Hi.

Based on the hope that one of the Moderators passes this on to Avid I'll report an issue with AVCHD Import into Avid MC (applies at least to versions 6.5.2 to 6.5.3).

I think we all know how weird the studio vs. fullswing thing can be with AVCHD … especially on MAC.
Now, on MC 5.5 (xy…) everything went fine with GH2 footage (MTS files recorded in studioswing have been imported accordingly into Avid MC).

The Panasonic GH3 also records video in studioswing but the files (*.mov files) are labelled with a fullswing tag for viewing purposes on a computer screen.
However, Avid MC (6.5.3) is clipping blacks on direct import (though import settings are set to rec 709).

To illustrate the issue I've attached screenshots of some test footage directly imported into MC 6.5.3 versus footage first transcoded to DNxHD (185x, 25p) through iFFmpeg and then fast imported into Avid MC (since the forum layout crops the screenshots please open the attchments in a seperate tab to view the full images...).

The direct import clearly shows crushed shadows and banding… while the iFFmpeg conversion to DNxHD shows smooth transitions and a higher differentiation in dark tonal values. To make the issue more obvious I've applied a tone curve to both of the screenshots in a second copy.

I was under the impression Avid MC (5.5 …) ignores flags and tags in mov and MTS files. Which was a good thing!! … IMO… since this way the actual luminance levels of the original footage has been preserved.

But apparently MC 6.5 (…) now seems to read flags and tags in AVCHD footage and therefore direct import doesn't work correctly anymore.

Would be cool, if Avid could fix this ... since right now the only way to preserve the original levels is to first transcode the footage to DNxHD using an external tool (in my case iFFmpeg).

Or maybe I am doing something wrong..? (but honestly I don't think so as I am pretty familar with the studio- vs. fullswing issue...).

GH3 patches (tone curve applied to the iFFmpeg import on the right side to utilze fullswing levels):

GH3 patches + curve (tone curve applied to the iFFmpeg import on the right side to utilze fullswing levels):

GH3 shadows (tone curve applied to the iFFmpeg import on the right side to utilze fullswing levels):

GH3 shadows + curve (tone curve applied to the iFFmpeg import on the right side to utilze fullswing levels):

No experience with either of these cams. However, MTS versus MOV might be quite a difference, as with the MOV files it will likely be QT doing the decoding.

However, the weird thing is that as far as I can tell, your pic shows the whites aren't clipped, but the blacks are. Which is weird, because if the cam records 16-235, remapping to full swing would not crush any blacks, as there would be no blacks below 16.

So to me, it looks like a gamma issue. Which is very likely caused by QT. There have been other issues with QT and gamma, and it would be great if somehow Avid could get the core media, bypassing any 'corrections' on the QT end.

Use Avid AMA to connect to files then transcode with Avid to DNXHD files. Let us know if that works for you.

It's the same with AMA -> transcode ...

Job ter Burg:

So to me, it looks like a gamma issue. Which is very likely caused by QT. There have been other issues with QT and gamma, and it would be great if somehow Avid could get the core media, bypassing any 'corrections' on the QT end.

Job ter Burg:

it would be great if somehow Avid could get the core media, bypassing any 'corrections' on the QT end.

For instance FFmpeg bypasses QT tags (set for vieweing purposes) of the source file. You can transcode to DNxHD through FFmpeg and get proper studioswing (by the way... FFmpeg even transcodes to DNxHD-x, so 10bit). Alternatively you can transcode to ProRes through FFmpeg ... EDIT: transcoding through FFmpeg to ProRes also preserves the original levels!

In 5DtoRGB you have the option to preselect whether the source file is studioswing or fullswing. So with 5DtoRGB you can also transcode to ProRes and still preserve studioswing.

So there are in fact options ... but it's a pitty that Avid's import tool (or AMA Plugin) doesn't offer a switch as the one provided in 5DtoRGB. You can only choose to remap from fullswing to studioswing ("RGB" settings) or you can choose not to remap levels (rec709 setting). But if Avid read's the source file wrong (due to QT related issues) the rec709 setting doesn't help at all ...

Job ter Burg:

it would be great if somehow Avid could get the core media, bypassing any 'corrections' on the QT end.

Cool