This IS the Avid L2: Re: [Avid-L2] "What are you grading this week 2013?", survey results.

Saturday, July 27, 2013

Re: [Avid-L2] "What are you grading this week 2013?", survey results.

There's also the issue where the same quicktime file renders differently in the same software on different os.

I did a tvc about 2 years ago that looked fine in all my lion boxes but the client kept complaining. Finally brought his laptop in and snow leopard was lifting the gamma and desaturation the clip.

Playback in vlc was ok, playback in quicktime player was bad. Tried everything, explicit 2.2 file header using x264 the works.

Snow leopard was the problem that time. Add in that half my clients are windows 7, or 8 and Ubuntu is used by several if my telecom clients and I got no idea what my clients are seeing.

Mike

On 28 Jul, 2013, at 8:07 AM, Bogdan Grigorescu <bogdan_grigorescu@yahoo.com> wrote:

> Hi Job, just wanted to say thank you for your extensive testing and for sharing the results.
> I agree with some of the conclusions - but not with all.
>
> I performed myself some testing(on a Mac) and came up with the following:
> -the Apple QT7 H264 encode preserves the levels and gamma
> -there are applications capable of correctly implementing the QT export. They are written by non Apple people, I assume using QT libraries and /or the SDK
> -the mere fact that a round trip ends up with wrong level does not necessarily mean the codec is flawed
> -most of the time is about flags in the QT file and how these are interpreted or modified by various apps, and not about the file essence(like video code values)
>
> So it seems to me that some developers are able to properly understand the QT framework, whereas others never manage to get it right and just resort to some workarounds.
> Maybe it's Apple fault for not documenting it completely or not willing to share all the details - which I doubt.
>
> As for the MXF OP1A, yes, it's nice and seems to become one of the top delivery wrappers along with MPEG2-TS and some others.
>
> cheers,
> BG
> www.finale.tv
>
> ________________________________
> From: Job ter Burg (L2B) <Job_L2@terburg.com>
> To: Avid-L2@yahoogroups.com
> Sent: Saturday, July 27, 2013 2:09 PM
> Subject: Re: [Avid-L2] "What are you grading this week 2013?", survey results.
>
>
>
>
> On 24 jul. 2013, at 08:33, Mark Spano <cutandcover@gmail.com> wrote:
>
> > Why is this insane? ProRes is perfectly fine to deliver for broadcast.
>
> I'm not arguing the quality of the ProRes codec. I AM arguing the Apple H264 codec, which is severely gamma-flawed.
>
> I'm also arguing using anythin QT as a broadcast delivery format, since no one seems to know how to check nor specify luma level range for QT delivery. A broadcaster sent me their ident in H264 and in IMX50, both had completely different gamma (the IMX50 being the best looking and probably correct one).
>
> And: Apple won't allow you to create ProRes on a PC. So it's severely limited to a platform. That to me makes it far from a desirable common delivery format. But OK, let's assume that we all buy a Mac just to get there. Then there's still the issue with QT. If you export from QT Pro or from the Custom export options in MC (basically using QT), you WILL get gamma shifts when exporting to ProRes. You cannot maintain gamma and luma levels when roundtripping.
>
> The same goes for FCP, which in my limited experience only seems to work when you ingest and export through external hardware. File-based import/export in FCP is always messing with gamma and luma levels. I was never able for instance to properly import or export the Belle Nuit Test chart with gamma and luma levels intact. All P2-to-QT reencodes I received from FCP had screwed up gamma when compared to the MXF camera original.
>
> The only way I know to properly deliver ProRes is to transcode or mixdown to ProRes in MC6.5 or later, then export Same As Source. Aything QT in the mix will mess with your stuff.
>
> I really do feel that Op1A MXF is a much nicer, and more professional way to handle things. And I really, really hate Quicktime. Not the idea of Quicktime, but the common practice of Quicktime. I use it when I have to, often, but reluctantly.
>
> J
>
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>
>

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