No speed difference, and this will allow for more flexible bit counting.
---
libavcodec/ac3enc.c | 47 +++++++++++++++++++++++++++++++----------------
1 files changed, 31 insertions(+), 16 deletions(-)
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 95bdc58..bb3490a 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -1008,6 +1008,34 @@ static void reset_block_bap(AC3EncodeContext *s)
/**
+ * Count the number of mantissa bits in the frame based on the bap values.
+ */
+static int count_mantissa_bits(AC3EncodeContext *s)
+{
+ int blk, ch;
+ int mantissa_bits;
+ int mant_cnt[5];
+
+ mantissa_bits = 0;
+ for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+ // initialize grouped mantissa counts. these are set so that they are
+ // padded to the next whole group size when bits are counted in
+ // compute_mantissa_size_final
+ mant_cnt[0] = mant_cnt[3] = 0;
+ mant_cnt[1] = mant_cnt[2] = 2;
+ mant_cnt[4] = 1;
+ for (ch = 0; ch < s->channels; ch++) {
+ mantissa_bits += s->ac3dsp.compute_mantissa_size(mant_cnt,
+ s->blocks[blk].exp_ref_block[ch]->bap[ch],
+ s->nb_coefs[ch]);
+ }
+ mantissa_bits += compute_mantissa_size_final(mant_cnt);
+ }
+ return mantissa_bits;
+}
+
+
+/**
* 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.
@@ -1017,42 +1045,29 @@ static void reset_block_bap(AC3EncodeContext *s)
static int bit_alloc(AC3EncodeContext *s, int snr_offset)
{
int blk, ch;
- int mantissa_bits;
- int mant_cnt[5];
snr_offset = (snr_offset - 240) << 2;
reset_block_bap(s);
- mantissa_bits = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
- AC3Block *ref_block;
- // initialize grouped mantissa counts. these are set so that they are
- // padded to the next whole group size when bits are counted in
- // compute_mantissa_size_final
- mant_cnt[0] = mant_cnt[3] = 0;
- mant_cnt[1] = mant_cnt[2] = 2;
- mant_cnt[4] = 1;
for (ch = 0; ch < s->channels; ch++) {
/* Currently the only bit allocation parameters which vary across
blocks within a frame are the exponent values. We can take
advantage of that by reusing the bit allocation pointers
whenever we reuse exponents. */
- ref_block = block->exp_ref_block[ch];
if (s->exp_strategy[ch][blk] != EXP_REUSE) {
+ AC3Block *ref_block = block->exp_ref_block[ch];
s->ac3dsp.bit_alloc_calc_bap(ref_block->mask[ch],
ref_block->psd[ch], 0,
s->nb_coefs[ch], snr_offset,
s->bit_alloc.floor, ff_ac3_bap_tab,
ref_block->bap[ch]);
}
- mantissa_bits += s->ac3dsp.compute_mantissa_size(mant_cnt,
- ref_block->bap[ch],
- s->nb_coefs[ch]);
}
- mantissa_bits += compute_mantissa_size_final(mant_cnt);
}
- return mantissa_bits;
+
+ return count_mantissa_bits(s);
}
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