[FFmpeg-devel] Uncompressed pixel format handling clarifications

[Kostya]

On Thu, May 14, 2009 at 10:59:17PM -0700, Baptiste Coudurier wrote:
> On Sun, May 10, 2009 at 01:34:30PM -0700, Baptiste Coudurier wrote:
> > Hi guys,
> > 
> > I'm quite confused regarding pixel format handling with uncompressed
> > video currently.
> > 
> > Quicktime supports almost every variant, be/le 565, 555, argb, rgba, bgra.
> > 
> > I'd like to understand which pixfmt can be invoked from commandline.
> > For example, on le arch I can request rgb565le, but not rgb565be,
> > however both can be stored in .mov.
> > 
> > When decompressing (rawdec.c) which pix_fmt should be used ? Considering
> > avpicture_layout (memcpy then) is used, LE/BE ones or NE one ?
> > 
> > When muxing ? LE/BE ones ?
> > 
> > Thanks for the clarification.
> 
> Sorry to insist, but is it really dumb to ask this ? :/

I've asked a question like this looooooong time ago. 
Operating non-native endian packed bits (i.e. 15/16) is silly.
(the rest is IMO)
Thus, for decoding it should be NE which may require swapping in a form
of hack in demuxer or bitstream filter or elsewhere.

For muxing it should be either BE (can be added to regtests, native for
QT since it originated on Motorola/PPC) or native endian (to avoid
byteswapping on LE CPUs).
 
> -- 
> Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA