Video Compression > New and Alternative Video Codecs

Problems with UT Video Codec

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Fullmetal Encoder:
Has anyone had any problems with UT Video Codec doing color space conversions even with a complete YV12 chain? I recently encoded a clip with the 64-bit version which came out in RGB32 even though Info() in Avisynth shows both the original VOB and the demuxed m2v to be in YV12. At the codec setup in VirtualDub64 I'm selecting ULY0 as the output. This should be producing a lossless 4:2:0 YV12 encode. When I installed the UT Video Codec I had the same problem that others have reported on Doom9 regarding incorrect registry links to the utvideo.dll in system32 showing "C?\" instead of "C:\". Incidentally, no matter how many times I try I can't get the codec to install in any other way. I've corrected those links and after encoding I can "confirm" with MediaInfo that the file is identified as Ut Video Codec file so I know that VirtualDub64 is engaging the utvideo.dll. So I am not sure what the problem could be.

Also, while MediaInfo correctly states that the FOURCC for the file is ULY0 it shows the color space as YUV 4:2:2 ???  Is MediaInfo a big fat liar or is UT Codec doing something wonky with it?

Something else I've noticed, and forgive my rather noobish question here, but it doesn't seem that FFDShow is capable of decoding UT Video Codec files. What I have noticed is that while playing a UT Codec encoded video using MPC-HC and FFDShow is that MPC-HC is chaining together both something called "AVI Decompressor" and FFDShow. This only works when I enable raw video processing in FFDShow. Does this mean that two decoding processes are underway? If so, is there any way to get FFDShow to decode the file directly? As I understand it, FFDShow isn't able to interpret the FOURCC produced by UT Video Codec. If this is the case isn't including FFDShow simply adding overhead to the video's playback? And if I disable raw video support in FFDShow then MPC-HC invokes something called "Color Space Converter" along with "AVI Decompressor" which I find quite disturbing. I'm concerned with quality and the impact on resources in the case where AVI Decompressor and FFDShow are both active and I'm thinking about using FFDShow for some real-time post processing.

I would have broached these issues on the main UT Video Codec thread at Doom9 but I haven't been able to access Doom9 for days. On that note, can anyone else reach Doom9? There is also some documentation there which I don't have access to. Does anyone know what kind of issues the site might be having or when it might be back up?

Thanks in advance to anyone who an bring me clarity on these issues.

nm:

--- Quote from: Fullmetal Encoder on January 30, 2011, 10:47:03 PM ---Has anyone had any problems with UT Video Codec doing color space conversions even with a complete YV12 chain? I recently encoded a clip with the 64-bit version which came out in RGB32 even though Info() in Avisynth shows both the original VOB and the demuxed m2v to be in YV12. At the codec setup in VirtualDub64 I'm selecting ULY0 as the output.
--- End quote ---

Well, have you set VirtualDub to "Fast recompress" mode? Otherwise it will convert to RGB for its own filtering system.


--- Quote ---Something else I've noticed, and forgive my rather noobish question here, but it doesn't seem that FFDShow is capable of decoding UT Video Codec files.
--- End quote ---

It's not because it doesn't contain a decoder for Ut. That's why you get an instance of the Ut VFW codec instead, encapsulated by the AVI Decompressor DirectShow filter.


--- Quote ---I'm concerned with quality and the impact on resources in the case where AVI Decompressor and FFDShow are both active and I'm thinking about using FFDShow for some real-time post processing.
--- End quote ---

When you enable "raw video processing" in ffdshow, you get what you asked for: postprocessing of raw video after it is decoded by the  Ut codec. If you don't have special filters activated, ffdshow only does a colorspace conversion.

If you disable "raw video processing", the system inserts a simple colorspace conversion filter to make rendering possible. Renderers only support a small number of raw video formats. I'm not a Windows user, so I don't really know if YV12 should work without the converter there.


--- Quote ---I would have broached these issues on the main UT Video Codec thread at Doom9 but I haven't been able to access Doom9 for days. On that note, can anyone else reach Doom9? There is also some documentation there which I don't have access to. Does anyone know what kind of issues the site might be having or when it might be back up?
--- End quote ---

See these threads for some info:
What's going on with forums out there?
Why Can't I Access The Blu-ray Section?

Fullmetal Encoder:

--- Quote from: nm on February 01, 2011, 03:13:55 PM ---It's not because it doesn't contain a decoder for Ut. That's why you get an instance of the Ut VFW codec instead, encapsulated by the AVI Decompressor DirectShow filter.
--- End quote ---

Oh okay, so really when I installed UT Video Codec it installed a decoder which is being used by Windows in the form of AVI Decompressor? That's interesting because for a while I kept thinking it was odd that the developer would release an ENcoder without there being any kind of optimized DEcoder made available.


--- Quote from: nm on February 01, 2011, 03:13:55 PM ---When you enable "raw video processing" in ffdshow, you get what you asked for: postprocessing of raw video after it is decoded by the  Ut codec. If you don't have special filters activated, ffdshow only does a colorspace conversion.
--- End quote ---

Yes, I'm definitely using "Fast recompress" in VirtualDub. In FFDShow I haven't really done anything with it but it sounds like no matter what I do a color space conversion is coming into play even with FFDShow. From what I've read UT Video Codec really should NOT be doing any color conversion at all so I'm going to wait until Doom9 forums are back up and see if someone there has any experience with it. Thanks for the information.

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