[FFmpeg-user] How to concatenate multiple mp4 files without re-encoding to an intermediate format

[Rares Pop]

Tom,

Many thanks !
With a minor correction (required by ffmpeg) it worked.
ffmpeg -i "concat:concat.ts|concat2.ts" -c copy -absf aac_adtstoasc concatAll.mp4

All of the commands executed very fast since no re-encoding was necessary. This was our goal after all since we're processing a lot files. Adding round of transcoding was not an option.
Thanks again.

Rares


On Aug 31, 2012, at 2:56 PM, Tom Evans <tevans.uk at googlemail.com> wrote:

> On Fri, Aug 31, 2012 at 11:33 AM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>> Rares Pop <raresp <at> axz.ro> writes:
>> 
>>> ffmpeg -i concat:'file1.mp4|file2.mp4' -vcodec copy -acodec copy  -y asset.mp4
>> 
>>> Result: asset.mp4 file is the same as file1.mp4.It behaves
>>> like it ignores file2.mp4
>> 
>> So it seems that this is unsupported.
>> You can try to concatenate the raw h264 and the raw aac streams
>> and mux the resulting streams but this may lead to A/V desync
>> (that you can try to eliminate by cutting the streams or inserting
>> silence but this will have to be done manually).
>> 
>> Please do not top-post here, Carl Eugen
>> 
> 
> Would re-muxing to TS as an intermediate help with this? Seems to work ok..
> 
> ffmpeg -i source1.mp4 -c copy -bsf h264_mp4toannexb -t 30 out1.ts
> ffmpeg -i source2.mp4 -c copy -bsf h264_mp4toannexb -t 30 out2.ts
> ffmpeg -i "concat:out1.ts|out2.ts" -c copy out.mp4
> ffprobe out.mp4 2>&1| grep Duration
>  Duration: 00:01:00.08, start: 0.000000, bitrate: 2086 kb/s
> 
> Cheers
> 
> Tom
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---------------------
Rares Pop
Chief Executive
M: +40 745 028 869 | E: raresp at axz.ro | Skype: ra_axz
www.azoth.eu | A: Grigore Alexandrescu 54, Bucuresti - Romania


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