dxva: move d3d11 locking/unlocking to functions

I want to make it non-mandatory to set a mutex in the D3D11 device
context, and replacing it with user callbacks seems like the best
solution. This is preparation for it. Also makes the code slightly more
readable.

Merges Libav commit 831cfe10.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

libavcodec/dxva2.c

@@ -29,6 +29,28 @@
 #include "avcodec.h"
 #include "dxva2_internal.h"
 
+static void ff_dxva2_lock(AVCodecContext *avctx)
+{
+#if CONFIG_D3D11VA
+    if (ff_dxva2_is_d3d11(avctx)) {
+        AVDXVAContext *ctx = DXVA_CONTEXT(avctx);
+        if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
+            WaitForSingleObjectEx(D3D11VA_CONTEXT(ctx)->context_mutex, INFINITE, FALSE);
+    }
+#endif
+}
+
+static void ff_dxva2_unlock(AVCodecContext *avctx)
+{
+#if CONFIG_D3D11VA
+    if (ff_dxva2_is_d3d11(avctx)) {
+        AVDXVAContext *ctx = DXVA_CONTEXT(avctx);
+        if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
+            ReleaseMutex(D3D11VA_CONTEXT(ctx)->context_mutex);
+    }
+#endif
+}
+
 static void *get_surface(const AVFrame *frame)
 {
     return frame->data[3];
@@ -153,14 +175,12 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
     unsigned type;
 
     do {
+        ff_dxva2_lock(avctx);
 #if CONFIG_D3D11VA
-        if (ff_dxva2_is_d3d11(avctx)) {
-            if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
-                WaitForSingleObjectEx(D3D11VA_CONTEXT(ctx)->context_mutex, INFINITE, FALSE);
+        if (ff_dxva2_is_d3d11(avctx))
             hr = ID3D11VideoContext_DecoderBeginFrame(D3D11VA_CONTEXT(ctx)->video_context, D3D11VA_CONTEXT(ctx)->decoder,
                                                       get_surface(frame),
                                                       0, NULL);
-        }
 #endif
 #if CONFIG_DXVA2
         if (avctx->pix_fmt == AV_PIX_FMT_DXVA2_VLD)
@@ -170,21 +190,13 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 #endif
         if (hr != E_PENDING || ++runs > 50)
             break;
-#if CONFIG_D3D11VA
-        if (ff_dxva2_is_d3d11(avctx))
-            if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
-                ReleaseMutex(D3D11VA_CONTEXT(ctx)->context_mutex);
-#endif
+        ff_dxva2_unlock(avctx);
         av_usleep(2000);
     } while(1);
 
     if (FAILED(hr)) {
         av_log(avctx, AV_LOG_ERROR, "Failed to begin frame: 0x%x\n", hr);
-#if CONFIG_D3D11VA
-        if (ff_dxva2_is_d3d11(avctx))
-            if (D3D11VA_CONTEXT(ctx)->context_mutex != INVALID_HANDLE_VALUE)
-                ReleaseMutex(D3D11VA_CONTEXT(ctx)->context_mutex);
-#endif
+        ff_dxva2_unlock(avctx);
         return -1;
     }
 
@@ -284,16 +296,14 @@ int ff_dxva2_common_end_frame(AVCodecContext *avctx, AVFrame *frame,
 
 end:
 #if CONFIG_D3D11VA
-    if (ff_dxva2_is_d3d11(avctx)) {
+    if (ff_dxva2_is_d3d11(avctx))
         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)
         hr = IDirectXVideoDecoder_EndFrame(DXVA2_CONTEXT(ctx)->decoder, NULL);
 #endif
+    ff_dxva2_unlock(avctx);
     if (FAILED(hr)) {
         av_log(avctx, AV_LOG_ERROR, "Failed to end frame: 0x%x\n", hr);
         result = -1;