d3d11va: WindowsPhone requires a mutex around ID3D11VideoContext

doc/APIchanges

@@ -13,6 +13,10 @@ libavutil:     2015-08-28
 
 API changes, most recent first:
 
+2015-xx-xx - xxxxxxx - lavc 57.2.0 - d3d11va.h
+  Add av_d3d11va_alloc_context(). This function must from now on be used for
+  allocating AVD3D11VAContext.
+
 2015-xx-xx - lavu 55.0.0
   xxxxxxx - Change type of AVPixFmtDescriptor.flags from uint8_t to uint64_t.
   xxxxxxx - Change type of AVComponentDescriptor fields from uint16_t to int

libavcodec/Makefile

@@ -581,7 +581,7 @@ OBJS-$(CONFIG_ADPCM_YAMAHA_DECODER)       += adpcm.o adpcm_data.o
 OBJS-$(CONFIG_ADPCM_YAMAHA_ENCODER)       += adpcmenc.o adpcm_data.o
 
 # hardware accelerators
-OBJS-$(CONFIG_D3D11VA)                    += dxva2.o
+OBJS-$(CONFIG_D3D11VA)                    += d3d11va.o dxva2.o
 OBJS-$(CONFIG_DXVA2)                      += dxva2.o
 OBJS-$(CONFIG_VAAPI)                      += vaapi.o
 OBJS-$(CONFIG_VDA)                        += vda.o

libavcodec/d3d11va.c

@@ -0,0 +1,33 @@
+/*
+ * Direct3D11 HW acceleration
+ *
+ * copyright (c) 2015 Steve Lhomme
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "config.h"
+#include "libavutil/mem.h"
+
+#include "d3d11va.h"
+
+AVD3D11VAContext *av_d3d11va_alloc_context(void)
+{
+    AVD3D11VAContext* res = av_mallocz(sizeof(AVD3D11VAContext));
+    res->context_mutex = INVALID_HANDLE_VALUE;
+    return res;
+}

libavcodec/d3d11va.h

@@ -53,8 +53,10 @@
  * to the Direct3D11 Libav HWAccel implementation.
  *
  * The application must make it available as AVCodecContext.hwaccel_context.
+ *
+ * Use av_d3d11va_alloc_context() exclusively to allocate an AVD3D11VAContext.
  */
-struct AVD3D11VAContext {
+typedef struct AVD3D11VAContext {
     /**
      * D3D11 decoder object
      */
@@ -89,7 +91,19 @@ struct AVD3D11VAContext {
      * Private to the Libav AVHWAccel implementation
      */
     unsigned report_id;
-};
+
+    /**
+      * Mutex to access video_context
+      */
+    HANDLE  context_mutex;
+} AVD3D11VAContext;
+
+/**
+ * Allocate an AVD3D11VAContext.
+ *
+ * @return Newly-allocated AVD3D11VAContext or NULL on failure.
+ */
+AVD3D11VAContext *av_d3d11va_alloc_context(void);
 
 /**
  * @}

libavcodec/dxva2.c

@@ -144,10 +144,13 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 
     do {
 #if CONFIG_D3D11VA
-        if (avctx->pix_fmt == AV_PIX_FMT_D3D11VA_VLD)
+        if (avctx->pix_fmt == AV_PIX_FMT_D3D11VA_VLD) {
+            if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
+                WaitForSingleObjectEx(D3D11VA_CONTEXT(ctx)->context_mutex, INFINITE, FALSE);
             hr = ID3D11VideoContext_DecoderBeginFrame(D3D11VA_CONTEXT(ctx)->video_context, D3D11VA_CONTEXT(ctx)->decoder,
                                                       ff_dxva2_get_surface(frame),
                                                       0, NULL);
+        }
 #endif
 #if CONFIG_DXVA2
         if (avctx->pix_fmt == AV_PIX_FMT_DXVA2_VLD)
@@ -161,6 +164,11 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 
     if (FAILED(hr)) {
         av_log(avctx, AV_LOG_ERROR, "Failed to begin frame: 0x%lx\n", hr);
+#if CONFIG_D3D11VA
+        if (avctx->pix_fmt == AV_PIX_FMT_D3D11VA_VLD)
+            if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
+                ReleaseMutex(D3D11VA_CONTEXT(ctx)->context_mutex);
+#endif
         return -1;
     }
 
@@ -260,8 +268,11 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 
 end:
 #if CONFIG_D3D11VA
-    if (avctx->pix_fmt == AV_PIX_FMT_D3D11VA_VLD)
+    if (avctx->pix_fmt == AV_PIX_FMT_D3D11VA_VLD) {
         hr = ID3D11VideoContext_DecoderEndFrame(D3D11VA_CONTEXT(ctx)->video_context, D3D11VA_CONTEXT(ctx)->decoder);
+        if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
+            ReleaseMutex(D3D11VA_CONTEXT(ctx)->context_mutex);
+    }
 #endif
 #if CONFIG_DXVA2
     if (avctx->pix_fmt == AV_PIX_FMT_DXVA2_VLD)

libavcodec/version.h

@@ -29,7 +29,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 57
-#define LIBAVCODEC_VERSION_MINOR  1
+#define LIBAVCODEC_VERSION_MINOR  2
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \