Internal filter support for lossless YUV color editing

[anakin94]

Hello,
the internal color filters are converting to RGB32.
The most videos are in YUV420 and changing colors will lack of quality when modifying and exporting back to YUV420.
The colorfilters in Avidemux working in YUV mode and don't have this issue.
For VirtualDub there is a plugin that can change saturation, Hue, contrast and brightness without conversion.
But there is no VD filter which can change Red, Green and Blue separatly in YUV, like Avidemux can.
So please can you add support for it?

[v0lt]

But there is no VD filter which can change Red, Green and Blue separatly in YUV, like Avidemux can.

To change the intensity of red, green, or blue, a video filter must convert the pixel from YCbCr to RGB.

So please can you add support for it?

I don't plan to redesign the built-in filters.

[anakin94]

I don't plan to redesign the built-in filters.

Okay.

To change the intensity of red, green, or blue, a video filter must convert the pixel from YCbCr to RGB.

I don't know how it works, but i Avidemux has no quality loss.
At VirtualDub the YUV420 to RGB to YUV420 conversion is visible, the blue color is more bending out.

Original YUV420:

Avidemux boosted blue by 2 units:

VirtualDub boosted blue by 2 units:

[radpopl]

I don't plan to redesign the built-in filters.

Okay.

To change the intensity of red, green, or blue, a video filter must convert the pixel from YCbCr to RGB.

I don't know how it works, but i Avidemux has no quality loss. At VirtualDub the YUV420 to RGB to YUV420 conversion is visible, the blue color is more bending out.

This is more of a plugin quality issue than a YUV->RGB conversion issue.
Is this also the case in the output (lossless) file?
I assume it's a screenshot?

Avidemux too can silently convert YUV->RGB->YUV for this conversion (ask author).

[anakin94]

This is more of a plugin quality issue than a YUV->RGB conversion issue. Is this also the case in the output (lossless) file? I assume it's a screenshot?

Yes, i tested it with lossless videocodec FFV1 and made screenshots from it and zoomed them 10 times to see the quality.

Avidemux too can silently convert YUV->RGB->YUV for this conversion (ask author).

AFAIK Avidemux changing YUV levels same as AviSynth can do.
http://avisynth.nl/index.php/ColorYUV
But off course to be sure, asking the dev is required.

[radpopl]

Have you checked whether this problem occurs if you only convert the file to RGB (Convert Format filter) without using other filters?

[anakin94]

Have you checked whether this problem occurs if you only convert the file to RGB (Convert Format filter) without using other filters?

When just converting to RGB and export the file to RGB the problem doesn't appears.
It also doesn't appears with filters converting to RGB and exporting file to RGB.

[radpopl]

So this looks like a problem with this Hue+Saturation plugin rather than a problem with VD.

[anakin94]

Please can you explain it?
I don't really understand why it's a plugin problem.

[radpopl]

If I understand correctly, if you're not using any filter/plugin, the file converted to RGB is still correct.
The errors appear if you add the "Hue, Saturation..." filter.
So where could the error be? Probably in the filter itself.

[anakin94]

No the error is not there with the filters if i stay at RGB.
As i wrote here:

Have you checked whether this problem occurs if you only convert the file to RGB (Convert Format filter) without using other filters?

... It also doesn't appears with filters converting to RGB and exporting file to RGB.

And the error also appears, when i use no filters and do a YUV420 to RGB to YUV420 conversion.