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HD to SD timeline

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Frank CannHD to SD timeline
by on Nov 25, 2010 at 3:47:32 pm

When I drag an HD timeline to an SD timeline - anything in the graphics track requires me to rework even when they are rendered ???

Also - I have been disappointed in the quality of the down converted video -after down converting the content looks way too soft - I often need to deliver (digital files) in both HD and SD - however the down converted SD looks far worse than if I shot it in SD to begin with.

I really do not want to have to use a 3rd party software...


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Eric PelletierRe: HD to SD timeline
by on Nov 25, 2010 at 4:29:49 pm


I really do not want to have to use a 3rd party software...



Though, I really recommend you do!
Like you, I often have to deliver both file formats/dimensions.
Using most of the time the Pro Res Codec, I export as a Quicktime movie a Pro Res or Uncompressed file in the original native dimensions (or in the DVCPRO Codec with its native size of 1280x1080). Then using MPEG Streamclip, I export downconverting to any other Qt codec. Sometimes very usefull for client approvals via email or FTP of your work-in-progress or simply to encode a delivery format. Latest version also has a very good deinterlacer module which is ideal to export progressive files.

Here's the link if you wanna give it a try

http://www.squared5.com/


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Floh PetersRe: HD to SD timeline
by on Nov 26, 2010 at 3:06:50 pm

Scaling from HD to SD is a process where you have to do some compromises. It is either fast or good. Media 100 did some compromises there by using the QuickTime scaler for the software conform, which is not too bad and relatively quick, but it is not great either. There are several other scaling algorithms in 3rd party apps (e.g. BitVice), which are better but also slower.
But I heard rumors that the whole framesize conversion is going to be somewhat more smoothly in the next release of Media 100 ;-)
The fact that Red titles sometimes do not conform correctly most likely is a bug. Ideally they should come through the conform without problems and should stay in their editable format.



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Michael SloweRe: HD to SD timeline
by on Nov 26, 2010 at 11:52:07 am

Frank, this has long been a problem, particularly for Media 100 users. The old pre Intel versions did a hardware down convert through the great (expensive) Hdx board. Apart from the expense that board would not operate with the new Intel Macs so was discontinued. The downscale is now done differently within Media 100 and is not quite as good.

Eric is right to suggest a third party application and there are many around. If you're going to SD DVD the best downscale is within the BitVice DVD encoding application, much superior to that within Media 100 but of course you don't want to end up with a DVD. Mind you, I do find that HD original material still looks better when downscaled (even by Media 100) than my old DVCAM original does, I'm surprised to see that you don't find this.

Michael Slowe


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Andy TaplinRe: HD to SD timeline
by on Nov 26, 2010 at 4:02:05 pm

This is an interesting thread as we all probably have to down convert to SD or smaller for the web.

So far I've had the best results by down converting in QT7, I've tried BitVice but only for MPEG2 and I was disappointed with the poor aliasing quality (maybe I need to do some more tests?). I found that the QT scaler was much smoother.


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Eric PelletierRe: HD to SD timeline
by on Nov 26, 2010 at 4:13:10 pm

I was disappointed with the poor aliasing quality (maybe I need to do some more tests?). I found that the QT scaler was much smoother.

Just be aware that interlacing matters.
When you playback on computer monitor, interlacing is very noticeable and you want to make your movies progressive. Usually HD native formats are upperfield first in the NTSC world (not sure PAL), that's why you need to deal with deinterlacer options , especially if you will deliver a file that will be used by other editors. Maybe thats where you see poor anti aliasing, which could simply be a deinterlacing issue.

So, unless you go directly to tape - master to tape - you'll always have , I believe, to consider deinterlacing. We see a lot of bad stuff on the internet because of that.


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Andy TaplinRe: HD to SD timeline
by on Nov 26, 2010 at 4:19:36 pm

My source was progressive pro-res so no trouble with fields - I just though the quality of BitVice MPEG2 from an HD source was really poor - but I'll look at it again at some point.


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Michael SloweRe: HD to SD timeline
by on Nov 27, 2010 at 12:00:03 pm

Andy, you surprise me. With earlier versions of BitVice I also found this but not with the latest (2.9 I think). I use Purifier as well which is now built in, but only use level 1. My DVD's are now equal to my tape masters in quality and can only see artifacts if say,we pan over a building or fence, and even then only slight. Innobits have done a lot of work with BitVice, do you have the latest version?

Michael Slowe


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Andy TaplinRe: HD to SD timeline
by on Dec 1, 2010 at 6:19:35 pm

Michael

I've got BitViceSD 2.9.6 I'l do some tests tomorrow as I'm sure it should perform better than I remember.


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Bernhard GriningerRe: HD to SD timeline
by on Nov 27, 2010 at 3:41:29 pm

Hello,

scaling is always a compromise.
A 'good' downscaling is not defined as 'the sharpest image'.
A 'good' downscaling is defined as the maximum sharpness at the minimum aliasing.

So every hardware scaler out there doesn't simply have a good scaling algorithm,
but performs tons of pre processing - take a look at this:
http://www.teranex.com/technology

There is not a single software scaler out there which could compete with hardware scalers.
I've tested them ALL. Either you get too smooth images every SD-cam would have delivered better,
or you get very sharp images with heavy aliasing so you get sick.

The best SW-job does MPEG Streamclip, but it is 8-bit only and the 8pxl wide black bars
need to be removed by cropping at scaling.
Purifier witch uses the same scaler as BitVice is indistinguishable from FCPs scaling (Motion Estimation set to 'best') even at pixel level. As if both were using 100% the same algorithm ...


If you need to scale for web, I recommend Matrox MAX (as ComporessHD board or in a MXO2).
It uses Matrox' hardware scaler file based!!!
Unfortunately it only outputs progressive H.264 (8bit) at the moment (but with HW-deinterlacing!).
This is perfect for web or BluRay, but not usable for further workflow processing.

It's really too bad we can't use the hardware scalers of our I/O devices file-based yet!
It's a shame - the perfect solution is so near ...


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