player: add complex filter graph support

See --lavfi-complex option.

This is still quite rough. There's no support for dynamic configuration
of any kind. There are probably corner cases where playback might freeze
or burn 100% CPU (due to dataflow problems when interaction with
libavfilter).

Future possible plans might include:
- freely switch tracks by providing some sort of default track graph
  label
- automatically enabling audio visualization
- automatically mix audio or stack video when multiple tracks are
  selected at once (similar to how multiple sub tracks can be selected)

1 files changed, 2 insertions, 0 deletions

diff --git a/options/options.c b/options/options.c
index 0377854c0e..4352b6ceed 100644
--- a/options/options.c
+++ b/options/options.c
@@ -226,6 +226,8 @@ const m_option_t mp_opts[] = {
     OPT_STRINGLIST("alang", stream_lang[STREAM_AUDIO], 0),
     OPT_STRINGLIST("slang", stream_lang[STREAM_SUB], 0),
 
+    OPT_STRING("lavfi-complex", lavfi_complex, 0),
+
     OPT_CHOICE("audio-display", audio_display, 0,
                ({"no", 0}, {"attachment", 1})),