MOV/h264 files too bright?

[Andur1l]

Hey guys,

I'm a fairly newbish user of Avidemux. I just spent the better part of an hour figuring out how to batch convert mov files from my Canon 600D into h264 .avi files with specific settings, but I finally managed to figure it out.

Then, after reviewing a few files, I noticed a strange difference between the original mov files opened in Media Player Classic:

https://www.dropbox.com/s/8l9v3ffsd2l7w0o/mpc.jpg

... and the same file opened in Avidemux:

https://www.dropbox.com/s/64wyqvk9iykagsq/avidemux.jpg

The whites are much more exposed/bright, losing lots of details that are there in MPC. The same result is then evident after converting these files through Avidemux, with the new files brighter than the originals.

As the newb I am, I have no idea why this occurs and how to change this. Also, if I am asking something completely stupid, feel free to point and laugh.

Any help would be seriously appreciated.

[Jan Gruuthuse]

Depending your specific settings: converting videos = re-encoding, loosing details (compression), applying filters could all be a source of what your observing.
Don't compare video in different players. Use vlc at its default settings. Even then results could be different on your monitor for the same player, specially these days with varying back lighting of lcd (zone) panels. Dragging a picture around your desktop could show this behavior.
When using only copy for video, the content should not differ (image wise)

[Andur1l]

Thanks for the reply, but the problem is that the difference in brightness is before any converting/reencoding in Avidemux. Just opening a file in Avidemux makes it brighter than opening the same file in MPC/VLC. The same file then converted through Avidemux comes out brighter (while viewed in VLC/MPC) than the original.

It's seems like Avidemux has a different way of decoding this type of files than VLC/MPC, making it brighter, which then reflects in the converted file too. Wouldn't be such a problem if it didnt cost me a whole lot of detail with such bright/white snowy scenes.

[Jan Gruuthuse]

Update to avidemux 2.5.6 & 2.6.1 latest build? Suspect you're on a older version of avidemux?
2.5.6: http://avidemux.razorbyte.com.au/
2.6.1 r#### win32: http://avidemux.org/nightly/

Check if vlc and avidemux have the same device (software wise) selected for output.
Avidemux 2.6.# : Main menu -> Edit -> Preferences: Video display. If you're lucky you have a choice here.
In Default Postprocessing: unselect
[ ] Horizontal deblocking
[ ] Vertical deblocking
[ ] Deringing

[zakk]

My guess is that 1 picture is processed by your video card and the other is not. Best way to really compare to videos is to open 3 sessions with the same software: 1st one will use hardware processing, then you can compare 2nd and 3rd in really same conditions.

[Andur1l]

Updated to the latest version and just checked out the things you are both suggesting .. it seems if the Video display/Output is set to OpenGL in Avidemux/VLC I get the brighter video. In VLC I normally have it set to Default (resulting in the darker video), but changing the video display to Default Raster (the only other option I have) in Avidemux doesnt change anything. Neither does unselecting the postprocessing options, unfortunately.

Disabling hardware video acceleration in VLC also doesnt change the brightness.