[FFmpeg-user] mp4 concat demuxer problem

Konrad Karl kk_konrad at gmx.at
Tue Apr 29 00:30:42 CEST 2014

Hi Carl Eugen!

On Mon, Apr 28, 2014 at 08:57:00PM +0000, Carl Eugen Hoyos wrote:
> Konrad Karl <kk_konrad <at> gmx.at> writes:
> > I tried to concatenate a few movies (h264/aac mp4, 
> > all produced by kdenlive/melt using the same rendering 
> > settings) 
> (The files have very different bitrates, are you sure 
> they were produced with the same settings?)

Yes, I am quite sure because I deliberately used the very same 
settings for these movies (two-pass  25 Mbit). I have tried
with several of the seven movies (one for each day of my holiday
trip, all but the first fading from and into black) and all
combinations I tried including reversing file ordering
failed to play after the first input file.

The moving Vietnamese flag on the first sample produces a higher
than average bitrate and the rather low bit rate of the second sample
seems to be caused by the fade-from-black transition. 

Original file size / duration comes quite close to 25 MBit/s.

Concatenating each file with itself seems to work OK.


> I opened ticket #3600, thank you for the report!
> Carl Eugen

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