Resolved: Converting from YUV to PNG issue.

[Iamiuru]

Hello everyone,

I'm working with a file that is captured from a firewire camera that is in YUV. I've switched to a newer Fedora (F17) and now my conversions from YUV to PNG have changed.

Old IM on F9: 6.7.1-0 Q16
New IM on F17: 6.7.9-3 Q16

The command and the raw yuv file is the same between systems, so I don't understand what is going on.

The command is:

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convert -size 1024x768 -sampling-factor 4:2:2 -depth 8 raw-example.yuv <outfile>.png

Here are my examples:
Old: New:

I am expecting/need the darker image for my mask generation. I suppose I can redarken the image, but not sure I can trust it if I don't know what magic is happening.

Here is the raw yuv file: http://www.foto-devel.com/images/raw-example.yuv (might need to right-click to save as)

The kicker is that the new one "raw" looks very much like my final image after I have applied my gamma correction

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convert inpng.png -evaluate Pow 0.45 outpng.png

Old system after gamma correction is applied:

I've searched the forums and changelog for YUV and 4:2:2. I haven't found much that reference much of anything. I also put the original IM 6.7.5-6 back on my F17 system to see if it did the same, and it did. I had to move up to IM6.7.9-3 due to a bug that was in IM6.7.5-6.

Any idea of what is going on here?
Thanks for your help in advance,
Jason

p.s. Sorry the model isn't very pretty.

[snibgo]

"With a new version of IM, my picture is lighter/darker than before."

This immediately suggests the new feature of IM assuming that everything is sRGB, or should be converted to sRGB, unless told otherwise.

convert -size 1024x768 -sampling-factor 4:2:2 -depth 8 raw-example.yuv -colorspace RGB out.png

[Iamiuru]

Thanks for the info I have tested it and it worked great.

I was just thinking too far into the issue.

Jason