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Histogram/Spectrum Analysis

Posted: 06 Apr 2010 22:51
by analog
This is my first post here. So here's a little background about me: I've been using VLC over five years now on multiple platforms and architectures. I'm highly interested in software development and engineering. I'm currently doing a Master Electronics and IT engineering course.

I was thinking it could be handy to show a histogram of the current image frame (so it's live when you play a movie) in the Video Effects (not sure, I translated from my dutch VLC). The same goes for a spectrum analysis for audio (Audio Effects). I think it would be pretty handy to be able to view your adjustments live in a histogram or spectrum analysis for image/sound. I'am aware both require quite some computing power: a histogram requires height*width*depth*intensity bit size sums (this can be optimized of course, HD example: 1 920 * 1 080 * 3 * 8 = 49 766 400) and a spectrum analysis requires mainly a fourier transformation over n samples. Sample size relates directly to computing requirements afaik.

Could we maybe abuse GIMP's libraries in order to implement this? How are the current Video and Audio equilizer options implemented? This would open possibilities to implement auto AV correction which would be a first in media player land afaik.

Re: Histogram/Spectrum Analysis

Posted: 07 Apr 2010 16:12
by VLC_help
Could we maybe abuse GIMP's libraries in order to implement this?
Yep.
How are the current Video and Audio equilizer options implemented?
http://git.videolan.org/?p=vlc.git;a=bl ... qualizer.c for audio filter
http://git.videolan.org/?p=vlc.git;a=bl ... r/adjust.c for video filter

Re: Histogram/Spectrum Analysis

Posted: 08 Apr 2010 04:19
by analog
Hi,
I have no experience in SVN/Git whatever it is you guys are using based software developement. I see VLC is programmed in C++ and altough I am currently engaged in a OpenGL c++ multiplatform project at school I am not sure if I am up for the job. I think the image histogram is the easiest to implement so if I get any free spare time I'll start experimenting. Would you have some references on how to start using your repository and setup a local test platform. Are there any programming guidelines or documentation available?

Re: Histogram/Spectrum Analysis

Posted: 08 Apr 2010 15:44
by VLC_help
http://wiki.videolan.org/Git that should explain git. You only need to know clone, commit and format-patch commands.

Re: Histogram/Spectrum Analysis

Posted: 08 Oct 2016 23:09
by bluer32
Thanks for three cases of no help at all. "You only need to know clone, commit and format-patch commands."