Is RGB24 to RGB32 conversion lossless?

[wayback]

I'm making timelapse videos. All the input stills are RGB24 jpegs, and the titles and credits are RGB24 BMP's.

I can create a completely uncompressed raw video file that's RGB24 and therefore presumably lossless. But the files would be awfully big, and I'm not sure I can find a version of Avidemux that will handle that. So it would be nice to just use HuffYUV and make it use RGB. It appears it will do that, but it would be RGB32.

So, just for my understanding, could someone tell me if anything is lost converting everything to RGB32? Is the extra byte just not used?

[Blue_MiSfit]

AFAIK, RGB32 is just RGB24 with an alpha channel, so it should be fine.

~MiSfit

[Gokumon]

It could potentially not be mathematically lossless, but visually any difference between them is going to be nigh imperceptible.

[Wilbert]

It could potentially not be mathematically lossless
It should be lossless. Otherwise there is a bug somewhere.

[Keiyakusha]

This is some kind of offtopic but how about RGB24 <-> YV24 conversion. Is it lossless?

[lych_necross]

Well, going from RGB24 to RGB32 is basically lossless, as Wilbert said. RGB24 is basically padded to RGB32. The converse is not true however (RGB32 to RGB24 is lossy).