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

Jeremy Oddo joddo at jerfu.com
Wed Mar 21 15:56:54 CET 2012

This is very interesting, Thomas. Thanks for your insight.

> 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.

I could be wrong (and I'll double-check this) but I believe our QTs
DID NOT have an audio track.

> 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.

Could you explain the "co64 atom" thing a bit? I don't know what co64 atom
is. Is it possible for FFMPEG to write ProRes QTs with a co64 atom or
is that related to some other codec?

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

Does this 32/64-bit offsets related to the OS or can a 64-bit MOV offset
be written from a 32-bit OS? Don't know if it matters but we're using the
64-bit FFMPEG.

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