fraps capturing and avidemux

[Tagert]

Hello people. I just did some capturing in fraps3. When I opened the clip in a media player such as zoom player or MPC classic the clip had normal gamma and so on.


But when opening it in avidemux it becomes darker and stays darker when encoding it to either x264 or huffyuv.

It seems though fraps is capturing it in a colourspace megui for example doesn't like and says it's done in the wrong one (fixes it for me) when I try to encode it to x264 there. I haven't noticed it saying that in Avidemux though.

There is a mode to enable lossless RGB capturing in fraps3 though.

Is this a colourspace problem?

I can provide sources if needed :)

[LoRd_MuldeR]

x264 requires the YUV12 colorspace. FRAPS probably captures at RGB24 or RGB32. So the RGB -> YUV conversion is unavoidable.

With MeGUI (Avisynth input) you would do this the following way:
AVISource("C:\My Fraps Capture.avi")
ConvertToYV12()

Avidemux will do the required conversion for you. But be aware that Avidemux has a problem with colors in its internal preview:
http://avidemux.org/admForum/viewtopic.php?id=5735

The encoded video will be 100% fine though!

You must make sure that your player uses the proper luminance range at playback-time though:
http://forum.doom9.org/showthread.php?t=143689

[Tagert]

Just tried this again.

In avidemux I used the following settings:
encoded to x264 5000bitrate two pass, didn't touch the other settings,
resized from 1280x1024 to 1080x864 w lancos3

The result is a dark video clip just as in the avidemux preview.

In megui I used the same settings,
resized with lancos4 though, don't think that matters though.
and converttoyv12 in the script.

Result was a much brighter video clip.



Opened both clips with MPC classic.

[Dark Shikari]

Sounds like a TV/PC levels issue. FRAPS likely captures at PC levels.

[Tagert]

To further explain the error I've encounted, I hereby attach the screenshots of the problem encoded in both avidemux and megui:

http://www.lern2play.se/test/error/made.in.avidemux.jpg
http://www.lern2play.se/test/error/made.in.megui.jpg

Not exactly the same frame, but the darkness is clearly distinguishable :)

Both files opened in latest VLC. screenshot taken with fraps.
I'm using a 19inch LCD screen. No gamma problems whatsoever in games or tabbing out and tabbing in.

[poisondeathray]

I just did some quick tests with avidemux r5422 and fraps (FPS1)

avidemux seems to do the RGB=>YV12 conversion full range with full expansion to 0-255 using BT.709

When you use ConvertToYV12() in avisynth, it will use Rec.601 in 16-235 range by default

If you use ConvertToYV12(matrix="pc.709") , this will use 0-255 range but BT.709 coefficients.
ConvertToYV12(matrix="rec709") => 16-235 range, BT.709
ConvertToYV12(matrix="pc.601") => 0-255 range, BT.601

I did these tests with avsp and histogram() to see levels

EDIT: also very important as LordMulder said earlier is how you are viewing these, and how you have your decoder, splitter, software configured. For example, using the default vfw fraps decoder using AVISource(), it will decompress in the 16-235 range, but default ffdshow directshow decoding using DirectShowSource() for fraps uses 0-255 range . Disabling ffdshow for fraps will result in a windows colorspace conversion and decompression to 16-235 the way I have it setup. You can visualize the directshow decoder chain with graphstudio. MPC with no internal or external filters enabled will use directshow.

[Tagert]

much appreciated, I think I understand it somewhat now :)