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ffmpeg.wasm-core
Commit b6a1e523 authored by Justin Ruggles's avatar Justin Ruggles
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Split out mantissa quantization into separate functions. 

Originally committed as revision 25997 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 5b44ede0
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Showing with 130 additions and 104 deletions
libavcodec/ac3enc.c
View file @ b6a1e523
......@@ -93,6 +93,7 @@ typedef struct AC3EncodeContext {
/* mantissa encoding */
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
} AC3EncodeContext;
......@@ -967,6 +968,127 @@ static inline int asym_quant(int c, int e, int qbits)
}
/**
* 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)
{
int i;
for (i = 0; i < n; i++) {
int v;
int c = mdct_coef[i];
int e = encoded_exp[i] - exp_shift;
int b = bap[i];
switch (b) {
case 0:
v = 0;
break;
case 1:
v = sym_quant(c, e, 3);
switch (s->mant1_cnt) {
case 0:
s->qmant1_ptr = &qmant[i];
v = 9 * v;
s->mant1_cnt = 1;
break;
case 1:
*s->qmant1_ptr += 3 * v;
s->mant1_cnt = 2;
v = 128;
break;
default:
*s->qmant1_ptr += v;
s->mant1_cnt = 0;
v = 128;
break;
}
break;
case 2:
v = sym_quant(c, e, 5);
switch (s->mant2_cnt) {
case 0:
s->qmant2_ptr = &qmant[i];
v = 25 * v;
s->mant2_cnt = 1;
break;
case 1:
*s->qmant2_ptr += 5 * v;
s->mant2_cnt = 2;
v = 128;
break;
default:
*s->qmant2_ptr += v;
s->mant2_cnt = 0;
v = 128;
break;
}
break;
case 3:
v = sym_quant(c, e, 7);
break;
case 4:
v = sym_quant(c, e, 11);
switch (s->mant4_cnt) {
case 0:
s->qmant4_ptr = &qmant[i];
v = 11 * v;
s->mant4_cnt = 1;
break;
default:
*s->qmant4_ptr += v;
s->mant4_cnt = 0;
v = 128;
break;
}
break;
case 5:
v = sym_quant(c, e, 15);
break;
case 14:
v = asym_quant(c, e, 14);
break;
case 15:
v = asym_quant(c, e, 16);
break;
default:
v = asym_quant(c, e, b - 1);
break;
}
qmant[i] = v;
}
}
/**
* 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])
{
int blk, ch;
for (blk = 0; blk < AC3_MAX_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]);
}
}
}
/**
* Write the AC-3 frame header to the output bitstream.
*/
......@@ -1005,16 +1127,12 @@ static void output_audio_block(AC3EncodeContext *s,
uint8_t exp_strategy[AC3_MAX_CHANNELS],
uint8_t encoded_exp[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int32_t mdct_coef[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int8_t exp_shift[AC3_MAX_CHANNELS],
uint16_t qmant[AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int block_num)
{
int ch, nb_groups, group_size, i, baie, rbnd;
uint8_t *p;
uint16_t qmant[AC3_MAX_CHANNELS][AC3_MAX_COEFS];
int exp0, exp1;
int mant1_cnt, mant2_cnt, mant4_cnt;
uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr;
int delta0, delta1, delta2;
for (ch = 0; ch < s->fbw_channels; ch++)
......@@ -1117,101 +1235,7 @@ static void output_audio_block(AC3EncodeContext *s,
put_bits(&s->pb, 1, 0); /* no delta bit allocation */
put_bits(&s->pb, 1, 0); /* no data to skip */
/* mantissa encoding : we use two passes to handle the grouping. A
one pass method may be faster, but it would necessitate to
modify the output stream. */
/* first pass: quantize */
mant1_cnt = mant2_cnt = mant4_cnt = 0;
qmant1_ptr = qmant2_ptr = qmant4_ptr = NULL;
for (ch = 0; ch < s->channels; ch++) {
int b, c, e, v;
for (i = 0; i < s->nb_coefs[ch]; i++) {
c = mdct_coef[ch][i];
e = encoded_exp[ch][i] - exp_shift[ch];
b = bap[ch][i];
switch (b) {
case 0:
v = 0;
break;
case 1:
v = sym_quant(c, e, 3);
switch (mant1_cnt) {
case 0:
qmant1_ptr = &qmant[ch][i];
v = 9 * v;
mant1_cnt = 1;
break;
case 1:
*qmant1_ptr += 3 * v;
mant1_cnt = 2;
v = 128;
break;
default:
*qmant1_ptr += v;
mant1_cnt = 0;
v = 128;
break;
}
break;
case 2:
v = sym_quant(c, e, 5);
switch (mant2_cnt) {
case 0:
qmant2_ptr = &qmant[ch][i];
v = 25 * v;
mant2_cnt = 1;
break;
case 1:
*qmant2_ptr += 5 * v;
mant2_cnt = 2;
v = 128;
break;
default:
*qmant2_ptr += v;
mant2_cnt = 0;
v = 128;
break;
}
break;
case 3:
v = sym_quant(c, e, 7);
break;
case 4:
v = sym_quant(c, e, 11);
switch (mant4_cnt) {
case 0:
qmant4_ptr = &qmant[ch][i];
v = 11 * v;
mant4_cnt = 1;
break;
default:
*qmant4_ptr += v;
mant4_cnt = 0;
v = 128;
break;
}
break;
case 5:
v = sym_quant(c, e, 15);
break;
case 14:
v = asym_quant(c, e, 14);
break;
case 15:
v = asym_quant(c, e, 16);
break;
default:
v = asym_quant(c, e, b - 1);
break;
}
qmant[ch][i] = v;
}
}
/* second pass : output the values */
/* mantissa encoding */
for (ch = 0; ch < s->channels; ch++) {
int b, q;
......@@ -1313,8 +1337,7 @@ static void output_frame(AC3EncodeContext *s,
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 bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int32_t mdct_coef[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])
{
int blk;
......@@ -1324,7 +1347,7 @@ static void output_frame(AC3EncodeContext *s,
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
output_audio_block(s, exp_strategy[blk], encoded_exp[blk],
bap[blk], mdct_coef[blk], exp_shift[blk], blk);
bap[blk], qmant[blk], blk);
}
output_frame_end(s);
......@@ -1346,6 +1369,7 @@ static int ac3_encode_frame(AVCodecContext *avctx,
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];
int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
uint16_t qmant[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
int frame_bits;
if (s->bit_alloc.sr_code == 1)
......@@ -1359,7 +1383,9 @@ static int ac3_encode_frame(AVCodecContext *avctx,
compute_bit_allocation(s, bap, encoded_exp, exp_strategy, frame_bits);
output_frame(s, frame, exp_strategy, encoded_exp, bap, mdct_coef, exp_shift);
quantize_mantissas(s, mdct_coef, exp_shift, encoded_exp, bap, qmant);
output_frame(s, frame, exp_strategy, encoded_exp, bap, qmant);
return s->frame_size;
}
......
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