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

Thomas Worth dev at rarevision.com
Sat Mar 24 07:08:15 CET 2012

>> It should also be pointed out that MOV/MP4 elst atoms aren't written
>> properly in many cases, at least not in a way that Apple's software
>> expects them. For example, sometimes the start value in elst will be
>> wrong if performing stream copies with B-frame'd H.264. The fix is to
>> go into a hex editor and change the start value to 1 or 1001,
>> depending on the PTS duration. ffmbc isn't affected by this since
>> Baptiste has taken the time to ensure the MOV/MP4 writer works in a
>> way that Apple software expects. IMHO, someone should follow ffmbc's
>> good example and fix the MOV muxer in ffmpeg, at least to the point
>> where it addresses these issues.
> For what it's worth, I encoded a ProRes QT using ffmbc and had the
> same issue (FCP not accepting the QT as ProRes (LT)). From your
> text above, I wasn't sure if you were pointing out that ffmbc could make
> "legal" ProRes (LT)'s or if you were merely saying that ffmbc deals with
> B-frame'd H.264's properly. (I should note that I didn't have an audio track
> if that is an issue.)

I don't know. I haven't used ffmbc to generate ProRes files. How did
you determine that FCP wouldn't accept the file as ProRes LT? I'm not
sure this even matters since ProRes should just be ProRes. As far as I
know, the only difference between the different ProRes flavors is
bitrate. Can someone confirm that?

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