Is it possible to render without re-encoding?  



I sometimes (often) use Cinelerra just to sync external audio to a video, or to precisely trim a video.  Is there a way to render without re-encoding in this case?

5 Answers

Unfortunately, no.  When Cinelerra loads a video/audio, it fills the timeline track by decoding.  This of course means to save the results, it has to be encoded.

Maybe ffmpeg will let you add an audio track to a video track without encoding, but I do not know that for sure.  Here is what the web states:

Copying the audio without re-encoding

If your output container can handle (almost) any codec – like MKV – then you can simply copy both audio and video streams:

ffmpeg -i video.mp4 -i audio.wav -c copy output.mkv


However, with just trimming a video like cutting off the end, sometimes the physical end of the media actually contains information like "moov" that is necessary for loading the video so I doubt you can do that easily in ffmpeg either.  But here is some information anyway:

This post was modified 8 months ago 3 times by phylsmith2004

Small, easy-to-use external programs are losslesscut and vidcutter:


With FFmpeg it is possible to define the start time as well as the duration of each individual track. The tracks will then only be cut and copied without loss. But this is complicated and has to be checked each time with the resulting new AV file. For simple cuts, Avidemux is more comfortable, and Avidemux also handles smart rendering.

And in addition to the solutions already mentioned, the solution for pros should also be mentioned. The combination of Ardour and Xjadeo is better suited for the precise synchronization of finished videos, because you can work with CD frames instead of video frames. However, it is only worth the effort if the audio data is lossless.


For lossless cutting I use Avidemux:


thanks a lot guys, i'll check these options out.