[FFmpeg-user] Encoding 3gp6 with MPEG-4 Visual and Simple <at> L1

Moritz Barsnick barsnick at gmx.net
Tue Sep 16 16:31:47 CEST 2014


> I’m not really sure.  If I use "-vcodec libx264", I get 3gp6, and if
> I use "-vcodec mpeg4", I get 3gp4. But if I do libx264, I can’t get
> MPEG-4 Visual and Simple at L1 to come out.

You're adhering to mediainfo a little bit too strictly here. Question
is: What does your device expect (and what does the standard expect!),
and what are you producing?

Either way: If you use libx264, you'll probably get H.264 and not
"MPEG-4 Visual". Still assuming you really need the latter.

This somewhat confusing table seems to show some details about the 3GPP
specs:

http://www.ftyps.com/3gpp.html

(But also take "note" of the "NOTE"s. :-))

As far as I can tell, 3gp6 should be backwards compatible (??? or
forwards?) to its "compatible brands" 3gp6, 3gp5, 3gp4, isom.

I'm still trying to understand: You get the "brand" 3gp4, but your
device (or just you?) expects 3gp6? I still think they should be
compatible. At the same time, there are several brands which match your
mpeg4+amr codec choice, namely 3gp4, 3gp5, 3gp6, 3gp7. Until we
understand what makes the difference here (just the metadata? anything
else? apparently movie fragments support starting with 3gp6), ffmpeg's
choice of brand may just be conservatively correct - or not, I
personally don't know. :-)

You will need to get a better understanding, or feedback from someone
who has it, and/or do some experimenting!

BTW, I haven't been able to force differing metadata with ffmpeg. And
AtomicParsley at first glance doesn't seem to support these fields.

Cheers,
Moritz


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