[FFmpeg-user] ProRes (LT) Quicktimes: Good for Windows. Not so good for Mac.

Thomas Worth dev at rarevision.com
Tue Mar 20 22:46:45 CET 2012

On Tue, Mar 20, 2012 at 2:22 PM, Andreas Gumm <andreas.gumm at gmx.de> wrote:
> Yes, this is a known issue! Your files has been correct encoded! FCP just
> complains sometimes about external encoded ProRes footage!
> It seem to be that some missing header informations or other stupid missing
> informations let FCP think the file looks not compatible!

About this, I think the Final Cut media warning may be related to the
A/V interleaving, i.e. the way the chunk offset tables are written. I
don't think it has as much to do with information in the QuickTime
header. Files written without audio don't show the warning. Baptiste
Coudurier might comment on this. If anyone knows why this is
happening, is would be him.

Also it should be noted that the media performance warning does not
occur when QuickTime files are written with a co64 atom. So, Final Cut
apparently likes FFmpeg MOV files written with 64 bit offsets. This is
just more evidence to support the theory that offset tables for both
video and audio that don't play well with each other may be
responsible for triggering the media warning. This should be fixed
because if the A/V offsets aren't occurring in contiguous order and/or
aligned, it is potentially hindering disk performance. Again, this is
only speculation but I am pretty sure this is where to look for the

Someone might take a gander at movenc.c and see if interleaving is
done differently with 64 bit MOV offsets vs. 32 bit ones.

More information about the ffmpeg-user mailing list