[FFmpeg-user] concatenating mp4 (non-h464) using mpegts

[Konrad Karl]

On Thu, Apr 05, 2012 at 05:26:24PM +0000, Carl Eugen Hoyos wrote:
> Konrad Karl <kk_konrad <at> gmx.at> writes:
> 
> > tried to concatenate several mp4 files w/o reencoding (they all come
> > from kdenlive using the same export settings) using mpegts as 
> > intermediate format but I failed - see below.
> 
> Stream copying ASP into a transport stream is not supported, 
> this is a very old feature request.
> (And yes, it is a bug imo that FFmpeg does not show an error message 
> if you try something unsupported.)

Thanks for clarifying. Is this technically difficult or not allowed
by some spec?

So what procedure would you recommend? I am also worrying about
keeping good A/V synchronization. All the files are 1080p50 and
have been rendered by kdenlive. 

-------

When looking with MP4Box -info 	the audio and video durations
are different.

At the moment I cannot use MP4Box for joining because it fails for
files > 2GB on my F16 x86_64 system.

~> MP4Box -info tag2-1.mp4 
* Movie Info *
        Timescale 1000 - Duration 00:07:37.457
        Fragmented File no - 2 track(s)
        File Brand isom - version 512
        Created: UNKNOWN DATE
File has no MPEG4 IOD/OD

iTunes Info:
        Encoder Software: Lavf54.2.100

Track # 1 Info - TrackID 1 - TimeScale 50 - Duration 00:07:37.360 <===
Media Info: Language "Undetermined" - Type "vide:mp4v" - 22868 samples
Visual Track layout: x=0 y=0 width=1920 height=1080
MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x20
MPEG-4 Visual Size 1920 x 1080 - Simple Profile @ Level 1
Pixel Aspect Ratio 1:1 - Indicated track size 1920 x 1080
Self-synchronized

Track # 2 Info - TrackID 2 - TimeScale 44100 - Duration 00:07:37.456 <===
Media Info: Language "Undetermined" - Type "soun:mp4a" - 17512 samples
MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x6b
MPEG-1 Audio - 2 Channel(s) - SampleRate 44100 - Layer 3
Synchronized on stream 1
Alternate Group ID 1

-----

another view of the same file:

~> kdenlive/20120405/bin/ffmpeg -i  tag2-1.mp4 
ffmpeg version N-35138-gfa1f92a Copyright (c) 2000-2012 the FFmpeg developers
  built on Apr  5 2012 14:05:40 with gcc 4.6.3 20120306 (Red Hat 4.6.3-2)
  configuration: --prefix=/home/ki/kdenlive/20120405 --disable-doc --disable-network --disable-ffserver --enable-gpl --enable-version3 --enable-shared --enable-debug --disable-stripping --enable-pthreads --enable-runtime-cpudetect --enable-libtheora --enable-libvorbis --enable-libmp3lame
--enable-libx264 --enable-libvpx
  libavutil      51. 44.100 / 51. 44.100
  libavcodec     54. 12.100 / 54. 12.100
  libavformat    54.  3.100 / 54.  3.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 66.101 /  2. 66.101
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 10.100 /  0. 10.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'tag2-1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf54.2.100
  Duration: 00:07:37.45, start: 0.000000, bitrate: 25132 kb/s
    Stream #0:0(und): Video: mpeg4 (Simple Profile) (mp4v / 0x7634706D), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 24810 kb/s, 50 fps, 50 tbr, 50 tbn, 50 tbc
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 319 kb/s
    Metadata:
      handler_name    : 

-------

Now I am curious if the A and V streams are really of different length or MP4Box is playing
games with me. At the moment I have 6 videos to join, each with similar A/V length 
differences. If those differences would accumulate it would be very noticeable I am afraid.

Suggestions and explanations are very welcome,

Konrad

> Carl Eugen