How Mac OSX still *screws* your GH2 / FS100 / NEX footage - A must read!!

[grayadamson]

Hey there, does anyone know if/how footage is affected using the camera import feature in FCP X?
Is it best to transcode the footage in FCP X, use proxy files or transcode using the 5DtoRGB app mentioned in the original post?

[see ya]

Which camera they're affected differently. If it's GH2 or FS100 would you possibly have a sample via dropbox or somewhere?

[emgesp]

This is what happens to all my T2i files on my PC.  VLC doesn't crush the blacks, but it clips the highlights, Windows Media Player crushes blacks and clips highlights, and Quicktime player keeps all the shadow and  highlight detail, but it has gamma curve that makes everything look washed out.  In Sony Vegas I choose full range and then use basic contrast/brightness controls to make everything look right before final encode.

[Francisco Rios]

I bought 5toRGB batch. The results are much better .
But, can anyone explain me about the decoding matrix?
Andrew suggest to use BT.601.
Best regards.

[see ya]

[quote author=Francisco Ríos link=topic=726.msg5569#msg5569 date=1337707996]
I bought 5toRGB batch. The results are much better .
But, can anyone explain me about the decoding matrix?
Andrew suggest to use BT.601.
Best regards.
[/quote]

BT601 for color matrix luma coefficients. There are three bits of metadata in camera video files that relate to 'correct' presentation of color and contrast. You can see all this metadata using something like mediainfo. The decompressing codec in your NLE reads the metadata for hints on how to handle and display the video.

1. The color primaries, for HD this is ITU BT709. This defines the color gamut in relation to the CIE 1931 spectrum.

2. The Transfer curve used in the conversion from linear RGB off the sensor to gamma encoded values for the h264 encoder.

3. The Color Matrix, luma coefficients to be used for the YCbCr <> RGB color space conversions. There are two usual choices BT601 or more commonly BT709, with Canon and Nikon they chose BT601.

A common mistake in transcoding is the loss of the color matrix metadata, if BT601 is not specifically flagged in the stream and transcoding usually removes the BT601 then the default matrix of BT709 will be assumed by the NLE or media player, so as a result certain colors are slightly skewed and contrast slightly more. The color skew is seen with pinks going towards orange so skin tone looks off and blues go a little green.

5DToRGB I believe either transfers the BT601 matrix to BT709 for codecs like DNxHD & ProRes that may well never see BT601 flagged and where BT709 is always assumed. To avoid the color skew.

[see ya]

[quote author=emgesp link=topic=726.msg5568#msg5568 date=1337706587]
This is what happens to all my T2i files on my PC.  VLC doesn't crush the blacks, but it clips the highlights, Windows Media Player crushes blacks and clips highlights, and Quicktime player keeps all the shadow and  highlight detail, but it has gamma curve that makes everything look washed out.  In Sony Vegas I choose full range and then use basic contrast/brightness controls to make everything look right before final encode.
[/quote]

Most non color managed media players will simply pull shadows down from 16 YCC to RGB 0 & 235 YCC pushed up to 255 RGB, so crush blacks and squeeze whites rather than clip. But with media players including VLC handling also depends on whether hardware acceleration is on or not and video cards settings 0 - 255 or 16 - 235 etc.

With regard to any Canon or Nikon DSLR video any decent media player + codec combinations will read the fullrange flag in the h264 and squeeze the full levels range into 16 - 235 to ensure nothing is clipped or crushed.

The only decent media player I'm aware of is Media Player Classic, free and open source, combined with madVR color management system and a LUT created by color calibrating your monitor will give you ideal playback of HD & SD with correct levels and color rendition.

Here's a simple couple of files to test media player handling such as having HW acceleration on and off etc. The files are created to 'match' handling of Canon & Nikon DSLR h264.

http://www.yellowspace.webspace.virginmedia.com/fullrangetest.zip

[sfrancis928]

Interesting, I tested this out with my NEX-5N footage and though it at first seems like transcoding with 5DtoRGB brings out more highlight and shadow detail, I've found that you can bring out the same detail just by flattening out the original footage in color correction. I imported the original footage and the transcoded 5DtoRGB footage into FCP X, then I brought the highlights down and the shadows up on the original, trying to match the 5DtoRGB footage (not perfect, but pretty close). I think it worked out pretty well. For instance, before correction, no detail of the upper light bulb could even be distinguished, but the information was all still there. I just had to lower the highlights. Same with the shadow detail in the bottom right of the frame. I just raised the blacks and the detail came back.

[img]http://farm9.staticflickr.com/8001/7254628168_903945fd48_b.jpg[/img]

So it seems to me that 5DtoRGB is just flattening the image for you, when you could really do it yourself in post and save a lot of hard drive space. Or am I wrong about this? I'm no professional, just a hobbyist, so if I'm wrong please correct me.

[see ya]

Could you make your NEX original MTS, 5DToRGB and UnWrap versions available to download?

[sfrancis928]

[quote author=yellow link=topic=726.msg5584#msg5584 date=1337776815]
Could you make your NEX original MTS, 5DToRGB and UnWrap versions available to download?
[/quote]

Yep:

Original .MTS: [url=http://files.me.com/sfrancis928/iq8kxk]files.me.com/sfrancis928/iq8kxk[/url]

FCP Unwrap: [url=http://files.me.com/sfrancis928/vsitcv.mov]files.me.com/sfrancis928/vsitcv.mov[/url]

5DtoRGB Lite Transcode: [url=http://files.me.com/sfrancis928/k6vvgw.mov]files.me.com/sfrancis928/k6vvgw.mov[/url]


Also here are the waveform scopes of the footage:

FCP Unwrap w/o correction:
[img]http://farm8.staticflickr.com/7087/7257042324_d8d935a04a_z.jpg[/img]

5DtoRGB w/o correction:
[img]http://farm8.staticflickr.com/7090/7257042492_ec0a2e50bf_z.jpg[/img]

Looks to me like the 5DtoRGB transcode has all the same information, just squashed.

[sfrancis928]

And I just got the same results in Premiere Pro using the original .MTS file.

[jacanaproductions]

I tried to see if this was happening in FCPx with my GH2. I converted a clip using the 5DtoRGB lite / free program and compared it to what was being created with FPCx as well as playing the native mts file with Movist.

I don't see any real difference, perhaps a slight gamma shift but nothing as drastic as you indicated.

Is this just a Premiere Pro issue or FCPx too? Perhaps I need the pay version of 5dtoRGB?

[see ya]

[quote author=sfrancis928 link=topic=726.msg5590#msg5590 date=1337799274]
And I just got the same results in Premiere Pro using the original .MTS file.
[/quote]

Many thanks for the files, using Avisynth to check levels, I see identical waveforms for both Original MTS and unwrapped files as per your FCPX Unwrapped waveform. 5DToRGB have been squeezed 16 - 235 and conversion to RGB give quantisation errors, ie: spikey histogram if treated as a 16 - 235 clip and if treated as a 0 - 255 YCC to RGB clip it uses less 8bit levels in RGB and appears brighter / washed out.

I'm not familiar with 'Unwrap', could you explain a little?

What waveform did you see for the original MTS if you don't mind.

[sfrancis928]

[quote author=yellow link=topic=726.msg5596#msg5596 date=1337813085]

I'm not familiar with 'Unwrap', could you explain a little?

What waveform did you see for the original MTS if you don't mind.
[/quote]

As I understand it, .MTS files are H.264 files that are "wrapped" in an AVCHD sort of "shell". FCP X cannot edit .MTS files natively, unlike Premiere. It has to "unwrap" the AVCHD shell and convert them into .mov files. The program does this on import from the camera. It's not transcoding, and it shouldn't have any effect on the video. That's why I didn't have a waveform of the .MTS file, because I can't open it in FCP X. But I looked at the waveform of the original file in Premiere and it was the same as the unwrapped FCP X version, as I expected.

[see ya]

Thanks, so its just remuxing them and should take no more than a few seconds each file, the reason I asked was theres a lot of Apple related metadata added, of coarse, but bitrate, duration etc vary between original and unwrapped. Thanks anyway. There seems absolutely no point in using 5DToRGB for FCPx or Premiere at least for these MTS files and the settings usex, unless its to solve playback issues.

[see ya]

This kind of concurs with my earlier posts that it could quite possibly be better to import into the NLE, yes preview may appear overly contrasty / dark but at least the files made it into the NLE unaffected, then grade to suit delivery rather than what happens to Canon & Nikon files which force the decompessing codec to squeeze levels at import so the display looks right immediately but the image has been squeezed into less 8bit levels like 5DToRGB output. Remuxing Canon & Nikon files with MP4Box to switch off the full range flag prevents this and gives full range levels in the NLE with a waveform like your Original unwrapped.

Prefer to adjust levels at 32bit precision in the NLE rather than transcode or squeeze levels at import at 8bit.

[sfrancis928]

Exactly what I was thinking. Thanks yellow!

[alexander]

Hi Guys,

I red the article and it got me curious since I have the NEX 5n and Premiere Pro CS6 on Windows 7 Workstation.

The whole "crushed whites" thing is also the case in Windows 7 in PP CS6.

It seems as if Premiere, VLC Player, WindowMediaPlayer and a few others are geting the 0-255 16-235 Levels kind of wrong. I think you have already stated it guys but why do you need to remux and transcode ... ? In PP cs6 and cs5.5 you can just bring all the Information that is above 1.0 in the waveform down with any 32 bit Filter that deals with Levels.
clipped whites:
[IMG]http://i46.tinypic.com/az9fm.jpg[/img]

Levels adjusted with 32 bit Filter in PP = No clipping in highlights
[IMG]http://i48.tinypic.com/ofrl86.jpg[/img]

In AfterEffects its different: You would have to work the whole AE Project in 32 bit to be able to save the clipped detail in the whites. If you work in 8bit (which is standard ae project) then AE will just cut off all the info above 1.0.
But you do not need to transcode or remux AVCHD footage.

But the question is: WHY is Adobe getting it wrong in the second consecutive Version of PP that is supposed to deal nativly with AVCHD???? 
Even the opensource FFDSHOW codec gets it spot on when played with mpclassic (as Andrew stated and I also can confirm this)

Exposure was set spot on shortly bevor clipping. Also when I connect the nex 5n with hdmi to my Plasma everything plays just fine no clipping at all!

[alexander]

Well Sony Vegas Displays everything correctly! Ni clipping at all. Waveform stays the same so there is still stuff above 1.0 but its not clipped in the render monitor. In the wave form there is an Option to choose between 16-235 and 0-255 but this only affects the scale of the waveform.

[see ya]

Hi Alexander, remuxing or last resort transcoding was specific to MTS file support in certain NLEs such as FCPx.

With regard to Canon & Nikon its to remove the full range flag. Further up the thread I think I gave a link to Canon Movs with flag set on and off, it would be intresting to see how CS 5.5 & 6 handle them.

Why 32bit and 8bit, this is due to the RGB conversion done by all NLEs for color processing internally. The video off our cameras is YCbCr color space, at 8bit conversion to RGB not all the information in the original file can be converted to RGB it creates negative RGB values and values over 1.0 in the Unity Cube creating invalid RGB so artifacts due to gamut errors can become visible particularly with close to clipping exposures and saturated colors.

Working at 32bit float allows the whole YCbCr color space to be held in RGB without loss. Vegas does this internally by default I think with recent versions.

[alexander]

Hi well You can see how cs6 handlesAVCHD NEX files  >:(. After just importing the file everything above 1.0 in the wave form is clipped due to 8 bit defaults when I apply a  fast colocorrector which is  32-bin Filter the info can be brought back below 1.0 with the value sliders ... look at the sliders.[b] But i do not want to do it for each and every file[/b]... and Vegas displays it right away "corectly" (due to 32 bit precision as You mentioned) in vegas i dont have to move any sliders or any thing.


If someone gave me 5d or t2i footage that is shot in a similar way like the examples above than i am happy to check it out in Premiere Pro cs6 in windows 7