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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.
* 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)
int coarse_snr_offset, int fine_snr_offset)
{
int blk, ch;
int snr_offset;
int snr_offset, mantissa_bits;
snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2;
mantissa_bits = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
s->mant1_cnt = 0;
s->mant2_cnt = 0;
@ -939,10 +940,10 @@ static int bit_alloc(AC3EncodeContext *s,
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]);
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])
{
int ch;
int frame_bits;
int bits_left;
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];
@ -975,36 +976,36 @@ static int compute_bit_allocation(AC3EncodeContext *s,
/* 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;
bits_left = 8 * s->frame_size - (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)
bit_alloc(s, mask, psd, bap, coarse_snr_offset, 0) > bits_left)
coarse_snr_offset -= SNR_INC1;
if (coarse_snr_offset < 0) {
return AVERROR(EINVAL);
}
while (coarse_snr_offset + SNR_INC1 <= 63 &&
bit_alloc(s, mask, psd, bap1, frame_bits,
coarse_snr_offset + SNR_INC1, 0) >= 0) {
bit_alloc(s, mask, psd, bap1,
coarse_snr_offset + SNR_INC1, 0) <= bits_left) {
coarse_snr_offset += SNR_INC1;
memcpy(bap, bap1, sizeof(bap1));
}
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++;
memcpy(bap, bap1, sizeof(bap1));
}
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) {
bit_alloc(s, mask, psd, bap1,
coarse_snr_offset, fine_snr_offset + SNR_INC1) <= bits_left) {
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) {
bit_alloc(s, mask, psd, bap1,
coarse_snr_offset, fine_snr_offset + 1) <= bits_left) {
fine_snr_offset++;
memcpy(bap, bap1, sizeof(bap1));
}