865476
typedef struct {
int channel_mode; ///< channel mode (acmod)
- int dolby_surround_mode; ///< dolby surround mode
- int blksw[AC3_MAX_CHANNELS]; ///< block switch flags
- int dithflag[AC3_MAX_CHANNELS]; ///< dither flags
+ int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags
+ int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags
int dither_all; ///< true if all channels are dithered
- int cplinu; ///< coupling in use
- int chincpl[AC3_MAX_CHANNELS]; ///< channel in coupling
- int phsflginu; ///< phase flags in use
- int cplbndstrc[18]; ///< coupling band structure
- int rematstr; ///< rematrixing strategy
- int nrematbnd; ///< number of rematrixing bands
- int rematflg[4]; ///< rematrixing flags
- int expstr[AC3_MAX_CHANNELS]; ///< exponent strategies
+ int cpl_in_use; ///< coupling in use
+ int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling
+ int phase_flags_in_use; ///< phase flags in use
+ int phase_flags[18]; ///< phase flags
+ int cpl_band_struct[18]; ///< coupling band structure
+ int num_rematrixing_bands; ///< number of rematrixing bands
+ int rematrixing_flags[4]; ///< rematrixing flags
+ int exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets
int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio)
int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
- int sampling_rate; ///< sample frequency, in Hz
+ int sample_rate; ///< sample frequency, in Hz
int bit_rate; ///< stream bit rate, in bits-per-second
int frame_size; ///< current frame size, in bytes
- int nchans; ///< number of total channels
- int nfchans; ///< number of full-bandwidth channels
+ int channels; ///< number of total channels
+ int fbw_channels; ///< number of full-bandwidth channels
int lfe_on; ///< lfe channel in use
int lfe_ch; ///< index of LFE channel
int output_mode; ///< output channel configuration
int out_channels; ///< number of output channels
+ int center_mix_level; ///< Center mix level index
+ int surround_mix_level; ///< Surround mix level index
float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
- float dialnorm[2]; ///< dialog normalization
- float dynrng[2]; ///< dynamic range
- float cplco[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
- int ncplbnd; ///< number of coupling bands
- int ncplsubnd; ///< number of coupling sub bands
- int startmant[AC3_MAX_CHANNELS]; ///< start frequency bin
- int endmant[AC3_MAX_CHANNELS]; ///< end frequency bin
+ float downmix_coeff_adjust[2]; ///< adjustment needed for each output channel when downmixing
+ float dynamic_range[2]; ///< dynamic range
+ int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
+ int num_cpl_bands; ///< number of coupling bands
+ int num_cpl_subbands; ///< number of coupling sub bands
+ int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin
+ int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin
AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
+ int fixed_coeffs[AC3_MAX_CHANNELS][256]; ///> fixed-point transform coefficients
DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
+ int downmixed; ///< indicates if coeffs are currently downmixed
/* For IMDCT. */
MDCTContext imdct_512; ///< for 512 sample IMDCT
float add_bias; ///< offset for float_to_int16 conversion
float mul_bias; ///< scaling for float_to_int16 conversion
- DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); ///< output after imdct transform and windowing
+ DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][256]); ///< output after imdct transform and windowing
DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
- DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); ///< delay - added to the next block
+ DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][256]); ///< delay - added to the next block
DECLARE_ALIGNED_16(float, tmp_imdct[256]); ///< temporary storage for imdct transform
DECLARE_ALIGNED_16(float, tmp_output[512]); ///< temporary storage for output before windowing
DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients
/* Miscellaneous. */
- GetBitContext gb; ///< bitstream reader
+ GetBitContext gbc; ///< bitstream reader
AVRandomState dith_state; ///< for dither generation
AVCodecContext *avctx; ///< parent context
} AC3DecodeContext;
-/**
- * Generate a Kaiser-Bessel Derived Window.
- */
-static void ac3_window_init(float *window)
-{
- int i, j;
- double sum = 0.0, bessel, tmp;
- double local_window[256];
- double alpha2 = (5.0 * M_PI / 256.0) * (5.0 * M_PI / 256.0);
-
- for (i = 0; i < 256; i++) {
- tmp = i * (256 - i) * alpha2;
- bessel = 1.0;
- for (j = 100; j > 0; j--) /* default to 100 iterations */
- bessel = bessel * tmp / (j * j) + 1;
- sum += bessel;
- local_window[i] = sum;
- }
-
- sum++;
- for (i = 0; i < 256; i++)
- window[i] = sqrt(local_window[i] / sum);
-}
-
/**
* Symmetrical Dequantization
* reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
* Tables 7.19 to 7.23
*/
-static inline float
+static inline int
symmetric_dequant(int code, int levels)
{
- return (code - (levels >> 1)) * (2.0f / levels);
+ return ((code - (levels >> 1)) << 24) / levels;
}
/*
* Initialize tables at runtime.
*/
-static void ac3_tables_init(void)
+static av_cold void ac3_tables_init(void)
{
int i;
reference: Section 7.7.1 Dynamic Range Control */
for(i=0; i<256; i++) {
int v = (i >> 5) - ((i >> 7) << 3) - 5;
- dynrng_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
- }
-
- /* generate dialog normalization table
- references: Section 5.4.2.8 dialnorm
- Section 7.6 Dialogue Normalization */
- for(i=1; i<32; i++) {
- dialnorm_tab[i] = expf((i-31) * M_LN10 / 20.0f);
+ dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
}
- dialnorm_tab[0] = dialnorm_tab[31];
-
- /* generate scale factors for exponents and asymmetrical dequantization
- reference: Section 7.3.2 Expansion of Mantissas for Asymmetric Quantization */
- for (i = 0; i < 25; i++)
- scale_factors[i] = pow(2.0, -i);
/* generate exponent tables
reference: Section 7.1.3 Exponent Decoding */
/**
* AVCodec initialization
*/
-static int ac3_decode_init(AVCodecContext *avctx)
+static av_cold int ac3_decode_init(AVCodecContext *avctx)
{
- AC3DecodeContext *ctx = avctx->priv_data;
- ctx->avctx = avctx;
+ AC3DecodeContext *s = avctx->priv_data;
+ s->avctx = avctx;
ac3_common_init();
ac3_tables_init();
- ff_mdct_init(&ctx->imdct_256, 8, 1);
- ff_mdct_init(&ctx->imdct_512, 9, 1);
- ac3_window_init(ctx->window);
- dsputil_init(&ctx->dsp, avctx);
- av_init_random(0, &ctx->dith_state);
+ ff_mdct_init(&s->imdct_256, 8, 1);
+ ff_mdct_init(&s->imdct_512, 9, 1);
+ ff_kbd_window_init(s->window, 5.0, 256);
+ dsputil_init(&s->dsp, avctx);
+ av_init_random(0, &s->dith_state);
/* set bias values for float to int16 conversion */
- if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) {
- ctx->add_bias = 385.0f;
- ctx->mul_bias = 1.0f;
+ if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
+ s->add_bias = 385.0f;
+ s->mul_bias = 1.0f;
} else {
- ctx->add_bias = 0.0f;
- ctx->mul_bias = 32767.0f;
+ s->add_bias = 0.0f;
+ s->mul_bias = 32767.0f;
+ }
+
+ /* allow downmixing to stereo or mono */
+ if (avctx->channels > 0 && avctx->request_channels > 0 &&
+ avctx->request_channels < avctx->channels &&
+ avctx->request_channels <= 2) {
+ avctx->channels = avctx->request_channels;
}
+ s->downmixed = 1;
return 0;
}
* GetBitContext within AC3DecodeContext must point to
* start of the synchronized ac3 bitstream.
*/
-static int ac3_parse_header(AC3DecodeContext *ctx)
+static int ac3_parse_header(AC3DecodeContext *s)
{
AC3HeaderInfo hdr;
- GetBitContext *gb = &ctx->gb;
- float center_mix_level, surround_mix_level;
+ GetBitContext *gbc = &s->gbc;
int err, i;
- err = ff_ac3_parse_header(gb->buffer, &hdr);
+ err = ff_ac3_parse_header(gbc->buffer, &hdr);
if(err)
return err;
+ if(hdr.bitstream_id > 10)
+ return AC3_PARSE_ERROR_BSID;
+
/* get decoding parameters from header info */
- ctx->bit_alloc_params.sr_code = hdr.sr_code;
- ctx->channel_mode = hdr.channel_mode;
- center_mix_level = gain_levels[center_levels[hdr.center_mix_level]];
- surround_mix_level = gain_levels[surround_levels[hdr.surround_mix_level]];
- ctx->dolby_surround_mode = hdr.dolby_surround_mode;
- ctx->lfe_on = hdr.lfe_on;
- ctx->bit_alloc_params.sr_shift = hdr.sr_shift;
- ctx->sampling_rate = hdr.sample_rate;
- ctx->bit_rate = hdr.bit_rate;
- ctx->nchans = hdr.channels;
- ctx->nfchans = ctx->nchans - ctx->lfe_on;
- ctx->lfe_ch = ctx->nfchans + 1;
- ctx->frame_size = hdr.frame_size;
+ s->bit_alloc_params.sr_code = hdr.sr_code;
+ s->channel_mode = hdr.channel_mode;
+ s->lfe_on = hdr.lfe_on;
+ s->bit_alloc_params.sr_shift = hdr.sr_shift;
+ s->sample_rate = hdr.sample_rate;
+ s->bit_rate = hdr.bit_rate;
+ s->channels = hdr.channels;
+ s->fbw_channels = s->channels - s->lfe_on;
+ s->lfe_ch = s->fbw_channels + 1;
+ s->frame_size = hdr.frame_size;
/* set default output to all source channels */
- ctx->out_channels = ctx->nchans;
- ctx->output_mode = ctx->channel_mode;
- if(ctx->lfe_on)
- ctx->output_mode |= AC3_OUTPUT_LFEON;
+ s->out_channels = s->channels;
+ s->output_mode = s->channel_mode;
+ if(s->lfe_on)
+ s->output_mode |= AC3_OUTPUT_LFEON;
+
+ /* set default mix levels */
+ s->center_mix_level = 3; // -4.5dB
+ s->surround_mix_level = 4; // -6.0dB
/* skip over portion of header which has already been read */
- skip_bits(gb, 16); // skip the sync_word
- skip_bits(gb, 16); // skip crc1
- skip_bits(gb, 8); // skip fscod and frmsizecod
- skip_bits(gb, 11); // skip bsid, bsmod, and acmod
- if(ctx->channel_mode == AC3_CHMODE_STEREO) {
- skip_bits(gb, 2); // skip dsurmod
+ skip_bits(gbc, 16); // skip the sync_word
+ skip_bits(gbc, 16); // skip crc1
+ skip_bits(gbc, 8); // skip fscod and frmsizecod
+ skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
+ if(s->channel_mode == AC3_CHMODE_STEREO) {
+ skip_bits(gbc, 2); // skip dsurmod
} else {
- if((ctx->channel_mode & 1) && ctx->channel_mode != AC3_CHMODE_MONO)
- skip_bits(gb, 2); // skip cmixlev
- if(ctx->channel_mode & 4)
- skip_bits(gb, 2); // skip surmixlev
+ if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO)
+ s->center_mix_level = center_levels[get_bits(gbc, 2)];
+ if(s->channel_mode & 4)
+ s->surround_mix_level = surround_levels[get_bits(gbc, 2)];
}
- skip_bits1(gb); // skip lfeon
+ skip_bits1(gbc); // skip lfeon
/* read the rest of the bsi. read twice for dual mono mode. */
- i = !(ctx->channel_mode);
+ i = !(s->channel_mode);
do {
- ctx->dialnorm[i] = dialnorm_tab[get_bits(gb, 5)]; // dialog normalization
- if (get_bits1(gb))
- skip_bits(gb, 8); //skip compression
- if (get_bits1(gb))
- skip_bits(gb, 8); //skip language code
- if (get_bits1(gb))
- skip_bits(gb, 7); //skip audio production information
+ skip_bits(gbc, 5); // skip dialog normalization
+ if (get_bits1(gbc))
+ skip_bits(gbc, 8); //skip compression
+ if (get_bits1(gbc))
+ skip_bits(gbc, 8); //skip language code
+ if (get_bits1(gbc))
+ skip_bits(gbc, 7); //skip audio production information
} while (i--);
- skip_bits(gb, 2); //skip copyright bit and original bitstream bit
+ skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
/* skip the timecodes (or extra bitstream information for Alternate Syntax)
TODO: read & use the xbsi1 downmix levels */
- if (get_bits1(gb))
- skip_bits(gb, 14); //skip timecode1 / xbsi1
- if (get_bits1(gb))
- skip_bits(gb, 14); //skip timecode2 / xbsi2
+ if (get_bits1(gbc))
+ skip_bits(gbc, 14); //skip timecode1 / xbsi1
+ if (get_bits1(gbc))
+ skip_bits(gbc, 14); //skip timecode2 / xbsi2
/* skip additional bitstream info */
- if (get_bits1(gb)) {
- i = get_bits(gb, 6);
+ if (get_bits1(gbc)) {
+ i = get_bits(gbc, 6);
do {
- skip_bits(gb, 8);
+ skip_bits(gbc, 8);
} while(i--);
}
- /* set stereo downmixing coefficients
- reference: Section 7.8.2 Downmixing Into Two Channels */
- for(i=0; i<ctx->nfchans; i++) {
- ctx->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[ctx->channel_mode][i][0]];
- ctx->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[ctx->channel_mode][i][1]];
+ return 0;
+}
+
+/**
+ * Set stereo downmixing coefficients based on frame header info.
+ * reference: Section 7.8.2 Downmixing Into Two Channels
+ */
+static void set_downmix_coeffs(AC3DecodeContext *s)
+{
+ int i;
+ float cmix = gain_levels[s->center_mix_level];
+ float smix = gain_levels[s->surround_mix_level];
+
+ for(i=0; i<s->fbw_channels; i++) {
+ s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
+ s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
}
- if(ctx->channel_mode > 1 && ctx->channel_mode & 1) {
- ctx->downmix_coeffs[1][0] = ctx->downmix_coeffs[1][1] = center_mix_level;
+ if(s->channel_mode > 1 && s->channel_mode & 1) {
+ s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix;
}
- if(ctx->channel_mode == AC3_CHMODE_2F1R || ctx->channel_mode == AC3_CHMODE_3F1R) {
- int nf = ctx->channel_mode - 2;
- ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf][1] = surround_mix_level * LEVEL_MINUS_3DB;
+ if(s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
+ int nf = s->channel_mode - 2;
+ s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
}
- if(ctx->channel_mode == AC3_CHMODE_2F2R || ctx->channel_mode == AC3_CHMODE_3F2R) {
- int nf = ctx->channel_mode - 4;
- ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf+1][1] = surround_mix_level;
+ if(s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
+ int nf = s->channel_mode - 4;
+ s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix;
}
- return 0;
+ /* calculate adjustment needed for each channel to avoid clipping */
+ s->downmix_coeff_adjust[0] = s->downmix_coeff_adjust[1] = 0.0f;
+ for(i=0; i<s->fbw_channels; i++) {
+ s->downmix_coeff_adjust[0] += s->downmix_coeffs[i][0];
+ s->downmix_coeff_adjust[1] += s->downmix_coeffs[i][1];
+ }
+ s->downmix_coeff_adjust[0] = 1.0f / s->downmix_coeff_adjust[0];
+ s->downmix_coeff_adjust[1] = 1.0f / s->downmix_coeff_adjust[1];
}
/**
* Decode the grouped exponents according to exponent strategy.
* reference: Section 7.1.3 Exponent Decoding
*/
-static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
+static void decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps,
uint8_t absexp, int8_t *dexps)
{
- int i, j, grp, grpsize;
+ int i, j, grp, group_size;
int dexp[256];
int expacc, prevexp;
/* unpack groups */
- grpsize = expstr + (expstr == EXP_D45);
+ group_size = exp_strategy + (exp_strategy == EXP_D45);
for(grp=0,i=0; grp<ngrps; grp++) {
- expacc = get_bits(gb, 7);
+ expacc = get_bits(gbc, 7);
dexp[i++] = exp_ungroup_tab[expacc][0];
dexp[i++] = exp_ungroup_tab[expacc][1];
dexp[i++] = exp_ungroup_tab[expacc][2];
prevexp = absexp;
for(i=0; i<ngrps*3; i++) {
prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
- for(j=0; j<grpsize; j++) {
- dexps[(i*grpsize)+j] = prevexp;
+ for(j=0; j<group_size; j++) {
+ dexps[(i*group_size)+j] = prevexp;
}
}
}
* range using the coupling coefficients and coupling coordinates.
* reference: Section 7.4.3 Coupling Coordinate Format
*/
-static void uncouple_channels(AC3DecodeContext *ctx)
+static void uncouple_channels(AC3DecodeContext *s)
{
int i, j, ch, bnd, subbnd;
subbnd = -1;
- i = ctx->startmant[CPL_CH];
- for(bnd=0; bnd<ctx->ncplbnd; bnd++) {
+ i = s->start_freq[CPL_CH];
+ for(bnd=0; bnd<s->num_cpl_bands; bnd++) {
do {
subbnd++;
for(j=0; j<12; j++) {
- for(ch=1; ch<=ctx->nfchans; ch++) {
- if(ctx->chincpl[ch])
- ctx->transform_coeffs[ch][i] = ctx->transform_coeffs[CPL_CH][i] * ctx->cplco[ch][bnd] * 8.0f;
+ for(ch=1; ch<=s->fbw_channels; ch++) {
+ if(s->channel_in_cpl[ch]) {
+ s->fixed_coeffs[ch][i] = ((int64_t)s->fixed_coeffs[CPL_CH][i] * (int64_t)s->cpl_coords[ch][bnd]) >> 23;
+ if (ch == 2 && s->phase_flags[bnd])
+ s->fixed_coeffs[ch][i] = -s->fixed_coeffs[ch][i];
+ }
}
i++;
}
- } while(ctx->cplbndstrc[subbnd]);
+ } while(s->cpl_band_struct[subbnd]);
}
}
* Grouped mantissas for 3-level 5-level and 11-level quantization
*/
typedef struct {
- float b1_mant[3];
- float b2_mant[3];
- float b4_mant[2];
+ int b1_mant[3];
+ int b2_mant[3];
+ int b4_mant[2];
int b1ptr;
int b2ptr;
int b4ptr;
* Get the transform coefficients for a particular channel
* reference: Section 7.3 Quantization and Decoding of Mantissas
*/
-static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
+static int get_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
{
- GetBitContext *gb = &ctx->gb;
+ GetBitContext *gbc = &s->gbc;
int i, gcode, tbap, start, end;
uint8_t *exps;
uint8_t *bap;
- float *coeffs;
+ int *coeffs;
- exps = ctx->dexps[ch_index];
- bap = ctx->bap[ch_index];
- coeffs = ctx->transform_coeffs[ch_index];
- start = ctx->startmant[ch_index];
- end = ctx->endmant[ch_index];
+ exps = s->dexps[ch_index];
+ bap = s->bap[ch_index];
+ coeffs = s->fixed_coeffs[ch_index];
+ start = s->start_freq[ch_index];
+ end = s->end_freq[ch_index];
for (i = start; i < end; i++) {
tbap = bap[i];
switch (tbap) {
case 0:
- coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) / 65535.0f) - 0.5f;
+ coeffs[i] = (av_random(&s->dith_state) & 0x7FFFFF) - 4194304;
break;
case 1:
if(m->b1ptr > 2) {
- gcode = get_bits(gb, 5);
+ gcode = get_bits(gbc, 5);
m->b1_mant[0] = b1_mantissas[gcode][0];
m->b1_mant[1] = b1_mantissas[gcode][1];
m->b1_mant[2] = b1_mantissas[gcode][2];
case 2:
if(m->b2ptr > 2) {
- gcode = get_bits(gb, 7);
+ gcode = get_bits(gbc, 7);
m->b2_mant[0] = b2_mantissas[gcode][0];
m->b2_mant[1] = b2_mantissas[gcode][1];
m->b2_mant[2] = b2_mantissas[gcode][2];
break;
case 3:
- coeffs[i] = b3_mantissas[get_bits(gb, 3)];
+ coeffs[i] = b3_mantissas[get_bits(gbc, 3)];
break;
case 4:
if(m->b4ptr > 1) {
- gcode = get_bits(gb, 7);
+ gcode = get_bits(gbc, 7);
m->b4_mant[0] = b4_mantissas[gcode][0];
m->b4_mant[1] = b4_mantissas[gcode][1];
m->b4ptr = 0;
break;
case 5:
- coeffs[i] = b5_mantissas[get_bits(gb, 4)];
+ coeffs[i] = b5_mantissas[get_bits(gbc, 4)];
break;
- default:
+ default: {
/* asymmetric dequantization */
- coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
+ int qlevel = quantization_tab[tbap];
+ coeffs[i] = get_sbits(gbc, qlevel) << (24 - qlevel);
break;
+ }
}
- coeffs[i] *= scale_factors[exps[i]];
+ coeffs[i] >>= exps[i];
}
return 0;
* Remove random dithering from coefficients with zero-bit mantissas
* reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
*/
-static void remove_dithering(AC3DecodeContext *ctx) {
+static void remove_dithering(AC3DecodeContext *s) {
int ch, i;
int end=0;
- float *coeffs;
+ int *coeffs;
uint8_t *bap;
- for(ch=1; ch<=ctx->nfchans; ch++) {
- if(!ctx->dithflag[ch]) {
- coeffs = ctx->transform_coeffs[ch];
- bap = ctx->bap[ch];
- if(ctx->chincpl[ch])
- end = ctx->startmant[CPL_CH];
+ for(ch=1; ch<=s->fbw_channels; ch++) {
+ if(!s->dither_flag[ch]) {
+ coeffs = s->fixed_coeffs[ch];
+ bap = s->bap[ch];
+ if(s->channel_in_cpl[ch])
+ end = s->start_freq[CPL_CH];
else
- end = ctx->endmant[ch];
+ end = s->end_freq[ch];
for(i=0; i<end; i++) {
- if(bap[i] == 0)
- coeffs[i] = 0.0f;
+ if(!bap[i])
+ coeffs[i] = 0;
}
- if(ctx->chincpl[ch]) {
- bap = ctx->bap[CPL_CH];
- for(; i<ctx->endmant[CPL_CH]; i++) {
- if(bap[i] == 0)
- coeffs[i] = 0.0f;
+ if(s->channel_in_cpl[ch]) {
+ bap = s->bap[CPL_CH];
+ for(; i<s->end_freq[CPL_CH]; i++) {
+ if(!bap[i])
+ coeffs[i] = 0;
}
}
}
/**
* Get the transform coefficients.
*/
-static int get_transform_coeffs(AC3DecodeContext * ctx)
+static int get_transform_coeffs(AC3DecodeContext *s)
{
int ch, end;
int got_cplchan = 0;
m.b1ptr = m.b2ptr = m.b4ptr = 3;
- for (ch = 1; ch <= ctx->nchans; ch++) {
+ for (ch = 1; ch <= s->channels; ch++) {
/* transform coefficients for full-bandwidth channel */
- if (get_transform_coeffs_ch(ctx, ch, &m))
+ if (get_transform_coeffs_ch(s, ch, &m))
return -1;
/* tranform coefficients for coupling channel come right after the
coefficients for the first coupled channel*/
- if (ctx->chincpl[ch]) {
+ if (s->channel_in_cpl[ch]) {
if (!got_cplchan) {
- if (get_transform_coeffs_ch(ctx, CPL_CH, &m)) {
- av_log(ctx->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
+ if (get_transform_coeffs_ch(s, CPL_CH, &m)) {
+ av_log(s->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
return -1;
}
- uncouple_channels(ctx);
+ uncouple_channels(s);
got_cplchan = 1;
}
- end = ctx->endmant[CPL_CH];
+ end = s->end_freq[CPL_CH];
} else {
- end = ctx->endmant[ch];
+ end = s->end_freq[ch];
}
do
- ctx->transform_coeffs[ch][end] = 0;
+ s->transform_coeffs[ch][end] = 0;
while(++end < 256);
}
/* if any channel doesn't use dithering, zero appropriate coefficients */
- if(!ctx->dither_all)
- remove_dithering(ctx);
+ if(!s->dither_all)
+ remove_dithering(s);
return 0;
}
* Stereo rematrixing.
* reference: Section 7.5.4 Rematrixing : Decoding Technique
*/
-static void do_rematrixing(AC3DecodeContext *ctx)
+static void do_rematrixing(AC3DecodeContext *s)
{
int bnd, i;
int end, bndend;
- float tmp0, tmp1;
+ int tmp0, tmp1;
- end = FFMIN(ctx->endmant[1], ctx->endmant[2]);
+ end = FFMIN(s->end_freq[1], s->end_freq[2]);
- for(bnd=0; bnd<ctx->nrematbnd; bnd++) {
- if(ctx->rematflg[bnd]) {
+ for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) {
+ if(s->rematrixing_flags[bnd]) {
bndend = FFMIN(end, rematrix_band_tab[bnd+1]);
for(i=rematrix_band_tab[bnd]; i<bndend; i++) {
- tmp0 = ctx->transform_coeffs[1][i];
- tmp1 = ctx->transform_coeffs[2][i];
- ctx->transform_coeffs[1][i] = tmp0 + tmp1;
- ctx->transform_coeffs[2][i] = tmp0 - tmp1;
+ tmp0 = s->fixed_coeffs[1][i];
+ tmp1 = s->fixed_coeffs[2][i];
+ s->fixed_coeffs[1][i] = tmp0 + tmp1;
+ s->fixed_coeffs[2][i] = tmp0 - tmp1;
}
}
}
/**
* Perform the 256-point IMDCT
*/
-static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
+static void do_imdct_256(AC3DecodeContext *s, int chindex)
{
int i, k;
DECLARE_ALIGNED_16(float, x[128]);
FFTComplex z[2][64];
- float *o_ptr = ctx->tmp_output;
+ float *o_ptr = s->tmp_output;
for(i=0; i<2; i++) {
/* de-interleave coefficients */
for(k=0; k<128; k++) {
- x[k] = ctx->transform_coeffs[chindex][2*k+i];
+ x[k] = s->transform_coeffs[chindex][2*k+i];
}
/* run standard IMDCT */
- ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct);
+ s->imdct_256.fft.imdct_calc(&s->imdct_256, o_ptr, x, s->tmp_imdct);
/* reverse the post-rotation & reordering from standard IMDCT */
for(k=0; k<32; k++) {
* Convert frequency domain coefficients to time-domain audio samples.
* reference: Section 7.9.4 Transformation Equations
*/
-static inline void do_imdct(AC3DecodeContext *ctx)
+static inline void do_imdct(AC3DecodeContext *s, int channels)
{
int ch;
- int nchans;
- /* Don't perform the IMDCT on the LFE channel unless it's used in the output */
- nchans = ctx->nfchans;
- if(ctx->output_mode & AC3_OUTPUT_LFEON)
- nchans++;
-
- for (ch=1; ch<=nchans; ch++) {
- if (ctx->blksw[ch]) {
- do_imdct_256(ctx, ch);
+ for (ch=1; ch<=channels; ch++) {
+ if (s->block_switch[ch]) {
+ do_imdct_256(s, ch);
} else {
- ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
- ctx->transform_coeffs[ch],
- ctx->tmp_imdct);
+ s->imdct_512.fft.imdct_calc(&s->imdct_512, s->tmp_output,
+ s->transform_coeffs[ch], s->tmp_imdct);
}
/* For the first half of the block, apply the window, add the delay
from the previous block, and send to output */
- ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output,
- ctx->window, ctx->delay[ch-1], 0, 256, 1);
+ s->dsp.vector_fmul_add_add(s->output[ch-1], s->tmp_output,
+ s->window, s->delay[ch-1], 0, 256, 1);
/* For the second half of the block, apply the window and store the
samples to delay, to be combined with the next block */
- ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256,
- ctx->window, 256);
+ s->dsp.vector_fmul_reverse(s->delay[ch-1], s->tmp_output+256,
+ s->window, 256);
}
}
/**
* Downmix the output to mono or stereo.
*/
-static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int nfchans,
- int output_mode, float coef[AC3_MAX_CHANNELS][2])
+static void ac3_downmix(AC3DecodeContext *s,
+ float samples[AC3_MAX_CHANNELS][256], int ch_offset)
{
int i, j;
- float v0, v1, s0, s1;
+ float v0, v1;
for(i=0; i<256; i++) {
- v0 = v1 = s0 = s1 = 0.0f;
- for(j=0; j<nfchans; j++) {
- v0 += samples[j][i] * coef[j][0];
- v1 += samples[j][i] * coef[j][1];
- s0 += coef[j][0];
- s1 += coef[j][1];
+ v0 = v1 = 0.0f;
+ for(j=0; j<s->fbw_channels; j++) {
+ v0 += samples[j+ch_offset][i] * s->downmix_coeffs[j][0];
+ v1 += samples[j+ch_offset][i] * s->downmix_coeffs[j][1];
}
- v0 /= s0;
- v1 /= s1;
- if(output_mode == AC3_CHMODE_MONO) {
- samples[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
- } else if(output_mode == AC3_CHMODE_STEREO) {
- samples[0][i] = v0;
- samples[1][i] = v1;
+ v0 *= s->downmix_coeff_adjust[0];
+ v1 *= s->downmix_coeff_adjust[1];
+ if(s->output_mode == AC3_CHMODE_MONO) {
+ samples[ch_offset][i] = (v0 + v1) * LEVEL_MINUS_3DB;
+ } else if(s->output_mode == AC3_CHMODE_STEREO) {
+ samples[ ch_offset][i] = v0;
+ samples[1+ch_offset][i] = v1;
}
}
}
+/**
+ * Upmix delay samples from stereo to original channel layout.
+ */
+static void ac3_upmix_delay(AC3DecodeContext *s)
+{
+ int channel_data_size = sizeof(s->delay[0]);
+ switch(s->channel_mode) {
+ case AC3_CHMODE_DUALMONO:
+ case AC3_CHMODE_STEREO:
+ /* upmix mono to stereo */
+ memcpy(s->delay[1], s->delay[0], channel_data_size);
+ break;
+ case AC3_CHMODE_2F2R:
+ memset(s->delay[3], 0, channel_data_size);
+ case AC3_CHMODE_2F1R:
+ memset(s->delay[2], 0, channel_data_size);
+ break;
+ case AC3_CHMODE_3F2R:
+ memset(s->delay[4], 0, channel_data_size);
+ case AC3_CHMODE_3F1R:
+ memset(s->delay[3], 0, channel_data_size);
+ case AC3_CHMODE_3F:
+ memcpy(s->delay[2], s->delay[1], channel_data_size);
+ memset(s->delay[1], 0, channel_data_size);
+ break;
+ }
+}
+
/**
* Parse an audio block from AC-3 bitstream.
*/
-static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
+static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
{
- int nfchans = ctx->nfchans;
- int channel_mode = ctx->channel_mode;
+ int fbw_channels = s->fbw_channels;
+ int channel_mode = s->channel_mode;
int i, bnd, seg, ch;
- GetBitContext *gb = &ctx->gb;
+ int different_transforms;
+ int downmix_output;
+ GetBitContext *gbc = &s->gbc;
uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
/* block switch flags */
- for (ch = 1; ch <= nfchans; ch++)
- ctx->blksw[ch] = get_bits1(gb);
+ different_transforms = 0;
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->block_switch[ch] = get_bits1(gbc);
+ if(ch > 1 && s->block_switch[ch] != s->block_switch[1])
+ different_transforms = 1;
+ }
/* dithering flags */
- ctx->dither_all = 1;
- for (ch = 1; ch <= nfchans; ch++) {
- ctx->dithflag[ch] = get_bits1(gb);
- if(!ctx->dithflag[ch])
- ctx->dither_all = 0;
+ s->dither_all = 1;
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->dither_flag[ch] = get_bits1(gbc);
+ if(!s->dither_flag[ch])
+ s->dither_all = 0;
}
/* dynamic range */
- i = !(ctx->channel_mode);
+ i = !(s->channel_mode);
do {
- if(get_bits1(gb)) {
- ctx->dynrng[i] = dynrng_tab[get_bits(gb, 8)];
+ if(get_bits1(gbc)) {
+ s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) *
+ s->avctx->drc_scale)+1.0;
} else if(blk == 0) {
- ctx->dynrng[i] = 1.0f;
+ s->dynamic_range[i] = 1.0f;
}
} while(i--);
/* coupling strategy */
- if (get_bits1(gb)) {
+ if (get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
- ctx->cplinu = get_bits1(gb);
- if (ctx->cplinu) {
+ s->cpl_in_use = get_bits1(gbc);
+ if (s->cpl_in_use) {
/* coupling in use */
- int cplbegf, cplendf;
+ int cpl_begin_freq, cpl_end_freq;
/* determine which channels are coupled */
- for (ch = 1; ch <= nfchans; ch++)
- ctx->chincpl[ch] = get_bits1(gb);
+ for (ch = 1; ch <= fbw_channels; ch++)
+ s->channel_in_cpl[ch] = get_bits1(gbc);
/* phase flags in use */
if (channel_mode == AC3_CHMODE_STEREO)
- ctx->phsflginu = get_bits1(gb);
+ s->phase_flags_in_use = get_bits1(gbc);
/* coupling frequency range and band structure */
- cplbegf = get_bits(gb, 4);
- cplendf = get_bits(gb, 4);
- if (3 + cplendf - cplbegf < 0) {
- av_log(ctx->avctx, AV_LOG_ERROR, "cplendf = %d < cplbegf = %d\n", cplendf, cplbegf);
+ cpl_begin_freq = get_bits(gbc, 4);
+ cpl_end_freq = get_bits(gbc, 4);
+ if (3 + cpl_end_freq - cpl_begin_freq < 0) {
+ av_log(s->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq);
return -1;
}
- ctx->ncplbnd = ctx->ncplsubnd = 3 + cplendf - cplbegf;
- ctx->startmant[CPL_CH] = cplbegf * 12 + 37;
- ctx->endmant[CPL_CH] = cplendf * 12 + 73;
- for (bnd = 0; bnd < ctx->ncplsubnd - 1; bnd++) {
- if (get_bits1(gb)) {
- ctx->cplbndstrc[bnd] = 1;
- ctx->ncplbnd--;
+ s->num_cpl_bands = s->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq;
+ s->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
+ s->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
+ for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) {
+ if (get_bits1(gbc)) {
+ s->cpl_band_struct[bnd] = 1;
+ s->num_cpl_bands--;
}
}
+ s->cpl_band_struct[s->num_cpl_subbands-1] = 0;
} else {
/* coupling not in use */
- for (ch = 1; ch <= nfchans; ch++)
- ctx->chincpl[ch] = 0;
+ for (ch = 1; ch <= fbw_channels; ch++)
+ s->channel_in_cpl[ch] = 0;
}
}
/* coupling coordinates */
- if (ctx->cplinu) {
- int cplcoe = 0;
-
- for (ch = 1; ch <= nfchans; ch++) {
- if (ctx->chincpl[ch]) {
- if (get_bits1(gb)) {
- int mstrcplco, cplcoexp, cplcomant;
- cplcoe = 1;
- mstrcplco = 3 * get_bits(gb, 2);
- for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
- cplcoexp = get_bits(gb, 4);
- cplcomant = get_bits(gb, 4);
- if (cplcoexp == 15)
- ctx->cplco[ch][bnd] = cplcomant / 16.0f;
+ if (s->cpl_in_use) {
+ int cpl_coords_exist = 0;
+
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ if (s->channel_in_cpl[ch]) {
+ if (get_bits1(gbc)) {
+ int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
+ cpl_coords_exist = 1;
+ master_cpl_coord = 3 * get_bits(gbc, 2);
+ for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+ cpl_coord_exp = get_bits(gbc, 4);
+ cpl_coord_mant = get_bits(gbc, 4);
+ if (cpl_coord_exp == 15)
+ s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
else
- ctx->cplco[ch][bnd] = (cplcomant + 16.0f) / 32.0f;
- ctx->cplco[ch][bnd] *= scale_factors[cplcoexp + mstrcplco];
+ s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
+ s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
}
}
}
}
/* phase flags */
- if (channel_mode == AC3_CHMODE_STEREO && ctx->phsflginu && cplcoe) {
- for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
- if (get_bits1(gb))
- ctx->cplco[2][bnd] = -ctx->cplco[2][bnd];
+ if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
+ for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+ s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
}
}
}
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
- ctx->rematstr = get_bits1(gb);
- if (ctx->rematstr) {
- ctx->nrematbnd = 4;
- if(ctx->cplinu && ctx->startmant[CPL_CH] <= 61)
- ctx->nrematbnd -= 1 + (ctx->startmant[CPL_CH] == 37);
- for(bnd=0; bnd<ctx->nrematbnd; bnd++)
- ctx->rematflg[bnd] = get_bits1(gb);
+ if (get_bits1(gbc)) {
+ s->num_rematrixing_bands = 4;
+ if(s->cpl_in_use && s->start_freq[CPL_CH] <= 61)
+ s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
+ for(bnd=0; bnd<s->num_rematrixing_bands; bnd++)
+ s->rematrixing_flags[bnd] = get_bits1(gbc);
}
}
/* exponent strategies for each channel */
- ctx->expstr[CPL_CH] = EXP_REUSE;
- ctx->expstr[ctx->lfe_ch] = EXP_REUSE;
- for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
- if(ch == ctx->lfe_ch)
- ctx->expstr[ch] = get_bits(gb, 1);
+ s->exp_strategy[CPL_CH] = EXP_REUSE;
+ s->exp_strategy[s->lfe_ch] = EXP_REUSE;
+ for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
+ if(ch == s->lfe_ch)
+ s->exp_strategy[ch] = get_bits(gbc, 1);
else
- ctx->expstr[ch] = get_bits(gb, 2);
- if(ctx->expstr[ch] != EXP_REUSE)
+ s->exp_strategy[ch] = get_bits(gbc, 2);
+ if(s->exp_strategy[ch] != EXP_REUSE)
bit_alloc_stages[ch] = 3;
}
/* channel bandwidth */
- for (ch = 1; ch <= nfchans; ch++) {
- ctx->startmant[ch] = 0;
- if (ctx->expstr[ch] != EXP_REUSE) {
- int prev = ctx->endmant[ch];
- if (ctx->chincpl[ch])
- ctx->endmant[ch] = ctx->startmant[CPL_CH];
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->start_freq[ch] = 0;
+ if (s->exp_strategy[ch] != EXP_REUSE) {
+ int prev = s->end_freq[ch];
+ if (s->channel_in_cpl[ch])
+ s->end_freq[ch] = s->start_freq[CPL_CH];
else {
- int chbwcod = get_bits(gb, 6);
- if (chbwcod > 60) {
- av_log(ctx->avctx, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
+ int bandwidth_code = get_bits(gbc, 6);
+ if (bandwidth_code > 60) {
+ av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code);
return -1;
}
- ctx->endmant[ch] = chbwcod * 3 + 73;
+ s->end_freq[ch] = bandwidth_code * 3 + 73;
}
- if(blk > 0 && ctx->endmant[ch] != prev)
+ if(blk > 0 && s->end_freq[ch] != prev)
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
}
- ctx->startmant[ctx->lfe_ch] = 0;
- ctx->endmant[ctx->lfe_ch] = 7;
+ s->start_freq[s->lfe_ch] = 0;
+ s->end_freq[s->lfe_ch] = 7;
/* decode exponents for each channel */
- for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
- if (ctx->expstr[ch] != EXP_REUSE) {
- int grpsize, ngrps;
- grpsize = 3 << (ctx->expstr[ch] - 1);
+ for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
+ if (s->exp_strategy[ch] != EXP_REUSE) {
+ int group_size, num_groups;
+ group_size = 3 << (s->exp_strategy[ch] - 1);
if(ch == CPL_CH)
- ngrps = (ctx->endmant[ch] - ctx->startmant[ch]) / grpsize;
- else if(ch == ctx->lfe_ch)
- ngrps = 2;
+ num_groups = (s->end_freq[ch] - s->start_freq[ch]) / group_size;
+ else if(ch == s->lfe_ch)
+ num_groups = 2;
else
- ngrps = (ctx->endmant[ch] + grpsize - 4) / grpsize;
- ctx->dexps[ch][0] = get_bits(gb, 4) << !ch;
- decode_exponents(gb, ctx->expstr[ch], ngrps, ctx->dexps[ch][0],
- &ctx->dexps[ch][ctx->startmant[ch]+!!ch]);
- if(ch != CPL_CH && ch != ctx->lfe_ch)
- skip_bits(gb, 2); /* skip gainrng */
+ num_groups = (s->end_freq[ch] + group_size - 4) / group_size;
+ s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
+ decode_exponents(gbc, s->exp_strategy[ch], num_groups, s->dexps[ch][0],
+ &s->dexps[ch][s->start_freq[ch]+!!ch]);
+ if(ch != CPL_CH && ch != s->lfe_ch)
+ skip_bits(gbc, 2); /* skip gainrng */
}
}
/* bit allocation information */
- if (get_bits1(gb)) {
- ctx->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gb, 2)] >> ctx->bit_alloc_params.sr_shift;
- ctx->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gb, 2)] >> ctx->bit_alloc_params.sr_shift;
- ctx->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gb, 2)];
- ctx->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gb, 2)];
- ctx->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gb, 3)];
- for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
+ if (get_bits1(gbc)) {
+ s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
+ s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
+ s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
+ for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
}
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
- if (get_bits1(gb)) {
+ if (get_bits1(gbc)) {
int csnr;
- csnr = (get_bits(gb, 6) - 15) << 4;
- for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) { /* snr offset and fast gain */
- ctx->snr_offset[ch] = (csnr + get_bits(gb, 4)) << 2;
- ctx->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gb, 3)];
+ csnr = (get_bits(gbc, 6) - 15) << 4;
+ for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
+ s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
+ s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
}
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
/* coupling leak information */
- if (ctx->cplinu && get_bits1(gb)) {
- ctx->bit_alloc_params.cpl_fast_leak = get_bits(gb, 3);
- ctx->bit_alloc_params.cpl_slow_leak = get_bits(gb, 3);
+ if (s->cpl_in_use && get_bits1(gbc)) {
+ s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
+ s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
}
/* delta bit allocation information */
- if (get_bits1(gb)) {
+ if (get_bits1(gbc)) {
/* delta bit allocation exists (strategy) */
- for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
- ctx->dba_mode[ch] = get_bits(gb, 2);
- if (ctx->dba_mode[ch] == DBA_RESERVED) {
- av_log(ctx->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
+ for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
+ s->dba_mode[ch] = get_bits(gbc, 2);
+ if (s->dba_mode[ch] == DBA_RESERVED) {
+ av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
return -1;
}
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
/* channel delta offset, len and bit allocation */
- for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
- if (ctx->dba_mode[ch] == DBA_NEW) {
- ctx->dba_nsegs[ch] = get_bits(gb, 3);
- for (seg = 0; seg <= ctx->dba_nsegs[ch]; seg++) {
- ctx->dba_offsets[ch][seg] = get_bits(gb, 5);
- ctx->dba_lengths[ch][seg] = get_bits(gb, 4);
- ctx->dba_values[ch][seg] = get_bits(gb, 3);
+ for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
+ if (s->dba_mode[ch] == DBA_NEW) {
+ s->dba_nsegs[ch] = get_bits(gbc, 3);
+ for (seg = 0; seg <= s->dba_nsegs[ch]; seg++) {
+ s->dba_offsets[ch][seg] = get_bits(gbc, 5);
+ s->dba_lengths[ch][seg] = get_bits(gbc, 4);
+ s->dba_values[ch][seg] = get_bits(gbc, 3);
}
}
}
} else if(blk == 0) {
- for(ch=0; ch<=ctx->nchans; ch++) {
- ctx->dba_mode[ch] = DBA_NONE;
+ for(ch=0; ch<=s->channels; ch++) {
+ s->dba_mode[ch] = DBA_NONE;
}
}
/* Bit allocation */
- for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
+ for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
if(bit_alloc_stages[ch] > 2) {
/* Exponent mapping into PSD and PSD integration */
- ff_ac3_bit_alloc_calc_psd(ctx->dexps[ch],
- ctx->startmant[ch], ctx->endmant[ch],
- ctx->psd[ch], ctx->band_psd[ch]);
+ ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
+ s->start_freq[ch], s->end_freq[ch],
+ s->psd[ch], s->band_psd[ch]);
}
if(bit_alloc_stages[ch] > 1) {
/* Compute excitation function, Compute masking curve, and
Apply delta bit allocation */
- ff_ac3_bit_alloc_calc_mask(&ctx->bit_alloc_params, ctx->band_psd[ch],
- ctx->startmant[ch], ctx->endmant[ch],
- ctx->fast_gain[ch], (ch == ctx->lfe_ch),
- ctx->dba_mode[ch], ctx->dba_nsegs[ch],
- ctx->dba_offsets[ch], ctx->dba_lengths[ch],
- ctx->dba_values[ch], ctx->mask[ch]);
+ ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
+ s->start_freq[ch], s->end_freq[ch],
+ s->fast_gain[ch], (ch == s->lfe_ch),
+ s->dba_mode[ch], s->dba_nsegs[ch],
+ s->dba_offsets[ch], s->dba_lengths[ch],
+ s->dba_values[ch], s->mask[ch]);
}
if(bit_alloc_stages[ch] > 0) {
/* Compute bit allocation */
- ff_ac3_bit_alloc_calc_bap(ctx->mask[ch], ctx->psd[ch],
- ctx->startmant[ch], ctx->endmant[ch],
- ctx->snr_offset[ch],
- ctx->bit_alloc_params.floor,
- ctx->bap[ch]);
+ ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
+ s->start_freq[ch], s->end_freq[ch],
+ s->snr_offset[ch],
+ s->bit_alloc_params.floor,
+ s->bap[ch]);
}
}
/* unused dummy data */
- if (get_bits1(gb)) {
- int skipl = get_bits(gb, 9);
+ if (get_bits1(gbc)) {
+ int skipl = get_bits(gbc, 9);
while(skipl--)
- skip_bits(gb, 8);
+ skip_bits(gbc, 8);
}
/* unpack the transform coefficients
this also uncouples channels if coupling is in use. */
- if (get_transform_coeffs(ctx)) {
- av_log(ctx->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
+ if (get_transform_coeffs(s)) {
+ av_log(s->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
return -1;
}
/* recover coefficients if rematrixing is in use */
- if(ctx->channel_mode == AC3_CHMODE_STEREO)
- do_rematrixing(ctx);
-
- /* apply scaling to coefficients (headroom, dialnorm, dynrng) */
- for(ch=1; ch<=ctx->nchans; ch++) {
- float gain = 2.0f * ctx->mul_bias;
- if(ctx->channel_mode == AC3_CHMODE_DUALMONO) {
- gain *= ctx->dialnorm[ch-1] * ctx->dynrng[ch-1];
+ if(s->channel_mode == AC3_CHMODE_STEREO)
+ do_rematrixing(s);
+
+ /* apply scaling to coefficients (headroom, dynrng) */
+ for(ch=1; ch<=s->channels; ch++) {
+ float gain = s->mul_bias / 4194304.0f;
+ if(s->channel_mode == AC3_CHMODE_DUALMONO) {
+ gain *= s->dynamic_range[ch-1];
} else {
- gain *= ctx->dialnorm[0] * ctx->dynrng[0];
+ gain *= s->dynamic_range[0];
}
- for(i=0; i<ctx->endmant[ch]; i++) {
- ctx->transform_coeffs[ch][i] *= gain;
+ for(i=0; i<256; i++) {
+ s->transform_coeffs[ch][i] = s->fixed_coeffs[ch][i] * gain;
}
}
- do_imdct(ctx);
+ /* 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. */
+ downmix_output = s->channels != s->out_channels &&
+ !((s->output_mode & AC3_OUTPUT_LFEON) &&
+ s->fbw_channels == s->out_channels);
+ if(different_transforms) {
+ /* the delay samples have already been downmixed, so we upmix the delay
+ samples in order to reconstruct all channels before downmixing. */
+ if(s->downmixed) {
+ s->downmixed = 0;
+ ac3_upmix_delay(s);
+ }
+
+ do_imdct(s, s->channels);
+
+ if(downmix_output) {
+ ac3_downmix(s, s->output, 0);
+ }
+ } else {
+ if(downmix_output) {
+ ac3_downmix(s, s->transform_coeffs, 1);
+ }
- /* downmix output if needed */
- if(ctx->nchans != ctx->out_channels && !((ctx->output_mode & AC3_OUTPUT_LFEON) &&
- ctx->nfchans == ctx->out_channels)) {
- ac3_downmix(ctx->output, ctx->nfchans, ctx->output_mode,
- ctx->downmix_coeffs);
+ if(!s->downmixed) {
+ s->downmixed = 1;
+ ac3_downmix(s, s->delay, 0);
+ }
+
+ do_imdct(s, s->out_channels);
}
/* convert float to 16-bit integer */
- for(ch=0; ch<ctx->out_channels; ch++) {
+ for(ch=0; ch<s->out_channels; ch++) {
for(i=0; i<256; i++) {
- ctx->output[ch][i] += ctx->add_bias;
+ s->output[ch][i] += s->add_bias;
}
- ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256);
+ s->dsp.float_to_int16(s->int_output[ch], s->output[ch], 256);
}
return 0;
/**
* Decode a single AC-3 frame.
*/
-static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
+static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
+ const uint8_t *buf, int buf_size)
{
- AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
+ AC3DecodeContext *s = avctx->priv_data;
int16_t *out_samples = (int16_t *)data;
int i, blk, ch, err;
/* initialize the GetBitContext with the start of valid AC-3 Frame */
- init_get_bits(&ctx->gb, buf, buf_size * 8);
+ init_get_bits(&s->gbc, buf, buf_size * 8);
/* parse the syncinfo */
- err = ac3_parse_header(ctx);
+ err = ac3_parse_header(s);
if(err) {
switch(err) {
case AC3_PARSE_ERROR_SYNC:
return -1;
}
- avctx->sample_rate = ctx->sampling_rate;
- avctx->bit_rate = ctx->bit_rate;
-
/* check that reported frame size fits in input buffer */
- if(ctx->frame_size > buf_size) {
+ if(s->frame_size > buf_size) {
av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
return -1;
}
+ /* check for crc mismatch */
+ if(avctx->error_resilience >= FF_ER_CAREFUL) {
+ if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) {
+ av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
+ return -1;
+ }
+ /* TODO: error concealment */
+ }
+
+ avctx->sample_rate = s->sample_rate;
+ avctx->bit_rate = s->bit_rate;
+
/* channel config */
- ctx->out_channels = ctx->nchans;
- if (avctx->channels == 0) {
- avctx->channels = ctx->out_channels;
- } else if(ctx->out_channels < avctx->channels) {
- av_log(avctx, AV_LOG_ERROR, "Cannot upmix AC3 from %d to %d channels.\n",
- ctx->out_channels, avctx->channels);
- return -1;
+ s->out_channels = s->channels;
+ if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
+ avctx->request_channels < s->channels) {
+ s->out_channels = avctx->request_channels;
+ s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
}
- if(avctx->channels == 2) {
- ctx->output_mode = AC3_CHMODE_STEREO;
- } else if(avctx->channels == 1) {
- ctx->output_mode = AC3_CHMODE_MONO;
- } else if(avctx->channels != ctx->out_channels) {
- av_log(avctx, AV_LOG_ERROR, "Cannot downmix AC3 from %d to %d channels.\n",
- ctx->out_channels, avctx->channels);
- return -1;
+ avctx->channels = s->out_channels;
+
+ /* set downmixing coefficients if needed */
+ if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
+ s->fbw_channels == s->out_channels)) {
+ set_downmix_coeffs(s);
}
- ctx->out_channels = avctx->channels;
/* parse the audio blocks */
for (blk = 0; blk < NB_BLOCKS; blk++) {
- if (ac3_parse_audio_block(ctx, blk)) {
+ if (ac3_parse_audio_block(s, blk)) {
av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
*data_size = 0;
- return ctx->frame_size;
+ return s->frame_size;
}
for (i = 0; i < 256; i++)
- for (ch = 0; ch < ctx->out_channels; ch++)
- *(out_samples++) = ctx->int_output[ch][i];
+ for (ch = 0; ch < s->out_channels; ch++)
+ *(out_samples++) = s->int_output[ch][i];
}
*data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
- return ctx->frame_size;
+ return s->frame_size;
}
/**
* Uninitialize the AC-3 decoder.
*/
-static int ac3_decode_end(AVCodecContext *avctx)
+static av_cold int ac3_decode_end(AVCodecContext *avctx)
{
- AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
- ff_mdct_end(&ctx->imdct_512);
- ff_mdct_end(&ctx->imdct_256);
+ AC3DecodeContext *s = avctx->priv_data;
+ ff_mdct_end(&s->imdct_512);
+ ff_mdct_end(&s->imdct_256);
return 0;
}
projects / ffmpeg / blobdiff