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Subject: Re: changing the hue prior to encoding - msg#00279List: video.mjpeg.user> From: scholnik@xxxxxxxxxxxxxxxxxx > I've done that a few times. What you want is yuvcorrect. Here's some > examples I've used to correct white balance: I was going to mention yuvcorrect but I see you've already done that ;) > What I'd really like is a tool that will scan the clip (or part of it) > and automatically correct white balance and/or maximize contrast. > Hand tweaking of yuvcorrect parameters is tedious. Have you tried yuvcorrect_tune? It's a bit tricky to get going but does allow interactive changes to be made and the effect immediately viewed. Cheers, Steven Schultz ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en Thread at a glance:
Previous Message by Date: click to view message previewmplex pict_rate vs picture_rateHi - Spot of trouble compiling mplex this afternoon: videostrm_in.cpp: In member function `void VideoStream::ScanFirstSeqHeader()': videostrm_in.cpp:50: `pict_rate' undeclared (first use this function) videostrm_in.cpp:50: (Each undeclared identifier is reported only once for each I see both 'pict_rate' and 'picture_rate' but it's not clear which direction the program is moving - is it towards pict_rate or picture_rate? Cheers, Steven Schultz ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en Next Message by Date: click to view message previewRe: changing the hue prior to encoding> What I'd really like is a tool that will scan the clip (or part of it) > and automatically correct white balance and/or maximize contrast. > Hand tweaking of yuvcorrect parameters is tedious. Have you tried yuvcorrect_tune? It's a bit tricky to get going but does allow interactive changes to be made and the effect immediately viewed. I did try it once. Not the friendliest interface in the world, but perhaps better than iterative tweaking. Still, I'm not that good at eyeballing color balance. I'd rather have the computer analyze the histograms and maximize the contrast while perhaps shifting the white balance. Gimp has about 6 different auto color-correction options, usually at least one looks better than what I started with. Although, if a scene is supposed to be all blue.... Dan ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en Previous Message by Thread: click to view message previewRe: changing the hue prior to encodingDoes anyone on this list know how I can change the hue of a video inside of the encoding pipeline? I made a recording with my camcorder and I forgot to do the proper white-balancing prior to the recording. As a consequence, I now have a DV file on my computer that has incorrectly calibrated colors, and I want to correct those colors before I encode the file to mpeg1/mpeg2. I've done that a few times. What you want is yuvcorrect. Here's some examples I've used to correct white balance: # approximate white balance correction for indoor (incandescent light) shot # using outdoor white-balance setting. yuvcorrect -M RGBFIRST \ -R R_1_0_255_0_180 \ -R G_1_0_255_0_215 \ -R B_1_0_215_0_255 \ -Y Y_1_0_190_0_255 # a milder version yuvcorrect -M RGBFIRST \ -R R_1_13_224_0_255 \ -R G_1_12_204_0_255 \ -R B_1_0_176_0_255 # outdoor natural light shot with indoor white-balance yuvcorrect -M RGBFIRST \ -R G_1_0_255_0_185 \ -R B_1_0_255_0_180 \ -R R_1_0_180_0_180 \ -Y Y_1_0_220_0_255 Note that in each case I'm not just adjusting white balance (which would just involve shifting), but also scaling to maximize contrast. These were in some cases ad-hoc tweaked until I liked how it looked, or in some cases I pulled a screenshot into the Gimp and checked out the histogram, etc. You can do some of the same stuff in YCbCr directly, but RGB is just easier to think in. What I'd really like is a tool that will scan the clip (or part of it) and automatically correct white balance and/or maximize contrast. Hand tweaking of yuvcorrect parameters is tedious. Dan ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en Next Message by Thread: click to view message previewRe: changing the hue prior to encoding> What I'd really like is a tool that will scan the clip (or part of it) > and automatically correct white balance and/or maximize contrast. > Hand tweaking of yuvcorrect parameters is tedious. Have you tried yuvcorrect_tune? It's a bit tricky to get going but does allow interactive changes to be made and the effect immediately viewed. I did try it once. Not the friendliest interface in the world, but perhaps better than iterative tweaking. Still, I'm not that good at eyeballing color balance. I'd rather have the computer analyze the histograms and maximize the contrast while perhaps shifting the white balance. Gimp has about 6 different auto color-correction options, usually at least one looks better than what I started with. Although, if a scene is supposed to be all blue.... Dan ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en Loading Comments...
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