[FFmpeg-cvslog] r25997 - trunk/libavcodec/ac3enc.c
jbr
subversion
Tue Dec 14 15:53:23 CET 2010
Author: jbr
Date: Tue Dec 14 15:53:23 2010
New Revision: 25997
Log:
Split out mantissa quantization into separate functions.
Modified:
trunk/libavcodec/ac3enc.c
Modified: trunk/libavcodec/ac3enc.c
==============================================================================
--- trunk/libavcodec/ac3enc.c Tue Dec 14 15:53:20 2010 (r25996)
+++ trunk/libavcodec/ac3enc.c Tue Dec 14 15:53:23 2010 (r25997)
@@ -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;
@@ -968,6 +969,127 @@ static inline int asym_quant(int c, int
/**
+ * 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.
*/
static void output_frame_header(AC3EncodeContext *s)
@@ -1005,16 +1127,12 @@ static void output_audio_block(AC3Encode
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(AC3Encode
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(AC3EncodeContex
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(AC3EncodeContex
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(AVCodecConte
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(AVCodecConte
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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