/*
* The simplest AC-3 encoder
* Copyright (c) 2000 Fabrice Bellard
+ * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
+ * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
*
* This file is part of FFmpeg.
*
#include "libavutil/crc.h"
#include "avcodec.h"
#include "put_bits.h"
+#include "dsputil.h"
#include "ac3.h"
#include "audioconvert.h"
-#define MDCT_NBITS 9
-#define MDCT_SAMPLES (1 << MDCT_NBITS)
-
/** Maximum number of exponent groups. +1 for separate DC exponent. */
#define AC3_MAX_EXP_GROUPS 85
/** Scale a float value by 2^bits and convert to an integer. */
#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
-/** Scale a float value by 2^15, convert to an integer, and clip to int16_t range. */
-#define FIX15(a) av_clip_int16(SCALE_FLOAT(a, 15))
+typedef int16_t SampleType;
+typedef int32_t CoefType;
+
+#define SCALE_COEF(a) (a)
+
+/** Scale a float value by 2^15, convert to an integer, and clip to range -32767..32767. */
+#define FIX15(a) av_clip(SCALE_FLOAT(a, 15), -32767, 32767)
/**
int16_t re,im;
} IComplex;
+typedef struct AC3MDCTContext {
+ const int16_t *window; ///< MDCT window function
+ int nbits; ///< log2(transform size)
+ int16_t *costab; ///< FFT cos table
+ int16_t *sintab; ///< FFT sin table
+ int16_t *xcos1; ///< MDCT cos table
+ int16_t *xsin1; ///< MDCT sin table
+ int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
+ IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
+} AC3MDCTContext;
+
+/**
+ * Data for a single audio block.
+ */
+typedef struct AC3Block {
+ uint8_t **bap; ///< bit allocation pointers (bap)
+ CoefType **mdct_coef; ///< MDCT coefficients
+ uint8_t **exp; ///< original exponents
+ uint8_t **grouped_exp; ///< grouped exponents
+ int16_t **psd; ///< psd per frequency bin
+ int16_t **band_psd; ///< psd per critical band
+ int16_t **mask; ///< masking curve
+ uint16_t **qmant; ///< quantized mantissas
+ uint8_t exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
+ int8_t exp_shift[AC3_MAX_CHANNELS]; ///< exponent shift values
+} AC3Block;
+
/**
* AC-3 encoder private context.
*/
typedef struct AC3EncodeContext {
PutBitContext pb; ///< bitstream writer context
+ DSPContext dsp;
+ AC3MDCTContext mdct; ///< MDCT context
+
+ AC3Block blocks[AC3_MAX_BLOCKS]; ///< per-block info
int bitstream_id; ///< bitstream id (bsid)
int bitstream_mode; ///< bitstream mode (bsmod)
int frame_size_min; ///< minimum frame size in case rounding is necessary
int frame_size; ///< current frame size in bytes
int frame_size_code; ///< frame size code (frmsizecod)
+ uint16_t crc_inv[2];
int bits_written; ///< bit count (used to avg. bitrate)
int samples_written; ///< sample count (used to avg. bitrate)
int channel_mode; ///< channel mode (acmod)
const uint8_t *channel_map; ///< channel map used to reorder channels
+ int cutoff; ///< user-specified cutoff frequency, in Hz
int bandwidth_code[AC3_MAX_CHANNELS]; ///< bandwidth code (0 to 60) (chbwcod)
int nb_coefs[AC3_MAX_CHANNELS];
int coarse_snr_offset; ///< coarse SNR offsets (csnroffst)
int fast_gain_code[AC3_MAX_CHANNELS]; ///< fast gain codes (signal-to-mask ratio) (fgaincod)
int fine_snr_offset[AC3_MAX_CHANNELS]; ///< fine SNR offsets (fsnroffst)
+ int frame_bits_fixed; ///< number of non-coefficient bits for fixed parameters
int frame_bits; ///< all frame bits except exponents and mantissas
int exponent_bits; ///< number of bits used for exponents
int mant1_cnt, mant2_cnt, mant4_cnt; ///< mantissa counts for bap=1,2,4
uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
- int16_t last_samples[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE]; ///< last 256 samples from previous frame
+ int16_t **planar_samples;
+ uint8_t *bap_buffer;
+ uint8_t *bap1_buffer;
+ CoefType *mdct_coef_buffer;
+ uint8_t *exp_buffer;
+ uint8_t *grouped_exp_buffer;
+ int16_t *psd_buffer;
+ int16_t *band_psd_buffer;
+ int16_t *mask_buffer;
+ uint16_t *qmant_buffer;
+
+ DECLARE_ALIGNED(16, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
} AC3EncodeContext;
-/** MDCT and FFT tables */
-static int16_t costab[64];
-static int16_t sintab[64];
-static int16_t xcos1[128];
-static int16_t xsin1[128];
+/**
+ * LUT for number of exponent groups.
+ * exponent_group_tab[exponent strategy-1][number of coefficients]
+ */
+static uint8_t exponent_group_tab[3][256];
+
+
+/**
+ * List of supported channel layouts.
+ */
+static const int64_t ac3_channel_layouts[] = {
+ AV_CH_LAYOUT_MONO,
+ AV_CH_LAYOUT_STEREO,
+ AV_CH_LAYOUT_2_1,
+ AV_CH_LAYOUT_SURROUND,
+ AV_CH_LAYOUT_2_2,
+ AV_CH_LAYOUT_QUAD,
+ AV_CH_LAYOUT_4POINT0,
+ AV_CH_LAYOUT_5POINT0,
+ AV_CH_LAYOUT_5POINT0_BACK,
+ (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
+ (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
+ AV_CH_LAYOUT_5POINT1,
+ AV_CH_LAYOUT_5POINT1_BACK,
+ 0
+};
/**
s->bits_written -= s->bit_rate;
s->samples_written -= s->sample_rate;
}
- s->frame_size = s->frame_size_min + 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
+ s->frame_size = s->frame_size_min +
+ 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
s->bits_written += s->frame_size * 8;
s->samples_written += AC3_FRAME_SIZE;
}
* Channels are reordered from FFmpeg's default order to AC-3 order.
*/
static void deinterleave_input_samples(AC3EncodeContext *s,
- const int16_t *samples,
- int16_t planar_samples[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE+AC3_FRAME_SIZE])
+ const SampleType *samples)
{
int ch, i;
/* deinterleave and remap input samples */
for (ch = 0; ch < s->channels; ch++) {
- const int16_t *sptr;
+ const SampleType *sptr;
int sinc;
/* copy last 256 samples of previous frame to the start of the current frame */
- memcpy(&planar_samples[ch][0], s->last_samples[ch],
- AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
+ memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
+ AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
/* deinterleave */
sinc = s->channels;
sptr = samples + s->channel_map[ch];
for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
- planar_samples[ch][i] = *sptr;
+ s->planar_samples[ch][i] = *sptr;
sptr += sinc;
}
-
- /* save last 256 samples for next frame */
- memcpy(s->last_samples[ch], &planar_samples[ch][6* AC3_BLOCK_SIZE],
- AC3_BLOCK_SIZE * sizeof(planar_samples[0][0]));
}
}
+/**
+ * Finalize MDCT and free allocated memory.
+ */
+static av_cold void mdct_end(AC3MDCTContext *mdct)
+{
+ mdct->nbits = 0;
+ av_freep(&mdct->costab);
+ av_freep(&mdct->sintab);
+ av_freep(&mdct->xcos1);
+ av_freep(&mdct->xsin1);
+ av_freep(&mdct->rot_tmp);
+ av_freep(&mdct->cplx_tmp);
+}
+
+
/**
* Initialize FFT tables.
* @param ln log2(FFT size)
*/
-static av_cold void fft_init(int ln)
+static av_cold int fft_init(AVCodecContext *avctx, AC3MDCTContext *mdct, int ln)
{
int i, n, n2;
float alpha;
n = 1 << ln;
n2 = n >> 1;
+ FF_ALLOC_OR_GOTO(avctx, mdct->costab, n2 * sizeof(*mdct->costab), fft_alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, mdct->sintab, n2 * sizeof(*mdct->sintab), fft_alloc_fail);
+
for (i = 0; i < n2; i++) {
alpha = 2.0 * M_PI * i / n;
- costab[i] = FIX15(cos(alpha));
- sintab[i] = FIX15(sin(alpha));
+ mdct->costab[i] = FIX15(cos(alpha));
+ mdct->sintab[i] = FIX15(sin(alpha));
}
+
+ return 0;
+fft_alloc_fail:
+ mdct_end(mdct);
+ return AVERROR(ENOMEM);
}
* Initialize MDCT tables.
* @param nbits log2(MDCT size)
*/
-static av_cold void mdct_init(int nbits)
+static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
+ int nbits)
{
- int i, n, n4;
+ int i, n, n4, ret;
n = 1 << nbits;
n4 = n >> 2;
- fft_init(nbits - 2);
+ mdct->nbits = nbits;
+
+ ret = fft_init(avctx, mdct, nbits - 2);
+ if (ret)
+ return ret;
+
+ mdct->window = ff_ac3_window;
+
+ FF_ALLOC_OR_GOTO(avctx, mdct->xcos1, n4 * sizeof(*mdct->xcos1), mdct_alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, mdct->xsin1, n4 * sizeof(*mdct->xsin1), mdct_alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp), mdct_alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp), mdct_alloc_fail);
for (i = 0; i < n4; i++) {
float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
- xcos1[i] = FIX15(-cos(alpha));
- xsin1[i] = FIX15(-sin(alpha));
+ mdct->xcos1[i] = FIX15(-cos(alpha));
+ mdct->xsin1[i] = FIX15(-sin(alpha));
}
+
+ return 0;
+mdct_alloc_fail:
+ mdct_end(mdct);
+ return AVERROR(ENOMEM);
}
* @param z complex input/output samples
* @param ln log2(FFT size)
*/
-static void fft(IComplex *z, int ln)
+static void fft(AC3MDCTContext *mdct, IComplex *z, int ln)
{
int j, l, np, np2;
int nblocks, nloops;
p++;
q++;
for(l = nblocks; l < np2; l += nblocks) {
- CMUL(tmp_re, tmp_im, costab[l], -sintab[l], q->re, q->im);
+ CMUL(tmp_re, tmp_im, mdct->costab[l], -mdct->sintab[l], q->re, q->im);
BF(p->re, p->im, q->re, q->im,
p->re, p->im, tmp_re, tmp_im);
p++;
* @param out 256 output frequency coefficients
* @param in 512 windowed input audio samples
*/
-static void mdct512(int32_t *out, int16_t *in)
+static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
{
- int i, re, im, re1, im1;
- int16_t rot[MDCT_SAMPLES];
- IComplex x[MDCT_SAMPLES/4];
+ int i, re, im, n, n2, n4;
+ int16_t *rot = mdct->rot_tmp;
+ IComplex *x = mdct->cplx_tmp;
+
+ n = 1 << mdct->nbits;
+ n2 = n >> 1;
+ n4 = n >> 2;
/* shift to simplify computations */
- for (i = 0; i < MDCT_SAMPLES/4; i++)
- rot[i] = -in[i + 3*MDCT_SAMPLES/4];
- for (;i < MDCT_SAMPLES; i++)
- rot[i] = in[i - MDCT_SAMPLES/4];
+ for (i = 0; i <n4; i++)
+ rot[i] = -in[i + 3*n4];
+ memcpy(&rot[n4], &in[0], 3*n4*sizeof(*in));
/* pre rotation */
- for (i = 0; i < MDCT_SAMPLES/4; i++) {
- re = ((int)rot[ 2*i] - (int)rot[MDCT_SAMPLES -1-2*i]) >> 1;
- im = -((int)rot[MDCT_SAMPLES/2+2*i] - (int)rot[MDCT_SAMPLES/2-1-2*i]) >> 1;
- CMUL(x[i].re, x[i].im, re, im, -xcos1[i], xsin1[i]);
+ for (i = 0; i < n4; i++) {
+ re = ((int)rot[ 2*i] - (int)rot[ n-1-2*i]) >> 1;
+ im = -((int)rot[n2+2*i] - (int)rot[n2-1-2*i]) >> 1;
+ CMUL(x[i].re, x[i].im, re, im, -mdct->xcos1[i], mdct->xsin1[i]);
}
- fft(x, MDCT_NBITS - 2);
+ fft(mdct, x, mdct->nbits - 2);
/* post rotation */
- for (i = 0; i < MDCT_SAMPLES/4; i++) {
+ for (i = 0; i < n4; i++) {
re = x[i].re;
im = x[i].im;
- CMUL(re1, im1, re, im, xsin1[i], xcos1[i]);
- out[ 2*i] = im1;
- out[MDCT_SAMPLES/2-1-2*i] = re1;
+ CMUL(out[n2-1-2*i], out[2*i], re, im, mdct->xsin1[i], mdct->xcos1[i]);
}
}
int i;
if (lshift > 0) {
- for(i = 0; i < n; i++)
+ for (i = 0; i < n; i++)
tab[i] <<= lshift;
} else if (lshift < 0) {
lshift = -lshift;
*
* @return exponent shift
*/
-static int normalize_samples(AC3EncodeContext *s,
- int16_t windowed_samples[AC3_WINDOW_SIZE])
+static int normalize_samples(AC3EncodeContext *s)
{
- int v = 14 - log2_tab(windowed_samples, AC3_WINDOW_SIZE);
+ int v = 14 - log2_tab(s->windowed_samples, AC3_WINDOW_SIZE);
v = FFMAX(0, v);
- lshift_tab(windowed_samples, AC3_WINDOW_SIZE, v);
+ lshift_tab(s->windowed_samples, AC3_WINDOW_SIZE, v);
return v - 9;
}
* This applies the KBD window and normalizes the input to reduce precision
* loss due to fixed-point calculations.
*/
-static void apply_mdct(AC3EncodeContext *s,
- int16_t planar_samples[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE+AC3_FRAME_SIZE],
- int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void apply_mdct(AC3EncodeContext *s)
{
int blk, ch;
- int16_t windowed_samples[AC3_WINDOW_SIZE];
for (ch = 0; ch < s->channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- const int16_t *input_samples = &planar_samples[ch][blk * AC3_BLOCK_SIZE];
+ AC3Block *block = &s->blocks[blk];
+ const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
- apply_window(windowed_samples, input_samples, ff_ac3_window, AC3_WINDOW_SIZE);
+ apply_window(s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
- exp_shift[blk][ch] = normalize_samples(s, windowed_samples);
+ block->exp_shift[ch] = normalize_samples(s);
- mdct512(mdct_coef[blk][ch], windowed_samples);
+ mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
}
}
}
+/**
+ * Initialize exponent tables.
+ */
+static av_cold void exponent_init(AC3EncodeContext *s)
+{
+ int i;
+ for (i = 73; i < 256; i++) {
+ exponent_group_tab[0][i] = (i - 1) / 3;
+ exponent_group_tab[1][i] = (i + 2) / 6;
+ exponent_group_tab[2][i] = (i + 8) / 12;
+ }
+ /* LFE */
+ exponent_group_tab[0][7] = 2;
+}
+
+
/**
* Extract exponents from the MDCT coefficients.
* This takes into account the normalization that was done to the input samples
* by adjusting the exponents by the exponent shift values.
*/
-static void extract_exponents(AC3EncodeContext *s,
- int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void extract_exponents(AC3EncodeContext *s)
{
int blk, ch, i;
- /* extract exponents */
for (ch = 0; ch < s->channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- /* compute "exponents". We take into account the normalization there */
+ AC3Block *block = &s->blocks[blk];
for (i = 0; i < AC3_MAX_COEFS; i++) {
int e;
- int v = abs(mdct_coef[blk][ch][i]);
+ int v = abs(SCALE_COEF(block->mdct_coef[ch][i]));
if (v == 0)
e = 24;
else {
- e = 23 - av_log2(v) + exp_shift[blk][ch];
+ e = 23 - av_log2(v) + block->exp_shift[ch];
if (e >= 24) {
e = 24;
- mdct_coef[blk][ch][i] = 0;
+ block->mdct_coef[ch][i] = 0;
}
}
- exp[blk][ch][i] = e;
+ block->exp[ch][i] = e;
}
}
}
}
-/**
- * Calculate the sum of absolute differences (SAD) between 2 sets of exponents.
- */
-static int calc_exp_diff(uint8_t *exp1, uint8_t *exp2, int n)
-{
- int sum, i;
- sum = 0;
- for (i = 0; i < n; i++)
- sum += abs(exp1[i] - exp2[i]);
- return sum;
-}
-
-
/**
* Exponent Difference Threshold.
* New exponents are sent if their SAD exceed this number.
/**
* Calculate exponent strategies for all blocks in a single channel.
*/
-static void compute_exp_strategy_ch(uint8_t *exp_strategy, uint8_t **exp)
+static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
+ uint8_t **exp)
{
int blk, blk1;
int exp_diff;
reused in the next frame */
exp_strategy[0] = EXP_NEW;
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
- exp_diff = calc_exp_diff(exp[blk], exp[blk-1], AC3_MAX_COEFS);
+ exp_diff = s->dsp.sad[0](NULL, exp[blk], exp[blk-1], 16, 16);
if (exp_diff > EXP_DIFF_THRESHOLD)
exp_strategy[blk] = EXP_NEW;
else
exp_strategy[blk] = EXP_REUSE;
}
+ emms_c();
/* now select the encoding strategy type : if exponents are often
recoded, we use a coarse encoding */
* Calculate exponent strategies for all channels.
* Array arrangement is reversed to simplify the per-channel calculation.
*/
-static void compute_exp_strategy(AC3EncodeContext *s,
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void compute_exp_strategy(AC3EncodeContext *s)
{
uint8_t *exp1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
uint8_t exp_str1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
for (ch = 0; ch < s->fbw_channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- exp1[ch][blk] = exp[blk][ch];
- exp_str1[ch][blk] = exp_strategy[blk][ch];
+ exp1[ch][blk] = s->blocks[blk].exp[ch];
+ exp_str1[ch][blk] = s->blocks[blk].exp_strategy[ch];
}
- compute_exp_strategy_ch(exp_str1[ch], exp1[ch]);
+ compute_exp_strategy_ch(s, exp_str1[ch], exp1[ch]);
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
- exp_strategy[blk][ch] = exp_str1[ch][blk];
+ s->blocks[blk].exp_strategy[ch] = exp_str1[ch][blk];
}
if (s->lfe_on) {
ch = s->lfe_channel;
- exp_strategy[0][ch] = EXP_D15;
- for (blk = 1; blk < 5; blk++)
- exp_strategy[blk][ch] = EXP_REUSE;
+ s->blocks[0].exp_strategy[ch] = EXP_D15;
+ for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
+ s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
}
}
* exponent in the same frequency bin of a following block.
* exp[i] = min(exp[i], exp1[i]
*/
-static void exponent_min(uint8_t exp[AC3_MAX_COEFS], uint8_t exp1[AC3_MAX_COEFS], int n)
+static void exponent_min(uint8_t *exp, uint8_t *exp1, int n)
{
int i;
for (i = 0; i < n; i++) {
/**
* Update the exponents so that they are the ones the decoder will decode.
*/
-static void encode_exponents_blk_ch(uint8_t encoded_exp[AC3_MAX_COEFS],
- uint8_t exp[AC3_MAX_COEFS],
- int nb_exps, int exp_strategy,
- uint8_t *num_exp_groups)
+static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy)
{
- int group_size, nb_groups, i, j, k, exp_min;
- uint8_t exp1[AC3_MAX_COEFS];
+ int nb_groups, i, k;
- group_size = exp_strategy + (exp_strategy == EXP_D45);
- *num_exp_groups = (nb_exps + (group_size * 3) - 4) / (3 * group_size);
- nb_groups = *num_exp_groups * 3;
+ nb_groups = exponent_group_tab[exp_strategy-1][nb_exps] * 3;
/* for each group, compute the minimum exponent */
- exp1[0] = exp[0]; /* DC exponent is handled separately */
- k = 1;
- for (i = 1; i <= nb_groups; i++) {
- exp_min = exp[k];
- assert(exp_min >= 0 && exp_min <= 24);
- for (j = 1; j < group_size; j++) {
- if (exp[k+j] < exp_min)
- exp_min = exp[k+j];
+ switch(exp_strategy) {
+ case EXP_D25:
+ for (i = 1, k = 1; i <= nb_groups; i++) {
+ uint8_t exp_min = exp[k];
+ if (exp[k+1] < exp_min)
+ exp_min = exp[k+1];
+ exp[i] = exp_min;
+ k += 2;
}
- exp1[i] = exp_min;
- k += group_size;
+ break;
+ case EXP_D45:
+ for (i = 1, k = 1; i <= nb_groups; i++) {
+ uint8_t exp_min = exp[k];
+ if (exp[k+1] < exp_min)
+ exp_min = exp[k+1];
+ if (exp[k+2] < exp_min)
+ exp_min = exp[k+2];
+ if (exp[k+3] < exp_min)
+ exp_min = exp[k+3];
+ exp[i] = exp_min;
+ k += 4;
+ }
+ break;
}
/* constraint for DC exponent */
- if (exp1[0] > 15)
- exp1[0] = 15;
+ if (exp[0] > 15)
+ exp[0] = 15;
/* decrease the delta between each groups to within 2 so that they can be
differentially encoded */
for (i = 1; i <= nb_groups; i++)
- exp1[i] = FFMIN(exp1[i], exp1[i-1] + 2);
- for (i = nb_groups-1; i >= 0; i--)
- exp1[i] = FFMIN(exp1[i], exp1[i+1] + 2);
+ exp[i] = FFMIN(exp[i], exp[i-1] + 2);
+ i--;
+ while (--i >= 0)
+ exp[i] = FFMIN(exp[i], exp[i+1] + 2);
/* now we have the exponent values the decoder will see */
- encoded_exp[0] = exp1[0];
- k = 1;
- for (i = 1; i <= nb_groups; i++) {
- for (j = 0; j < group_size; j++)
- encoded_exp[k+j] = exp1[i];
- k += group_size;
+ switch (exp_strategy) {
+ case EXP_D25:
+ for (i = nb_groups, k = nb_groups * 2; i > 0; i--) {
+ uint8_t exp1 = exp[i];
+ exp[k--] = exp1;
+ exp[k--] = exp1;
+ }
+ break;
+ case EXP_D45:
+ for (i = nb_groups, k = nb_groups * 4; i > 0; i--) {
+ exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i];
+ k -= 4;
+ }
+ break;
}
}
* deltas between adjacent exponent groups so that they can be differentially
* encoded.
*/
-static void encode_exponents(AC3EncodeContext *s,
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t num_exp_groups[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void encode_exponents(AC3EncodeContext *s)
{
int blk, blk1, blk2, ch;
+ AC3Block *block, *block1, *block2;
for (ch = 0; ch < s->channels; ch++) {
- /* for the EXP_REUSE case we select the min of the exponents */
blk = 0;
+ block = &s->blocks[0];
while (blk < AC3_MAX_BLOCKS) {
blk1 = blk + 1;
- while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1][ch] == EXP_REUSE) {
- exponent_min(exp[blk][ch], exp[blk1][ch], s->nb_coefs[ch]);
+ block1 = block + 1;
+ /* for the EXP_REUSE case we select the min of the exponents */
+ while (blk1 < AC3_MAX_BLOCKS && block1->exp_strategy[ch] == EXP_REUSE) {
+ exponent_min(block->exp[ch], block1->exp[ch], s->nb_coefs[ch]);
blk1++;
+ block1++;
}
- encode_exponents_blk_ch(encoded_exp[blk][ch],
- exp[blk][ch], s->nb_coefs[ch],
- exp_strategy[blk][ch],
- &num_exp_groups[blk][ch]);
+ encode_exponents_blk_ch(block->exp[ch], s->nb_coefs[ch],
+ block->exp_strategy[ch]);
/* copy encoded exponents for reuse case */
- for (blk2 = blk+1; blk2 < blk1; blk2++) {
- memcpy(encoded_exp[blk2][ch], encoded_exp[blk][ch],
+ block2 = block + 1;
+ for (blk2 = blk+1; blk2 < blk1; blk2++, block2++) {
+ memcpy(block2->exp[ch], block->exp[ch],
s->nb_coefs[ch] * sizeof(uint8_t));
}
blk = blk1;
+ block = block1;
}
}
}
* 3 delta-encoded exponents are in each 7-bit group. The number of groups
* varies depending on exponent strategy and bandwidth.
*/
-static void group_exponents(AC3EncodeContext *s,
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t num_exp_groups[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t grouped_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_EXP_GROUPS])
+static void group_exponents(AC3EncodeContext *s)
{
int blk, ch, i;
- int group_size, bit_count;
+ int group_size, nb_groups, bit_count;
uint8_t *p;
int delta0, delta1, delta2;
int exp0, exp1;
bit_count = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ AC3Block *block = &s->blocks[blk];
for (ch = 0; ch < s->channels; ch++) {
- if (exp_strategy[blk][ch] == EXP_REUSE) {
- num_exp_groups[blk][ch] = 0;
+ if (block->exp_strategy[ch] == EXP_REUSE) {
continue;
}
- group_size = exp_strategy[blk][ch] + (exp_strategy[blk][ch] == EXP_D45);
- bit_count += 4 + (num_exp_groups[blk][ch] * 7);
- p = encoded_exp[blk][ch];
+ group_size = block->exp_strategy[ch] + (block->exp_strategy[ch] == EXP_D45);
+ nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
+ bit_count += 4 + (nb_groups * 7);
+ p = block->exp[ch];
/* DC exponent */
exp1 = *p++;
- grouped_exp[blk][ch][0] = exp1;
+ block->grouped_exp[ch][0] = exp1;
/* remaining exponents are delta encoded */
- for (i = 1; i <= num_exp_groups[blk][ch]; i++) {
+ for (i = 1; i <= nb_groups; i++) {
/* merge three delta in one code */
exp0 = exp1;
exp1 = p[0];
p += group_size;
delta2 = exp1 - exp0 + 2;
- grouped_exp[blk][ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
+ block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
}
}
}
* Extract exponents from MDCT coefficients, calculate exponent strategies,
* and encode final exponents.
*/
-static void process_exponents(AC3EncodeContext *s,
- int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t num_exp_groups[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t grouped_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_EXP_GROUPS])
+static void process_exponents(AC3EncodeContext *s)
+{
+ extract_exponents(s);
+
+ compute_exp_strategy(s);
+
+ encode_exponents(s);
+
+ group_exponents(s);
+}
+
+
+/**
+ * Count frame bits that are based solely on fixed parameters.
+ * This only has to be run once when the encoder is initialized.
+ */
+static void count_frame_bits_fixed(AC3EncodeContext *s)
{
- extract_exponents(s, mdct_coef, exp_shift, exp);
+ static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
+ int blk;
+ int frame_bits;
+
+ /* assumptions:
+ * no dynamic range codes
+ * no channel coupling
+ * no rematrixing
+ * bit allocation parameters do not change between blocks
+ * SNR offsets do not change between blocks
+ * no delta bit allocation
+ * no skipped data
+ * no auxilliary data
+ */
+
+ /* header size */
+ frame_bits = 65;
+ frame_bits += frame_bits_inc[s->channel_mode];
- compute_exp_strategy(s, exp_strategy, exp);
+ /* audio blocks */
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
+ if (s->channel_mode == AC3_CHMODE_STEREO) {
+ frame_bits++; /* rematstr */
+ if (!blk)
+ frame_bits += 4;
+ }
+ frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
+ if (s->lfe_on)
+ frame_bits++; /* lfeexpstr */
+ frame_bits++; /* baie */
+ frame_bits++; /* snr */
+ frame_bits += 2; /* delta / skip */
+ }
+ frame_bits++; /* cplinu for block 0 */
+ /* bit alloc info */
+ /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
+ /* csnroffset[6] */
+ /* (fsnoffset[4] + fgaincod[4]) * c */
+ frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
- encode_exponents(s, exp, exp_strategy, num_exp_groups, encoded_exp);
+ /* auxdatae, crcrsv */
+ frame_bits += 2;
+
+ /* CRC */
+ frame_bits += 16;
- group_exponents(s, encoded_exp, exp_strategy, num_exp_groups, grouped_exp);
+ s->frame_bits_fixed = frame_bits;
}
s->slow_decay_code = 2;
s->fast_decay_code = 1;
s->slow_gain_code = 1;
- s->db_per_bit_code = 2;
+ s->db_per_bit_code = 3;
s->floor_code = 4;
for (ch = 0; ch < s->channels; ch++)
s->fast_gain_code[ch] = 4;
s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
+
+ count_frame_bits_fixed(s);
}
/**
* Count the bits used to encode the frame, minus exponents and mantissas.
+ * Bits based on fixed parameters have already been counted, so now we just
+ * have to add the bits based on parameters that change during encoding.
*/
-static void count_frame_bits(AC3EncodeContext *s,
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS])
+static void count_frame_bits(AC3EncodeContext *s)
{
- static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
int blk, ch;
- int frame_bits;
+ int frame_bits = 0;
- /* header size */
- frame_bits = 65;
- frame_bits += frame_bits_inc[s->channel_mode];
-
- /* audio blocks */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- frame_bits++; /* rematstr */
- if (!blk)
- frame_bits += 4;
- }
- frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
- if (s->lfe_on)
- frame_bits++; /* lfeexpstr */
+ uint8_t *exp_strategy = s->blocks[blk].exp_strategy;
for (ch = 0; ch < s->fbw_channels; ch++) {
- if (exp_strategy[blk][ch] != EXP_REUSE)
+ if (exp_strategy[ch] != EXP_REUSE)
frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
}
- frame_bits++; /* baie */
- frame_bits++; /* snr */
- frame_bits += 2; /* delta / skip */
}
- frame_bits++; /* cplinu for block 0 */
- /* bit alloc info */
- /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
- /* csnroffset[6] */
- /* (fsnoffset[4] + fgaincod[4]) * c */
- frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
-
- /* auxdatae, crcrsv */
- frame_bits += 2;
-
- /* CRC */
- frame_bits += 16;
-
- s->frame_bits = frame_bits;
+ s->frame_bits = s->frame_bits_fixed + frame_bits;
}
/**
* Calculate the number of bits needed to encode a set of mantissas.
*/
-static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
+static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs)
{
- int bits, mant, i;
+ int bits, b, i;
bits = 0;
for (i = 0; i < nb_coefs; i++) {
- mant = m[i];
- switch (mant) {
- case 0:
- /* nothing */
- break;
- case 1:
- /* 3 mantissa in 5 bits */
- if (s->mant1_cnt == 0)
- bits += 5;
- if (++s->mant1_cnt == 3)
- s->mant1_cnt = 0;
- break;
- case 2:
- /* 3 mantissa in 7 bits */
- if (s->mant2_cnt == 0)
- bits += 7;
- if (++s->mant2_cnt == 3)
- s->mant2_cnt = 0;
- break;
- case 3:
- bits += 3;
- break;
- case 4:
- /* 2 mantissa in 7 bits */
- if (s->mant4_cnt == 0)
- bits += 7;
- if (++s->mant4_cnt == 2)
- s->mant4_cnt = 0;
- break;
- case 14:
- bits += 14;
- break;
- case 15:
- bits += 16;
- break;
- default:
- bits += mant - 1;
- break;
+ b = bap[i];
+ if (b <= 4) {
+ // bap=1 to bap=4 will be counted in compute_mantissa_size_final
+ mant_cnt[b]++;
+ } else if (b <= 13) {
+ // bap=5 to bap=13 use (bap-1) bits
+ bits += b - 1;
+ } else {
+ // bap=14 uses 14 bits and bap=15 uses 16 bits
+ bits += (b == 14) ? 14 : 16;
}
}
return bits;
}
+/**
+ * Finalize the mantissa bit count by adding in the grouped mantissas.
+ */
+static int compute_mantissa_size_final(int mant_cnt[5])
+{
+ // bap=1 : 3 mantissas in 5 bits
+ int bits = (mant_cnt[1] / 3) * 5;
+ // bap=2 : 3 mantissas in 7 bits
+ // bap=4 : 2 mantissas in 7 bits
+ bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
+ // bap=3 : each mantissa is 3 bits
+ bits += mant_cnt[3] * 3;
+ return bits;
+}
+
+
/**
* Calculate masking curve based on the final exponents.
* Also calculate the power spectral densities to use in future calculations.
*/
-static void bit_alloc_masking(AC3EncodeContext *s,
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS])
+static void bit_alloc_masking(AC3EncodeContext *s)
{
int blk, ch;
- int16_t band_psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ AC3Block *block = &s->blocks[blk];
for (ch = 0; ch < s->channels; ch++) {
- if(exp_strategy[blk][ch] == EXP_REUSE) {
- memcpy(psd[blk][ch], psd[blk-1][ch], AC3_MAX_COEFS*sizeof(psd[0][0][0]));
- memcpy(mask[blk][ch], mask[blk-1][ch], AC3_CRITICAL_BANDS*sizeof(mask[0][0][0]));
- } else {
- ff_ac3_bit_alloc_calc_psd(encoded_exp[blk][ch], 0,
+ /* We only need psd and mask for calculating bap.
+ Since we currently do not calculate bap when exponent
+ strategy is EXP_REUSE we do not need to calculate psd or mask. */
+ if (block->exp_strategy[ch] != EXP_REUSE) {
+ ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
s->nb_coefs[ch],
- psd[blk][ch], band_psd[blk][ch]);
- ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, band_psd[blk][ch],
+ block->psd[ch], block->band_psd[ch]);
+ ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
0, s->nb_coefs[ch],
ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
ch == s->lfe_channel,
DBA_NONE, 0, NULL, NULL, NULL,
- mask[blk][ch]);
+ block->mask[ch]);
}
}
}
}
+/**
+ * Ensure that bap for each block and channel point to the current bap_buffer.
+ * They may have been switched during the bit allocation search.
+ */
+static void reset_block_bap(AC3EncodeContext *s)
+{
+ int blk, ch;
+ if (s->blocks[0].bap[0] == s->bap_buffer)
+ return;
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ for (ch = 0; ch < s->channels; ch++) {
+ s->blocks[blk].bap[ch] = &s->bap_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
+ }
+ }
+}
+
+
/**
* Run the bit allocation with a given SNR offset.
* This calculates the bit allocation pointers that will be used to determine
* the quantization of each mantissa.
- * @return the number of remaining bits (positive or negative) if the given
- * SNR offset is used to quantize the mantissas.
+ * @return the number of bits needed for mantissas if the given SNR offset is
+ * is used.
*/
-static int bit_alloc(AC3EncodeContext *s,
- int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS],
- int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int frame_bits, int coarse_snr_offset, int fine_snr_offset)
+static int bit_alloc(AC3EncodeContext *s, int snr_offset)
{
int blk, ch;
- int snr_offset;
+ int mantissa_bits;
+ int mant_cnt[5];
- snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2;
+ snr_offset = (snr_offset - 240) << 2;
+ reset_block_bap(s);
+ mantissa_bits = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- s->mant1_cnt = 0;
- s->mant2_cnt = 0;
- s->mant4_cnt = 0;
+ AC3Block *block = &s->blocks[blk];
+ // initialize grouped mantissa counts. these are set so that they are
+ // padded to the next whole group size when bits are counted in
+ // compute_mantissa_size_final
+ mant_cnt[0] = mant_cnt[3] = 0;
+ mant_cnt[1] = mant_cnt[2] = 2;
+ mant_cnt[4] = 1;
for (ch = 0; ch < s->channels; ch++) {
- ff_ac3_bit_alloc_calc_bap(mask[blk][ch], psd[blk][ch], 0,
- s->nb_coefs[ch], snr_offset,
- s->bit_alloc.floor, ff_ac3_bap_tab,
- bap[blk][ch]);
- frame_bits += compute_mantissa_size(s, bap[blk][ch], s->nb_coefs[ch]);
+ /* Currently the only bit allocation parameters which vary across
+ blocks within a frame are the exponent values. We can take
+ advantage of that by reusing the bit allocation pointers
+ whenever we reuse exponents. */
+ if (block->exp_strategy[ch] == EXP_REUSE) {
+ memcpy(block->bap[ch], s->blocks[blk-1].bap[ch], AC3_MAX_COEFS);
+ } else {
+ ff_ac3_bit_alloc_calc_bap(block->mask[ch], block->psd[ch], 0,
+ s->nb_coefs[ch], snr_offset,
+ s->bit_alloc.floor, ff_ac3_bap_tab,
+ block->bap[ch]);
+ }
+ mantissa_bits += compute_mantissa_size(mant_cnt, block->bap[ch], s->nb_coefs[ch]);
}
+ mantissa_bits += compute_mantissa_size_final(mant_cnt);
}
- return 8 * s->frame_size - frame_bits;
+ return mantissa_bits;
}
-#define SNR_INC1 4
-
/**
- * Perform bit allocation search.
- * Finds the SNR offset value that maximizes quality and fits in the specified
- * frame size. Output is the SNR offset and a set of bit allocation pointers
- * used to quantize the mantissas.
+ * Constant bitrate bit allocation search.
+ * Find the largest SNR offset that will allow data to fit in the frame.
*/
-static int compute_bit_allocation(AC3EncodeContext *s,
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS])
+static int cbr_bit_allocation(AC3EncodeContext *s)
{
int ch;
- int frame_bits;
- int coarse_snr_offset, fine_snr_offset;
- uint8_t bap1[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];
-
- /* count frame bits other than exponents and mantissas */
- count_frame_bits(s, exp_strategy);
-
- /* calculate psd and masking curve before doing bit allocation */
- bit_alloc_masking(s, encoded_exp, exp_strategy, psd, mask);
-
- /* now the big work begins : do the bit allocation. Modify the snr
- offset until we can pack everything in the requested frame size */
-
- frame_bits = s->frame_bits + s->exponent_bits;
- coarse_snr_offset = s->coarse_snr_offset;
- while (coarse_snr_offset >= 0 &&
- bit_alloc(s, mask, psd, bap, frame_bits, coarse_snr_offset, 0) < 0)
- coarse_snr_offset -= SNR_INC1;
- if (coarse_snr_offset < 0) {
+ int bits_left;
+ int snr_offset, snr_incr;
+
+ bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
+
+ snr_offset = s->coarse_snr_offset << 4;
+
+ while (snr_offset >= 0 &&
+ bit_alloc(s, snr_offset) > bits_left) {
+ snr_offset -= 64;
+ }
+ if (snr_offset < 0)
return AVERROR(EINVAL);
+
+ FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
+ for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
+ while (snr_offset + 64 <= 1023 &&
+ bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
+ snr_offset += snr_incr;
+ FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
+ }
+ }
+ FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
+ reset_block_bap(s);
+
+ s->coarse_snr_offset = snr_offset >> 4;
+ for (ch = 0; ch < s->channels; ch++)
+ s->fine_snr_offset[ch] = snr_offset & 0xF;
+
+ return 0;
+}
+
+
+/**
+ * Downgrade exponent strategies to reduce the bits used by the exponents.
+ * This is a fallback for when bit allocation fails with the normal exponent
+ * strategies. Each time this function is run it only downgrades the
+ * strategy in 1 channel of 1 block.
+ * @return non-zero if downgrade was unsuccessful
+ */
+static int downgrade_exponents(AC3EncodeContext *s)
+{
+ int ch, blk;
+
+ for (ch = 0; ch < s->fbw_channels; ch++) {
+ for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
+ if (s->blocks[blk].exp_strategy[ch] == EXP_D15) {
+ s->blocks[blk].exp_strategy[ch] = EXP_D25;
+ return 0;
+ }
+ }
}
- while (coarse_snr_offset + SNR_INC1 <= 63 &&
- bit_alloc(s, mask, psd, bap1, frame_bits,
- coarse_snr_offset + SNR_INC1, 0) >= 0) {
- coarse_snr_offset += SNR_INC1;
- memcpy(bap, bap1, sizeof(bap1));
+ for (ch = 0; ch < s->fbw_channels; ch++) {
+ for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
+ if (s->blocks[blk].exp_strategy[ch] == EXP_D25) {
+ s->blocks[blk].exp_strategy[ch] = EXP_D45;
+ return 0;
+ }
+ }
}
- while (coarse_snr_offset + 1 <= 63 &&
- bit_alloc(s, mask, psd, bap1, frame_bits, coarse_snr_offset + 1, 0) >= 0) {
- coarse_snr_offset++;
- memcpy(bap, bap1, sizeof(bap1));
+ for (ch = 0; ch < s->fbw_channels; ch++) {
+ /* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
+ the block number > 0 */
+ for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
+ if (s->blocks[blk].exp_strategy[ch] > EXP_REUSE) {
+ s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
+ return 0;
+ }
+ }
}
+ return -1;
+}
- fine_snr_offset = 0;
- while (fine_snr_offset + SNR_INC1 <= 15 &&
- bit_alloc(s, mask, psd, bap1, frame_bits,
- coarse_snr_offset, fine_snr_offset + SNR_INC1) >= 0) {
- fine_snr_offset += SNR_INC1;
- memcpy(bap, bap1, sizeof(bap1));
- }
- while (fine_snr_offset + 1 <= 15 &&
- bit_alloc(s, mask, psd, bap1, frame_bits,
- coarse_snr_offset, fine_snr_offset + 1) >= 0) {
- fine_snr_offset++;
- memcpy(bap, bap1, sizeof(bap1));
+
+/**
+ * Reduce the bandwidth to reduce the number of bits used for a given SNR offset.
+ * This is a second fallback for when bit allocation still fails after exponents
+ * have been downgraded.
+ * @return non-zero if bandwidth reduction was unsuccessful
+ */
+static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code)
+{
+ int ch;
+
+ if (s->bandwidth_code[0] > min_bw_code) {
+ for (ch = 0; ch < s->fbw_channels; ch++) {
+ s->bandwidth_code[ch]--;
+ s->nb_coefs[ch] = s->bandwidth_code[ch] * 3 + 73;
+ }
+ return 0;
}
+ return -1;
+}
- s->coarse_snr_offset = coarse_snr_offset;
- for (ch = 0; ch < s->channels; ch++)
- s->fine_snr_offset[ch] = fine_snr_offset;
- return 0;
+/**
+ * Perform bit allocation search.
+ * Finds the SNR offset value that maximizes quality and fits in the specified
+ * frame size. Output is the SNR offset and a set of bit allocation pointers
+ * used to quantize the mantissas.
+ */
+static int compute_bit_allocation(AC3EncodeContext *s)
+{
+ int ret;
+
+ count_frame_bits(s);
+
+ bit_alloc_masking(s);
+
+ ret = cbr_bit_allocation(s);
+ while (ret) {
+ /* fallback 1: downgrade exponents */
+ if (!downgrade_exponents(s)) {
+ extract_exponents(s);
+ encode_exponents(s);
+ group_exponents(s);
+ ret = compute_bit_allocation(s);
+ continue;
+ }
+
+ /* fallback 2: reduce bandwidth */
+ /* only do this if the user has not specified a specific cutoff
+ frequency */
+ if (!s->cutoff && !reduce_bandwidth(s, 0)) {
+ process_exponents(s);
+ ret = compute_bit_allocation(s);
+ continue;
+ }
+
+ /* fallbacks were not enough... */
+ break;
+ }
+
+ return ret;
}
v = (v + 1) >> 1;
v = (levels >> 1) - v;
}
- assert (v >= 0 && v < levels);
+ assert(v >= 0 && v < levels);
return v;
}
/**
* Quantize a set of mantissas for a single channel in a single block.
*/
-static void quantize_mantissas_blk_ch(AC3EncodeContext *s,
- int32_t *mdct_coef, int8_t exp_shift,
- uint8_t *encoded_exp, uint8_t *bap,
- uint16_t *qmant, int n)
+static void quantize_mantissas_blk_ch(AC3EncodeContext *s, CoefType *mdct_coef,
+ int8_t exp_shift, uint8_t *exp,
+ uint8_t *bap, uint16_t *qmant, int n)
{
int i;
for (i = 0; i < n; i++) {
int v;
- int c = mdct_coef[i];
- int e = encoded_exp[i] - exp_shift;
+ int c = SCALE_COEF(mdct_coef[i]);
+ int e = exp[i] - exp_shift;
int b = bap[i];
switch (b) {
case 0:
/**
* Quantize mantissas using coefficients, exponents, and bit allocation pointers.
*/
-static void quantize_mantissas(AC3EncodeContext *s,
- int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint16_t qmant[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void quantize_mantissas(AC3EncodeContext *s)
{
int blk, ch;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ AC3Block *block = &s->blocks[blk];
s->mant1_cnt = s->mant2_cnt = s->mant4_cnt = 0;
s->qmant1_ptr = s->qmant2_ptr = s->qmant4_ptr = NULL;
for (ch = 0; ch < s->channels; ch++) {
- quantize_mantissas_blk_ch(s, mdct_coef[blk][ch], exp_shift[blk][ch],
- encoded_exp[blk][ch], bap[blk][ch],
- qmant[blk][ch], s->nb_coefs[ch]);
+ quantize_mantissas_blk_ch(s, block->mdct_coef[ch], block->exp_shift[ch],
+ block->exp[ch], block->bap[ch],
+ block->qmant[ch], s->nb_coefs[ch]);
}
}
}
/**
* Write one audio block to the output bitstream.
*/
-static void output_audio_block(AC3EncodeContext *s,
- uint8_t exp_strategy[AC3_MAX_CHANNELS],
- uint8_t num_exp_groups[AC3_MAX_CHANNELS],
- uint8_t grouped_exp[AC3_MAX_CHANNELS][AC3_MAX_EXP_GROUPS],
- uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint16_t qmant[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int block_num)
+static void output_audio_block(AC3EncodeContext *s, int block_num)
{
int ch, i, baie, rbnd;
+ AC3Block *block = &s->blocks[block_num];
+ /* block switching */
for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 0); /* no block switching */
+ put_bits(&s->pb, 1, 0);
+
+ /* dither flags */
for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 1); /* no dither */
- put_bits(&s->pb, 1, 0); /* no dynamic range */
+ put_bits(&s->pb, 1, 1);
+
+ /* dynamic range codes */
+ put_bits(&s->pb, 1, 0);
+
+ /* channel coupling */
if (!block_num) {
put_bits(&s->pb, 1, 1); /* coupling strategy present */
put_bits(&s->pb, 1, 0); /* no coupling strategy */
put_bits(&s->pb, 1, 0); /* no new coupling strategy */
}
+ /* stereo rematrixing */
if (s->channel_mode == AC3_CHMODE_STEREO) {
if (!block_num) {
/* first block must define rematrixing (rematstr) */
/* exponent strategy */
for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 2, exp_strategy[ch]);
-
+ put_bits(&s->pb, 2, block->exp_strategy[ch]);
if (s->lfe_on)
- put_bits(&s->pb, 1, exp_strategy[s->lfe_channel]);
+ put_bits(&s->pb, 1, block->exp_strategy[s->lfe_channel]);
/* bandwidth */
for (ch = 0; ch < s->fbw_channels; ch++) {
- if (exp_strategy[ch] != EXP_REUSE)
+ if (block->exp_strategy[ch] != EXP_REUSE)
put_bits(&s->pb, 6, s->bandwidth_code[ch]);
}
/* exponents */
for (ch = 0; ch < s->channels; ch++) {
- if (exp_strategy[ch] == EXP_REUSE)
+ int nb_groups;
+
+ if (block->exp_strategy[ch] == EXP_REUSE)
continue;
- /* first exponent */
- put_bits(&s->pb, 4, grouped_exp[ch][0]);
+ /* DC exponent */
+ put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
- /* next ones are delta-encoded and grouped */
- for (i = 1; i <= num_exp_groups[ch]; i++)
- put_bits(&s->pb, 7, grouped_exp[ch][i]);
+ /* exponent groups */
+ nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
+ for (i = 1; i <= nb_groups; i++)
+ put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
+ /* gain range info */
if (ch != s->lfe_channel)
- put_bits(&s->pb, 2, 0); /* no gain range info */
+ put_bits(&s->pb, 2, 0);
}
/* bit allocation info */
put_bits(&s->pb, 1, 0); /* no delta bit allocation */
put_bits(&s->pb, 1, 0); /* no data to skip */
- /* mantissa encoding */
+ /* mantissas */
for (ch = 0; ch < s->channels; ch++) {
int b, q;
-
for (i = 0; i < s->nb_coefs[ch]; i++) {
- q = qmant[ch][i];
- b = bap[ch][i];
+ q = block->qmant[ch][i];
+ b = block->bap[ch][i];
switch (b) {
case 0: break;
case 1: if (q != 128) put_bits(&s->pb, 5, q); break;
*/
static void output_frame_end(AC3EncodeContext *s)
{
- int frame_size, frame_size_58, pad_bytes, crc1, crc2, crc_inv;
+ const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
+ int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
uint8_t *frame;
- frame_size = s->frame_size; /* frame size in words */
- /* align to 8 bits */
+ frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
+
+ /* pad the remainder of the frame with zeros */
flush_put_bits(&s->pb);
- /* add zero bytes to reach the frame size */
frame = s->pb.buf;
pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
assert(pad_bytes >= 0);
if (pad_bytes > 0)
memset(put_bits_ptr(&s->pb), 0, pad_bytes);
- /* Now we must compute both crcs : this is not so easy for crc1
- because it is at the beginning of the data... */
- frame_size_58 = ((frame_size >> 2) + (frame_size >> 4)) << 1;
-
- crc1 = av_bswap16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
- frame + 4, frame_size_58 - 4));
-
- /* XXX: could precompute crc_inv */
- crc_inv = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
+ /* compute crc1 */
+ /* this is not so easy because it is at the beginning of the data... */
+ crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
+ crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
AV_WB16(frame + 2, crc1);
- crc2 = av_bswap16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
- frame + frame_size_58,
- frame_size - frame_size_58 - 2));
- AV_WB16(frame + frame_size - 2, crc2);
+ /* compute crc2 */
+ crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
+ s->frame_size - frame_size_58 - 3);
+ crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
+ /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
+ if (crc2 == 0x770B) {
+ frame[s->frame_size - 3] ^= 0x1;
+ crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
+ }
+ crc2 = av_bswap16(crc2);
+ AV_WB16(frame + s->frame_size - 2, crc2);
}
/**
* Write the frame to the output bitstream.
*/
-static void output_frame(AC3EncodeContext *s,
- unsigned char *frame,
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t num_exp_groups[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t grouped_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_EXP_GROUPS],
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- uint16_t qmant[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+static void output_frame(AC3EncodeContext *s, unsigned char *frame)
{
int blk;
output_frame_header(s);
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- output_audio_block(s, exp_strategy[blk], num_exp_groups[blk],
- grouped_exp[blk], bap[blk], qmant[blk], blk);
- }
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
+ output_audio_block(s, blk);
output_frame_end(s);
}
/**
* Encode a single AC-3 frame.
*/
-static int ac3_encode_frame(AVCodecContext *avctx,
- unsigned char *frame, int buf_size, void *data)
+static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
+ int buf_size, void *data)
{
AC3EncodeContext *s = avctx->priv_data;
- const int16_t *samples = data;
- int16_t planar_samples[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE+AC3_FRAME_SIZE];
- int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
- uint8_t encoded_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- uint8_t num_exp_groups[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
- uint8_t grouped_exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_EXP_GROUPS];
- uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
- int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
- uint16_t qmant[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
+ const SampleType *samples = data;
int ret;
if (s->bit_alloc.sr_code == 1)
adjust_frame_size(s);
- deinterleave_input_samples(s, samples, planar_samples);
+ deinterleave_input_samples(s, samples);
- apply_mdct(s, planar_samples, exp_shift, mdct_coef);
+ apply_mdct(s);
- process_exponents(s, mdct_coef, exp_shift, exp, exp_strategy,
- encoded_exp, num_exp_groups, grouped_exp);
+ process_exponents(s);
- ret = compute_bit_allocation(s, bap, encoded_exp, exp_strategy);
+ ret = compute_bit_allocation(s);
if (ret) {
av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
return ret;
}
- quantize_mantissas(s, mdct_coef, exp_shift, encoded_exp, bap, qmant);
+ quantize_mantissas(s);
- output_frame(s, frame, exp_strategy, num_exp_groups, grouped_exp, bap, qmant);
+ output_frame(s, frame);
return s->frame_size;
}
*/
static av_cold int ac3_encode_close(AVCodecContext *avctx)
{
+ int blk, ch;
+ AC3EncodeContext *s = avctx->priv_data;
+
+ for (ch = 0; ch < s->channels; ch++)
+ av_freep(&s->planar_samples[ch]);
+ av_freep(&s->planar_samples);
+ av_freep(&s->bap_buffer);
+ av_freep(&s->bap1_buffer);
+ av_freep(&s->mdct_coef_buffer);
+ av_freep(&s->exp_buffer);
+ av_freep(&s->grouped_exp_buffer);
+ av_freep(&s->psd_buffer);
+ av_freep(&s->band_psd_buffer);
+ av_freep(&s->mask_buffer);
+ av_freep(&s->qmant_buffer);
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ AC3Block *block = &s->blocks[blk];
+ av_freep(&block->bap);
+ av_freep(&block->mdct_coef);
+ av_freep(&block->exp);
+ av_freep(&block->grouped_exp);
+ av_freep(&block->psd);
+ av_freep(&block->band_psd);
+ av_freep(&block->mask);
+ av_freep(&block->qmant);
+ }
+
+ mdct_end(&s->mdct);
+
av_freep(&avctx->coded_frame);
return 0;
}
s->bit_rate = avctx->bit_rate;
s->frame_size_code = i << 1;
+ /* validate cutoff */
+ if (avctx->cutoff < 0) {
+ av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
+ return AVERROR(EINVAL);
+ }
+ s->cutoff = avctx->cutoff;
+ if (s->cutoff > (s->sample_rate >> 1))
+ s->cutoff = s->sample_rate >> 1;
+
return 0;
}
* The user can optionally supply a cutoff frequency. Otherwise an appropriate
* default value will be used.
*/
-static av_cold void set_bandwidth(AC3EncodeContext *s, int cutoff)
+static av_cold void set_bandwidth(AC3EncodeContext *s)
{
int ch, bw_code;
- if (cutoff) {
+ if (s->cutoff) {
/* calculate bandwidth based on user-specified cutoff frequency */
int fbw_coeffs;
- cutoff = av_clip(cutoff, 1, s->sample_rate >> 1);
- fbw_coeffs = cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
+ fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
bw_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
} else {
/* use default bandwidth setting */
}
+static av_cold int allocate_buffers(AVCodecContext *avctx)
+{
+ int blk, ch;
+ AC3EncodeContext *s = avctx->priv_data;
+
+ FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
+ alloc_fail);
+ for (ch = 0; ch < s->channels; ch++) {
+ FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
+ (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
+ alloc_fail);
+ }
+ FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->bap_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * s->channels *
+ 128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * s->channels *
+ 64 * sizeof(*s->band_psd_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * s->channels *
+ 64 * sizeof(*s->mask_buffer), alloc_fail);
+ FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * s->channels *
+ AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ AC3Block *block = &s->blocks[blk];
+ FF_ALLOC_OR_GOTO(avctx, block->bap, s->channels * sizeof(*block->bap),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, s->channels * sizeof(*block->mdct_coef),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->exp, s->channels * sizeof(*block->exp),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, s->channels * sizeof(*block->grouped_exp),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->psd, s->channels * sizeof(*block->psd),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, s->channels * sizeof(*block->band_psd),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->mask, s->channels * sizeof(*block->mask),
+ alloc_fail);
+ FF_ALLOCZ_OR_GOTO(avctx, block->qmant, s->channels * sizeof(*block->qmant),
+ alloc_fail);
+
+ for (ch = 0; ch < s->channels; ch++) {
+ block->bap[ch] = &s->bap_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
+ block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
+ block->exp[ch] = &s->exp_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
+ block->grouped_exp[ch] = &s->grouped_exp_buffer[128 * (blk * s->channels + ch)];
+ block->psd[ch] = &s->psd_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
+ block->band_psd[ch] = &s->band_psd_buffer [64 * (blk * s->channels + ch)];
+ block->mask[ch] = &s->mask_buffer [64 * (blk * s->channels + ch)];
+ block->qmant[ch] = &s->qmant_buffer [AC3_MAX_COEFS * (blk * s->channels + ch)];
+ }
+ }
+
+ return 0;
+alloc_fail:
+ return AVERROR(ENOMEM);
+}
+
+
/**
* Initialize the encoder.
*/
static av_cold int ac3_encode_init(AVCodecContext *avctx)
{
AC3EncodeContext *s = avctx->priv_data;
- int ret;
+ int ret, frame_size_58;
avctx->frame_size = AC3_FRAME_SIZE;
s->samples_written = 0;
s->frame_size = s->frame_size_min;
- set_bandwidth(s, avctx->cutoff);
+ /* calculate crc_inv for both possible frame sizes */
+ frame_size_58 = (( s->frame_size >> 2) + ( s->frame_size >> 4)) << 1;
+ s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
+ if (s->bit_alloc.sr_code == 1) {
+ frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
+ s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
+ }
+
+ set_bandwidth(s);
+
+ exponent_init(s);
bit_alloc_init(s);
- mdct_init(9);
+ ret = mdct_init(avctx, &s->mdct, 9);
+ if (ret)
+ goto init_fail;
+
+ ret = allocate_buffers(avctx);
+ if (ret)
+ goto init_fail;
avctx->coded_frame= avcodec_alloc_frame();
- avctx->coded_frame->key_frame= 1;
+
+ dsputil_init(&s->dsp, avctx);
return 0;
+init_fail:
+ ac3_encode_close(avctx);
+ return ret;
}
#include "libavutil/lfg.h"
+#define MDCT_NBITS 9
+#define MDCT_SAMPLES (1 << MDCT_NBITS)
#define FN (MDCT_SAMPLES/4)
-static void fft_test(AVLFG *lfg)
+static void fft_test(AC3MDCTContext *mdct, AVLFG *lfg)
{
IComplex in[FN], in1[FN];
int k, n, i;
in[i].im = av_lfg_get(lfg) % 65535 - 32767;
in1[i] = in[i];
}
- fft(in, 7);
+ fft(mdct, in, 7);
/* do it by hand */
for (k = 0; k < FN; k++) {
}
-static void mdct_test(AVLFG *lfg)
+static void mdct_test(AC3MDCTContext *mdct, AVLFG *lfg)
{
int16_t input[MDCT_SAMPLES];
int32_t output[AC3_MAX_COEFS];
input1[i] = input[i];
}
- mdct512(output, input);
+ mdct512(mdct, output, input);
/* do it by hand */
for (k = 0; k < AC3_MAX_COEFS; k++) {
int main(void)
{
AVLFG lfg;
+ AC3MDCTContext mdct;
+ mdct.avctx = NULL;
av_log_set_level(AV_LOG_DEBUG);
- mdct_init(9);
+ mdct_init(&mdct, 9);
- fft_test(&lfg);
- mdct_test(&lfg);
+ fft_test(&mdct, &lfg);
+ mdct_test(&mdct, &lfg);
return 0;
}
NULL,
.sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
- .channel_layouts = (const int64_t[]){
- AV_CH_LAYOUT_MONO,
- AV_CH_LAYOUT_STEREO,
- AV_CH_LAYOUT_2_1,
- AV_CH_LAYOUT_SURROUND,
- AV_CH_LAYOUT_2_2,
- AV_CH_LAYOUT_QUAD,
- AV_CH_LAYOUT_4POINT0,
- AV_CH_LAYOUT_5POINT0,
- AV_CH_LAYOUT_5POINT0_BACK,
- (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
- AV_CH_LAYOUT_5POINT1,
- AV_CH_LAYOUT_5POINT1_BACK,
- 0 },
+ .channel_layouts = ac3_channel_layouts,
};
projects / ffmpeg / blobdiff