Difference between Codec "None" and 422HQ

[zack zhou]

a guy is helping us compress our film using CinemaCraft SP for dvd output. he requested Codec "None" instead of 422 HQ. will there be a change in quality? which codec will be better to preserve quality?

[Uli Plank]

You won't see a change in quality, but you'll need plenty of space.

Maybe he doesn't know that the ProRes decoder is available for free for the PC too.

[Dan Hudgins]

If you compress to a format between the original size files and the DVD compression format, you will get double compression losses.

[Pawel Achtel]

a guy is helping us compress our film using CinemaCraft SP for dvd output. he requested Codec "None" instead of 422 HQ. will there be a change in quality? which codec will be better to preserve quality?

It depends.

If you going to do colour correction downstream, then always chose "none". 4:2:2 sub-samples chroma and you end up with half-resolution in chroma channel. If you have done colour grading upstream and simply compress your finished programme, then there is going to be very little difference because MPEG-2 (DVD video stream) will decimate your footage anyway.

[Alexander Ibrahim]

a guy is helping us compress our film using CinemaCraft SP for dvd output. he requested Codec "None" instead of 422 HQ. will there be a change in quality? which codec will be better to preserve quality?

Codec "none" is uncompressed. It should also have no subsampling. So, it should be 10 bit 4:4:4 uncompressed video.

Uncompressed is higher quality than any compressed format.

Strictly speaking there will be no change in quality. Uncompressed will be an exact representation of your ProRes 422 HQ footage.

Without the details of the exact workflow, its hard to say if there will be any advantage to working this way.

The real goal is to minimize disadvantages.

To maximize the advantages, change your sequence settings in Final Cut to the "none" codec and re-render everything before exporting. This will help avoid multiple compression artifacts and minimize/eliminate data concatenation.

Make sure you have a TON of space on your scratch disks and on your output drives. You also want them to be very very fast. This codec could use up to 380 MB/s. That's Megabytes per second.

[Uli Plank]

I was referring to Cinema Craft's results, since that is normally used for DVD encoding. We did extensiv tests from ProRes intermediates and uncompressed and couldn't spot any differences on the final DVD.

[Alexander Ibrahim]

We did extensiv tests from ProRes intermediates and uncompressed and couldn't spot any differences on the final DVD.

I agree. Uncompressed is overkill.

I frankly expect that for DVD output- and quite probably BlueRay output as well- that the difference between uncompressed and ProRes HQ is not noticeable, or if noticeable then certainly negligible.

I would ask the compressionist if they are aware that a ProRes decoder is available for Windows.

Also, have you considered ProRes 4:4:4:4 ? Also overkill, but it may make the compressionist happy. Sometimes making people happy is as important as making good technical decisions. ProRes 4444 uses 330mbps as opposed to ProResHQ which uses 220Mbps. So, its only 50% more data to store and move- but its unquestionably master quality.

[zack zhou]

ah thanks guys!
i have another question,

i exported Prores 422HQ from my original 4k Sequence in final cut (6 not 7), there is quite a significant loss in quality. On the other hand, my c
olorist's copy exported (using same FCP 6), the colors are vibrant, and similar. There is a difference in quality, sharpness, and my version seems to lose color and become brighter.

is there a mistake i made in the settings (fcp or export)?. I exported with "quicktime compressor" -> ProRes 422HQ -> enable "chroma filter"-> size full HD. (my colorist did the same export). is there a way you guys can suggest to reduce quality loss?

(i Dont have fcp7, so prores 4444 is impossible for now)

[Stephen Strangways]

I'm a big fan of Lagarith, a rather efficient lossless codec. It's a bit tricky to use on a Mac, and HuffYUV is a little easier there, if less efficient.

But Zack, you can probably ignore all that, as it sounds like you have to deal with a Quicktime gamma bug now, and possibly the crappy downscaling algorithms in FCP.

[Uli Plank]

Aside from gamma issues, if you are transcoding from proxies in FCP, I'd except far less quality than in Color.