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Code Issues Releases Activity

Change bit_alloc() to return the mantissa bit count.

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Originally committed as revision 26009 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 22:45:19 +00:00
parent 937cd1467c
commit 70fcd7ea80
1 changed files with 17 additions and 16 deletions
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33
libavcodec/ac3enc.c
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@ -916,20 +916,21 @@ static void bit_alloc_masking(AC3EncodeContext *s,
* Run the bit allocation with a given SNR offset. * Run the bit allocation with a given SNR offset.
* This calculates the bit allocation pointers that will be used to determine * This calculates the bit allocation pointers that will be used to determine
* the quantization of each mantissa. * the quantization of each mantissa.
* @return the number of remaining bits (positive or negative) if the given * @return the number of bits needed for mantissas if the given SNR offset is
* SNR offset is used to quantize the mantissas. * is used.
*/ */
static int bit_alloc(AC3EncodeContext *s, static int bit_alloc(AC3EncodeContext *s,
int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS], int16_t mask[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS],
int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS], int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
uint8_t bap[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) int coarse_snr_offset, int fine_snr_offset)
{ {
int blk, ch; int blk, ch;
int snr_offset; int snr_offset, mantissa_bits;
snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2; snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2;
mantissa_bits = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
s->mant1_cnt = 0; s->mant1_cnt = 0;
s->mant2_cnt = 0; s->mant2_cnt = 0;
@ -939,10 +940,10 @@ static int bit_alloc(AC3EncodeContext *s,
s->nb_coefs[ch], snr_offset, s->nb_coefs[ch], snr_offset,
s->bit_alloc.floor, ff_ac3_bap_tab, s->bit_alloc.floor, ff_ac3_bap_tab,
bap[blk][ch]); bap[blk][ch]);
frame_bits += compute_mantissa_size(s, bap[blk][ch], s->nb_coefs[ch]); mantissa_bits += compute_mantissa_size(s, bap[blk][ch], s->nb_coefs[ch]);
} }
} }
return 8 * s->frame_size - frame_bits; return mantissa_bits;
} }
@ -960,7 +961,7 @@ static int compute_bit_allocation(AC3EncodeContext *s,
uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]) uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS])
{ {
int ch; int ch;
int frame_bits; int bits_left;
int coarse_snr_offset, fine_snr_offset; int coarse_snr_offset, fine_snr_offset;
uint8_t bap1[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS]; 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 psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
@ -975,36 +976,36 @@ static int compute_bit_allocation(AC3EncodeContext *s,
/* now the big work begins : do the bit allocation. Modify the snr /* now the big work begins : do the bit allocation. Modify the snr
offset until we can pack everything in the requested frame size */ offset until we can pack everything in the requested frame size */
frame_bits = s->frame_bits + s->exponent_bits; bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
coarse_snr_offset = s->coarse_snr_offset; coarse_snr_offset = s->coarse_snr_offset;
while (coarse_snr_offset >= 0 && while (coarse_snr_offset >= 0 &&
bit_alloc(s, mask, psd, bap, frame_bits, coarse_snr_offset, 0) < 0) bit_alloc(s, mask, psd, bap, coarse_snr_offset, 0) > bits_left)
coarse_snr_offset -= SNR_INC1; coarse_snr_offset -= SNR_INC1;
if (coarse_snr_offset < 0) { if (coarse_snr_offset < 0) {
return AVERROR(EINVAL); return AVERROR(EINVAL);
} }
while (coarse_snr_offset + SNR_INC1 <= 63 && while (coarse_snr_offset + SNR_INC1 <= 63 &&
bit_alloc(s, mask, psd, bap1, frame_bits, bit_alloc(s, mask, psd, bap1,
coarse_snr_offset + SNR_INC1, 0) >= 0) { coarse_snr_offset + SNR_INC1, 0) <= bits_left) {
coarse_snr_offset += SNR_INC1; coarse_snr_offset += SNR_INC1;
memcpy(bap, bap1, sizeof(bap1)); memcpy(bap, bap1, sizeof(bap1));
} }
while (coarse_snr_offset + 1 <= 63 && while (coarse_snr_offset + 1 <= 63 &&
bit_alloc(s, mask, psd, bap1, frame_bits, coarse_snr_offset + 1, 0) >= 0) { bit_alloc(s, mask, psd, bap1, coarse_snr_offset + 1, 0) <= bits_left) {
coarse_snr_offset++; coarse_snr_offset++;
memcpy(bap, bap1, sizeof(bap1)); memcpy(bap, bap1, sizeof(bap1));
} }
fine_snr_offset = 0; fine_snr_offset = 0;
while (fine_snr_offset + SNR_INC1 <= 15 && while (fine_snr_offset + SNR_INC1 <= 15 &&
bit_alloc(s, mask, psd, bap1, frame_bits, bit_alloc(s, mask, psd, bap1,
coarse_snr_offset, fine_snr_offset + SNR_INC1) >= 0) { coarse_snr_offset, fine_snr_offset + SNR_INC1) <= bits_left) {
fine_snr_offset += SNR_INC1; fine_snr_offset += SNR_INC1;
memcpy(bap, bap1, sizeof(bap1)); memcpy(bap, bap1, sizeof(bap1));
} }
while (fine_snr_offset + 1 <= 15 && while (fine_snr_offset + 1 <= 15 &&
bit_alloc(s, mask, psd, bap1, frame_bits, bit_alloc(s, mask, psd, bap1,
coarse_snr_offset, fine_snr_offset + 1) >= 0) { coarse_snr_offset, fine_snr_offset + 1) <= bits_left) {
fine_snr_offset++; fine_snr_offset++;
memcpy(bap, bap1, sizeof(bap1)); memcpy(bap, bap1, sizeof(bap1));
} }