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60d to avid to web (workflow for colors)

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Justin Crowell
60d to avid to web (workflow for colors)
on Mar 7, 2012 at 6:59:30 am

Hi everybody,
There are at least hundreds of pages on this around the web, but much of it is over my head and includes products I can't afford (sorenson squeeze, chief among them). I'm looking for a best practices workflow to go from:

60d > AVID (MC6) > web export (presumably h.264)

1) Import: I have been setting up my avid projects as 709. Files are AMA linked then transcoded as DNxHD 115.
2) Files are color graded on the timeline.
3) Exported either h.264 from AVID -OR- QTref from AVID, h.264 from qt7pro, mpeg streamclip, or After Effects.

I know I'm suffering from the whole 16-235 broadcast color clipping issue, but it seems odd to me given that all of my work is destined for the web (isn't my footage 0-255? shouldn't it be a direct line to monitor-ready full spectrum color?).

My h.264 conversions seem to always be DARKER than my AVID timeline (less detail, crushed blacks?), regardless of my export approach (AE does the best job, but is not ideal as it runs slowly on my machine).

So...anyone have any practical advice?
Thanks so much,
Justin

Video editor, animator, composer, producer
SarasotaTheBand.com


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Job ter Burg
Re: 60d to avid to web (workflow for colors)
on Mar 7, 2012 at 2:56:43 pm

Avoid the Quicktime H264 codec (you are using it when you export straight from Avid [QT export module] or when exporting from QT Pro).

The issue of the gamma shift has something to do with Apple's H264 QT codec. Google 'gamma shift h264' and you will see many more people experiencing the issue.

Try to use something like the Main Concept x264 encoder that is in Sorensen Squeeze, for example (QT ref or QT Same-As-Source from Avid, convert to 264 using Squeeze).


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Michael Phillips
Re: 60d to avid to web (workflow for colors)
on Mar 7, 2012 at 5:04:35 pm

While Media Composer is a REC601/709 editing system, you can work with 0-255 levels within that color space. It's just that you have to pay more attention to the steps inputting and outputting. Canon DSLR files are NTSC color space (why? I don't know), but that aside, you can AMA to them directly and with the source settings indicate how you want "levels" to behave. You have three options: leave it alone, scale to video levels (16-235), scale to graphics levels (0-255). There is a histogram to work with and see what is going on in that particular shot. You can choose at the point where you want the full level range to fall. Edge to edge is 0-255 while the white bars indicate 16-235. In your case, let's assume you choose to work with full range 0-255.

When color correcting and such, you don't want to use any of the auto black/white as that assumes REC709 video levels and will raise blacks and scale whites that are in the 0-15 and 236-255 range. When you color correct, you can use the waveform vectorscope, and just work with the full range as a guide.

The important part is when exporting either a QuickTime reference or an embedded QuickTime - based on the above workflow, you would choose REC709 as export setting. What this really does is "do nothing" to the image as it assumes that you have worked correctly at REC709 all the time. If you select RGB, it will want to help you out and scale 16 to 0 and 235 to 255. If you had any detail in the 0-15 and 236-255 range, it would be lost.

Many people just work at 16-235 levels as that is their primary delivery format, but streaming formats can be done by selecting RGB on export allowing for dual output based on needs.

It would be nice for Media Composer to have a "web/graphics" mode for those who work for web and streaming only, but it does not. And then again, streaming takes on an interesting challenge if devices are set to stream to home television which is expecting REC709... usually there are modes like "cinema" and stuff which basically do a 16-235 to 0-255 level scale but in this scenario, you would lose those 0-15 and 235-255 details. Propoer color space and levels metadata would help, but that has always been the QuickTime player Achilles heel - trying to compensate for things when you didn't need it to, or want to.

I would also suggest looking at the x.264 codec, it has been reported to be more stable in reflecting original color space and levels over H.264. It can be added as a codec from: http://en.wikipedia.org/wiki/X264


Michael

Michael Phillips


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Justin Crowell
Re: 60d to avid to web (workflow for colors)
on Mar 7, 2012 at 11:45:20 pm

Thanks for the replies, gentleman:

Job: I've read a ton around the web about how bad qt h.264 is...just trying to find a workaround that I can afford (so, squeeze and main concept are out).

Michael: thanks so much. This is the detail I need! My question, though: I understand that I can set my source type upon AMA (which I'd almost definitely do as 0-255), but...what about on the transcode? My computer isn't powerful enough to edit the AMA linked h.264s without some serious stutter.

on color correct: So, basically I should be trusting the vectorscope more than the image I'm seeing on screen? So I will actually be GOING for a more washed-out image than I seek upon export?

If what I'm reading is correct, then I should be doing a 709 export to a QT reference, and then converting that in an external converter (qt7, mpeg streamclip)? I'll give the x264 a shot tonight (great tip, thanks)....but I suppose I'm not seeing where this workflow alters what I've already done--I guess the devil is in the AMA and the transcode moment?

Thanks so much...this stuff is absurdly confusing...

Video editor, animator, composer, producer
SarasotaTheBand.com


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Justin Crowell
Re: 60d to avid to web (workflow for colors)
on Mar 7, 2012 at 11:46:59 pm

Oh, and: I recently switched to AVID from FCP(7 & X). Do those suites not have this issue at all, or is it partly/mostly an h.264 problem? Would I be wise to reconsider Apple?

Video editor, animator, composer, producer
SarasotaTheBand.com


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Michael Phillips
Re: 60d to avid to web (workflow for colors)
on Mar 8, 2012 at 3:16:55 am

It's a combination of things. Media Composer is a REC601/709 editing system and assumes that a critical viewing is done via calibrated REC601/708 monitors via a hardware I/O. The UI screens are not designed for critical color viewing. The inverse is true (regardless of NLE being used) that using a typical GUI monitor for color correction will not give you proper broadcast levels.

If you want to do "monitoring" for your situation, then you can view the either the source/record monitor full screen and set the "full screen" setting to show "full range.' If you have a two monitor set up via the graphics card, then you can leave one full screen all the time as your "client monitor" in this mode for your work.

Michael

Michael Phillips


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Justin Crowell
Re: 60d to avid to web (workflow for colors)
on Mar 8, 2012 at 6:19:34 am

Good call about the client monitor (I am working on a dual monitor system). Thanks for that one.

So, I've TEDIOUSLY spent the entire day comparing every sort of export I could, and I've compiled them below. After AMAing, I changed the source files to the 0-255 setting and then transcoded to DNxHD 115 (hence the "expand tra" text). All vids had FFs with other import and transcode methods, but I thought I'd start with this (I think it will give adequate results).

I compared:
converted to h264 and x264 in Mpeg Streamclip - QTref 709, QTref 709 Avid codecs, QTref RGB, QTref RGB Avid codecs
AVID h264 709, AVID h264 RGB
AVID x264 709, AVID x264 RGB .

All files were viewed in QT 10 (I've found it does an adequate job predicting youtube) and compared to the AVID viewer. I looked at her face color, hair color, vest darkness/detail, and railing color.

All the matters to me here is perceived accuracy--so no concern about scopes and things. My favorite? AVID x264 709, though it desaturates a touch and lightens the blacks a smidge. What do you guys think?





Video editor, animator, composer, producer
SarasotaTheBand.com


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