Video & Audio Not Synchronized
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Video & Audio Not Synchronized
I am using the current release 3.7.2 on Linux Fedora and having problems with the waveform viewer syncing with the video. Since I'm using an avi file I had to extract the audio into a separate wav file and link it into the ELAN project. This created the audio sample plot in the waveform viewer as expected but the audio is a few seconds ahead of the actual audio from the avi file.
When I use media synchronization mode and adjust player 1 (which I believe to be the video from the avi file) to compensate for error, it seems to also adjust the wav file as well because my waveform shifts to the same degree... leaving nothing changed.
Is there any way to fix this or to only shift the waveform?
Re: Video & Audio Not Synchronized
The fact that you can only adjust the offset for the video is, I guess, the result of a "historic" assumption: namely that if a .wav file has the same name as one of the video files (except for the extension) it is extracted from the video (and therefore synchronized!). In the older days this was the way to find an extracted .wav file.
So, I assume that if you rename the .wav file, you will have 2 players in the Synchronisation mode. You could also change the order in Edit -> Linked Files and put the .wav file at the top; then you'll have two players to synchronize as well.
Unfortunately, if you would reset the order of the media files after synchronisation, the offsets will be equal again.
Are you sure the shift between audio and video is the same throughout the entire length of the file? I would be a bit worried if an extracted audio track/file isn't in sync with the master video.
-Han
Re: Re: Video & Audio Not Synchronized
Han, you were right that if I renamed the .wav file it would not assume it is extracted from the avi. However it automatically sets the extraction to that file, leaving only one player in the synchronization mode still. If I unlink it (say it isn't extracted from the avi file) two players show up in sync mode but the waveform viewer just vanishes and will not return...
If I try the other strategy and make the audio the master media, both the waveform and the video viewer disappear. If I try to revert back to the video file being the master media, the waveform returns but with no audio present and all my annotations are gone (sometimes the program just crashes instead).
I believe the reason why it is offset is because the bit rates are different once extracted into a .wav file... Do you have any other suggestions?
Re: Re: Re: Video & Audio Not Synchronized
I installed ELAN on a laptop running Windows OS and none of these problems occur. I am able to shift player 1 & player 2... but the shift between Audio and Video is indeed inconsistent... is there anyway I can fix this or manage offsets in multiple places in the timeline?
Re: Re: Re: Re: Video & Audio Not Synchronized
No, it is not possible to manage multiple offsets in the timeline. The 2 files should really be synchronized, except for maybe a single offset for the starting point. Otherwise it won't work. I don't know right now what application best to use when extracting wav from avi. I'll ask some colleagues.
If you have special problems on Linux that you don't see on Windows, it is probably because of JMF that might have some difficulty in playing avi files?
-Han
Re: Re: Re: Re: Re: Video & Audio Not Synchronized
It probably is an issue with JMF, although I am not certain. If you do find a decent program to use to extract .wav from avi I would greatly appreciate it - it may solve my problem.
Re: Re: Re: Re: Re: Re: Video & Audio Not Synchronized
I've been told that Audition would be a good choice but that an "avi2wav" should normally do as well. (I have no personal experience in this.)
-Han
Release of ELAN 4.3.0
