lavc: external hardware frame pool initialization

This adds a new API, which allows the API user to query the required
AVHWFramesContext parameters. This also reduces code duplication across
the hwaccels by introducing ff_decode_get_hw_frames_ctx(), which uses
the new API function. It takes care of initializing the hw_frames_ctx
if needed, and does additional error handling and API usage checking.

Support for VDA and Cuvid missing.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

doc/APIchanges

@@ -13,6 +13,9 @@ libavutil:     2017-03-23
 
 API changes, most recent first:
 
+2017-xx-xx - xxxxxxx - lavc 58.5.0 - avcodec.h
+  Add avcodec_get_hw_frames_parameters().
+
 2017-xx-xx - xxxxxxx - lavu 56.6.0 - pixdesc.h
   Add av_color_range_from_name(), av_color_primaries_from_name(),
   av_color_transfer_from_name(), av_color_space_from_name(), and

libavcodec/avcodec.h

@@ -2990,6 +2990,16 @@ typedef struct AVHWAccel {
      * Internal hwaccel capabilities.
      */
     int caps_internal;
+
+    /**
+     * Fill the given hw_frames context with current codec parameters. Called
+     * from get_format. Refer to avcodec_get_hw_frames_parameters() for
+     * details.
+     *
+     * This CAN be called before AVHWAccel.init is called, and you must assume
+     * that avctx->hwaccel_priv_data is invalid.
+     */
+    int (*frame_params)(AVCodecContext *avctx, AVBufferRef *hw_frames_ctx);
 } AVHWAccel;
 
 /**
@@ -3984,6 +3994,109 @@ int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame);
  */
 int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt);
 
+/**
+ * Create and return a AVHWFramesContext with values adequate for hardware
+ * decoding. This is meant to get called from the get_format callback, and is
+ * a helper for preparing a AVHWFramesContext for AVCodecContext.hw_frames_ctx.
+ * This API is for decoding with certain hardware acceleration modes/APIs only.
+ *
+ * The returned AVHWFramesContext is not initialized. The caller must do this
+ * with av_hwframe_ctx_init().
+ *
+ * Calling this function is not a requirement, but makes it simpler to avoid
+ * codec or hardware API specific details when manually allocating frames.
+ *
+ * Alternatively to this, an API user can set AVCodecContext.hw_device_ctx,
+ * which sets up AVCodecContext.hw_frames_ctx fully automatically, and makes
+ * it unnecessary to call this function or having to care about
+ * AVHWFramesContext initialization at all.
+ *
+ * There are a number of requirements for calling this function:
+ *
+ * - It must be called from get_format with the same avctx parameter that was
+ *   passed to get_format. Calling it outside of get_format is not allowed, and
+ *   can trigger undefined behavior.
+ * - The function is not always supported (see description of return values).
+ *   Even if this function returns successfully, hwaccel initialization could
+ *   fail later. (The degree to which implementations check whether the stream
+ *   is actually supported varies. Some do this check only after the user's
+ *   get_format callback returns.)
+ * - The hw_pix_fmt must be one of the choices suggested by get_format. If the
+ *   user decides to use a AVHWFramesContext prepared with this API function,
+ *   the user must return the same hw_pix_fmt from get_format.
+ * - The device_ref passed to this function must support the given hw_pix_fmt.
+ * - After calling this API function, it is the user's responsibility to
+ *   initialize the AVHWFramesContext (returned by the out_frames_ref parameter),
+ *   and to set AVCodecContext.hw_frames_ctx to it. If done, this must be done
+ *   before returning from get_format (this is implied by the normal
+ *   AVCodecContext.hw_frames_ctx API rules).
+ * - The AVHWFramesContext parameters may change every time time get_format is
+ *   called. Also, AVCodecContext.hw_frames_ctx is reset before get_format. So
+ *   you are inherently required to go through this process again on every
+ *   get_format call.
+ * - It is perfectly possible to call this function without actually using
+ *   the resulting AVHWFramesContext. One use-case might be trying to reuse a
+ *   previously initialized AVHWFramesContext, and calling this API function
+ *   only to test whether the required frame parameters have changed.
+ * - Fields that use dynamically allocated values of any kind must not be set
+ *   by the user unless setting them is explicitly allowed by the documentation.
+ *   If the user sets AVHWFramesContext.free and AVHWFramesContext.user_opaque,
+ *   the new free callback must call the potentially set previous free callback.
+ *   This API call may set any dynamically allocated fields, including the free
+ *   callback.
+ *
+ * The function will set at least the following fields on AVHWFramesContext
+ * (potentially more, depending on hwaccel API):
+ *
+ * - All fields set by av_hwframe_ctx_alloc().
+ * - Set the format field to hw_pix_fmt.
+ * - Set the sw_format field to the most suited and most versatile format. (An
+ *   implication is that this will prefer generic formats over opaque formats
+ *   with arbitrary restrictions, if possible.)
+ * - Set the width/height fields to the coded frame size, rounded up to the
+ *   API-specific minimum alignment.
+ * - Only _if_ the hwaccel requires a pre-allocated pool: set the initial_pool_size
+ *   field to the number of maximum reference surfaces possible with the codec,
+ *   plus 1 surface for the user to work (meaning the user can safely reference
+ *   at most 1 decoded surface at a time), plus additional buffering introduced
+ *   by frame threading. If the hwaccel does not require pre-allocation, the
+ *   field is left to 0, and the decoder will allocate new surfaces on demand
+ *   during decoding.
+ * - Possibly AVHWFramesContext.hwctx fields, depending on the underlying
+ *   hardware API.
+ *
+ * Essentially, out_frames_ref returns the same as av_hwframe_ctx_alloc(), but
+ * with basic frame parameters set.
+ *
+ * The function is stateless, and does not change the AVCodecContext or the
+ * device_ref AVHWDeviceContext.
+ *
+ * @param avctx The context which is currently calling get_format, and which
+ *              implicitly contains all state needed for filling the returned
+ *              AVHWFramesContext properly.
+ * @param device_ref A reference to the AVHWDeviceContext describing the device
+ *                   which will be used by the hardware decoder.
+ * @param hw_pix_fmt The hwaccel format you are going to return from get_format.
+ * @param out_frames_ref On success, set to a reference to an _uninitialized_
+ *                       AVHWFramesContext, created from the given device_ref.
+ *                       Fields will be set to values required for decoding.
+ *                       Not changed if an error is returned.
+ * @return zero on success, a negative value on error. The following error codes
+ *         have special semantics:
+ *      AVERROR(ENOENT): the decoder does not support this functionality. Setup
+ *                       is always manual, or it is a decoder which does not
+ *                       support setting AVCodecContext.hw_frames_ctx at all,
+ *                       or it is a software format.
+ *      AVERROR(EINVAL): it is known that hardware decoding is not supported for
+ *                       this configuration, or the device_ref is not supported
+ *                       for the hwaccel referenced by hw_pix_fmt.
+ */
+int avcodec_get_hw_frames_parameters(AVCodecContext *avctx,
+                                     AVBufferRef *device_ref,
+                                     enum AVPixelFormat hw_pix_fmt,
+                                     AVBufferRef **out_frames_ref);
+
+
 
 /**
  * @defgroup lavc_parsing Frame parsing

libavcodec/decode.c

@@ -669,6 +669,88 @@ static AVHWAccel *find_hwaccel(enum AVCodecID codec_id,
     return NULL;
 }
 
+int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
+                                enum AVHWDeviceType dev_type)
+{
+    AVHWDeviceContext *device_ctx;
+    AVHWFramesContext *frames_ctx;
+    int ret;
+
+    if (!avctx->hwaccel)
+        return AVERROR(ENOSYS);
+
+    if (avctx->hw_frames_ctx)
+        return 0;
+    if (!avctx->hw_device_ctx) {
+        av_log(avctx, AV_LOG_ERROR, "A hardware frames or device context is "
+                "required for hardware accelerated decoding.\n");
+        return AVERROR(EINVAL);
+    }
+
+    device_ctx = (AVHWDeviceContext *)avctx->hw_device_ctx->data;
+    if (device_ctx->type != dev_type) {
+        av_log(avctx, AV_LOG_ERROR, "Device type %s expected for hardware "
+               "decoding, but got %s.\n", av_hwdevice_get_type_name(dev_type),
+               av_hwdevice_get_type_name(device_ctx->type));
+        return AVERROR(EINVAL);
+    }
+
+    ret = avcodec_get_hw_frames_parameters(avctx,
+                                           avctx->hw_device_ctx,
+                                           avctx->hwaccel->pix_fmt,
+                                           avctx->hw_frames_ctx);
+    if (ret < 0) {
+        av_buffer_unref(&avctx->hw_frames_ctx);
+        return ret;
+    }
+
+    frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
+
+
+    if (frames_ctx->initial_pool_size) {
+        // We guarantee 4 base work surfaces. The function above guarantees 1
+        // (the absolute minimum), so add the missing count.
+        frames_ctx->initial_pool_size += 3;
+
+        // Add an additional surface per thread is frame threading is enabled.
+        if (avctx->active_thread_type & FF_THREAD_FRAME)
+            frames_ctx->initial_pool_size += avctx->thread_count;
+    }
+
+    ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);
+    if (ret < 0) {
+        av_buffer_unref(&avctx->hw_frames_ctx);
+        return ret;
+    }
+
+    return 0;
+}
+
+int avcodec_get_hw_frames_parameters(AVCodecContext *avctx,
+                                     AVBufferRef *device_ref,
+                                     enum AVPixelFormat hw_pix_fmt,
+                                     AVBufferRef **out_frames_ref)
+{
+    AVBufferRef *frames_ref = NULL;
+    AVHWAccel *hwa = find_hwaccel(avctx->codec_id, hw_pix_fmt);
+    int ret;
+
+    if (!hwa || !hwa->frame_params)
+        return AVERROR(ENOENT);
+
+    frames_ref = av_hwframe_ctx_alloc(device_ref);
+    if (!frames_ref)
+        return AVERROR(ENOMEM);
+
+    ret = hwa->frame_params(avctx, frames_ref);
+    if (ret >= 0) {
+        *out_frames_ref = frames_ref;
+    } else {
+        av_buffer_unref(&frames_ref);
+    }
+    return ret;
+}
+
 static int setup_hwaccel(AVCodecContext *avctx,
                          const enum AVPixelFormat fmt,
                          const char *name)

libavcodec/decode.h

@@ -23,6 +23,7 @@
 
 #include "libavutil/buffer.h"
 #include "libavutil/frame.h"
+#include "libavutil/hwcontext.h"
 
 #include "avcodec.h"
 
@@ -70,4 +71,12 @@ int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt);
 
 void ff_decode_bsfs_uninit(AVCodecContext *avctx);
 
+/**
+ * Make sure avctx.hw_frames_ctx is set. If it's not set, the function will
+ * try to allocate it from hw_device_ctx. If that is not possible, an error
+ * message is printed, and an error code is returned.
+ */
+int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx,
+                                enum AVHWDeviceType dev_type);
+
 #endif /* AVCODEC_DECODE_H */

libavcodec/dxva2.c

@@ -29,6 +29,7 @@
 #include "libavutil/time.h"
 
 #include "avcodec.h"
+#include "decode.h"
 #include "dxva2_internal.h"
 
 /* define all the GUIDs used directly here,
@@ -572,14 +573,20 @@ static void ff_dxva2_unlock(AVCodecContext *avctx)
 #endif
 }
 
-// This must work before the decoder is created.
-// This somehow needs to be exported to the user.
-static void dxva_adjust_hwframes(AVCodecContext *avctx, AVHWFramesContext *frames_ctx)
+int ff_dxva2_common_frame_params(AVCodecContext *avctx,
+                                 AVBufferRef *hw_frames_ctx)
 {
-    FFDXVASharedContext *sctx = DXVA_SHARED_CONTEXT(avctx);
+    AVHWFramesContext *frames_ctx = (AVHWFramesContext *)hw_frames_ctx->data;
+    AVHWDeviceContext *device_ctx = frames_ctx->device_ctx;
     int surface_alignment, num_surfaces;
 
-    frames_ctx->format = sctx->pix_fmt;
+    if (device_ctx->type == AV_HWDEVICE_TYPE_DXVA2) {
+        frames_ctx->format = AV_PIX_FMT_DXVA2_VLD;
+    } else if (device_ctx->type == AV_HWDEVICE_TYPE_D3D11VA) {
+        frames_ctx->format = AV_PIX_FMT_D3D11;
+    } else {
+        return AVERROR(EINVAL);
+    }
 
     /* decoding MPEG-2 requires additional alignment on some Intel GPUs,
     but it causes issues for H.264 on certain AMD GPUs..... */
@@ -592,8 +599,8 @@ static void dxva_adjust_hwframes(AVCodecContext *avctx, AVHWFramesContext *frame
     else
         surface_alignment = 16;
 
-    /* 4 base work surfaces */
-    num_surfaces = 4;
+    /* 1 base work surface */
+    num_surfaces = 1;
 
     /* add surfaces based on number of possible refs */
     if (avctx->codec_id == AV_CODEC_ID_H264 || avctx->codec_id == AV_CODEC_ID_HEVC)
@@ -627,12 +634,16 @@ static void dxva_adjust_hwframes(AVCodecContext *avctx, AVHWFramesContext *frame
         frames_hwctx->BindFlags |= D3D11_BIND_DECODER;
     }
 #endif
+
+    return 0;
 }
 
 int ff_dxva2_decode_init(AVCodecContext *avctx)
 {
     FFDXVASharedContext *sctx = DXVA_SHARED_CONTEXT(avctx);
-    AVHWFramesContext *frames_ctx = NULL;
+    AVHWFramesContext *frames_ctx;
+    enum AVHWDeviceType dev_type = avctx->hwaccel->pix_fmt == AV_PIX_FMT_DXVA2_VLD
+                            ? AV_HWDEVICE_TYPE_DXVA2 : AV_HWDEVICE_TYPE_D3D11VA;
     int ret = 0;
 
     // Old API.
@@ -642,32 +653,14 @@ int ff_dxva2_decode_init(AVCodecContext *avctx)
     // (avctx->pix_fmt is not updated yet at this point)
     sctx->pix_fmt = avctx->hwaccel->pix_fmt;
 
-    if (!avctx->hw_frames_ctx && !avctx->hw_device_ctx) {
-        av_log(avctx, AV_LOG_ERROR, "Either a hw_frames_ctx or a hw_device_ctx needs to be set for hardware decoding.\n");
-        return AVERROR(EINVAL);
-    }
-
-    if (avctx->hw_frames_ctx) {
-        frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
-    } else {
-        avctx->hw_frames_ctx = av_hwframe_ctx_alloc(avctx->hw_device_ctx);
-        if (!avctx->hw_frames_ctx)
-            return AVERROR(ENOMEM);
-
-        frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
-
-        dxva_adjust_hwframes(avctx, frames_ctx);
-
-        ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);
-        if (ret < 0)
-            goto fail;
-    }
+    ret = ff_decode_get_hw_frames_ctx(avctx, dev_type);
+    if (ret < 0)
+        return ret;
 
+    frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
     sctx->device_ctx = frames_ctx->device_ctx;
 
-    if (frames_ctx->format != sctx->pix_fmt ||
-        !((sctx->pix_fmt == AV_PIX_FMT_D3D11 && CONFIG_D3D11VA) ||
-          (sctx->pix_fmt == AV_PIX_FMT_DXVA2_VLD && CONFIG_DXVA2))) {
+    if (frames_ctx->format != sctx->pix_fmt) {
         av_log(avctx, AV_LOG_ERROR, "Invalid pixfmt for hwaccel!\n");
         ret = AVERROR(EINVAL);
         goto fail;

libavcodec/dxva2_h264.c

@@ -523,6 +523,7 @@ AVHWAccel ff_h264_dxva2_hwaccel = {
     .start_frame    = dxva2_h264_start_frame,
     .decode_slice   = dxva2_h264_decode_slice,
     .end_frame      = dxva2_h264_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -539,6 +540,7 @@ AVHWAccel ff_h264_d3d11va_hwaccel = {
     .start_frame    = dxva2_h264_start_frame,
     .decode_slice   = dxva2_h264_decode_slice,
     .end_frame      = dxva2_h264_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -555,6 +557,7 @@ AVHWAccel ff_h264_d3d11va2_hwaccel = {
     .start_frame    = dxva2_h264_start_frame,
     .decode_slice   = dxva2_h264_decode_slice,
     .end_frame      = dxva2_h264_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };

libavcodec/dxva2_hevc.c

@@ -432,6 +432,7 @@ AVHWAccel ff_hevc_dxva2_hwaccel = {
     .start_frame    = dxva2_hevc_start_frame,
     .decode_slice   = dxva2_hevc_decode_slice,
     .end_frame      = dxva2_hevc_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct hevc_dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -448,6 +449,7 @@ AVHWAccel ff_hevc_d3d11va_hwaccel = {
     .start_frame    = dxva2_hevc_start_frame,
     .decode_slice   = dxva2_hevc_decode_slice,
     .end_frame      = dxva2_hevc_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct hevc_dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -464,6 +466,7 @@ AVHWAccel ff_hevc_d3d11va2_hwaccel = {
     .start_frame    = dxva2_hevc_start_frame,
     .decode_slice   = dxva2_hevc_decode_slice,
     .end_frame      = dxva2_hevc_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct hevc_dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };

libavcodec/dxva2_internal.h

@@ -156,6 +156,9 @@ int ff_dxva2_decode_init(AVCodecContext *avctx);
 
 int ff_dxva2_decode_uninit(AVCodecContext *avctx);
 
+int ff_dxva2_common_frame_params(AVCodecContext *avctx,
+                                 AVBufferRef *hw_frames_ctx);
+
 int ff_dxva2_is_d3d11(const AVCodecContext *avctx);
 
 #endif /* AVCODEC_DXVA2_INTERNAL_H */

libavcodec/dxva2_mpeg2.c

@@ -328,6 +328,7 @@ AVHWAccel ff_mpeg2_dxva2_hwaccel = {
     .start_frame    = dxva2_mpeg2_start_frame,
     .decode_slice   = dxva2_mpeg2_decode_slice,
     .end_frame      = dxva2_mpeg2_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -344,6 +345,7 @@ AVHWAccel ff_mpeg2_d3d11va_hwaccel = {
     .start_frame    = dxva2_mpeg2_start_frame,
     .decode_slice   = dxva2_mpeg2_decode_slice,
     .end_frame      = dxva2_mpeg2_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -360,6 +362,7 @@ AVHWAccel ff_mpeg2_d3d11va2_hwaccel = {
     .start_frame    = dxva2_mpeg2_start_frame,
     .decode_slice   = dxva2_mpeg2_decode_slice,
     .end_frame      = dxva2_mpeg2_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };

libavcodec/dxva2_vc1.c

@@ -328,6 +328,7 @@ AVHWAccel ff_wmv3_dxva2_hwaccel = {
     .start_frame    = dxva2_vc1_start_frame,
     .decode_slice   = dxva2_vc1_decode_slice,
     .end_frame      = dxva2_vc1_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -344,6 +345,7 @@ AVHWAccel ff_vc1_dxva2_hwaccel = {
     .start_frame    = dxva2_vc1_start_frame,
     .decode_slice   = dxva2_vc1_decode_slice,
     .end_frame      = dxva2_vc1_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -360,6 +362,7 @@ AVHWAccel ff_wmv3_d3d11va_hwaccel = {
     .start_frame    = dxva2_vc1_start_frame,
     .decode_slice   = dxva2_vc1_decode_slice,
     .end_frame      = dxva2_vc1_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -376,6 +379,7 @@ AVHWAccel ff_wmv3_d3d11va2_hwaccel = {
     .start_frame    = dxva2_vc1_start_frame,
     .decode_slice   = dxva2_vc1_decode_slice,
     .end_frame      = dxva2_vc1_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };
@@ -392,6 +396,7 @@ AVHWAccel ff_vc1_d3d11va_hwaccel = {
     .start_frame    = dxva2_vc1_start_frame,
     .decode_slice   = dxva2_vc1_decode_slice,
     .end_frame      = dxva2_vc1_end_frame,
+    .frame_params   = ff_dxva2_common_frame_params,
     .frame_priv_data_size = sizeof(struct dxva2_picture_context),
     .priv_data_size = sizeof(FFDXVASharedContext),
 };

libavcodec/vaapi_decode.h

@@ -53,8 +53,6 @@ typedef struct VAAPIDecodePicture {
 } VAAPIDecodePicture;
 
 typedef struct VAAPIDecodeContext {
-    VAProfile             va_profile;
-    VAEntrypoint          va_entrypoint;
     VAConfigID            va_config;
     VAContextID           va_context;
 
@@ -96,4 +94,7 @@ int ff_vaapi_decode_cancel(AVCodecContext *avctx,
 int ff_vaapi_decode_init(AVCodecContext *avctx);
 int ff_vaapi_decode_uninit(AVCodecContext *avctx);
 
+int ff_vaapi_common_frame_params(AVCodecContext *avctx,
+                                 AVBufferRef *hw_frames_ctx);
+
 #endif /* AVCODEC_VAAPI_DECODE_H */

libavcodec/vaapi_h264.c

@@ -399,6 +399,7 @@ AVHWAccel ff_h264_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vaapi_hevc.c

@@ -434,6 +434,7 @@ AVHWAccel ff_hevc_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePictureHEVC),
     .init                 = ff_vaapi_decode_init,
     .uninit               = ff_vaapi_decode_uninit,
+    .frame_params         = ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vaapi_mpeg2.c

@@ -184,6 +184,7 @@ AVHWAccel ff_mpeg2_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vaapi_mpeg4.c

@@ -200,6 +200,7 @@ AVHWAccel ff_mpeg4_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
@@ -217,6 +218,7 @@ AVHWAccel ff_h263_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vaapi_vc1.c

@@ -399,6 +399,7 @@ AVHWAccel ff_wmv3_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };
@@ -415,6 +416,7 @@ AVHWAccel ff_vc1_vaapi_hwaccel = {
     .frame_priv_data_size = sizeof(VAAPIDecodePicture),
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
+    .frame_params         = &ff_vaapi_common_frame_params,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vaapi_vp8.c

@@ -232,5 +232,6 @@ AVHWAccel ff_vp8_vaapi_hwaccel = {
     .init                 = &ff_vaapi_decode_init,
     .uninit               = &ff_vaapi_decode_uninit,
     .priv_data_size       = sizeof(VAAPIDecodeContext),
+    .frame_params         = &ff_vaapi_common_frame_params,
     .caps_internal        = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vdpau.c

@@ -24,6 +24,7 @@
 #include <limits.h>
 
 #include "avcodec.h"
+#include "decode.h"
 #include "internal.h"
 #include "h264dec.h"
 #include "vc1.h"
@@ -100,6 +101,25 @@ int av_vdpau_get_surface_parameters(AVCodecContext *avctx,
     return 0;
 }
 
+int ff_vdpau_common_frame_params(AVCodecContext *avctx,
+                                 AVBufferRef *hw_frames_ctx)
+{
+    AVHWFramesContext *hw_frames = (AVHWFramesContext*)hw_frames_ctx->data;
+    VdpChromaType type;
+    uint32_t width;
+    uint32_t height;
+
+    if (av_vdpau_get_surface_parameters(avctx, &type, &width, &height))
+        return AVERROR(EINVAL);
+
+    hw_frames->format    = AV_PIX_FMT_VDPAU;
+    hw_frames->sw_format = avctx->sw_pix_fmt;
+    hw_frames->width     = width;
+    hw_frames->height    = height;
+
+    return 0;
+}
+
 int ff_vdpau_common_init(AVCodecContext *avctx, VdpDecoderProfile profile,
                          int level)
 {
@@ -115,6 +135,7 @@ int ff_vdpau_common_init(AVCodecContext *avctx, VdpDecoderProfile profile,
     VdpChromaType type;
     uint32_t width;
     uint32_t height;
+    int ret;
 
     vdctx->width            = UINT32_MAX;
     vdctx->height           = UINT32_MAX;
@@ -142,41 +163,14 @@ int ff_vdpau_common_init(AVCodecContext *avctx, VdpDecoderProfile profile,
             type != VDP_CHROMA_TYPE_420)
             return AVERROR(ENOSYS);
     } else {
-        AVHWFramesContext *frames_ctx = NULL;
+        AVHWFramesContext *frames_ctx;
         AVVDPAUDeviceContext *dev_ctx;
 
-        // We assume the hw_frames_ctx always survives until ff_vdpau_common_uninit
-        // is called. This holds true as the user is not allowed to touch
-        // hw_device_ctx, or hw_frames_ctx after get_format (and ff_get_format
-        // itself also uninits before unreffing hw_frames_ctx).
-        if (avctx->hw_frames_ctx) {
-            frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
-        } else if (avctx->hw_device_ctx) {
-            int ret;
-
-            avctx->hw_frames_ctx = av_hwframe_ctx_alloc(avctx->hw_device_ctx);
-            if (!avctx->hw_frames_ctx)
-                return AVERROR(ENOMEM);
-
-            frames_ctx            = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
-            frames_ctx->format    = AV_PIX_FMT_VDPAU;
-            frames_ctx->sw_format = avctx->sw_pix_fmt;
-            frames_ctx->width     = avctx->coded_width;
-            frames_ctx->height    = avctx->coded_height;
-
-            ret = av_hwframe_ctx_init(avctx->hw_frames_ctx);
-            if (ret < 0) {
-                av_buffer_unref(&avctx->hw_frames_ctx);
-                return ret;
-            }
-        }
-
-        if (!frames_ctx) {
-            av_log(avctx, AV_LOG_ERROR, "A hardware frames context is "
-                   "required for VDPAU decoding.\n");
-            return AVERROR(EINVAL);
-        }
+        ret = ff_decode_get_hw_frames_ctx(avctx, AV_HWDEVICE_TYPE_VDPAU);
+        if (ret < 0)
+            return ret;
 
+        frames_ctx = (AVHWFramesContext*)avctx->hw_frames_ctx->data;
         dev_ctx = frames_ctx->device_ctx->hwctx;
 
         vdctx->device           = dev_ctx->device;

libavcodec/vdpau_h264.c

@@ -273,6 +273,7 @@ AVHWAccel ff_h264_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_h264_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vdpau_hevc.c

@@ -424,6 +424,7 @@ AVHWAccel ff_hevc_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_hevc_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vdpau_internal.h

@@ -119,5 +119,7 @@ int ff_vdpau_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 int ff_vdpau_mpeg_end_frame(AVCodecContext *avctx);
 int ff_vdpau_add_buffer(struct vdpau_picture_context *pic, const uint8_t *buf,
                         uint32_t buf_size);
+int ff_vdpau_common_frame_params(AVCodecContext *avctx,
+                                 AVBufferRef *hw_frames_ctx);
 
 #endif /* AVCODEC_VDPAU_INTERNAL_H */

libavcodec/vdpau_mpeg12.c

@@ -149,6 +149,7 @@ AVHWAccel ff_mpeg2_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_mpeg2_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vdpau_mpeg4.c

@@ -118,6 +118,7 @@ AVHWAccel ff_mpeg4_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_mpeg4_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/vdpau_vc1.c

@@ -143,6 +143,7 @@ AVHWAccel ff_wmv3_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_vc1_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };
@@ -159,6 +160,7 @@ AVHWAccel ff_vc1_vdpau_hwaccel = {
     .frame_priv_data_size = sizeof(struct vdpau_picture_context),
     .init           = vdpau_vc1_init,
     .uninit         = ff_vdpau_common_uninit,
+    .frame_params   = ff_vdpau_common_frame_params,
     .priv_data_size = sizeof(VDPAUContext),
     .caps_internal  = HWACCEL_CAP_ASYNC_SAFE,
 };

libavcodec/version.h

@@ -28,7 +28,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 58
-#define LIBAVCODEC_VERSION_MINOR  4
+#define LIBAVCODEC_VERSION_MINOR  5
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \