HD>SD downconversion Mac/FCP only

[Dominik Seibold]

Originally Posted by Mitchell Lewis

Everyone's talking about converting their footage to SD. What about converting a finished project with graphics, titles, etc....?

The quality of a rescaler is measured by how near it can approximate the nyquist-limit without producing aliasing. That specification is independent of the type of image-source.
So yes, compressor does a great job with graphics and titles, too.

[Mitchell Lewis]

Very interesting Dominik. I'm embarrassed to admit that's a bit over my head, but interesting none the less.

I'm glad that you feel Compressor does a great job with graphics and titles too.

[Mitchell Lewis]

SOLUTION!! I just remembered that our company subscribes to the training website Lynda.com (only $25 per month....well worth it!). Anyway, they have a training video titled Compressor 3 Essential Training with Larry Jordan. The "solution" was at the end of the video is the following chapter:

CHAPTER 15: Transcoding
-Understanding Transcoding
-Converting HD to SD-maintaining a 16x9 aspect ratio
-Converting HD to SD-using a 4x3 center cut
-Converting HD to SD-using custom frame areas (really cool!)
-Creating a 16x9 letterbox from 4x3 footage (stupid)
-Converting HD to ProRes
-Converting NTSC to PAL
-Converting PAL to NTSC

I watched all of them except the NTSC to PAL versions and it looks like Compressor is the solution! He has some very specific settings that he changes to make it work, but it's all based on the Apple presets. Unfortunately, I'm at home right now so I can't do any testing to see how good the quality is. (sorry if this sounds like an ad for Lynda.com, but for $25, I figured you would want to know)

[Matt Davis]

Originally Posted by Mitchell Lewis

Everyone's talking about converting their footage to SD. What about converting a finished project with graphics, titles, etc....? Is no one interested in that? (other than me)

Me too - but I don't mention it because I didn't want to sound like I was introducing the Holy Hand Grenade of Antioch with nods to duck-billed platipode, oranutans and bacilli et cetera. There's lots to be aware of with down converting motion graphics et al. In fact, EX1 footage has a lot in common, being rather sharp in its natural form.

After all, there was - once upon a time - rules regarding colours, font sizes, line thicknesses, pixel/scanline-per-second speeds. Strong colours in geometric shapes in a 4:2:0 codec were a no-no. Lots of things to worry about other than the need to blur before big downscales.

But I digress.

Originally Posted by Mitchell Lewis

I would like to shoot and edit in HD <snip> But then, I'd like a good solution to converting the entire project to SD so I could <make many versions> ... I'm hoping that Compressor is going to be the solution.

Warning: General Rant Mode is ON.

Compressor is a very good solution, though it is a widely misunderstood solution as it is far too easy to mistake a pep-talk - "compressor, take this movie and make it look really good" with a mission - "compressor, take this movie and do everything you can possibly do, including disturbing the fundamental physics of reality and upsetting the space time continuum, to make this the best it could ever be".

Compressor is very powerful - not in a Thug kind of way, but in a Commando/SEAL kind of way. So when you ask it to nail something, it sometimes decides to plot the vector of every pixel in your three hour long opus, which is why one needs to know how to chop up a long job so it only does the Mission Impossible bits on what needs to be done, and take the bus everywhere else.

There's a great little training package from Ripple Training that opens your eyes to the mentality of Compressor. Highly recommended. Then its a case of Caning it round the track to understand when to switch the gear on.

I am highly excited by the CRAMcompressor pack previously mentioned, though aware that with 300+ presets it may require a manual to enable you to choose which one.

But Compressor is up to the job. I have Episode, Squeeze, Compressor, DV Kitchen, MegaPEG Pro, Flix Pro, and a whole lot of others, and in the last few months I am finding the world increasingly compressor-shaped. Mainly because I think I'm finally understanding it. Or grokking it, if we're now dropping Nyquist into this...

[Perrone Ford]

Am I going to step into this Mac discussion, and I ask this question truly out of ignorance.

On the NLE's I've used on the PC, We drop our video (of whatever source size onto the timeline. The graphics, titles, etc. are laid on in separate tracks. We then render out to the size we need.

There is no need to down-res the graphics as they are not "raster based" and as such are perfectly scalable up or down with no loss of quality. In the print world this is done with postscript. In the video world this is vector based graphics.

Does it not work this way on the timelines in Mac-based NLEs? There should be no aliasing whatsoever because the graphics are not a part of the video until render time. Thus I should be able to render a 2K version and a 320x240 without touching the graphics and with no aliasing at all.

Am I just missing something in how the Mac handles this kind of thing?

[Matt Davis]

Originally Posted by Perrone Ford

Am I going to step into this Mac discussion ...

Brave soul...

Originally Posted by Perrone Ford

...Does it not work this way on the timelines in Mac-based NLEs? There should be no aliasing whatsoever because the graphics are not a part of the video until render time. Thus I should be able to render a 2K version and a 320x240 without touching the graphics and with no aliasing at all.

Am I just missing something in how the Mac handles this kind of thing?

Actually, there's lots and lots of things going on. Dynamic rounding, perception of twitter and edge artifacts. I am not going to go there because it's christmas. But suffice to say that the PC world is just as pernickety as this odd little corner of Macdom.

This is not a Mac vs PC or Avid vs FCP issue. I can use FCP to make an SD version of an HD timeline, and with the right boxes checked, it will make a pretty good go at it, but there be dragons! Sharpening, blurring, graphics, twitter of near-horizontal lines, the scaling artifacts of different methods, ooooh, it's a rocky road.

The best thing is that most people don't see all the little give-away tell-tale signs of a less than perfect downconvert. But people who buy for broadcast, or malcontent geeks like us, do and so we hand over to specialist software - which in this case seems to be Compressor.

Trouble is that the PC method of introducing a little bit of gaussian blur to help high contrast edges avoid turning into staircases isn't there in the rubber-glove Compressor interface. So is it there 'anyway'? Compressor reinterlaces movies through a deinterlace command... Does the Detail Levels - used to help edges in UPscales - work in reverse when doing downscales?

Time will tell. I can't - I'm buried until mid February so can't play until then.

So to answer your question, i) Welcome to Macdom, ii) Most of the time, default setting work well but there's better quality to be had for a few mouse clicks, iii) You could do it in FCP (I and a colleague wrote about it in a Ken Stone article), but we think we could do better now. iv) There's always some wretched movie that crops up that simply doesn't look as good as most movies using the standard process, so we have to try anything - I have a couple of patient chickens standing by for these times - to make it work.

[Barry J. Anwender]

Originally Posted by Mitchell Lewis

SOLUTION!! I just remembered that our company subscribes to the training website Lynda.com (only $25 per month....well worth it!). Anyway, they have a training video titled Compressor 3 Essential Training with Larry Jordan. The "solution" was at the end of the video is the following chapter:

CHAPTER 15: Transcoding

Mitchell, I have this entire training video. Larry Jodan's HD->SD workflow is specific to a DVCPRO-HD source!

Definition: DVCPRO HD encodes using 4:2:2 color sampling, compared to 4:2:0 or 4:1:1 for lower-bitrate video formats. DVCPRO HD horizontally compresses recorded images to 960x720 pixels for 720p output, 1280x1080 for 1080/59.94i or 1440x1080 for 1080/50i. This horizontal compression is similar to but more significant than that of other HD formats such as HDCam, HDV, AVCHD and AVCCAM.

In other words, this tutorial is extremely dated and its workflow pre-dates Sony's XDCAM/XDCAM-EX video format. Hence, the FCP worklfow considerations and Compressor dynamics for producing SD from an HD XDCAM-EX source are totally different.

Larry Jordan has since created a more contemporary tutorial entitled "Workflows for FCP Studio 2.0" which includes the HD XDCAM video format delivered by our EX1/EX3 camera's. In this tutorial, you will find a very good "overview" of the considerations needed to achieve a desired output for delivery. However, Larry Jordan is very clear about planning for your final output/delivery. He provides no details on Compressor specifics for "Full HD" to SD conversion. For this Apple's FCP engineers have filled in the details with their Pro Training road trip sessions.

Bottom line: Full HD XDCAM workflows from our EX1/EX3 camera's are at this time, still an emerging/new technologically with very different considerations to make when compared to the traditional "tape based" video formats such as DV/DVCPRO-HD etc. Cheers!

[Mitchell Lewis]

Perrone: You are correct. But....at least in my case I do 90% of my editing in Adobe After Effects. Because I mostly create 30 second television commercials, there are many, many layers, 3D effects, titles, logos, etc....in my projects. My work flow is to render a file (haven't determined the best type yet....ProRes HQ maybe?) out in AfterEffects and then import it into FCP for realtime playback on the timeline. Then I go to tape, dvd, mov, what ever for delivery. So in my case, the graphics will be "flattened" with the video when I import into FCP. I do use a lot of vector graphics (text, logos, etc..) in After Effects, so when I'm in AE, my graphics do scale accordingly. Now on the other hand, when I'm producing a long format project, I use FCP for 80% of the project with AfterEffects graphics sprinkled in the timeline when needed. So even then, many of my graphics, since they came from AE, will be flattened.

Barry: If you re-read my post, you see that the title of his tutorial is "Compressor 3 Essential Training". Compressor 3 came out with Final Cut Studio 2. So I guess my response to your post could be summed up as.......huh? :)

I think you need to watch the tutorial I'm referring to again. He specifically mentions XDCAM numerous times. He even talks about how one format uses square pixels and another doesn't, and what to do in each case. It's definitely current.

[Barry J. Anwender]

Yes we are talking about the same training video, Lynda.com "Compressor 3 Essential Training"

My version is based upon DVCPRO-HD. It is possible that there has been a recent update. In any event, Apple engineers recommend to make the EX-XDCAM HD to SD translation in the FCP timeline and indeed this workflow provides excellent SD DVD results. Cheers!

[Peter Kraft]

Maybe someone has tested the following workflow already with good results?

Edit video.

Render final version (HD) to MP4.

Play MP4 out to SDHC Card as archive master via MxR, SDHC, SxS or the likes which, if I remember correctly writes the data onto the card within a complete new BPAV folder combo.

Open that BPAV folder in XDCAM ClipBrowser and save video in DV format.

Sony has a legacy of offering very good downscales.

[Perrone Ford]

Why would you write a final master to a highly compressed format with little color depth?

[Andy Nickless]

Originally Posted by Perrone Ford

Andy, why stick anything on it? If you are playing into an Aja, or Blackmagic card, just let it save the files to your hard drive, and make your DVD from there. Why go OUT to a deck, which you'd then have to digitize back in the computer?

Maybe no one's suggesting anything because it's totally unnecessary.

Thanks Perrone - but if you read this post (Apple Forum) you'll see why I'm confused about this!
Apple - Support - Discussions - Output XDCAM EX to SD via What Card and ...

Please can you describe a workflow for saving files to the HD via Card - I find it very attractive but I've never used one, so it's all a mystery to me, I'm afraid.

[Perrone Ford]

I completely misunderstood. You want to play OUT to something, I thought you were trying to play IN. Shane has it absolutely correct. This is an absolutely backward way to get to an SD downconversion. And totally unnecesary. A hardware downconversion is not going to be any better than a GOOD software downconversion. In fact, I can just about guarantee that it won't be as good, since it has to be realtime or near realtime.

All you need is a rescaler that uses Lanczos scaling. I've posted workflows here before that outline how to do it. And the software is free on PCs. Not sure what's out there for the Mac, but there has to be something. Works as good or better than any hardware solution out there.

If you REALLY want to get a hardware conversion, then connect the component outs from the camera to the input jacks on the card, and record to hard drive. It will be a real time transfer, but you'll get your conversion in camera. The EX1 can output HD or SD over that component connection.

[Peter Kraft]

Originally Posted by Perrone Ford

Why would you write a final master to a highly compressed format with little color depth?

Perrone, you're right, had a knot in my thoughts. Too early in the morning;)

[Andy Nickless]

You want to play OUT to something, I thought you were trying to play IN.

No!
(I should have linked to the whole thread - sorry).
I want to try a Hardware Downconversion and I was asking Shane whether I had to have a Deck as well as a Capture Card (it seemed strange that a Capture Card couldn't do the Downconversion and somehow shove it back onto the HD without having to output to Tape and then Capture it again).
Shane misunderstood me.

A hardware downconversion is not going to be any better than a GOOD software downconversion. In fact, I can just about guarantee that it won't be as good, since it has to be realtime or near realtime.

OK - maybe, but I'd like to try.

If you REALLY want to get a hardware conversion, then connect the component outs from the camera to the input jacks on the card, and record to hard drive

That's excellent news! You've explained a lot and I'm beginning to see the light now but I wanted to Downconvert my Timeline using Hardware Conversion - just to try for myself. I can't see how I could do that unless I could export the Timeline as MXF - any ideas?

All you need is a rescaler that uses Lanczos scaling..

I'll look for this - maybe another Software method to try!
_______________________

Once again Perrone, thanks for your help and your patience!