vdpau: don't assume Picture and H264Picture are the same

The code passed H264Picture* and Picture*, and assumed the
hwaccel_picture_private field was in the same place in both
structs. Somehow this happened to work in Libav, but broke in
FFmpeg (and probably subtly breaks in Libav too).
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/vdpau.c

@@ -38,12 +38,10 @@
  * @{
  */
 
-int ff_vdpau_common_start_frame(Picture *pic,
+int ff_vdpau_common_start_frame(struct vdpau_picture_context *pic_ctx,
                                 av_unused const uint8_t *buffer,
                                 av_unused uint32_t size)
 {
-    struct vdpau_picture_context *pic_ctx = pic->hwaccel_picture_private;
-
     pic_ctx->bitstream_buffers_allocated = 0;
     pic_ctx->bitstream_buffers_used      = 0;
     pic_ctx->bitstream_buffers           = NULL;
@@ -71,9 +69,9 @@ int ff_vdpau_mpeg_end_frame(AVCodecContext *avctx)
 }
 #endif
 
-int ff_vdpau_add_buffer(Picture *pic, const uint8_t *buf, uint32_t size)
+int ff_vdpau_add_buffer(struct vdpau_picture_context *pic_ctx,
+                        const uint8_t *buf, uint32_t size)
 {
-    struct vdpau_picture_context *pic_ctx = pic->hwaccel_picture_private;
     VdpBitstreamBuffer *buffers = pic_ctx->bitstream_buffers;
 
     buffers = av_fast_realloc(buffers, &pic_ctx->bitstream_buffers_allocated,

libavcodec/vdpau_h264.c

@@ -162,7 +162,7 @@ static int vdpau_h264_start_frame(AVCodecContext *avctx,
 
     vdpau_h264_set_reference_frames(avctx);
 
-    return ff_vdpau_common_start_frame(pic, buffer, size);
+    return ff_vdpau_common_start_frame(pic_ctx, buffer, size);
 }
 
 static const uint8_t start_code_prefix[3] = { 0x00, 0x00, 0x01 };
@@ -175,11 +175,11 @@ static int vdpau_h264_decode_slice(AVCodecContext *avctx,
     struct vdpau_picture_context *pic_ctx = pic->hwaccel_picture_private;
     int val;
 
-    val = ff_vdpau_add_buffer(pic, start_code_prefix, 3);
+    val = ff_vdpau_add_buffer(pic_ctx, start_code_prefix, 3);
     if (val)
         return val;
 
-    val = ff_vdpau_add_buffer(pic, buffer, size);
+    val = ff_vdpau_add_buffer(pic_ctx, buffer, size);
     if (val)
         return val;
 

libavcodec/vdpau_internal.h

@@ -70,9 +70,10 @@ struct vdpau_picture_context {
     VdpBitstreamBuffer *bitstream_buffers;
 };
 
-int ff_vdpau_common_start_frame(Picture *pic,
+int ff_vdpau_common_start_frame(struct vdpau_picture_context *pic,
                                 const uint8_t *buffer, uint32_t size);
 int ff_vdpau_mpeg_end_frame(AVCodecContext *avctx);
-int ff_vdpau_add_buffer(Picture *pic, const uint8_t *buf, uint32_t buf_size);
+int ff_vdpau_add_buffer(struct vdpau_picture_context *pic, const uint8_t *buf,
+                        uint32_t buf_size);
 
 #endif /* AVCODEC_VDPAU_INTERNAL_H */

libavcodec/vdpau_mpeg12.c

@@ -75,7 +75,7 @@ static int vdpau_mpeg_start_frame(AVCodecContext *avctx,
         info->non_intra_quantizer_matrix[i] = s->inter_matrix[i];
     }
 
-    return ff_vdpau_common_start_frame(pic, buffer, size);
+    return ff_vdpau_common_start_frame(pic_ctx, buffer, size);
 }
 
 static int vdpau_mpeg_decode_slice(AVCodecContext *avctx,
@@ -86,7 +86,7 @@ static int vdpau_mpeg_decode_slice(AVCodecContext *avctx,
     struct vdpau_picture_context *pic_ctx = pic->hwaccel_picture_private;
     int val;
 
-    val = ff_vdpau_add_buffer(pic, buffer, size);
+    val = ff_vdpau_add_buffer(pic_ctx, buffer, size);
     if (val < 0)
         return val;
 

libavcodec/vdpau_mpeg4.c

@@ -77,8 +77,8 @@ static int vdpau_mpeg4_start_frame(AVCodecContext *avctx,
         info->non_intra_quantizer_matrix[i] = s->inter_matrix[i];
     }
 
-    ff_vdpau_common_start_frame(pic, buffer, size);
-    return ff_vdpau_add_buffer(pic, buffer, size);
+    ff_vdpau_common_start_frame(pic_ctx, buffer, size);
+    return ff_vdpau_add_buffer(pic_ctx, buffer, size);
 }
 
 static int vdpau_mpeg4_decode_slice(av_unused AVCodecContext *avctx,

libavcodec/vdpau_vc1.c

@@ -89,7 +89,7 @@ static int vdpau_vc1_start_frame(AVCodecContext *avctx,
     info->deblockEnable     = v->postprocflag & 1;
     info->pquant            = v->pq;
 
-    return ff_vdpau_common_start_frame(pic, buffer, size);
+    return ff_vdpau_common_start_frame(pic_ctx, buffer, size);
 }
 
 static int vdpau_vc1_decode_slice(AVCodecContext *avctx,
@@ -101,7 +101,7 @@ static int vdpau_vc1_decode_slice(AVCodecContext *avctx,
     struct vdpau_picture_context *pic_ctx = pic->hwaccel_picture_private;
     int val;
 
-    val = ff_vdpau_add_buffer(pic, buffer, size);
+    val = ff_vdpau_add_buffer(pic_ctx, buffer, size);
     if (val < 0)
         return val;