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Colors change with QTSource 
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Joined: Mon, 2015/10/12 2:19 pm
Posts: 2
Unread post Colors change with QTSource
Hello, I'll introduce myself:

I am new to QTSource and Avisynth, I use it to deinterlace by QTGMC my video editing I make with Cinelerra-cv 2.3 under Linux. Obviously it is with Windows-7 that I use QTSource, Avisynt and QTGMC...

I'm not a developer and my knowledge of the language of codes and scripts is extremely limited.

I use QTSource to import YUV2 editing render file (of sequences shot in DV-NTSC) into Avisynth for the final step of deinterlacing.

Obviously I want to avoid the maximum qualities loss of the image and change of colors.

Here is the script lines that I use with your "QTSource_20131222" (recovered here on this site):

#f = "filename.mov"
QTInput (f, color = 2, quality = 100, audio = 2, mode = 1, raw = "YUV2")

So I try to avoid changes in the YUV color space.

But even if the quality of deinterlacing with QTGMC (placebo) is spectacular, I observe nevertheless a slight color changes ... in particular the skintone gets a little bit more yellow.

I also tried with modes = 0,2,3 and it is worse; These modes cause compression of video levels and therefore contrast.

Is there anything I could do, so that the colors are not altered ?

The images in attachment illustrate the (light) colors change problem:


Attachments:
File comment: Original Skintone render in yuv2 from DV-NTSC
Skintone original (dv-yuv2).png
Skintone original (dv-yuv2).png [ 207.61 KiB | Viewed 6552 times ]
File comment: Result skintone after input with QTSource and proces in Avisynth
Skintone after QTSource_Avisynth.png
Skintone after QTSource_Avisynth.png [ 199.25 KiB | Viewed 6552 times ]
File comment: VideoScope of the result color-bars after QTSource-Avissynth proces
VideoScope after QTSource-Avisynth.png
VideoScope after QTSource-Avisynth.png [ 69.8 KiB | Viewed 6552 times ]
Mon, 2015/10/12 5:30 pm
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Joined: Sun, 2005/04/03 7:02 pm
Posts: 302
Location: Los Angeles, CA USA
Unread post Re: Colors change with QTSource
The only thing you can do to change the ouput from QTSource is to change mode & color. In my DV tests, QTSource produces the correct colors.

How do you know that whatever produced "Skintone original (dv-yuv2).png" did it correctly? How do you know that whatever software you used to convert to DV format did it correctly? You have no real reference that you can 100% positively state is correct.

Also, there is no such thing as YUV2 and DV is YV12 and QTSource can decode it to RGB or YUY2.

Here are my examples using an AviSynth script as the color bar source, ColorBars(720,480,pixel_type="YV12"), converted to a Quicktime file (Avid DV Codec) using Quicktime and QTSource decodes the colors correctly.


Attachments:
File comment: AviSynth Source File
01_YV12_Bars_AviSynth.png
01_YV12_Bars_AviSynth.png [ 3.45 KiB | Viewed 6548 times ]
File comment: Quicktime video decoded by AfterFX, correct colors
01_YV12_Bars_AfterFX.png
01_YV12_Bars_AfterFX.png [ 11.25 KiB | Viewed 6548 times ]
File comment: Quicktime video decoded by QTSource, mode=0, color=2, correct colors. (mode =0, color=1 also seems to work)
01_YV12_Bars_QTSource.png
01_YV12_Bars_QTSource.png [ 10.15 KiB | Viewed 6548 times ]
File comment: Quicktime video decoded by FFMpegSource, incorrect colors
01_YV12_Bars_FFMpegSource.png
01_YV12_Bars_FFMpegSource.png [ 8.69 KiB | Viewed 6548 times ]
Mon, 2015/10/12 6:18 pm
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Joined: Mon, 2015/10/12 2:19 pm
Posts: 2
Unread post Re: Colors change with QTSource
Thank you for your response.

First, do not take my questions for critical, this is not the case. My knowledge of this whole universe of color treatments is very limited and I'm just trying to find solutions to my problems.

Of course I do not know if it's QTSource introducing color errors. I'm trying to eliminate possibilities.

As for the colors of the image of the "original Skintone (dv-YUV2) .png" file, she was captured by its compressed version of HandBrake (MP4, H264) as all the video I finish. I compared with the original source DV and there is no visible color difference.

The YUV2 file that I mention is a rendering formats that can produce Cinelerra-cv. This NLE software can also produce "YUV 4: 2: 0 Planar" but I have not managed to get it accepted by Avisynth and I was instead advised to use "YUV2" because it is 4 : 2: 2 and that there would be no loss with the DV-NTSC is 4: 1: 1.

Of course QTGMC apply many changes to my file and its release in YUY2 is then converted to Huffyuv and finally MP4-H264 by Handbrake. Anywhere during this process, color changes can occur ... I was just trying to follow the path from the beginning to see if adjustment of my configurations could improve things.

Sorry if you found that my question was inapropriate.


Mon, 2015/10/12 7:25 pm
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Joined: Sun, 2005/04/03 7:02 pm
Posts: 302
Location: Los Angeles, CA USA
Unread post Re: Colors change with QTSource
With all of the conversions you are doing, color changes could be introduced anywhere. You have no idea what Handbrake is doing. You said "I compared with the original source DV and there is no visible color difference." How do you know that software you used to compare them isn't doing something to the output? You'd be better off asking this in a Handbrake or AviSynth forum, as this is specifically just for my plugins.


Mon, 2015/10/12 7:33 pm
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