avutil/hwcontext_vaapi: Allocate pub and priv frames hwctx together

This is possible because the lifetime of both coincide.
Besides reducing the number of allocations this also simplifies
access to VAAPIFramesContext as one no longer has to
go through AVHWFramesInternal.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/hwcontext_vaapi.c

@@ -86,6 +86,11 @@ typedef struct VAAPIDeviceContext {
 } VAAPIDeviceContext;
 
 typedef struct VAAPIFramesContext {
+    /**
+     * The public AVVAAPIFramesContext. See hwcontext_vaapi.h for it.
+     */
+    AVVAAPIFramesContext p;
+
     // Surface attributes set at create time.
     VASurfaceAttrib *attributes;
     int           nb_attributes;
@@ -503,9 +508,9 @@ static void vaapi_buffer_free(void *opaque, uint8_t *data)
 static AVBufferRef *vaapi_pool_alloc(void *opaque, size_t size)
 {
     AVHWFramesContext     *hwfc = opaque;
-    VAAPIFramesContext     *ctx = hwfc->internal->priv;
+    VAAPIFramesContext     *ctx = hwfc->hwctx;
+    AVVAAPIFramesContext  *avfc = &ctx->p;
     AVVAAPIDeviceContext *hwctx = hwfc->device_ctx->hwctx;
-    AVVAAPIFramesContext  *avfc = hwfc->hwctx;
     VASurfaceID surface_id;
     VAStatus vas;
     AVBufferRef *ref;
@@ -546,8 +551,8 @@ static AVBufferRef *vaapi_pool_alloc(void *opaque, size_t size)
 
 static int vaapi_frames_init(AVHWFramesContext *hwfc)
 {
-    AVVAAPIFramesContext  *avfc = hwfc->hwctx;
-    VAAPIFramesContext     *ctx = hwfc->internal->priv;
+    VAAPIFramesContext     *ctx = hwfc->hwctx;
+    AVVAAPIFramesContext  *avfc = &ctx->p;
     AVVAAPIDeviceContext *hwctx = hwfc->device_ctx->hwctx;
     const VAAPIFormatDescriptor *desc;
     VAImageFormat *expected_format;
@@ -698,8 +703,8 @@ fail:
 
 static void vaapi_frames_uninit(AVHWFramesContext *hwfc)
 {
-    AVVAAPIFramesContext *avfc = hwfc->hwctx;
-    VAAPIFramesContext    *ctx = hwfc->internal->priv;
+    VAAPIFramesContext    *ctx = hwfc->hwctx;
+    AVVAAPIFramesContext *avfc = &ctx->p;
 
     av_freep(&avfc->surface_ids);
     av_freep(&ctx->attributes);
@@ -796,7 +801,7 @@ static int vaapi_map_frame(AVHWFramesContext *hwfc,
                            AVFrame *dst, const AVFrame *src, int flags)
 {
     AVVAAPIDeviceContext *hwctx = hwfc->device_ctx->hwctx;
-    VAAPIFramesContext *ctx = hwfc->internal->priv;
+    VAAPIFramesContext *ctx = hwfc->hwctx;
     VASurfaceID surface_id;
     const VAAPIFormatDescriptor *desc;
     VAImageFormat *image_format;
@@ -1075,7 +1080,7 @@ static int vaapi_map_from_drm(AVHWFramesContext *src_fc, AVFrame *dst,
                               const AVFrame *src, int flags)
 {
 #if VA_CHECK_VERSION(1, 1, 0)
-    VAAPIFramesContext     *src_vafc = src_fc->internal->priv;
+    VAAPIFramesContext    *src_vafc = src_fc->hwctx;
     int use_prime2;
 #else
     int k;
@@ -2014,8 +2019,7 @@ const HWContextType ff_hwcontext_type_vaapi = {
 
     .device_hwctx_size      = sizeof(VAAPIDeviceContext),
     .device_hwconfig_size   = sizeof(AVVAAPIHWConfig),
-    .frames_hwctx_size      = sizeof(AVVAAPIFramesContext),
-    .frames_priv_size       = sizeof(VAAPIFramesContext),
+    .frames_hwctx_size      = sizeof(VAAPIFramesContext),
 
     .device_create          = &vaapi_device_create,
     .device_derive          = &vaapi_device_derive,