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RGB or 601 to Broadcast

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William Edwards
RGB or 601 to Broadcast
on Feb 16, 2014 at 11:14:47 pm
Last Edited By William Edwards on Feb 16, 2014 at 11:20:28 pm

Hello,

Just wanted to confirm, on export of a QT for broadcast, do you export RGB or 601/709?

I'm assuming RGB as I don't want to remap anything, but wanted to make sure.

What I heard on a previous posting is: "avid will always output at rec709."


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Michael Phillips
Re: RGB or 601 to Broadcast
on Feb 16, 2014 at 11:53:57 pm

Depends on what the delivery requirements are for a particular network/program type. The program master from Avid can be done in either an RGB 709 project or a YCbCr 709 project. RGB/YCbCr is color space while the 709 denotes that black levels are per SMPTE standards of 16/235 for 8 bit and 64/940 for 10 bit. Broadcast itself is YCbCr 709.

Also, what codec/file type you are starting with will help determine whether you need to master as RGB 709 to start with.

Michael


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William Edwards
Re: RGB or 601 to Broadcast
on Feb 17, 2014 at 1:31:50 am

DG FastChannel.

I am outputting a DNX 175. I see the native output of this spec in the QT options is Rec709 though, which is awesome for me, right?


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Bill Ravens
Re: RGB or 601 to Broadcast
on Feb 17, 2014 at 12:04:24 pm

What Michael Philips said notwithstanding, the Media Composer nomenclature is confusing and ambiguous. In Avid-speak, "RGB" means MC expects the data to be full range (0-1023) and so it will remap the data. "601/709" means MC expects the data to be "broadcast range" (64-940); and so it will import/export as is, without remapping.



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Michael Phillips
Re: RGB or 601 to Broadcast
on Feb 17, 2014 at 1:48:32 pm

Agreed - it would be nice to clean up all that ambiguity as there are so many threads on many forums with the same question. And using the wrong nomenclature with no added explanation doesn't help.

Michael


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Job ter Burg
Re: RGB or 601 to Broadcast
on Feb 18, 2014 at 7:50:49 pm
Last Edited By Job ter Burg on Feb 18, 2014 at 7:51:52 pm

Selecting RGB _does_ force a remap!
http://www.jobterburg.nl/Publications/601_709_RGB.pdf


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Richard Boghosian
Re: GB or 601 to Broadcast
on Feb 21, 2014 at 1:42:33 am

Actually depends on the version you're on. Avid changed it in MC7. So the real answer is to export a QT file in each flavor and then import that file back into your project. The one that matches the look of your sequence is the correct one.

Richard Boghosian
Bogh AV Productions

AVID 7.03 MacPro 2014 16Gb ram BMD Ultra 4K


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Bruce Coffy
Re: GB or 601 to Broadcast
on May 27, 2015 at 4:10:45 pm

I realize this is an older post but I am hoping someone can confirm my workflow for me.

I record directly to AJA KiPro using the DNxHD codec.
I use AMA Link for editing in MC 8.3.1
I export "Same As"
I then use Sorenson Squeeze to compress to a QT H.264 file for streaming from the exported QT file.
I also use the same exported file to create my DVD .iso file

So, am I correct in assuming that the best option is the 601/709 color space? I do find that the compressed file seems a bit washed out at least on my work screens.


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Job ter Burg
Re: GB or 601 to Broadcast
on May 28, 2015 at 12:00:33 pm

601/709 will look washed out on a computer monitor (which is normally not calibrated to legal 601/709).

If you use your export to create a DVD, it depends whether or not your DVD encoding application is expecting 16-235 or 0-255. A lot of apps will assume your are feeding it 0-255, and they remap - which of course yields wrong results if your export already is video legal.


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Bruce Coffy
Re: GB or 601 to Broadcast
on May 28, 2015 at 2:17:15 pm

Thanks Job!
I just use Avid DVD By Sonic. I'll see if there are any settings in there. We upload our MP4 videos to Amazon S3 for streaming on our site as well as YouTube. They both look pretty good.

Bruce


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Job ter Burg
Re: GB or 601 to Broadcast
on May 30, 2015 at 12:00:02 pm

Sonic Avid DVD assumes 0-255 and I have never found a way to change that. So it will remap whatever you feed it to 16-235. Which means it would be best to export with the 'RGB' button ticked in MC.


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Bruce Coffy
Re: GB or 601 to Broadcast
on May 30, 2015 at 6:15:41 pm

Well, that's frustrating. A broadcast editing company puts out a software application which is not broadcast standard. So, essentially what that means is that I need to export two files. One for broadcast levels for archive and another for DVD creation. I have MC on a PC. Do you know any other good DVD creation programs which assume 16-235 color standard?


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Michael Phillips
Re: GB or 601 to Broadcast
on May 30, 2015 at 6:30:21 pm

It's so much the authoring side as it is the encoding. You can always use the included Sorenson Squeeze encoder which does have a check box allowing you to indicate that levels are 16-235 for the MPEG2 encode.


Michael


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Job ter Burg
Re: GB or 601 to Broadcast
on May 28, 2015 at 11:58:24 am

This was not changed in v7.
RGB remaps luma levels, during import or export.
601/RGB maintains luma levels during import or export.


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