videotoolbox: add hwcontext support

This adds tons of code for no other benefit than making VideoToolbox
support conform with the new hwaccel API (using hw_device_ctx and
hw_frames_ctx).

Since VideoToolbox decoding does not actually require the user to
allocate frames, the new code does mostly nothing.

One benefit is that ffmpeg_videotoolbox.c can be dropped once generic
hwaccel support for ffmpeg.c is merged from Libav.

Does not consider VDA or VideoToolbox encoding.

Fun fact: the frame transfer functions are copied from vaapi, as the
mapping makes copying generic boilerplate. Mapping itself is not
exported by the VT code, because I don't know how to test.

1 files changed, 7 insertions, 0 deletions

diff --git a/libavcodec/vda_vt_internal.h b/libavcodec/vda_vt_internal.h
index 9ff63ccc52..e55a813899 100644
--- a/libavcodec/vda_vt_internal.h
+++ b/libavcodec/vda_vt_internal.h
@@ -40,6 +40,13 @@ typedef struct VTContext {
 
     // The core video buffer
     CVImageBufferRef            frame;
+
+    // Current dummy frames context (depends on exact CVImageBufferRef params).
+    struct AVBufferRef         *cached_hw_frames_ctx;
+
+    // Non-NULL if the new hwaccel API is used. This is only a separate struct
+    // to ease compatibility with the old API.
+    struct AVVideotoolboxContext *vt_ctx;
 } VTContext;
 
 int ff_videotoolbox_alloc_frame(AVCodecContext *avctx, AVFrame *frame);