Friday, October 7, 2011

[Avid-L2] Re: Squeeze H.264 Bad Video Level Mystery

 

Thanks for that explanation.

Is it your opinion, that Squeeze prefers 709 over RGB?

Or have I just lucked-into a group of settings that finally allows me to see unity between the source file in my Avid timeline -- and the H.264 file created in Squeeze with my gamma and saturation tweeks?

--- In Avid-L2@yahoogroups.com, "Dom Q. Silverio" <domqsilverio@...> wrote:
>
> FFDShow is a set of codecs. Normally it should not interfere with the
> decoding "normal" QT codecs like Avid as Squeeze usually use it for
> other formats like XiVD and such. But I did come across your problem and
> one of the steps I took was removing the FFDshow codecs.
>
> Considering your recent post, I don't think FFDshow is the culprit. I
> think this is just another QT app that cannot interpret the color space
> information correctly (again). I think this is one of the reasons why
> even Apple has given up on QT 7 (though QT X is not perfect either).
>
>
>
>
>
> On 10/7/2011 8:22 PM, blafarm wrote:
> > Thanks for your response Dom.
> >
> > I just determined the following:
> >
> > 1. Squeeze seems to want an Avid exported 709 file -- and not RGB
> >
> > 2. Using 709 - I can apply a Squeeze -13 gamma shift - and pretty much nail the gamma. I have tested this by re-importing the resulting H.264 file (Avid import set to 0-255) and comparing it to the source shot on my timeline -- both visually and with BMD Ultrascope out of my MojoDX.
> >
> > 3. At that point, I need to add +3 of Squeeze saturation to resolve the chroma differences between the two.
> >
> > Based on those findings, does that change your opinion of the possible necessity of uninstalling FFDShow (which, for the record, I did install with Squeeze)?
> >
> > And can you please tell me why removing that app might change the outcome -- as I'm using Squeeze's MainConcept H.264 codec?
> >
> > Thanks
> >
> >
> >
> >
> >
> >
> > --- In Avid-L2@yahoogroups.com, "Dom Q. Silverio"<domqsilverio@> wrote:
> >> If you installed it with Squeeze, try uninstalling the FFDShow codecs.
> >>
> >>
> >>
> >> On 10/7/2011 7:03 PM, blafarm wrote:
> >>> Just tested a slew of Gamma adjustments (in both directions) in Squeeze 7 -- and it definitely doesn't seem like it's Gamma.
> >>>
> >>> Also tested exporting 709 QT and using that as a source for compressions -- again -- and still no joy.
> >>>
> >>> Can't figure out why Avid can export an H.264 that is in "unity" with the timeline -- but Squeeze cannot.
> >>>
> >>> And I'd use Avid, but the quality level is terrible.
> >>>
> >>>
> >>>
> >>>
> >>> --- In Avid-L2@yahoogroups.com, "blafarm"<blafarm@> wrote:
> >>>> Thanks for your response.
> >>>>
> >>>> The source files are Cannon 5D imported as RGB.
> >>>> The Avid project is YCbCR 709.
> >>>> And I exported all of the QT's as RGB.
> >>>>
> >>>> At first I thought it might be gamma.
> >>>> Then I thought it might 0-255 vs. 16-235 mapping.
> >>>>
> >>>> My Squeeze presets are "known quantities".
> >>>> And I realize I could get into the filter thing...
> >>>> But I was hoping to find the [possible] error of my ways.
> >>>> And just nail this problem without a lot of trial and error.
> >>>>
> >>>>
> >>>>
> >>>> --- In Avid-L2@yahoogroups.com, Jeff Cook<jeff@> wrote:
> >>>>> Not sure about Squeeze, but a problem with Cleaner used to be that
> >>>>> anybody could overwrite the presets without necessarily knowing it, so
> >>>>> check that you're not using altered settings.
> >>>>>
> >>>>> Otherwise, and unless it's a bug, can you add a video filter inside
> >>>>> Squeeze and get good levels out that way? Only other thing that occurs
> >>>>> just now is, are you sure it's the black levels and not a gamma/gray
> >>>>> levels issue?
> >>>>>
> >>>>> --
> >>>>> Jeff Cook
> >>>>> jeff@
> >>>>> 703-980-1104 (cell)
> >>>>>
> >>>>> CookStudios.com
> >>>>> Freelance Video Editing
> >>>>> Washington DC& Portable
> >>>>>
> >>>>>
> >>>>> Quoting blafarm<blafarm@>:
> >>>>>
> >>>>>> Every H.264 file we create in Sorenson Squeeze 7 (PC) has elevated
> >>>>>> black levels and reduced contrast. If I didn't know better I would
> >>>>>> have thought it was a RGB vs. 709 issue -- but I think we've
> >>>>>> disproved that.
> >>>>>>
> >>>>>> We have exported test files from Avid (PC) using three different
> >>>>>> types of uncompressed QuickTime RGB (0-255) files -- Same as Source,
> >>>>>> Avid Codecs and Avid 1:1x.
> >>>>>>
> >>>>>> And to check them for "unity" -- we re-imported them back into Avid
> >>>>>> as RGB -- and they match perfectly with the timeline.
> >>>>>>
> >>>>>> Then we imported those uncompressed QuickTime files into Squeeze and
> >>>>>> compressed them using three different types of H.264 codecs --
> >>>>>> MainConcept, Apple and Sorenson.
> >>>>>>
> >>>>>> We have viewed all of these compressed files in QuickTime, Windows
> >>>>>> Media Player, VLC, Firefox, Chrome and Internet Explorer -- and they
> >>>>>> all have the same black and contrast problem.
> >>>>>>
> >>>>>> The we imported all of the H.264 files back into Avid as RGB -- and
> >>>>>> they exhibit the exact same problem -- and do not match the timeline.
> >>>>>>
> >>>>>> Finally, we exported an H.264 file directly out of Avid -- which I
> >>>>>> believe uses QuickTime codecs -- and the video levels are fine. And
> >>>>>> then we re-imported that Avid H.264 file back into Avid as RGB --
> >>>>>> and the levels match the timeline perfectly.
> >>>>>>
> >>>>>> I realize H.264 colorspace is different -- but the black level and
> >>>>>> contrast differences we are seeing are significant. More confusing
> >>>>>> -- is that the Avid H.264 export matches the timeline perfectly.
> >>>>>>
> >>>>>> And, lastly, the "Black Normalization to 16" checkbox in Squeeze 7
> >>>>>> -- has had absolutely no affect in any of our tests.
> >>>>>>
> >>>>>> Anyone else see this problem -- or have a solution?
> >>>>>>
> >>>>>> Thanks in advance.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> ------------------------------------
> >>>>>>
> >>>>>> Search the official Complete Avid-L archives at:
> >>>>>> http://archives.bengrosser.com/avid/
> >>>>>> Yahoo! Groups Links
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>
> >>>
> >>> ------------------------------------
> >>>
> >>> Search the official Complete Avid-L archives at: http://archives.bengrosser.com/avid/
> >>> Yahoo! Groups Links
> >>>
> >>>
> >>>
> >>>
> >
> >
> >
> > ------------------------------------
> >
> > Search the official Complete Avid-L archives at: http://archives.bengrosser.com/avid/
> > Yahoo! Groups Links
> >
> >
> >
> >
>

__._,_.___
Recent Activity:
Search the official Complete Avid-L archives at:   http://archives.bengrosser.com/avid/
MARKETPLACE

Stay on top of your group activity without leaving the page you're on - Get the Yahoo! Toolbar now.

.

__,_._,___

No comments:

Post a Comment

Share it