MERGE_REF          88 libavfilter/formats.c     MERGE_REF(ret, a, fmts, type, fail);                                        \
MERGE_REF          89 libavfilter/formats.c     MERGE_REF(ret, b, fmts, type, fail);                                        \
MERGE_REF         149 libavfilter/formats.c         MERGE_REF(a, b, formats, AVFilterFormats, fail);
MERGE_REF         152 libavfilter/formats.c         MERGE_REF(b, a, formats, AVFilterFormats, fail);
MERGE_REF         193 libavfilter/formats.c         MERGE_REF(b, a, channel_layouts, AVFilterChannelLayouts, fail);
MERGE_REF         241 libavfilter/formats.c     MERGE_REF(ret, a, channel_layouts, AVFilterChannelLayouts, fail);
MERGE_REF         242 libavfilter/formats.c     MERGE_REF(ret, b, channel_layouts, AVFilterChannelLayouts, fail);