/**
- * Calculate exponent strategies for all blocks in a single channel.
- */
-static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
- uint8_t *exp)
-{
- int blk, blk1;
- int exp_diff;
-
- /* estimate if the exponent variation & decide if they should be
- reused in the next frame */
- exp_strategy[0] = EXP_NEW;
- exp += AC3_MAX_COEFS;
- for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
- exp_diff = s->dsp.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
- if (exp_diff > EXP_DIFF_THRESHOLD)
- exp_strategy[blk] = EXP_NEW;
- else
- exp_strategy[blk] = EXP_REUSE;
- exp += AC3_MAX_COEFS;
- }
-
- /* now select the encoding strategy type : if exponents are often
- recoded, we use a coarse encoding */
- blk = 0;
- while (blk < AC3_MAX_BLOCKS) {
- blk1 = blk + 1;
- while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
- blk1++;
- switch (blk1 - blk) {
- case 1: exp_strategy[blk] = EXP_D45; break;
- case 2:
- case 3: exp_strategy[blk] = EXP_D25; break;
- default: exp_strategy[blk] = EXP_D15; break;
- }
- blk = blk1;
- }
-}
-
-
-/**
* Calculate exponent strategies for all channels.
* Array arrangement is reversed to simplify the per-channel calculation.
*/
static void compute_exp_strategy(AC3EncodeContext *s)
{
- int ch, blk;
+ int ch, blk, blk1;
for (ch = 0; ch < s->fbw_channels; ch++) {
- compute_exp_strategy_ch(s, s->exp_strategy[ch], s->blocks[0].exp[ch]);
+ uint8_t *exp_strategy = s->exp_strategy[ch];
+ uint8_t *exp = s->blocks[0].exp[ch];
+ int exp_diff;
+
+ /* estimate if the exponent variation & decide if they should be
+ reused in the next frame */
+ exp_strategy[0] = EXP_NEW;
+ exp += AC3_MAX_COEFS;
+ for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
+ exp_diff = s->dsp.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
+ if (exp_diff > EXP_DIFF_THRESHOLD)
+ exp_strategy[blk] = EXP_NEW;
+ else
+ exp_strategy[blk] = EXP_REUSE;
+ exp += AC3_MAX_COEFS;
+ }
+
+ /* now select the encoding strategy type : if exponents are often
+ recoded, we use a coarse encoding */
+ blk = 0;
+ while (blk < AC3_MAX_BLOCKS) {
+ blk1 = blk + 1;
+ while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
+ blk1++;
+ switch (blk1 - blk) {
+ case 1: exp_strategy[blk] = EXP_D45; break;
+ case 2:
+ case 3: exp_strategy[blk] = EXP_D25; break;
+ default: exp_strategy[blk] = EXP_D15; break;
+ }
+ blk = blk1;
+ }
}
if (s->lfe_on) {
ch = s->lfe_channel;