mirror of https://git.ffmpeg.org/ffmpeg.git
pixdesc: clarify AV_PIX_FMT_FLAG_ALPHA doxygen
Also make clear that PAL8 can have alpha. Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
parent
92e3a6fdac
commit
c247fc63e4
|
@ -139,8 +139,19 @@ typedef struct AVPixFmtDescriptor {
|
||||||
* An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
|
* An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
|
||||||
*/
|
*/
|
||||||
#define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
|
#define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
|
||||||
|
|
||||||
/**
|
/**
|
||||||
* The pixel format has an alpha channel.
|
* The pixel format has an alpha channel. This is set on all formats that
|
||||||
|
* support alpha in some way. The exception is AV_PIX_FMT_PAL8, which can
|
||||||
|
* carry alpha as part of the palette. Details are explained in the
|
||||||
|
* AVPixelFormat enum, and are also encoded in the corresponding
|
||||||
|
* AVPixFmtDescriptor.
|
||||||
|
*
|
||||||
|
* The alpha is always straight, never pre-multiplied.
|
||||||
|
*
|
||||||
|
* If a codec or a filter does not support alpha, it should set all alpha to
|
||||||
|
* opaque, or use the equivalent pixel formats without alpha component, e.g.
|
||||||
|
* AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
|
||||||
*/
|
*/
|
||||||
#define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
|
#define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
|
||||||
|
|
||||||
|
|
|
@ -44,11 +44,11 @@
|
||||||
* big-endian CPUs.
|
* big-endian CPUs.
|
||||||
*
|
*
|
||||||
* @par
|
* @par
|
||||||
* When the pixel format is palettized RGB (AV_PIX_FMT_PAL8), the palettized
|
* When the pixel format is palettized RGB32 (AV_PIX_FMT_PAL8), the palettized
|
||||||
* image data is stored in AVFrame.data[0]. The palette is transported in
|
* image data is stored in AVFrame.data[0]. The palette is transported in
|
||||||
* AVFrame.data[1], is 1024 bytes long (256 4-byte entries) and is
|
* AVFrame.data[1], is 1024 bytes long (256 4-byte entries) and is
|
||||||
* formatted the same as in AV_PIX_FMT_RGB32 described above (i.e., it is
|
* formatted the same as in AV_PIX_FMT_RGB32 described above (i.e., it is
|
||||||
* also endian-specific). Note also that the individual RGB palette
|
* also endian-specific). Note also that the individual RGB32 palette
|
||||||
* components stored in AVFrame.data[1] should be in the range 0..255.
|
* components stored in AVFrame.data[1] should be in the range 0..255.
|
||||||
* This is important as many custom PAL8 video codecs that were designed
|
* This is important as many custom PAL8 video codecs that were designed
|
||||||
* to run on the IBM VGA graphics adapter use 6-bit palette components.
|
* to run on the IBM VGA graphics adapter use 6-bit palette components.
|
||||||
|
|
Loading…
Reference in New Issue