final word on RGBA byte order

[ffmpeg.git] / libavcodec / avcodec.h

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 16fe4ed..75ad80e 100644 (file)
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -115,7 +115,19 @@ enum CodecType {
 };
 
 /**
 };
 
 /**

- * Pixel format.
+ * Pixel format. Notes: 
+ *
+ * PIX_FMT_RGBA32 is handled in an endian-specific manner. A RGBA
+ * color is put together as:
+ *  (A << 24) | (R << 16) | (G << 8) | B
+ * This is stored as BGRA on little endian CPU architectures and ARGB on
+ * big endian CPUs.
+ *
+ * When the pixel format is palettized RGB (PIX_FMT_PAL8), the palettized
+ * image data is stored in AVFrame.data[0]. The palette is transported in
+ * AVFrame.data[1] and, is 1024 bytes long (256 4-byte entries) and is
+ * formatted the same as in PIX_FMT_RGBA32 described above (i.e., it is
+ * also endian-specific).

  */
 enum PixelFormat {
     PIX_FMT_YUV420P,   ///< Planar YUV 4:2:0 (1 Cr & Cb sample per 2x2 Y samples)
  */
 enum PixelFormat {
     PIX_FMT_YUV420P,   ///< Planar YUV 4:2:0 (1 Cr & Cb sample per 2x2 Y samples)


@@ -124,7 +136,7 @@ enum PixelFormat {
     PIX_FMT_BGR24,     ///< Packed pixel, 3 bytes per pixel, BGRBGR...
     PIX_FMT_YUV422P,   ///< Planar YUV 4:2:2 (1 Cr & Cb sample per 2x1 Y samples)
     PIX_FMT_YUV444P,   ///< Planar YUV 4:4:4 (1 Cr & Cb sample per 1x1 Y samples)
     PIX_FMT_BGR24,     ///< Packed pixel, 3 bytes per pixel, BGRBGR...
     PIX_FMT_YUV422P,   ///< Planar YUV 4:2:2 (1 Cr & Cb sample per 2x1 Y samples)
     PIX_FMT_YUV444P,   ///< Planar YUV 4:4:4 (1 Cr & Cb sample per 1x1 Y samples)

-    PIX_FMT_RGBA32,    ///< Packed pixel, 4 bytes per pixel, BGRABGRA...
+    PIX_FMT_RGBA32,    ///< Packed pixel, 4 bytes per pixel, BGRABGRA..., stored in cpu endianness

     PIX_FMT_YUV410P,   ///< Planar YUV 4:1:0 (1 Cr & Cb sample per 4x4 Y samples)
     PIX_FMT_YUV411P,   ///< Planar YUV 4:1:1 (1 Cr & Cb sample per 4x1 Y samples)
     PIX_FMT_RGB565,    ///< always stored in cpu endianness 
     PIX_FMT_YUV410P,   ///< Planar YUV 4:1:0 (1 Cr & Cb sample per 4x4 Y samples)
     PIX_FMT_YUV411P,   ///< Planar YUV 4:1:1 (1 Cr & Cb sample per 4x1 Y samples)
     PIX_FMT_RGB565,    ///< always stored in cpu endianness