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  1. Member
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    I have Hauppauge's first generation Colossus. I've been using it to record shows on cable for years, but I've never been able to set the capture settings in order to match the cable box video output. I'm using the HDMI output to capture to the Colossus, through a ViewHD HDMI splitter.

    I've attached 2 jpegs from captures : one using the firewire output from the cable box, the other using the Colossus (at default proc amp settings).

    The reds on the Colossus captures have more orange than the firewire capture, while the luma is darker. The Colossus has proc amp settings, for brightness, contrast, hue and saturation, but I cannot find the right combination that will give me something close to the firewire output.

    (I know, the easiest solution would be to capture only through firewire, but this isn't an option for me : my cable company uses the infamous SA83000 boxes, which produce dropouts on the firewire capture when the bitrate goes over 15 Mbps)

    Can anybody share their Colossus proc amp capture settings ?
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  2. rec.601 vs rec.708 colors.
    https://forum.videohelp.com/threads/329866-incorrect-collor-display-in-video-playback#post2045830

    The levels differences aren't big enough to be full-range vs. limited-range luma. It's just a matter of adjusting the proc amp to get them right. Use a video scope display to check them.
    Last edited by jagabo; 17th Jun 2018 at 08:25.
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    Thanks for your reply Jagabo. Indeed the luma should be pretty easy to fix.
    I've read the other thread, but I'm not sure it's the same thing here. From what I understand on the other thread, the difference in color comes from the conversion done by the PC while reading the file. In my case, using a number of programs (VLC, Videoredo, TMPEGEnc) and different PCs (the older one, running Win7 x64, which has the Colossus card and a newer one that can play UHD video, running Win10), I'm always getting the same difference. Does this mean the conversion issue happens before the encoding ? If so, anything I can do other than using the Colossus proc amp ?
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    Does your cable box have any adjustments for the HDMI output?
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  5. Originally Posted by rds11 View Post
    Does this mean the conversion issue happens before the encoding ?
    Color format conversion happen at both ends -- when the video is converted from RGB to YUV for transmission/compression, or when the video is converted from YUV to RGB for viewing. It doesn't really matter which matrix is used as long as both conversions use the same one.

    Originally Posted by rds11 View Post
    anything I can do other than using the Colossus proc amp ?
    I don't think there's anything you can do to force the Colossus to use rec.601 or rec.709. It's just going to use the one it does. Saturation and Hue adjustments won't fix the problem. You need to get your player/editor to perform the conversion as the Colossus.

    For precise analysis it's best if you upload short overlapping video samples without any conversion (use a tool that doesn't reencode). We can analyze what's really in the videos -- before they've been converted to RGB for making JPG images.
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    Originally Posted by jagabo View Post
    For precise analysis it's best if you upload short overlapping video samples without any conversion (use a tool that doesn't reencode). We can analyze what's really in the videos -- before they've been converted to RGB for making JPG images.
    I've attached both samples. The Colossus one is a direct recording, no other tool was used. The firewire sample was edited using the 'trim and copy' option of Videoredo.

    Originally Posted by JVRaines View Post
    Does your cable box have any adjustments for the HDMI output?
    No adjustment. I guess I could use the component output instead, to see if the splitter could be causing this.
    Image Attached Files
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  7. MediaInfo reports that firewire.ts is flagged with rec.709 colors -- which is normal for high definition video. colossus.m2ts has no flag but it has rec.601 colors. Colossus.m2ts also has a slightly brighter picture (and crushed brights) with all Y values raised by about 12 units. That extra brightness is probably from your proc amp settings. Converting the colossus image to rec.709 and reducing the brightness (in AviSynth with .ColorYUV(off_y=-12).ColorMatrix(mode="rec.601->rec.709")) gives a picture much closer to the firewire video.

    But... How did you make the sample images you posted? With VLC? VLC always uses rec.601 when it saves jpg images. So your colossus image has the correct colors (though the wrong brightness). Your firewire image has the wrong colors (but the correct brightness).

    There may be one way to get rec.709 from the Colossus: If you can force the cable box to output YCbCr instead of RGB the colossus should receive the original rec.709 and may leave it as that. I believe your current setup has the cable box converting to RGB before sending the video over HDMI. Then the Colossues converts back to YCbCr as rec.601 and compresses it.
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    Originally Posted by jagabo View Post
    There may be one way to get rec.709 from the Colossus: If you can force the cable box to output YCbCr instead of RGB the colossus should receive the original rec.709 and may leave it as that. I believe your current setup has the cable box converting to RGB before sending the video over HDMI. Then the Colossues converts back to YCbCr as rec.601 and compresses it.
    Thanks for looking at the samples. There is no option to select what color matrix is being output from the box. So I tried a few things to see if it would make any difference, like removing the HDMI cable going to the Colossus, rebooting the SA8300hd and then plugging the HDMI cable back, but I still get the same result. I also tried other type of outputs, as the sa8300hd allows a 'fix' output (such as 1080i or 720p for all channels), up-conversion and the native output, but all of them didn't change a thing.

    That being said, I had another recording I had done years ago of the same game, this time with the Hauppauge original HD-PVR 1212 (that one didn't have any HDMI input, just component) and the colors are correct. I'll try to record with the component cable with the Colossus and see how it goes. I was trying to avoid the digital/analog/digital conversion, but I'll see if it's not too bad...

    Originally Posted by jagabo View Post
    But... How did you make the sample images you posted? With VLC? VLC always uses rec.601 when it saves jpg images. So your colossus image has the correct colors (though the wrong brightness). Your firewire image has the wrong colors (but the correct brightness).
    I did the images using Videoredo ('capture frame' option). Fyi, I've attached a screen shot from the same file (the firewire capture), using Videoredo and then VLC.
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  9. Here's what I get from the firewire video with AviSynth and ConvertToRGB(interlaced=true, matrix="rec709"):

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    I consider this to be pretty much definitive. Neither of your images matches that. But if I convert the Colossus video from rec.601 to rec.709 and reduce the brightness, it has almost exactly the same colors.

    Keep in mind that there are many places where errors can occur depending on the hardware and software being used. Before capture, during capture, in an editor or player, the graphics card, the monitor...
    Last edited by jagabo; 17th Jun 2018 at 22:08.
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