Slight brightness difference between RGB source and encoded I444 video

[aufkrawall]

Hello,
when I convert FRAPS RGB to x264 I444 there's a slight brightness difference, at least for some colors like green.
It goes away if I force RGB output, so theoretically the video contains all information to look right.

How it should look like:
http://www.ld-host.de/uploads/thumbnails/d4d23206be8d6e0ef59c7d359cf2f49f.png (http://www.ld-host.de/show/d4d23206be8d6e0ef59c7d359cf2f49f.png)

How it actually looks, unfortunately (too dark):
http://www.ld-host.de/uploads/thumbnails/ae7124a71ffa783b84ddf8ad7d726383.png (http://www.ld-host.de/show/ae7124a71ffa783b84ddf8ad7d726383.png)

With RGB output when decoding while playing it looks like the first picture.
When converting to x264 there's CSP conversion from PC.601 to Rec709. Doesn't matter if I do it via Avisynth or x264.

Is there anything I can do about it? :(
There is no way to force a decoder to convert to RGB, right?

[richardpl]

What FRAPS decoder are you using? FFmpeg/Libav decoder always output in BGR24 or YUVJ420P depending on FRAPS version.

Here is what ImageMagick gives me for your pngs:
compare -verbose -metric mae ae7124a71ffa783b84ddf8ad7d726383.png d4d23206be8d6e0ef59c7d359cf2f49f.png difference.png
ae7124a71ffa783b84ddf8ad7d726383.png PNG 1280x1024 1280x1024+0+0 8-bit DirectClass 2.234MB 0.148u 0:00.156
d4d23206be8d6e0ef59c7d359cf2f49f.png PNG 1280x1024 1280x1024+0+0 8-bit DirectClass 2.049MB 0.156u 0:00.164
Image: ae7124a71ffa783b84ddf8ad7d726383.png
Channel distortion: MAE
red: 363.981 (0.00555399)
green: 407.947 (0.00622487)
blue: 404.13 (0.00616662)
all: 392.019 (0.00598183)
ae7124a71ffa783b84ddf8ad7d726383.png=>difference.png PNG 1280x1024 1280x1024+0+0 8-bit DirectClass 1.622MB 3.297u 0:03.460

RGB->I444 is not lossless.

[aufkrawall]

What FRAPS decoder are you using? FFmpeg/Libav decoder always output in BGR24 or YUVJ420P depending on FRAPS version.

I tried every decoder, it doesn't matter.


RGB->I444 is not lossless.
This is not the issue. ;)
The difference in the pictures isn't by information loss, it's just a decode issue.