vo_opengl: add direct rendering support

Can be enabled via --vd-lavc-dr=yes. See manpage additions for what it
does.

This reminds of the MPlayer -dr flag, but the implementation is
completely different. It's the same basic concept: letting the decoder
render into a GPU buffer to avoid a copy. Unlike MPlayer, this doesn't
try to go through filters (libavfilter doesn't support this anyway).
Unless a filter can work in-place, DR will be silently disabled. MPlayer
had very complex semantics about buffer types and management (which
apparently nobody ever understood) and weird restrictions that mostly
limited it to mpeg2 style codecs. The mpv code does not do any of this,
and just lets the decoder allocate an arbitrary number of untyped
images. (No MPlayer code was used.)

Parts of the code based on work by atomnuker (starting point for the
generic code) and haasn (some GL definitions, some basic PBO code, and
correct fencing).

1 files changed, 7 insertions, 0 deletions

diff --git a/video/decode/lavc.h b/video/decode/lavc.h
index 44b103e3f5..9e27a6e18c 100644
--- a/video/decode/lavc.h
+++ b/video/decode/lavc.h
@@ -2,6 +2,7 @@
 #define MPV_LAVC_H
 
 #include <stdbool.h>
+#include <pthread.h>
 
 #include <libavcodec/avcodec.h>
 
@@ -72,6 +73,12 @@ typedef struct lavc_ctx {
     struct mp_image_pool *hwdec_swpool;
 
     AVBufferRef *cached_hw_frames_ctx;
+
+    // --- The following fields are protected by dr_lock.
+    pthread_mutex_t dr_lock;
+    bool dr_failed;
+    struct mp_image_pool *dr_pool;
+    int dr_imgfmt, dr_w, dr_h, dr_stride_align;
 } vd_ffmpeg_ctx;
 
 struct vd_lavc_hwdec {