video and audio not playing synchroneously

Posted by Tashram at 2007-03-12 15:43

hi there,
when i play a selection the sound doesn't come with the video, but sets in somewhat late.
the delay makes a proper transcription rather difficult. the files are already downsized to 100-300mb max, but the timing is still bad. computer has 1.99 ghz and 1gb ram, don't suppose that's the difficulty. but maybe the programme needs some fine-tuning?
what do you suggest?
regards,
marsha

Re: video and audio not playing synchroneously

Posted by hasloe at 2007-03-14 11:32

The size of the media files will indeed not be the problem, nor the computer specifications.
What is the operating system and how are the files encoded?

If you have extracted a separate audio file you could make this the first file in the list of associated media files (Edit -> Linked Files). The sound will then be produced from this file instead of from the video file, this might improve the play selection synchronicity.

Han

Re: Re: video and audio not playing synchroneously

Posted by Tashram at 2007-03-15 23:19

ok, but there's just one single mpeg file in there anyway? problem is that whereever i put the crosshairs the video starts without playing the audio (not just in selection mode). then it stops and when the audio sets in, the video comes along too. does the programme split audio from video or something? i just wonder where this temporary asynchronity comes from.

marsha

Re: Re: video and audio not playing synchroneously

Posted by Tashram at 2007-03-20 10:53

What is the operating system and how are the files encoded?

windows xp home edition, mpeg files

Re: Re: Re: video and audio not playing synchroneously

Posted by hasloe at 2007-03-20 15:09

ELAN doesn't do anything to the video file, it merely passes the file to the underlying media framework. In the case of XP this means the Windows Media Player (more accurate Direct Show).
Do you see the same effect in Windows Media Player when hitting the play/pause button several times?

Re: Re: Re: Re: video and audio not playing synchroneously

Posted by Tashram at 2007-03-20 17:12

hi. ok, when i open the file with wmp the sound comes instantly, but the picture is a split sec delayed? with elan it's the other way round.

Re: Re: Re: Re: Re: video and audio not playing synchroneously

Posted by hasloe at 2007-03-21 16:15

That is strange. But it still seems to indicate that there is something special with the file?

Re: Re: Re: Re: Re: Re: video and audio not playing synchroneously

Posted by Tashram at 2007-03-26 15:58

hi there, the programm we changed the original avi video into mpeg was TMPGEnc (http://www.tmpgenc.net/de/index.html). oddly enough my collegue opened the file with ELAN 3.0 on the institute's computer and it worked without any delays? *sigh* must be something about my computer... i was told that maybe some codec was missing, could that be a problem? (so i downloaded divx) marsha

Re: Re: Re: Re: Re: Re: Re: video and audio not playing synchroneously

Posted by hasloe at 2007-03-28 09:53

It could also be that there is a codec installed that causes this problem. ELAN logs the detected codec in it's log file in <user_home>/.elan_data/elan0.log (or elan1.log).
If you open ELAN, open one of your problem files and close ELAN again, you'll find a list of codecs actually in the 'chain' for the associated file(s). You could compare this list with that from another computer and maybe identify the 'problematic' codec.

Han

Re: video and audio not playing synchroneously

Posted by Hilppo at 2008-08-27 14:04

Hi there,

I´m experiencing a similar problem as described bellow by Marsha but w/ Elan version 3.6.0 and Mac OS X (version 10.5.4). When using "Selection mode" I can chose and annotate the first selection I make, but when I continue there is a dissynchronus of vid and sound of about 20 sec (that wasn´t there in the first take). With out th selection mode, and when I start the vid from the beginning, both sound and picture are in synch.

I´v tried downgrading to ELAN 3.4.0, creating new .eaf documents from beginning and chancing the vids I annotate, but the problem remains.

Hope someone has cracked this one already :o).

Regards Jake

Ps. The funny thing is that the dissycronus does apprear also whe I paly the vids on Quicktime, but not when I use VLC player. Could they use different codecs (original vid. format is xvid packed .avi) which creates the problem?

Tashram-2007-03-12 15:43:49

hi there, when i play a selection the sound doesn't come with the video, but sets in somewhat late. the delay makes a proper transcription rather difficult. the files are already downsized to 100-300mb max, but the timing is still bad. computer has 1.99 ghz and 1gb ram, don't suppose that's the difficulty. but maybe the programme needs some fine-tuning? what do you suggest? regards, marsha

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