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View Full Version : Which ProRes 422 to choose in Mpeg Streamclip



jrod81
12-13-2009, 11:02 PM
I am converting everything to Apple Pro Res to start editing in FCP and was just wondering what the difference in the two choices of Pro Res 422 are... should I use the first or second in the list?

Thomas Lew
12-14-2009, 01:03 AM
What are those 2 choices exactly? There's 4 different flavors of ProRes

:bath:

RyanT
12-14-2009, 02:35 AM
It doesn't look like there's any difference at all...There labeled exactly the same.

But I wonder if there is a difference. Anyone know?

Michael Olsen
12-14-2009, 08:44 AM
Excellent question. I had no idea what the difference was, I had been using ProRes LT for most things.

I ended up finding the Apple White Paper document which really offered some interesting insights into the process. I'll summarize it here, but the link follows as well if you want to read it yourself (I recommend it).

Apple Pro Res White Paper (http://images.apple.com/finalcutstudio/docs/Apple_ProRes_White_Paper_July_2009.pdf)

In general, the higher quality the codec, the better the output will match the source footage. You've actually got five choices:
1) Apple ProRes 444
2) Apple ProRes 422 (HQ)
3) Apple ProRes 422
4) Apple ProRes 422 (LT)
5) Apple ProRes Proxy

The better the name sounds, the better the codec quality. 444 is better than 422. HQ is better than LT is better than Proxy.

The better the quality, the more chroma and more luma information preserved. 444 has more chroma than the 422. HQ has better luma rendition than LT.

http://www.michael-olsen.com/random/luma.png

The better the quality, the higher the bitrate, thus higher filesizes. Lighter files play back easier, take up less space, and are quicker to move.

http://www.michael-olsen.com/random/filesizes.png

Also, the better the codec, the lower the likelihood of first-generational loss.

http://www.michael-olsen.com/random/degrade.png



So what does this mean in the real world for the 7D. As we all know, the 7D can produce some very pleasing images, but isn't really a performance spec stunner (re: charts, 4:2:0, codec). Because of that, I personally believe that using ProRes 444 is totally unnecessary. And I doubt (nor have I seen in my own very unscientific experiments) a significant difference would exist between HQ, Standard, and LT. I have never used Proxy.

Apple's suggestion:
http://www.michael-olsen.com/random/avchd.png

My suggestion: shoot a test scene with macbeth chart or a scene with lots of different colors and gradations. Take the same source file and encode it differently. Watch them. Pixel peep. See if you can really find a difference.


Note: This is all in regard to the 7D and only the 7D. If you are shooting on a 4K camera or dealing with IMAX footage then this does not apply. Of course, if you are shooting on a 4K camera, I should be asking you questions!

Ryan Farnes
12-14-2009, 09:21 AM
As far as choosing between 422 (HQ) and 422, I always use 422. Spoke with an Apple rep at a conference doing workshops about codecs and workflows. Apparently he was the go to guy from Apple for the Cohen brothers whenever they had tech issues with Final Cut Studio.

When I asked about converting Long-GOP EX1 footage to Prores, he specifically stated that 422 (HQ) was unnecessary and the plain 422 was more than sufficient. I imagine that the 7D is in the same boat and you're not dealing with a major digital film or broadcast piece where the extra space is negligible, and you want to preserve every last minuscule detail. For lots of 7D work, I'll be using normal Prores 422. If I ever make a short film where I "spare no cost," I'll go with the 422 (HQ) just to appease my sense of pristine quality all the way.

TadM
12-14-2009, 09:34 AM
Wow thanks for that, Michael.

Very informative.

jimbee
12-14-2009, 09:49 AM
The thing that is mysterious to me is, what happens when you convert the 7D or 5D footage from H.264 to ProRes. Suddenly the file size is tripled -- if it was a data rate of 8 megabytes per second out of the 5D, it becomes roughly 24 megs/sec. A 300-megabyte file is now about a 1-gigabyte file. Where does all that new data come from? Is Mpeg Streamclip making pixels up as it converts from H.264 to ProRes? You can't get something for nothing can you? ProRes won't look any better than the original footage, will it?

Michael Olsen
12-14-2009, 10:17 AM
The thing that is mysterious to me is, what happens when you convert the 7D or 5D footage from H.264 to ProRes. Suddenly the file size is tripled -- if it was a data rate of 8 megabytes per second out of the 5D, it becomes roughly 24 megs/sec. A 300-megabyte file is now about a 1-gigabyte file. Where does all that new data come from? Is Mpeg Streamclip making pixels up as it converts from H.264 to ProRes? You can't get something for nothing can you? ProRes won't look any better than the original footage, will it?

Hi Jimbee,
I'm going to mess around with the order of your questions a little bit, but will do my best to answer them all.



ProRes won't look any better than the original footage, will it?

Nope. But that's not what it is supposed to do. ProRes is designed as a lossless intermediate format. Lossless meaning there is very little degradation to the quality. Intermediate meaning that it is used more or less only for editing, not capture, delivery, or storage.


You can't get something for nothing can you?

Not here, you can't. ProRes won't make your footage look feel, or sound better. It will, however, make it easier to work with in post.


Is Mpeg Streamclip making pixels up as it converts from H.264 to ProRes?

Nope. Streamclip isn't making your 1080p into 2K or 4K. And it isn't doing anything to correct for the pixel-binning. And while it is encoding at 4:2:2 or 4:4:4, if the information isn't in the source material (4:2:0 for 7D) it won't be there in the ProRes file.


Where does all that new data come from?
H.264 is a very processor heavy codec, requiring a great deal of power. ProRes is designed to be light and easy to run.

When moving from H.264 to ProRes, Streamclip is sort of uncompressing the files slightly, making them easier for the computer to understand.

Think of it in terms of English. A sentence of H.264 may read:

It ws th bst f tms t ws th wrst f tms.

The computer then has to take the instructions and fill in all the blanks in order to get:

It was the best of times, it was the worst of times.

Pro Res, on the other hand, would take care of some of that for the computer. Reading, for example:

It was th best f tims it was th worst f tims.

It is still compressed, but larger than the H.264 version. It is easier for the computer to recreate the sentence...or in the real world, the video.

I'm sure that analogy is flawed (as all are) but it provides the basic idea. In order for the file format to be easier for the computer to read, thus allowing real-time editing and playback, it must be less compressed and therefore larger.

Thomas Lew
12-14-2009, 12:18 PM
Michael.. that was an AMAZING description of why files get larger when converting to ProRes. THANK YOU for that. x100

:bath:

_JD_
12-14-2009, 12:34 PM
Read somewhere today (think it was Skywalker discussion) that Philip Bloom uses 422 (LT) and that it's "more than sufficient" or words to that effect.

rallymatt
12-14-2009, 12:56 PM
In MPEG Streamclip, the TOP ProRes listed is LT, and the Bottom is HQ.

boo
12-15-2009, 02:14 PM
LT is more than appropriate for the 7D.

Ryan Farnes
12-16-2009, 11:51 AM
I have Final Cut Studio 2 (FCP 6) and I appear to only have 2 Prores options.

In Quicktime/FCP/Compressor:

Apple ProRes 422 (HQ)
Apple ProRes 422

In MPEG Streamclip:

Apple ProRes 422
Apple ProRes 422

Is the top LT and the bottom HQ? I don't see the LT option listed anywhere else on any of my encoding programs. Michael Olsen listed 5 different versions of ProRes. ProRes 444, ProRes 422 HQ, ProRes 422, ProRes 422 LT, and the Proxy version. Do you have to have Final Cut Studio 3 to get all those otions?

I'm just curious. I've had solid success just using the normal Apple ProRes 422 (not HQ) and the amount of space is not an issue as I'm doing sporadic work, not constantly filling up drives.

Michael Olsen
12-16-2009, 12:02 PM
I have Final Cut Studio 2 (FCP 6) and I appear to only have 2 Prores options.

In Quicktime/FCP/Compressor:

Apple ProRes 422 (HQ)
Apple ProRes 422


My understanding is that FCP 6 comes with just what you have there - 422 HQ and plain old 422. No 444 or LT or Proxy.



In MPEG Streamclip:

Apple ProRes 422
Apple ProRes 422

Is the top LT and the bottom HQ?


No idea. On my computer it is listed in descending order, but it also shows HQ, LT, and Proxy in the name.

My recommendation? Take a short clip - a couple minutes or so. Encode using option #1. Then encode again from the source to option #2. Whichever one (1 or 2) is bigger is the HQ.



I don't see the LT option listed anywhere else on any of my encoding programs. Michael Olsen listed 5 different versions of ProRes. ProRes 444, ProRes 422 HQ, ProRes 422, ProRes 422 LT, and the Proxy version. Do you have to have Final Cut Studio 3 to get all those options?

My understanding is that yes, you do. I don't believe they are available for download separately.

I also don't know what would happen if you tried to open a 422 (LT) project in FCP 6, either.


I'm just curious. I've had solid success just using the normal Apple ProRes 422 (not HQ) and the amount of space is not an issue as I'm doing sporadic work, not constantly filling up drives.

Straight 422 is better than LT in terms of quality, so you've got nothing to worry about if everything has been going well for you so far!

Hope that helped!

Ryan Farnes
12-16-2009, 01:49 PM
Ok, yeah cool. That was what I thought perhaps was the case. Final Cut Studio 3 has some new ProRes 422 variants.

Cool. Thanks.

craigglaspell
01-02-2010, 07:02 PM
What other options 'should' we be choosing in streamclip when converting 7D files? Like the frame rate box, the interlaced scaling, field dominance, etc....
can someone post a screengrab of optimal global settings for conversion.

And regarding that 422LT is ok for 7d files, I need to find a link that had a 422HQ vs LT screengrabs and the difference was noticeable.