{"request_channels", "set desired number of audio channels", OFFSET(request_channels), FF_OPT_TYPE_INT, DEFAULT, 0, INT_MAX, A|D},
{"drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), FF_OPT_TYPE_FLOAT, 1.0, 0.0, 1.0, A|D},
{"reservoir", "use bit reservoir", 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_BIT_RESERVOIR, INT_MIN, INT_MAX, A|E, "flags2"},
+{"mbtree", "use macroblock tree ratecontrol (x264 only)", 0, FF_OPT_TYPE_CONST, CODEC_FLAG2_MBTREE, INT_MIN, INT_MAX, V|E, "flags2"},
{"bits_per_raw_sample", NULL, OFFSET(bits_per_raw_sample), FF_OPT_TYPE_INT, DEFAULT, INT_MIN, INT_MAX},
{"channel_layout", NULL, OFFSET(channel_layout), FF_OPT_TYPE_INT64, DEFAULT, 0, INT64_MAX, A|E|D, "channel_layout"},
{"request_channel_layout", NULL, OFFSET(request_channel_layout), FF_OPT_TYPE_INT64, DEFAULT, 0, INT64_MAX, A|D, "request_channel_layout"},