This IS the Avid L2: [Avid-L2] Re: QT video levels?

Thursday, May 9, 2013

[Avid-L2] Re: QT video levels?

Thanks, Michael! I read the thread you posted. Very helpful.

My end goal is preserve the 709 levels in a Same-As-Source export of a ProRes MXF sequence. And for various reasons, I'd like to avoid transcoding to DNxHD before export. I'd much prefer to convert the exported Quicktime file to 709 somehow.

Could I export Same-As-Source with 709 setting (resulting in a file flagged as RGB), then re-import to DNxHD 115 with the 709 setting (thereby resetting the levels and gaining access to the original detail/information), and then export as 709?

Or would I experience some kind of generational loss as a result of this process?

Thanks.

--- In Avid-L2@yahoogroups.com, Michael Brockington <brocking@...> wrote:
>
> Hi Mike:
>
> I haven't seen it documented, only observed what happens under
> testing. It looks to me like there is a flag set in the file that
> indicates it should be interpreted as RGB, rather than a change to
> underlying pixel values. But the effect is the same (of dropping the
> blacks and lifting the whites) unless you can force another application
> to disregard the flag. For instance, in After Effects you can fool
> around with colour management as I describe at the bottom of this thread:
> http://community.avid.com/forums/p/113013/677905.aspx
>
> You could also download a trial version of Avid 6.5 and do your own
> testing. The belle-nuit test chart can be downloaded here:
> http://www.belle-nuit.com/test-chart
>
> Sounds like a good exercise for one of your students!
>
> Cheers,
> --Michael
>
> On 13-05-08 8:15 AM, michaeljshen76 wrote:
> >
> > Michael, thank you so much for the reply.
> >
> > Does "flagged" mean the same as "converted", i.e., the blacks will go
> > down, the whites will go up, and the levels will be clipped on a video
> > monitor?
> >
> > Does anyone know if 709 Same-As-Source ProRes exports are working in
> > version 6.5? It would be a lot easier to upgrade one school machine to
> > 6.5 and export all the student sequences using that machine, rather
> > than convert all the films to DNxHD.
> >
> > Sigh.
> > -Mike
> >
> > --- In Avid-L2@yahoogroups.com <mailto:Avid-L2%40yahoogroups.com>,
> > Michael Brockington <brocking@> wrote:
> > >
> > > Yes, I believe your colour levels will be flagged as RGB on export.
> > >
> > > I guess one workaround would be to transcode the finished pieces to
> > > DnxHD at a suitable bitrate, and export that same-as-source using
> > > 601/709 levels.
> > >
> > > Cheers,
> > > --Michael
> > >
> > >
> > > On 13-05-07 9:48 AM, michaeljshen76 wrote:
> > > >
> > > > I have a number of students exporting their finished thesis films.
> > > > They've been editing in on MC 6.03 in Apple ProRes MXF. The plan was
> > > > to color-correct in the 709 color space, and then have them export a
> > > > Same-As-Source .mov using 601/709 settings. This would be their final
> > > > master.
> > > >
> > > > Am I correct in understanding that the 601/709 setting won't work,
> > and
> > > > that color levels will expand to RGB levels upon export? What's the
> > > > best workaround for this?
> > > >
> > > > Thanks for helping my offline editor brain with these online
> > conundrums!
> > > >
> > > > Cheers,
> > > > Mike
> > > >
> > > > --- In Avid-L2@yahoogroups.com <mailto:Avid-L2%40yahoogroups.com>
> > <mailto:Avid-L2%40yahoogroups.com>,
> > > > Michael Brockington <brocking@> wrote:
> > > > >
> > > > > On 6.0.3 this flag seems to be set properly by Avid for DNxHD
> > exports.
> > > > > ProRes exports in that version seem to be always flagged as RGB.
> > > > >
> > > > > I reported some testing results here comparing DNxHD vs ProRes
> > > > > same-as-source exports on Mac:
> > > > > http://community.avid.com/forums/p/113013/677905.aspx
> > > > >
> > > > > I suspect not all applications observe the flag that is set.
> > > > >
> > > > > Cheers,
> > > > > --Michael
> > > > >
> > > > > On 13-05-07 3:57 AM, Fabrice Altman wrote:
> > > > > >
> > > > > > So... moving on from the goose ;)
> > > > > >
> > > > > > Apparently there is an internal flag in the exported DNxHD QT file
> > > > > > that is supposed to be set to either RGB or 709 according to the
> > > > > > export settings.
> > > > > >
> > > > > > However, this flag seems always set to 709 on export from MC 5.5,
> > > > > > whatever the export settings are. Can anyone confirm this is a
> > bug
> > > > and
> > > > > > has been fixed in later releases?
> > > > > > (The flag seems to work on export from AFX).
> > > > > > Does a similar flag exist in ProRes?
> > > > > >
> > > > > > Cheers,
> > > > > > F.
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
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