The header pixfmt.h contains the following comment in the pixel format list doxygen:
* @note * Make sure that all newly added big-endian formats have (pix_fmt & 1) == 1 * and that all newly added little-endian formats have (pix_fmt & 1) == 0. * This allows simpler detection of big vs little-endian. This is currently broken for the following formats: nv20le/be gbrap16le/be Obviously, this can't be fixed until the next ABI bump. But more importantly, this looks like a stupid convention, and doesn't even allow you to distinguish formats that need endian swapping and those that don't. Wouldn't it be better to have a flag that indicates whether the format is endian-independent? I would define the flag as follows: if there is a swapped-endian format defined, both formats have the flag set. I think this would be useful to the API user. (You can create this flag yourself with the currently available API and without using the LSB-trick mentioned above, but it's rather painful. For example, RGB444 can be accessed in an endian-independent way according to its pixdesc, and av_read_image_line() does only 1 byte reads for this format, because the components are neatly aligned.) Should I write a patch that adds a AV_PIX_FMT_FLAG_ENDIAN flag? Also, we should discuss whether swapped-endian formats should even exist. From what I can see, only the raw decoders/encoders make effective use of them. Wouldn't it be simpler to let the decoders/encoders do the byte-swapping? _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
