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authorNicolas George <nicolas.george@normalesup.org>2013-02-21 14:02:13 +0100
committerNicolas George <nicolas.george@normalesup.org>2013-02-24 11:58:52 +0100
commit2d98dd3d142b5905852571a9c4c5d873945b2a37 (patch)
treeb951babb00a74f326f3b3be525dfc93a5fd8cb2f
parent3d7f4f87267cf260795f28de1f669c3f45e05a28 (diff)
downloadffmpeg-2d98dd3d142b5905852571a9c4c5d873945b2a37.tar.gz
lavfi: fix merging of formats and clarify exception.
The following commit: b97d61f avfilter/ff_merge_formats: only merge if doing so does not loose chroma or alpha introduced an exception to avoid lossy conversions. Add a comment to explain the logic. Fix the call to avoid applying it on audio formats.
-rw-r--r--libavfilter/avfiltergraph.c8
-rw-r--r--libavfilter/formats.c11
-rw-r--r--libavfilter/formats.h3
3 files changed, 16 insertions, 6 deletions
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 0bc8464e1d..d0b6b1687f 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -272,8 +272,8 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
continue;
if (link->in_formats != link->out_formats &&
- !ff_merge_formats(link->in_formats,
- link->out_formats))
+ !ff_merge_formats(link->in_formats, link->out_formats,
+ link->type))
convert_needed = 1;
if (link->type == AVMEDIA_TYPE_AUDIO) {
if (link->in_channel_layouts != link->out_channel_layouts &&
@@ -337,8 +337,8 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
filter_query_formats(convert);
inlink = convert->inputs[0];
outlink = convert->outputs[0];
- if (!ff_merge_formats( inlink->in_formats, inlink->out_formats) ||
- !ff_merge_formats(outlink->in_formats, outlink->out_formats))
+ if (!ff_merge_formats( inlink->in_formats, inlink->out_formats, inlink->type) ||
+ !ff_merge_formats(outlink->in_formats, outlink->out_formats, outlink->type))
ret |= AVERROR(ENOSYS);
if (inlink->type == AVMEDIA_TYPE_AUDIO &&
(!ff_merge_samplerates(inlink->in_samplerates,
diff --git a/libavfilter/formats.c b/libavfilter/formats.c
index eb9d94022c..58762806bf 100644
--- a/libavfilter/formats.c
+++ b/libavfilter/formats.c
@@ -89,7 +89,8 @@ do {
MERGE_REF(ret, b, fmts, type, fail); \
} while (0)
-AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b)
+AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b,
+ enum AVMediaType type)
{
AVFilterFormats *ret = NULL;
int i, j;
@@ -99,6 +100,14 @@ AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b)
if (a == b)
return a;
+ /* Do not lose chroma or alpha in merging.
+ It happens if both lists have formats with chroma (resp. alpha), but
+ the only formats in common do not have it (e.g. YUV+gray vs.
+ RGB+gray): in that case, the merging would select the gray format,
+ possibly causing a lossy conversion elsewhere in the graph.
+ To avoid that, pretend that there are no common formats to force the
+ insertion of a conversion filter. */
+ if (type == AVMEDIA_TYPE_VIDEO)
for (i = 0; i < a->format_count; i++)
for (j = 0; j < b->format_count; j++) {
const AVPixFmtDescriptor *adesc = av_pix_fmt_desc_get(a->formats[i]);
diff --git a/libavfilter/formats.h b/libavfilter/formats.h
index a476e70c2e..c06f6dfa3c 100644
--- a/libavfilter/formats.h
+++ b/libavfilter/formats.h
@@ -218,7 +218,8 @@ AVFilterFormats *ff_planar_sample_fmts(void);
* If a and b do not share any common formats, neither is modified, and NULL
* is returned.
*/
-AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
+AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b,
+ enum AVMediaType type);
/**
* Add *ref as a new reference to formats.