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lavfi: better channel layout negotiation

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Allow substitution of channel pairs in the input for nearby channel pairs in
the output in order to get a closer match. Also weigh LFE channel mismatch
differently to favor matching the same layout without LFE over one less
channel with LFE.
This commit is contained in:
Justin Ruggles 2012-07-13 20:22:08 -04:00
parent 81f548de57
commit 743f07062a
1 changed files with 72 additions and 11 deletions
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83
libavfilter/avfiltergraph.c
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@ -424,11 +424,44 @@ static void swap_samplerates(AVFilterGraph *graph)
swap_samplerates_on_filter(graph->filters[i]);
}
#define CH_CENTER_PAIR (AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER)
#define CH_FRONT_PAIR (AV_CH_FRONT_LEFT | AV_CH_FRONT_RIGHT)
#define CH_STEREO_PAIR (AV_CH_STEREO_LEFT | AV_CH_STEREO_RIGHT)
#define CH_WIDE_PAIR (AV_CH_WIDE_LEFT | AV_CH_WIDE_RIGHT)
#define CH_SIDE_PAIR (AV_CH_SIDE_LEFT | AV_CH_SIDE_RIGHT)
#define CH_DIRECT_PAIR (AV_CH_SURROUND_DIRECT_LEFT | AV_CH_SURROUND_DIRECT_RIGHT)
#define CH_BACK_PAIR (AV_CH_BACK_LEFT | AV_CH_BACK_RIGHT)
/* allowable substitutions for channel pairs when comparing layouts,
* ordered by priority for both values */
static const uint64_t ch_subst[][2] = {
{ CH_FRONT_PAIR, CH_CENTER_PAIR },
{ CH_FRONT_PAIR, CH_WIDE_PAIR },
{ CH_FRONT_PAIR, AV_CH_FRONT_CENTER },
{ CH_CENTER_PAIR, CH_FRONT_PAIR },
{ CH_CENTER_PAIR, CH_WIDE_PAIR },
{ CH_CENTER_PAIR, AV_CH_FRONT_CENTER },
{ CH_WIDE_PAIR, CH_FRONT_PAIR },
{ CH_WIDE_PAIR, CH_CENTER_PAIR },
{ CH_WIDE_PAIR, AV_CH_FRONT_CENTER },
{ AV_CH_FRONT_CENTER, CH_FRONT_PAIR },
{ AV_CH_FRONT_CENTER, CH_CENTER_PAIR },
{ AV_CH_FRONT_CENTER, CH_WIDE_PAIR },
{ CH_SIDE_PAIR, CH_DIRECT_PAIR },
{ CH_SIDE_PAIR, CH_BACK_PAIR },
{ CH_SIDE_PAIR, AV_CH_BACK_CENTER },
{ CH_BACK_PAIR, CH_DIRECT_PAIR },
{ CH_BACK_PAIR, CH_SIDE_PAIR },
{ CH_BACK_PAIR, AV_CH_BACK_CENTER },
{ AV_CH_BACK_CENTER, CH_BACK_PAIR },
{ AV_CH_BACK_CENTER, CH_DIRECT_PAIR },
{ AV_CH_BACK_CENTER, CH_SIDE_PAIR },
};
static void swap_channel_layouts_on_filter(AVFilterContext *filter)
{
AVFilterLink *link = NULL;
uint64_t chlayout;
int i, j;
int i, j, k;
for (i = 0; i < filter->nb_inputs; i++) {
link = filter->inputs[i];
@ -440,27 +473,55 @@ static void swap_channel_layouts_on_filter(AVFilterContext *filter)
if (i == filter->nb_inputs)
return;
chlayout = link->out_channel_layouts->channel_layouts[0];
for (i = 0; i < filter->nb_outputs; i++) {
AVFilterLink *outlink = filter->outputs[i];
int best_idx, best_score = INT_MIN;
int best_idx, best_score = INT_MIN, best_count_diff = INT_MAX;
if (outlink->type != AVMEDIA_TYPE_AUDIO ||
outlink->in_channel_layouts->nb_channel_layouts < 2)
continue;
for (j = 0; j < outlink->in_channel_layouts->nb_channel_layouts; j++) {
uint64_t in_chlayout = link->out_channel_layouts->channel_layouts[0];
uint64_t out_chlayout = outlink->in_channel_layouts->channel_layouts[j];
int matched_channels = av_get_channel_layout_nb_channels(chlayout &
out_chlayout);
int extra_channels = av_get_channel_layout_nb_channels(out_chlayout &
(~chlayout));
int score = matched_channels - extra_channels;
int in_channels = av_get_channel_layout_nb_channels(in_chlayout);
int out_channels = av_get_channel_layout_nb_channels(out_chlayout);
int count_diff = out_channels - in_channels;
int matched_channels, extra_channels;
int score = 0;
if (score > best_score) {
/* channel substitution */
for (k = 0; k < FF_ARRAY_ELEMS(ch_subst); k++) {
uint64_t cmp0 = ch_subst[k][0];
uint64_t cmp1 = ch_subst[k][1];
if (( in_chlayout & cmp0) && (!(out_chlayout & cmp0)) &&
(out_chlayout & cmp1) && (!( in_chlayout & cmp1))) {
in_chlayout &= ~cmp0;
out_chlayout &= ~cmp1;
/* add score for channel match, minus a deduction for
having to do the substitution */
score += 10 * av_get_channel_layout_nb_channels(cmp1) - 2;
}
}
/* no penalty for LFE channel mismatch */
if ( (in_chlayout & AV_CH_LOW_FREQUENCY) &&
(out_chlayout & AV_CH_LOW_FREQUENCY))
score += 10;
in_chlayout &= ~AV_CH_LOW_FREQUENCY;
out_chlayout &= ~AV_CH_LOW_FREQUENCY;
matched_channels = av_get_channel_layout_nb_channels(in_chlayout &
out_chlayout);
extra_channels = av_get_channel_layout_nb_channels(out_chlayout &
(~in_chlayout));
score += 10 * matched_channels - 5 * extra_channels;
if (score > best_score ||
(count_diff < best_count_diff && score == best_score)) {
best_score = score;
best_idx = j;
best_count_diff = count_diff;
}
}
FFSWAP(uint64_t, outlink->in_channel_layouts->channel_layouts[0],