encode: add locking

Since the AO will run in a thread, and there's lots of shared state with
encoding, we have to add locking.

One case this doesn't handle correctly are the encode_lavc_available()
calls in ao_lavc.c and vo_lavc.c. They don't do much (and usually only
to protect against doing --ao=lavc with normal playback), and changing
it would be a bit messy. So just leave them.

1 files changed, 7 insertions, 0 deletions

diff --git a/common/encode_lavc.h b/common/encode_lavc.h
index deaf42b684..af7f4fba3d 100644
--- a/common/encode_lavc.h
+++ b/common/encode_lavc.h
@@ -22,6 +22,8 @@
 #ifndef MPLAYER_ENCODE_LAVC_H
 #define MPLAYER_ENCODE_LAVC_H
 
+#include <pthread.h>
+
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 #include <libavutil/avstring.h>
@@ -37,6 +39,11 @@ struct encode_lavc_context {
     struct encode_output_conf *options;
     struct mp_log *log;
 
+    // All entry points must be guarded with the lock. Functions called by
+    // the playback core lock this automatically, but ao_lavc.c and vo_lavc.c
+    // must lock manually before accessing state.
+    pthread_mutex_t lock;
+
     float vo_fps;
 
     // these are processed from the options