[FFmpeg-user] moov atom way too big + udta added

Carl Eugen Hoyos ceffmpeg at gmail.com
Fri Jun 7 16:23:17 EEST 2019

Am Fr., 7. Juni 2019 um 11:46 Uhr schrieb Mayescid Ocomance
<MayescidOcomance at gmail.com>:

> I'm creating serveral mp4 derivatives of other mp4s and m2ts using ffmpeg.
> It's an automated process. So far I have used this command line for one of
> the derivaties:
> -s 1280x720  -c:v libx264 -profile:v main -crf 10 -maxrate 2M -bufsize 2M
> -c:a aac -ac 2 -b:a 128k -ar 44100 -f mp4 -movflags +faststart
> The file is fine, however, when I compare its structure using AtomicParsley
> to a file with the same specifics but created by another programm, I'm
> getting way too big moov atoms, which seems to be caused by way too big
> stscm, stszm, stco, (and ctts for audio) atoms in both streams.

How do you define "too big"?

> (Keep in mind this is just a 2-3 minute video. The difference is even 4-5x
> when encoding 1-2h videos).
> Does anyone have an idea, what I could change to reduce the moov atom file ?
> So far I have tried forcing keyframe intervals, bigger GOPs, disabling
> metadata, maping chapters differenty, alas without any or only teeny tiny
> progress in moov reduction.

> (and any idea how to get rid of the udta that is not part of the original
> input and seemingly is generated by ffmpeg by default ?!)

It is always written.

Carl Eugen

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