[FFmpeg-user] mp4 concat demuxer problem

[Konrad Karl]

Hi,

On Sun, May 04, 2014 at 11:58:21AM +0200, Nicolas George wrote:
> Le nonidi 9 flor?al, an CCXXII, Konrad Karl a ?crit?:
......
> > ffmpeg -f concat -i concat-test -c copy out.mp4
> > The output file fails to play after the first input file (mplayer, ffplay, vlc)
.....
> 
> Can you test the new "-auto_convert 1" option to the concat demuxer and see
> if it helps things? Note that the output will be in "annex B" format, and
> needs an extra BSF to be muxed to MP4.

works fine (using git 421b21ca8a):

ffmpeg -y -auto_convert 1 -f concat -i concat-list.txt -c copy out.mp4

......
  libswresample   0. 18.100 /  0. 18.100
  libpostproc    52.  3.100 / 52.  3.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 0xe08de0] Auto-inserting h264_mp4toannexb
bitstream filter
[concat @ 0xdffd80] Estimating duration from bitrate, this may be
inaccurate
Input #0, concat, from 'concat-list.txt':
......


Q1: what would have been the proper command line before the invention of -auto_convert ?

Q2: the -auto-convert description says: .... This is necessary in particular
    if there are resolution changes.... :  I am failing to notice any
    resolution changes, so where/how they are hiding?

Many thanks,
Konrad

> Regards,
> -- 
>   Nicolas George