blend: support BGRA blending

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/video_filter/blend.cpp

@@ -268,9 +268,15 @@ public:
     CPictureRGBX(const CPicture &cfg) : CPicture(cfg)
     {
         if (has_alpha) {
+            if (fmt->i_chroma == VLC_CODEC_BGRA) {
+                offset_r = 2;
+                offset_g = 1;
+                offset_b = 0;
+            } else {
                 offset_r = 0;
                 offset_g = 1;
                 offset_b = 2;
+            }
             offset_a = 3;
         } else {
 #ifdef WORDS_BIGENDIAN
@@ -403,6 +409,7 @@ typedef CPictureYUVPacked<0, 3, 1> CPictureYVYU;
 typedef CPictureYUVPacked<1, 2, 0> CPictureVYUY;
 
 typedef CPictureRGBX<4, true>  CPictureRGBA;
+typedef CPictureRGBX<4, true>  CPictureBGRA;
 typedef CPictureRGBX<4, false> CPictureRGB32;
 typedef CPictureRGBX<3, false> CPictureRGB24;
 
@@ -565,6 +572,7 @@ static const struct {
     RGB(VLC_CODEC_RGB24,    CPictureRGB24,    convertNone),
     RGB(VLC_CODEC_RGB32,    CPictureRGB32,    convertNone),
     RGB(VLC_CODEC_RGBA,     CPictureRGBA,     convertNone),
+    RGB(VLC_CODEC_BGRA,     CPictureBGRA,     convertNone),
 
     YUV(VLC_CODEC_YV9,      CPictureYV9,      convertNone),
     YUV(VLC_CODEC_I410,     CPictureI410_8,   convertNone),

src/video_output/vout_subpictures.c

@@ -1433,12 +1433,14 @@ subpicture_t *spu_Render(spu_t *spu,
         VLC_CODEC_YUVA,
         VLC_CODEC_RGBA,
         VLC_CODEC_ARGB,
+        VLC_CODEC_BGRA,
         VLC_CODEC_YUVP,
         0,
     };
     static const vlc_fourcc_t chroma_list_default_rgb[] = {
         VLC_CODEC_RGBA,
         VLC_CODEC_ARGB,
+        VLC_CODEC_BGRA,
         VLC_CODEC_YUVA,
         VLC_CODEC_YUVP,
         0,