I installed cinelerra on my debian system (2.1.0) in order to do the
simple (?) task of concatenating two movie clips (from the same source)
together into one clip with a transition between them. The clips start
in mjpeg format in a quicktime container. I have been successful at
combining them WITHOUT a transition using ffmpeg to convert to an mpg
container, cat, and then recoding to h.264. But a transition would be
nice.
So I start cinelerra and select "load file(s)" and pick clip1.mov. The
clip appears in the main window. Then I select "load file(s)" and set
the option to concatenate at the end of the project and pick clip2.mov.
It appears right after clip1. Now I have from here selected a video
transition (dissolve) and an audio transition (crossfade). But I have
also tried doing no transition at all just to see if I can get cinelerra
to work.
I can't get sound from within cinelerra (bunch of OSS errors), and
trying to watch the clips inside is ridiculously slow, so I select
"render". I initially used "quicktime for linux" with the defaults.
Audio frame sample was set to 44.1kHz, video frame rate 30 fps, video is
1280x720. I have about 4000 frames total in the two clips, about 2
minutes of material. Apparently the default codec has no compression as
it writes an 8 GB output file. My system can't play this file, I guess
because it can't read it off the disk fast enough, so I recode it using
ffmpeg to h.264 the same as I've been encoding other stuff. When I play
the resulting file the audio cuts out a few times and stutters at the
transition point.
Now the coding process for 2 minutes of video is taking about half an
hour to write out the 8GB file and then to recode it, so it's a bit time
consuming to do a lot of experiments. I tried some different codecs but
I haven't found a way to get the sound to come out OK at the
transition. I tried just putting clip1 after clip2 without an
transitions and saving the result and that sounds bad too. Comparison
to the same operation done in ffmpeg clearly shows that cinelerra has
mangled the sound around the transition.
So is this a cinelerra bug? Or some sort of "user error"?
Note: please include me on your reply as I am not subscribed to the list.
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