[FFmpeg-user] How to compress .MOV file compatible to Canon camera

Carl Eugen Hoyos ceffmpeg at gmail.com
Wed Apr 1 17:12:59 EEST 2020

Am Mi., 1. Apr. 2020 um 01:18 Uhr schrieb Ulf Zibis <Ulf.Zibis at gmx.de>:
> Am 01.04.20 um 00:47 schrieb Carl Eugen Hoyos:
> > Am Mi., 1. Apr. 2020 um 00:45 Uhr schrieb Ulf Zibis <Ulf.Zibis at gmx.de>:
> >
> >> Am 31.03.20 um 01:02 schrieb Carl Eugen Hoyos:
> >>> But the relevant test - imo - is not to change the file that does not play
> >>> but instead change the playing file and find out which change breaks
> >>> playback.
> >>>
> >>> You can overwrite each atom name with "free" and the file stays a
> >>> valid (but possible unplayable) isom/mp4/mov file.
> >> I now have overwitten "udta" with "free" in the original video.
> > What happens if you instead only overwrite (some of) its content?
> I filled it with 0x00 (65596 bytes).
> Result: it does no more play in the camera, even it does not show the
> thumbnail anymore.

What happens if you only overwrite part of it?

> > (Which part of the udta atom is needed or is it sufficient if there
> > is one?)
> I don't know. For what it would be worth? Even if I find the minimum
> needed content, I would have to find a way how to insert it in the file
> including reparsing the moov box index data.

Sounds relatively trivial to me, after all, we deal with open-source
software here.

If the content is difficult to understand, this is of course less trivial
than if we only have to fill a few bytes.

Carl Eugen

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