> Excerpts from Ralf Mardorf's message of 2011-06-10 19:24:54 +0200: >> On Fri, 2011-06-10 at 18:57 +0200, Renato wrote: >> > On Fri, 10 Jun 2011 17:58:46 +0200 >> > Philipp <hollunder@xxxxxxxxxxx> wrote: >> > >> > > Hi, >> > > sorry for abusing this list for a mostly video editing question, but >> I >> > > didn't find a proper list and knew that we have some video people on >> > > this list. >> > > >> > > I'd like to fix some videos that have partially out of sync video >> and >> > > audio, meaning that beginning at a certain point in the video the >> > > audio is suddenly out of sync by a couple of seconds. There's no >> > > constant change, the delay seems fixed once it's there. >> > > >> > > I wonder how to fix such a thing. The files are xvid encoded videos >> > > and vbr mp3 audio inside avi containers. I thought it should be >> > > reasonably easy to cut and move the audio (re-encode if unavoidable, >> > > but I know it's in principle possible without) and put it back in a >> > > container, but I didn't manage. >> > > >> > > Can someone recommend a program/workflow that would allow this? >> > > >> > > I tried: >> > > - Avidemux: seems like actual editing is not what this program was >> > > written for, couldn't figure it out, but it seems close >> > > >> > > - openshot: couldn't figure out how to separate video/audio >> > > >> > > - kino: seems to only work with DV-files, apparently takes ages to >> > > decode the file, doesn't seem to be what I need >> > > >> > > - openmovieeditor: I figured it might work by dragging the file to >> > > both a video and an audio track, but I got extremely garbled audio >> > > output, no idea what's wrong >> > > >> > > - cinelerra-cv: Doesn't start. No error message, it simply shows no >> > > window, nothing. Well, it does something with the screen, but it >> > > shows nothing. >> > > >> > > - pitivi: Doesn't seem like it can play back the video. I can drag >> the >> > > video to the tracks and it starts to draw a waveform, I guess no >> > > video thumbnails because of: gst.ElementNotFoundError: pngenc >> > > Doesn't seem to be able to play the video. >> > > >> > > - kdenlive: would require me to install 30 additional packages, >> total >> > > about 200MB, no thanks. >> > > >> > > I thought it would be a simple task, really nothing fancy. Seems >> like >> > > I was wrong. >> > > >> > > Regards, >> > > Philipp >> > > >> > >> > Hi, unfortunately can't give you a full solution, but only a hint: in >> > mplayer with "-" and "+" you can adjust audio/video syncronization by >> > multiples of 100ms (maybe you cand do finer, but I'm not sure). >> > >> > maybe you could then somehow record the output to a new file? > > Thanks Renato, I've played with that already and know the approximate > offsets, but that doesn't help much. I'm not sure screen recorders > typically can pause and resume, and even then it would be less than > optimal anyway due to the transcoding of both audio and video. > > Also, to clarify, those offsets are constant but only appear beginning > at a certain point in the file, imaginary example: after 97 Minutes the > offset is suddenly approximately -9600ms. Hence shifting the offset of > the whole file doesn't help. > I went through this a couple of years back with pretty much the same result. The general consensus round here was that it is not possible to shrink a video to fit with an audio track. Instead you should stretch the audio track to fit the video. I ended up using Blender to edit the video into chunks and align chunks of audio to fit as best as possible. I don't understand why it is not possible to resize a video track. It seems to me that dropping video frames is significantly easier programatically than time stretching audio. >> I don't think so, assumed you can display the video without side effects >> in a way, that you could 'record your desktop', than you only would be >> able to record video, but AFAIK not audio. >> An app like Cinelerra can separate the container's audio and video, but >> using video apps on Linux can become a PITA ... >> >> 21.9 Improving performance >> >> For the moment GNU/Linux is not an excellent desktop. It is more >> of a server. Most of what you will find on modern GNU/Linux >> distributions are faceless, network-only programs strategically >> designed to counteract one Microsoft server feature or another >> and not to perform very well at user interaction. There are a >> number of parameters on GNU/Linux, which ordinary people can >> adjust to make it behave more like a thoroughbred in desktop >> usage. >> 21.9.1 Disabling swap space >> 21.9.2 Enlarging sound buffers >> 21.9.3 Freeing more shared memory >> 21.9.4 Speeding up the hard drive >> 21.9.5 Disabling cron >> 21.9.6 Reducing USB mouse sensitivity >> 21.9.7 Assorted X tweeks >> 21.9.8 Speeding up the file system >> http://cinelerra.org/docs/cinelerra_cv_manual_en.html >> >> ... if the app after editing should make a container again, it can >> happen that the old man became a voice like Mickey Mouse or the >> beautiful woman is transformed to a Conehead. After 12 hours using all >> resources of your computer you will know if the video is ok or not. I >> nearly have forgotten to mention, that it also can happen that audio and >> video get out of sync during this process ;). YMMV. >> >> On my machine Cinelerra always 'worked' OOTB! On Philipp's it doesn't >> run. >> >> Regards, >> >> Ralf > > Thanks Ralf, > I had looked at the typical problems but they all mention error messages > while I get none: > > ----- > > $ cinelerra > Cinelerra 2.1.5CV GIT::01dc4375a0fb65d10dd95151473d0e195239175f (C) > 2010 Heroine Virtual Ltd. > External ffmpeg > Compiled on Mon Mar 28 20:17:50 UTC 2011 > > Cinelerra is free software, covered by the GNU General Public License, > and you are welcome to change it and/or distribute copies of it under > certain conditions. There is absolutely no warranty for Cinelerra. > > ----- > > That's it, nothing else happens in the console and no visible window > appears, though an invisible does appear (I can tell from the reaction > of my window manager, it tiles the invisible window but nothing is > painted there). > > I thought cutting and aligning audio/video on a timeline would be a > basic operation and possible in every NLVE... > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/listinfo/linux-audio-user > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
