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ac3enc: restructure coupling coordinate reuse calculation

This commit is contained in:
Justin Ruggles 2011-08-05 17:34:53 -04:00
parent c3d63262fe
commit fce33f9ead
1 changed files with 27 additions and 21 deletions
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48
libavcodec/ac3enc_template.c
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@ -202,33 +202,29 @@ static void apply_channel_coupling(AC3EncodeContext *s)
bnd++;
}
/* calculate coupling coordinates for all blocks for all channels */
for (blk = 0; blk < s->num_blocks; blk++) {
AC3Block *block = &s->blocks[blk];
if (!block->cpl_in_use)
continue;
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (!block->channel_in_cpl[ch])
continue;
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
energy[blk][CPL_CH][bnd]);
}
}
}
/* determine which blocks to send new coupling coordinates for */
for (blk = 0; blk < s->num_blocks; blk++) {
AC3Block *block = &s->blocks[blk];
AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
CoefSumType coord_diff[AC3_MAX_CHANNELS] = {0,};
memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords));
if (block->cpl_in_use) {
/* calculate coupling coordinates for all blocks and calculate the
average difference between coordinates in successive blocks */
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (!block->channel_in_cpl[ch])
continue;
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
energy[blk][CPL_CH][bnd]);
if (blk > 0 && block0->cpl_in_use &&
block0->channel_in_cpl[ch]) {
coord_diff[ch] += fabs(cpl_coords[blk-1][ch][bnd] -
cpl_coords[blk ][ch][bnd]);
}
}
coord_diff[ch] /= s->num_cpl_bands;
}
/* send new coordinates if this is the first block, if previous
* block did not use coupling but this block does, the channels
* using coupling has changed from the previous block, or the
@ -239,8 +235,18 @@ static void apply_channel_coupling(AC3EncodeContext *s)
block->new_cpl_coords[ch] = 1;
} else {
for (ch = 1; ch <= s->fbw_channels; ch++) {
if ((block->channel_in_cpl[ch] && !block0->channel_in_cpl[ch]) ||
(block->channel_in_cpl[ch] && coord_diff[ch] > 0.03)) {
if (!block->channel_in_cpl[ch])
continue;
if (!block0->channel_in_cpl[ch]) {
block->new_cpl_coords[ch] = 1;
} else {
CoefSumType coord_diff = 0;
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
coord_diff += fabs(cpl_coords[blk-1][ch][bnd] -
cpl_coords[blk ][ch][bnd]);
}
coord_diff /= s->num_cpl_bands;
if (coord_diff > 0.03)
block->new_cpl_coords[ch] = 1;
}
}