msdk: return the right pointer

The first channel in memory for MFX_FOURCC_RGB4 (VA_FOURCC_ARGB or
GST_VIDEO_FORMAT_BGRA) is B, not A. In MSDK, channle B is used to access
data for RGB4 surface. In addition, the returned pointers for
MFX_FOURCC_AYUV and MFX_FOURCC_Y410 in gst_msdk_video_memory_map_full
were wrong too before this fix.

sys/msdk/gstmsdkallocator_libva.c

@@ -343,10 +343,10 @@ gst_msdk_frame_lock (mfxHDL pthis, mfxMemId mid, mfxFrameData * data)
         break;
       case VA_FOURCC_ARGB:
         data->Pitch = mem_id->image.pitches[0];
-        data->R = buf + mem_id->image.offsets[0];
+        data->B = buf + mem_id->image.offsets[0];
-        data->G = data->R + 1;
+        data->G = data->B + 1;
-        data->B = data->R + 2;
+        data->R = data->B + 2;
-        data->A = data->R + 3;
+        data->A = data->B + 3;
         break;
 #if (MFX_VERSION >= 1028)
       case VA_FOURCC_RGB565:

sys/msdk/gstmsdksystemmemory.c

@@ -109,9 +109,10 @@ ensure_data (GstMsdkSystemMemory * mem)
       mem->surface->Data.Pitch = mem->destination_pitches[0];
       break;
     case GST_VIDEO_FORMAT_BGRA:
-      mem->surface->Data.R = mem->cached_data[0];
+      mem->surface->Data.B = mem->cached_data[0];
-      mem->surface->Data.G = mem->surface->Data.R + 1;
+      mem->surface->Data.G = mem->surface->Data.B + 1;
-      mem->surface->Data.B = mem->surface->Data.R + 2;
+      mem->surface->Data.R = mem->surface->Data.B + 2;
+      mem->surface->Data.A = mem->surface->Data.B + 3;
       mem->surface->Data.Pitch = mem->destination_pitches[0];
       break;
 #if (MFX_VERSION >= 1028)
@@ -237,15 +238,22 @@ gst_msdk_system_memory_map_full (GstMemory * base_mem, GstMapInfo * info,
     return NULL;
   }
 
-  /* The first channel in memory is V for MFX_FOURCC_AYUV (GST_VIDEO_FORMAT_VUYA) format */
+  switch (mem->surface->Info.FourCC) {
-  if (mem->surface->Info.FourCC == MFX_FOURCC_AYUV)
+    case MFX_FOURCC_RGB4:
-    return mem->surface->Data.V;
+      return mem->surface->Data.B;      /* The first channel is B */
+
+      /* The first channel in memory is V for MFX_FOURCC_AYUV (GST_VIDEO_FORMAT_VUYA) format */
+    case MFX_FOURCC_AYUV:
+      return mem->surface->Data.V;
+
 #if (MFX_VERSION >= 1027)
-  else if (mem->surface->Info.FourCC == MFX_FOURCC_Y410)
+    case MFX_FOURCC_Y410:
-    return mem->surface->Data.U;        /* Data.Y410 */
+      return mem->surface->Data.U;      /* Data.Y410 */
 #endif
-  else
+
-    return mem->surface->Data.Y;
+    default:
+      return mem->surface->Data.Y;
+  }
 }
 
 static void

sys/msdk/gstmsdkvideomemory.c

@@ -237,15 +237,26 @@ gst_video_meta_map_msdk_memory (GstVideoMeta * meta, guint plane,
   pitch = mem_id->pitch;
 #endif
 
-  /* The first channel in memory is V for GST_VIDEO_FORMAT_VUYA */
+  switch (meta->format) {
-  if (meta->format == GST_VIDEO_FORMAT_VUYA)
+    case GST_VIDEO_FORMAT_BGRA:
-    *data = mem->surface->Data.V + offset;
+      *data = mem->surface->Data.B + offset;
-  else if (meta->format == GST_VIDEO_FORMAT_Y410)
+      break;
-    *data = mem->surface->Data.U + offset;      /* Data.Y410 */
-  else
-    *data = mem->surface->Data.Y + offset;
-  *stride = pitch;
 
+      /* The first channel in memory is V for GST_VIDEO_FORMAT_VUYA */
+    case GST_VIDEO_FORMAT_VUYA:
+      *data = mem->surface->Data.V + offset;
+      break;
+
+    case GST_VIDEO_FORMAT_Y410:
+      *data = mem->surface->Data.U + offset;    /* Data.Y410 */
+      break;
+
+    default:
+      *data = mem->surface->Data.Y + offset;
+      break;
+  }
+
+  *stride = pitch;
   info->flags = flags;
   ret = (*data != NULL);
 
@@ -300,7 +311,23 @@ gst_msdk_video_memory_map_full (GstMemory * base_mem, GstMapInfo * info,
 
   gst_msdk_frame_lock (msdk_video_allocator->context, mem->surface->Data.MemId,
       &mem->surface->Data);
-  return mem->surface->Data.Y;
+
+  switch (mem->surface->Info.FourCC) {
+    case MFX_FOURCC_RGB4:
+      return mem->surface->Data.B;      /* The first channel is B */
+
+      /* The first channel in memory is V for MFX_FOURCC_AYUV (GST_VIDEO_FORMAT_VUYA) format */
+    case MFX_FOURCC_AYUV:
+      return mem->surface->Data.V;
+
+#if (MFX_VERSION >= 1027)
+    case MFX_FOURCC_Y410:
+      return mem->surface->Data.U;      /* Data.Y410 */
+#endif
+
+    default:
+      return mem->surface->Data.Y;
+  }
 }
 
 static void