[Lossless] Ut Video Codec

[Mister Hatt]

I have no idea how Premiere does it but I could ask around. Obviously it will have the same resampling problems as there is no way around that, but as far as RGB conversions go I would imagine that it picks a matrix either arbitrarily or based on vertical resolution and is consistant with that.

[Cannonaire]

I stumbled upon what I think is the reason UTVideo 420 wasn't working for me. Neither 420 nor 422 will play back in anything aside from VirtualDub for me if they are not mod16. Tested using a 720x480 video clip, cropped it to 712x480 and 704x480 and saved both with the same UTVideo settings (actually, I saved them both twice, with 420 and 422). The 704x480 files will all play normally, but none of the 712x480 files will play in anything other than VirtualDub.

Is it specified somewhere that UTVideo resolution must be mod16?

[mirkosp]

I have no idea how Premiere does it but I could ask around. Obviously it will have the same resampling problems as there is no way around that, but as far as RGB conversions go I would imagine that it picks a matrix either arbitrarily or based on vertical resolution and is consistant with that.

Premiere acts a bit differently. Some effects are YUV and others are RGB (from what I saw of CS5, this is especially stated for each effect), so depending on the colourspace of the clips and effects you use, you might be able to get the whole thing through without a colourspace correction.

[BasharOfTheAges]

How noticeable would these conversions be? Are we talking the visual equivalent of an audiophile claiming to be able to tell which kind of speaker wire you're using? Something that'd be less important than the temperature of your monitor (or even the lighting in the room) on color? Or something normal people would actually notice?

[Zarxrax]

How noticeable would these conversions be? Are we talking the visual equivalent of an audiophile claiming to be able to tell which kind of speaker wire you're using? Something that'd be less important than the temperature of your monitor (or even the lighting in the room) on color? Or something normal people would actually notice?

Normal people can't even notice an incorrect aspect ratio, so I think this is not a problem

[mirkosp]

How noticeable would these conversions be? Are we talking the visual equivalent of an audiophile claiming to be able to tell which kind of speaker wire you're using? Something that'd be less important than the temperature of your monitor (or even the lighting in the room) on color? Or something normal people would actually notice?

It can get noticeable depending on how it's done. If it's done properly, it won't be an issue at all. If done wrong, it does get obvious. Done wrong aka using the wrong colourmatrix when doing the conversion, because greens and reds will get shifted in colour. Unfortunately I don't know how well NLEs handle the conversions...
Of course, if you haven't seen how the original colours were, chances are you might not notice anything wrong (unless different parts of a scene have been split and have had different effects applied in the editing, which might cause a colour flicker depending on what is done... somewhat of a limit situation, not exactly common).

[BasharOfTheAges]

It can get noticeable depending on how it's done. If it's done properly, it won't be an issue at all. If done wrong, it does get obvious. Done wrong aka using the wrong colourmatrix when doing the conversion, because greens and reds will get shifted in colour. Unfortunately I don't know how well NLEs handle the conversions...
Of course, if you haven't seen how the original colours were, chances are you might not notice anything wrong (unless different parts of a scene have been split and have had different effects applied in the editing, which might cause a colour flicker depending on what is done... somewhat of a limit situation, not exactly common).

Well, The question was framed in the parameters of within an NLE. Premiere or Vegas for example. I guess the greater question would be is this something noticeable when you spit your timeline out of premiere. Or, even more to the point, is it even something worth worrying about in the first place? Would it stop you from suggesting people use the codec in Premiere or Vegas because of it?

Normal people can't even notice an incorrect aspect ratio, so I think this is not a problem

Stop making me so depressed. I want to smack people watching SD broadcasts in 16:9.

[mirkosp]

Well, The question was framed in the parameters of within an NLE. Premiere or Vegas for example. I guess the greater question would be is this something noticeable when you spit your timeline out of premiere. Or, even more to the point, is it even something worth worrying about in the first place?

Depends... generally not, you only have to look out on specific scenes depending on what you're doing, I guess, but again, rare occurences, and if conversions are kept to a minimum, possibly unnoticeable even if wrong.

Would it stop you from suggesting people use the codec in Premiere or Vegas because of it?

It's less about the codec and more about quit using them entirely if you really start worrying at that point, because they do conversions with any input at one point or the other, depending on the effects you apply and the format you output to. So yeah, I don't think it's worth hitting the head over.

[Cannonaire]

A conversion from say YV12 to RGB is unnoticeable if done correctly, especially when you consider that viewing on a monitor it must be changed to RGB eventually, since that is how your monitor works. Problems arise when one part of a clip may have effects applied, but another part doesn't, and this could introduce color flicker as Mirko said, or you could also see degradation if conversions are done multiple times. As with any lossy process, you lose information every time it's done. If you start with a DVD source and your NLE does do a conversion to RGB, at minimum you will go YV12 -> RGB -> YV12 (distribution encode) -> RGB (viewing on a PC monitor). I think this is generally an acceptable number of conversions, and you'll see way more loss of detail/color information from the final encoding process than from the colorspace conversions in this case. I think the main point is you should try to maintain original quality as long as possible, which is the reason for using a lossless codec to begin with.

I think in the case of Vegas, if I know I'm going to use an effect in a certain scene, I might as well change colorspace in Avisynth beforehand to make sure everything stays correct and, most importantly, consistent. Now I have to test the UTVideo RGB modes...

[Mister Hatt]

Stop making me so depressed. I want to smack people watching SD broadcasts in 16:9.

I want to smack people who think that SD can't be widescreen.