This is slightly more complicated but it makes the per-channel calculation more
generic in terms of the data structure of exponents and exponent strategies.
This will allow different algorithms to be more easily plugged in to the
encoder.
---
libavcodec/ac3enc.c | 47 +++++++++++++++++++++++++++++++----------------
1 files changed, 31 insertions(+), 16 deletions(-)
diff --git libavcodec/ac3enc.c libavcodec/ac3enc.c
index 0db0846..5760794 100644
--- libavcodec/ac3enc.c
+++ libavcodec/ac3enc.c
@@ -361,25 +361,25 @@ static int calc_exp_diff(uint8_t *exp1, uint8_t *exp2, int n)
return sum;
}
-static void compute_exp_strategy(uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
- uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
- int ch, int is_lfe)
+static void compute_exp_strategy_ch(uint8_t exp_strategy[AC3_MAX_BLOCKS],
+ uint8_t *exp[AC3_MAX_BLOCKS],
+ int is_lfe)
{
int blk, blk1;
int exp_diff;
/* estimate if the exponent variation & decide if they should be
reused in the next frame */
- exp_strategy[0][ch] = EXP_NEW;
+ exp_strategy[0] = EXP_NEW;
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
- exp_diff = calc_exp_diff(exp[blk][ch], exp[blk-1][ch], AC3_MAX_COEFS);
+ exp_diff = calc_exp_diff(exp[blk], exp[blk-1], AC3_MAX_COEFS);
#ifdef DEBUG_EXPONENTS
dprintf(NULL, "exp_diff=%d\n", exp_diff);
#endif
if (exp_diff > EXP_DIFF_THRESHOLD)
- exp_strategy[blk][ch] = EXP_NEW;
+ exp_strategy[blk] = EXP_NEW;
else
- exp_strategy[blk][ch] = EXP_REUSE;
+ exp_strategy[blk] = EXP_REUSE;
}
if (is_lfe)
return;
@@ -389,24 +389,43 @@ static void compute_exp_strategy(uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CH
blk = 0;
while (blk < AC3_MAX_BLOCKS) {
blk1 = blk + 1;
- while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1][ch] == EXP_REUSE)
+ while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
blk1++;
switch(blk1 - blk) {
case 1:
- exp_strategy[blk][ch] = EXP_D45;
+ exp_strategy[blk] = EXP_D45;
break;
case 2:
case 3:
- exp_strategy[blk][ch] = EXP_D25;
+ exp_strategy[blk] = EXP_D25;
break;
default:
- exp_strategy[blk][ch] = EXP_D15;
+ exp_strategy[blk] = EXP_D15;
break;
}
blk = blk1;
}
}
+static void compute_exp_strategy(AC3EncodeContext *s,
+ uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
+ uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS])
+{
+ uint8_t *exp1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
+ uint8_t exp_str1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
+ int ch, blk;
+
+ for (ch = 0; ch < s->fbw_channels; ch++) {
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ exp1[ch][blk] = exp[blk][ch];
+ exp_str1[ch][blk] = exp_strategy[blk][ch];
+ }
+ compute_exp_strategy_ch(exp_str1[ch], exp1[ch], ch == s->lfe_ch);
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
+ exp_strategy[blk][ch] = exp_str1[ch][blk];
+ }
+}
+
/* set exp[i] to min(exp[i], exp1[i]) */
static void exponent_min(uint8_t exp[AC3_MAX_COEFS], uint8_t exp1[AC3_MAX_COEFS], int n)
{
@@ -521,13 +540,9 @@ static void process_exponents(AC3EncodeContext *s,
uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
int8_t exp_shift[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS])
{
- int ch;
-
calculate_exponents(s, mdct_coef, exp, exp_shift);
- for (ch = 0; ch < s->channels; ch++) {
- compute_exp_strategy(exp_strategy, exp, ch, ch == s->lfe_ch);
- }
+ compute_exp_strategy(s, exp_strategy, exp);
encode_exponents(s, exp, exp_strategy);
}
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