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define AC3_CRITICAL_BANDS and use it in the AC-3 encoder and decoder.

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Originally committed as revision 25967 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 14:51:40 +00:00
parent 0454b55801
commit 47ae6e795b
4 changed files with 15 additions and 14 deletions
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14
libavcodec/ac3.c
View File

@ -33,7 +33,7 @@
/**
* Starting frequency coefficient bin for each critical band.
*/
static const uint8_t band_start_tab[51] = {
static const uint8_t band_start_tab[AC3_CRITICAL_BANDS+1] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 31,
@ -127,7 +127,7 @@ int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
uint8_t *dba_lengths, uint8_t *dba_values,
int16_t *mask)
{
int16_t excite[50]; /* excitation */
int16_t excite[AC3_CRITICAL_BANDS]; /* excitation */
int band;
int band_start, band_end, begin, end1;
int lowcomp, fastleak, slowleak;
@ -198,7 +198,7 @@ int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
band = 0;
for (seg = 0; seg < dba_nsegs; seg++) {
band += dba_offsets[seg];
if (band >= 50 || dba_lengths[seg] > 50-band)
if (band >= AC3_CRITICAL_BANDS || dba_lengths[seg] > AC3_CRITICAL_BANDS-band)
return -1;
if (dba_values[seg] >= 4) {
delta = (dba_values[seg] - 3) << 7;
@ -247,8 +247,8 @@ void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
uint8_t *dba_values)
{
int16_t psd[256]; /* scaled exponents */
int16_t band_psd[50]; /* interpolated exponents */
int16_t mask[50]; /* masking value */
int16_t band_psd[AC3_CRITICAL_BANDS]; /* interpolated exponents */
int16_t mask[AC3_CRITICAL_BANDS]; /* masking value */
ff_ac3_bit_alloc_calc_psd(exp, start, end, psd, band_psd);
@ -270,12 +270,12 @@ av_cold void ac3_common_init(void)
#if !CONFIG_HARDCODED_TABLES
/* compute bndtab and masktab from bandsz */
int bin = 0, band;
for (band = 0; band < 50; band++) {
for (band = 0; band < AC3_CRITICAL_BANDS; band++) {
int band_end = bin + ff_ac3_critical_band_size_tab[band];
band_start_tab[band] = bin;
while (bin < band_end)
bin_to_band_tab[bin++] = band;
}
band_start_tab[50] = bin;
band_start_tab[AC3_CRITICAL_BANDS] = bin;
#endif /* !CONFIG_HARDCODED_TABLES */
}

1
libavcodec/ac3.h
View File

@ -37,6 +37,7 @@
#define AC3_MAX_BLOCKS 6
#define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256)
#define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2)
#define AC3_CRITICAL_BANDS 50
/* exponent encoding strategy */
#define EXP_REUSE 0

4
libavcodec/ac3dec.h
View File

@ -168,8 +168,8 @@ typedef struct {
int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain)
uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers
int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents
int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents
int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< masking curve values
int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets

10
libavcodec/ac3enc.c
View File

@ -506,16 +506,16 @@ 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][50])
int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS])
{
int blk, ch;
int16_t band_psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][50];
int16_t band_psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];
for (blk = 0; blk < AC3_MAX_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], 50*sizeof(mask[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,
s->nb_coefs[ch],
@ -540,7 +540,7 @@ static void bit_alloc_masking(AC3EncodeContext *s,
* SNR offset is used to quantize the mantissas.
*/
static int bit_alloc(AC3EncodeContext *s,
int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][50],
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)
@ -584,7 +584,7 @@ static int compute_bit_allocation(AC3EncodeContext *s,
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][50];
int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS];
static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
/* init default parameters */