mplayer: selectively reset track selection when playing multiple files

Normally, video/audio/sub track selection is persistent across files
played in the same mplayer instance. This is wanted, because settings
should not be reset across files in general. However, if the track
layout of a file is completely different from the previous, this will
essentially select random tracks. In this case, keeping the track
selection is confusing and unwanted.

Reset the track selection to default if the track layout changes. The
track layout is determined by number of tracks, track order, default
flag, whether the track is an external subtitle, and track language.
If a track layout change is detected when playing a new file, the -sid,
-aid and -vid options are reset to "auto".

This behavior is enabled only if the user selects tracks manually (via
keybinds and the "switch_audio" slave properties etc.). If no user
interactions take place, options specified on the command line will
follow the old behavior.

1 files changed, 1 insertions, 0 deletions

diff --git a/mp_core.h b/mp_core.h
index e42beb40c5..9a9c6589e9 100644
--- a/mp_core.h
+++ b/mp_core.h
@@ -251,6 +251,7 @@ typedef struct MPContext {
 
     struct screenshot_ctx *screenshot_ctx;
 
+    char *track_layout_hash;
 } MPContext;