[FFmpeg-user] Hello and newbie question

[Kirk Rutter]

Hi,

I'm a new joiner just dipping into the world of Linux and Ubuntu. I am creating lecture capture
 units based on Ubuntu 12.04 and software called Galicaster. We are using 2 networked devices
to produce 2 separate streams that are combined in the Galicaster software. Still as independent
streams but played together. However some offset information seems to keep being added as
when played back they are out of sync but when I drop both files into a video editor they are in sync.

After a bit of reading I used ffprobe to look at  both files and the start times are different.

here are the results:

Input #0, flv, from 'screen.flv':
  Metadata:
    gstfiller       :
    AspectRatioX    : 1
    AspectRatioY    : 1
    metadatacreator : GStreamer FLV muxer
    creationdate    : Tue Feb 11 11:36:59 2014
  Duration: 00:15:16.64, start: 616.070000, bitrate: 128 kb/s
    Stream #0.0: Video: h264 (Main), yuvj420p, 1920x1080 [PAR 1:1 DAR 16:9], 24.92 tbr, 1k tbn, 30 tbc
    Stream #0.1: Audio: mp3, 22050 Hz, stereo, s16, 128 kb/s
galicasterca2 at Galicasterca2:~/Desktop/GC Media/media-packeages/gc_HHMobile_20140211T11h30m43$

-----------------------------------

Input #0, flv, from 'CAMERA.mp4':
  Metadata:
    gstfiller       :
    AspectRatioX    : 1
    AspectRatioY    : 1
    metadatacreator : GStreamer FLV muxer
    creationdate    : Tue Feb 11 11:36:59 2014
  Duration: 00:15:16.63, start: 616.637000, bitrate: N/A
    Stream #0.0: Video: h264 (Baseline), yuvj420p, 800x450 [PAR 1:1 DAR 16:9], 25 tbr, 1k tbn, 2k tbc


I'm a complete newbie so would really appreciate some help with this. Is there a way to reset the offset
information to put these in sync? If so is there a command that I can run after each recording to reset
this?

Any help would be good, I know some people will be tempted to suggest having the video containing the
audio, but sometimes we need to switch between screen / video recording only and 1 device has much
better sound codex options than the other.

we are using:

Epiphan DVI Broadcaster

Axis P5534 IP Camera



Kirk Rutter


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