CH_FRONT_PAIR 917 libavfilter/avfiltergraph.c { CH_FRONT_PAIR, CH_CENTER_PAIR }, CH_FRONT_PAIR 918 libavfilter/avfiltergraph.c { CH_FRONT_PAIR, CH_WIDE_PAIR }, CH_FRONT_PAIR 919 libavfilter/avfiltergraph.c { CH_FRONT_PAIR, AV_CH_FRONT_CENTER }, CH_FRONT_PAIR 920 libavfilter/avfiltergraph.c { CH_CENTER_PAIR, CH_FRONT_PAIR }, CH_FRONT_PAIR 923 libavfilter/avfiltergraph.c { CH_WIDE_PAIR, CH_FRONT_PAIR }, CH_FRONT_PAIR 926 libavfilter/avfiltergraph.c { AV_CH_FRONT_CENTER, CH_FRONT_PAIR },