[FFmpeg-user] Is there a way to speed up this ffmpeg command execution time?

Eric Hollis eric.hollis at gmail.com
Sat Aug 20 02:01:30 CEST 2011


Hello.  Looking for some additional guidance. Thanks in advance for
looking...

The command line below, when run on my Win 7 Pro 32 bit, Core2 Duo E8400
@3.0Ghz, 3G RAM machine, takes 3.86 seconds to write a pic to the disk.  I
have written a script that calls this command line each time a frame
advances on my film scanner. I was hoping for an execute time of 1 to 2
seconds, since I am digitizing hundreds of thousands (probably millions) of
frames of film.  Any suggestions on how this could be made to run faster?

     ffmpeg.exe -r 1 -rtbufsize 100000000 -f vfwcap -s hd720 -i 0 -vframes 1
-vf crop=943:686:180:3,hflip test.tif

At this point, I'm willing to entertain switching platforms to Linux, and
dedicating a machine to this process. Ideas welcome.

Thanks again for the help I've received from this group over the past couple
of days!

Eric

(Short description of project)
8/17/11
I currently use ffmpeg to assemble still images into movies.  I have
developed a 16mm film scanner, based on a projector, that gathers frames,
similar to this project, which was the inspiration to my machine.  (
http://hackaday.com/2011/01/15/converting-8mm-film-to-digital/) I am using a
webcam (Microsoft LifeCam) in front of the projector lens. As each frame
advances, the projector "clicks" an embedded mouse, taking a high res jpg
image, utilizing the (gag) Microsoft lifecam software that the camera came
with.  I then use irfanview to crop/flip/renumber the images, and ffmpeg to
assemble them into the movie. The trouble is...the Microsoft Lifecam
Software has a memory leak, and after about 5000 frames (about 2 hours), the
software chokes.  So, I'm rethinking the workflow.
8/19/11
I have now gotten the command line above to grab the frame and save it as a
much-preferred uncompressed tif, replacing the Microsoft LifeCam software
and the Irfanview crop/flip stage.  Now all I need to do is finish the
script that will invoke this command each time the projector sends a "left
click".  The projector can be slowed to ~ 2.5 seconds between frames, but
ideally, it should run in the 1 second per frame range.


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