vdpau: add a constructor for AVVDPAUContext.

We will likely want to add new fields to it in the future, so this is
needed to avoid breaking ABI.

2 files changed, 16 insertions, 0 deletions

diff --git a/libavcodec/vdpau.c b/libavcodec/vdpau.c
index cc0bcffc5f..d8a35eeb3b 100644
--- a/libavcodec/vdpau.c
+++ b/libavcodec/vdpau.c
@@ -133,4 +133,9 @@ do {                        \
     return AVERROR(EINVAL);
 }
 
+AVVDPAUContext *av_vdpau_alloc_context(void)
+{
+    return av_mallocz(sizeof(AVVDPAUContext));
+}
+
 /* @}*/
diff --git a/libavcodec/vdpau.h b/libavcodec/vdpau.h
index bf8c8e8b2c..75cb1bf7a3 100644
--- a/libavcodec/vdpau.h
+++ b/libavcodec/vdpau.h
@@ -74,6 +74,10 @@ union AVVDPAUPictureInfo {
  * during initialization or through each AVCodecContext.get_buffer()
  * function call. In any case, they must be valid prior to calling
  * decoding functions.
+ *
+ * The size of this structure is not a part of the public ABI and must not
+ * be used outside of libavcodec. Use av_vdpau_alloc_context() to allocate an
+ * AVVDPAUContext.
  */
 typedef struct AVVDPAUContext {
     /**
@@ -127,6 +131,13 @@ typedef struct AVVDPAUContext {
 } AVVDPAUContext;
 
 /**
+ * Allocate an AVVDPAUContext.
+ *
+ * @return Newly-allocated AVVDPAUContext or NULL on failure.
+ */
+AVVDPAUContext *av_vdpau_alloc_context(void);
+
+/**
  * Get a decoder profile that should be used for initializing a VDPAU decoder.
  * Should be called from the AVCodecContext.get_format() callback.
  *