[Libav-user] ffmpeg ; splitting an input movie into multiple tracks in a single output movie, possible?

"René J.V. Bertin" rjvbertin at gmail.com
Fri Dec 7 16:33:28 CET 2012

Are we really speaking about the same thing, generating multiple tracks in a QuickTime movie, and not a track with 4 overlays or a multi-channel (audio) track? May I ask what the name of the filter is that merges the crop filter outputs in 4 tracks in a single output (not overlay, not amerge ... I must have overlooked the relevant one)?

For reference, what I'm doing now is create a pipe to

ffmpeg -y -v 1 -i - -vf crop=360:288:0:0 -b:v 500k -vcodec mjpeg cam1.mov -vcodec mjpeg -vf crop=360:288:360:0 -b:v 500k cam2.mov -vf crop=360:288:0:288 -vcodec mjpeg -b:v 500k cam3.mov -vf crop=360:288:360:288 -vcodec mjpeg -b:v 500k cam4.mov

to generate single-track 4 quicktime movies from an m4v 4000kbit/s stream that contains the recorded output of 4 cameras, in 'quad' arrangement. I then combine those 4 movies into a single QuickTime movie with 4 tracks using QuickTime SDK functions.
NB: at 12Hz there isn't much gain of mpeg4 encoding over mjpeg encoding, which however plays back much smoother on a wider range of hardware.


On Dec 07, 2012, at 13:19, Carl Eugen Hoyos wrote:

> René J.V. Bertin <rjvbertin at ...> writes:
>> I discovered yesterday that it's possible to split an input 
>> movie (a raw m4v stream) into 4 separate output movies (.mov) 
>> each containing a quarter of the original image (obtained with 
>> -vf crop=w/2:h/2:x:y), using a single invocation of ffmpeg.
>> Is it possible to generate a single output movie with 4 
>> tracks instead
> The complex filter allows this, please RTFM for examples.
> Carl Eugen

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