lavfi: check refcount before merging.

When merging the formats around the automatically inserted
convert filters, the refcount of the format lists can not be 0.
Coverity does not detect it, and suspects a memory leak,
because if refcount is 0 the newly allocated lists are not
stored anywhere. That gives CIDs 1224282, 1224283 and 1224284.
Lists with refcount 0 are used in can_merge_formats(), so the
asserts can not be moved inside the merge functions.

diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index f12491ea180bcd8e7c47405af46420f1d640daca..9178939f771609ee6663732b4721e00007261d9b 100644 (file)
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -562,6 +562,20 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
                 filter_query_formats(convert);
                 inlink  = convert->inputs[0];
                 outlink = convert->outputs[0];
+                av_assert0( inlink-> in_formats->refcount > 0);
+                av_assert0( inlink->out_formats->refcount > 0);
+                av_assert0(outlink-> in_formats->refcount > 0);
+                av_assert0(outlink->out_formats->refcount > 0);
+                if (outlink->type == AVMEDIA_TYPE_AUDIO) {
+                    av_assert0( inlink-> in_samplerates->refcount > 0);
+                    av_assert0( inlink->out_samplerates->refcount > 0);
+                    av_assert0(outlink-> in_samplerates->refcount > 0);
+                    av_assert0(outlink->out_samplerates->refcount > 0);
+                    av_assert0( inlink-> in_channel_layouts->refcount > 0);
+                    av_assert0( inlink->out_channel_layouts->refcount > 0);
+                    av_assert0(outlink-> in_channel_layouts->refcount > 0);
+                    av_assert0(outlink->out_channel_layouts->refcount > 0);
+                }
                 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);