Error : ffmpeg: could not seek to start of file

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adhamdwikat

Error : ffmpeg: could not seek to start of file

Post by adhamdwikat » 05 Apr 2014, 23:11

i have an error message appears when i dispatch the Restart event for movieclip
the file chosen is FLV file encoded with Premiere
the error message says :
Error : ffmpeg: could not seek to start of file, some audio is missing. (video is ok)

when the message appears the movie refuse to playback
the strange thing is when i put the movie in an empty scene it works fine even if the message appear !!

adhamdwikat

Re: Error : ffmpeg: could not seek to start of file

Post by adhamdwikat » 06 Apr 2014, 12:47

i found that this message is nothing to do with movie not playing back

the movie was not playing back because i forgot to set changed=true; in the script node .

but i still don't know why the error message is shown ! the movie is already contain audio !.

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Dierk Ohlerich
Posts: 74
Joined: 10 Jul 2012, 09:01
Location: Hamburg, Germany

Re: Error : ffmpeg: could not seek to start of file

Post by Dierk Ohlerich » 14 Apr 2014, 11:00

This message comes when Ventuz tries to pre-load the video and audio for the loop point.

Many streams put audio ahead so that it is already decoded when the video gets decoded. So when the video time is at 100 seconds, the audio time may be already 102 seconds. This is better than the other way around since audio is easier to buffer than video. The downside is when you seek to a position, you may have to wait a bit until audio is ready.

In order to get the audio for the loop point, Ventuz will have to seek before the loop point. But there is a limit to how far Ventuz will adjust the seek position, and when this limit is reached two things can happen: It finds video but no audio, then it gives "could not seek to start of file, some audio is missing. (video is ok)". Or it does not get audio and video, then the error message is the mysterious "seek failed somehow" (I never seen this on correctly encoded streams).

Will change the error message to "could not seek to loop point, some audio is missing. (video is ok)".

So what to do? Play with the encoder options, possibly change the container format. More key-frames will help.
-- Dierk Ohlerich

errox

Re: Error : ffmpeg: could not seek to start of file

Post by errox » 01 Sep 2015, 15:42

Hi Dierk,

is "seek for restart fell to far, will compensate for that in future. trying again..." something similiar (loop-point loading)?
I got this message very often... but maybe because of the "try again" it's working well...

Regards

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