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Applying video filter to specific samples of frames.

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matt kim
Applying video filter to specific samples of frames.
on Jun 28, 2011 at 5:57:42 pm

What is the best way to perform a specific video filter on random samples of frames?

At the moment I've found that the best way is to just use a -ss command along with the select command of the -vf option.

Thanks.


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Michael Rampe
Re: Applying video filter to specific samples of frames.
on Jul 4, 2011 at 12:57:37 am

[matt kim] "What is the best way to perform a specific video filter on random samples of frames?

At the moment I've found that the best way is to just use a -ss command along with the select command of the -vf option."


This seems like the best way to me as well....

Is there something that you cannot achieve using this method?

Michael


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matt kim
Re: Applying video filter to specific samples of frames.
on Jul 4, 2011 at 3:41:23 am

I was just wondering if there is a standard way of achieving this that I am not aware of, because I have just started using FFmpeg.


However, I still wish the -ss option was much faster because at the moment it is not running fast enough as I need to apply this option to thousands of videos.

I am aware that positioning the -ss option before the -i option may allow it to run faster. But it would seem that the videos that I am filtering are unable to do this as well. So at the moment the -ss option runs very slowly--about 1 sec per 1 minute.

Does anyone know of a specific way where I could speed up the execution time of the -ss option?

Thanks,
Matt Kim


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Michael Rampe
Re: Applying video filter to specific samples of frames.
on Jul 4, 2011 at 10:44:22 pm

[matt kim] "I am aware that positioning the -ss option before the -i option may allow it to run faster. But it would seem that the videos that I am filtering are unable to do this as well. So at the moment the -ss option runs very slowly--about 1 sec per 1 minute."

Putting the -ss option before -i skips through the I frames only and is not truly frame accurate. Putting it after the -i decodes every frame to find the exact one you set and is thus much slower.

What is your source codec?

Michael


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matt kim
Re: Applying video filter to specific samples of frames.
on Jul 5, 2011 at 12:40:47 am

When I put -ss before -i it starts running the cropdetect filter (i forgot to mention this is what I'm trying to run) at frame 0.

My source codec is H.264


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