HD Guide for Vimeo, YouTube and the Web

[Jerry Amende]

Stephen,

I read your post a couple of times and I'm not sure where you're going with this. You do understand that this phenomena is not specific to YouTube, don't you? It's observed when YT's Flash Player plays an h.264/mp4 format video.

In our testing, we observed the same expansion of color space in every player tested - whether played locally or web based e.g. Windows Media Player, VLC, FlowPlayer, JW Player, Silverlight, HTML5 and several others.

To confuse the issue, if you drag the h.264/mp4 back to the Sony Vegas timeline, the colorspace is perceived as compressed again (and to my knowledge that's the only place you will see this).

So, the before and after YouTube is really not pertinent to the subject. Once footage is rendered to h.264/mp4 all players we've tested will expand the color space observed in Sony Vegas. The YouTube re-render does nothing to the color space that hasn't already been done. Re-renders are not additive - once it gets to the h.264/mp4 format.

Does that help? Or am I misunderstanding what you're doing.

...Jerry

[Nick Hope]

Stephen, don't do anything to the blacks! They're perfect as they are. Anything in your original footage that you see below 16 in the histogram or below 0 in the studio-RGB waveform is rubbish such as noise and sharpening-artifacts that it's quite OK to clip. Look on your histogram. The [shoulder/elbow/knee]* in the luminance is perfectly at around 20, falling to 16 before it hits the noise where the slope flattens out.

So just reel in the whites and you will see more detail in the highlights when it plays back from YouTube, particularly in the players' arms/hands where the levels would otherwise be blown out. Actually this is a perfect clip to illustrate the salvaging of highlights. It's not earth-shattering, it's subtle, but it's definitely better.

I have uploaded a V8 veg file here (also attached to this post) containing a color curve FX (with explanation) that, IMO, works really well on your clip. You can open the veg in V8 or later and save the FX as a preset. I have attached a screen grab of it.

Even if you're going to process your highlights like this in post-production, I would still try to reduce the exposure a bit when you shoot. As they are, your red and blue channels are hard up against 255. But you might then need to deal with the blacks if they dip below 16 too.

* - insert body-joint of choice

[Nick Hope]

Oh, and as Jerry says, YT don't "do anything" to your levels. Assuming you upload a Y'CbCr codec such as AVC to them, they simply encode it to AVC at lower bitrates. i.e. Y'CbCr to Y'CbCr. The levels "expansion", for want of a better term, happens when your player (e.g. Adobe Flash Player browser plugin) converts that Y'CbCr to RGB for your screen. So when you download an mp4 from YT and compare it against the footage you uploaded, you shouldn't see any significant difference in levels, but just the differences where YT have mangled the detail in your footage with their crappy encoder.

To convert a 16-235 Y'CbCr to 0-255 RGB is, arguably, correct behaviour, since that is what happens in the TV world. If anything it's the cameras that are wrong for shooting outside "legal" levels.

This correction we are talking about is nothing new. It's exactly the same as the correction we should be doing if we want to "legalise" levels for DVD etc..

[Stephen Crye]

Hi;

Nick and Jerry, thanks for the insight. I'm sorry it took me so long to get back - suuuper busy at work, no time for any editing.

I'm digesting the new information provided. I hope everyone understands that I am not disputing anything, I am confused and seeking guidance.

As soon as I have something cogent to post, I will get back, probably with some more results. The first thing I'm going to do is take the raw clip, render it without any levels adjustment, bring it back into Vegas, and take a snapshot of the waveform scope. If I understand you correctly, I will see the purported levels expansion - or am I still confused?

I'm beginning to realize that I am probably confusing several things, they are all mixed up in my mind:
* changes to levels introduced by rendering to AVC (what exactly is changed?)
* changes to levels introduced by rendering to other formats (such as when rendering for Blu-Ray or DVD - does this happen?)
* changes to levels when a rendered clip is played in the players listed (all but Sony Vegas are guilty? What about the Sony Picture Motion Browser Player?)

Finally, I have been told by Atomos and others (although Sony is tight-lipped) that my NX70's raw real-time HDMI output is "4:2:2 8-bit" . When I plug the NX70 into my LED flatscreen TV, what I see in real time (in terms of levels and color balance) does not look much different than what I see when I subsequently play what I was recording (after transferring the clip) using Sony PMB, although it does seem to have less compression artifacts. I've read that AVCHD compression in the camera results in 4:2:0 files . No matter how many times I read the Wikipedia articles on 4:2:0 vs 4:2:2 vs 4:4:4 I get more confused ... help.

Sorry for all the questions, I really appreciate the help. All this stuff is clear to gurus, but beginners like me struggle to put it all together.

Steve

[Nick Hope]

Originally Posted by Stephen Crye

The first thing I'm going to do is take the raw clip, render it without any levels adjustment, bring it back into Vegas, and take a snapshot of the waveform scope. If I understand you correctly, I will see the purported levels expansion - or am I still confused?

No, in that case you shouldn't see a change in the levels. The Vegas scopes reflect what you see in the preview window.

Whether you see levels "expanded' during decoding and playback depends on your computer's graphics card and its settings, and the particular media player and its settings. It varies from computer to computer. Even on my computer one of my 24" monitors behaves differently to the other. And GOM Player on my computer behaves differently to GOM Player on other computers. A tool like Takecolor can help you measure the behaviour.

What I can say is that an AVC file that displays black at 16 and white at 235 on Sony Vegas' scopes will end up displaying black at 0 and white at 255 in Adobe Flash Player (YouTube, Vimeo and JW Player) in the majority of cases. That behaviour is the same as it should be on Blu-ray and DVD playback.

[Ray Turcotte]

I have two follow up questions to this excellent discussion.

I wish to clarify what are the necessary steps to get the most accurate playback from video i post on the net.

The reason I ask this is there are 7 places on a typical Vegas editing station where color can be adjusted.

1) on the monitor itself (theater mode, srgb mode, standard mode, user mode...)

2) third party color correction software (i use the Huey pro)

3) on the graphics card drivers (color profiles, sliders for gamma, saturation etc)

4) within video player internal settings (Vlc wmplayer qtplayer etc...)

5) within Vegas itself by globally turning on or off Options > Preferences >Preview Device > Adjust levels from Studio RGB to Computer RGB

6) applying color correction FX filters on directly Vegas media bin files, or on the time line;

7) applying presets discussed in this thread on the project output preview player.


Seems to me there is much opportunity to over correct and get a false final render for posting on the web.


The current steps I am using is

1) monitor is set to user mode and calibrated with the HeueyPro;

2) graphic driver is set to defaults

3) all video players at default settings.

4) the global switch "Adjust levels from Studio RGB to Computer RGB" is checked on

5) I apply color correction FX on the clips in the media bin to color match.

6) apply the setting recommended in this post on the output player preview window.

7) render out to the web.


As a bonus question, newer cameras and camcorders can be set to record in x.v.color space which is wider than srgb. Most computer monitors at best only can display srgb. How should such footage be handled on the vegas time line?

Thanks

[Jerry Amende]

Ray,

I'm pretty sure you'll be just fine with that procedure, however, I do have some comments.

I don't use an external monitor, but I'm pretty sure that "4) the global switch "Adjust levels from Studio RGB to Computer RGB" is checked on" is correct and only affects the way you observe the preview - not the render itself.

I've never applied color correction as a Media FX, but I don't see way that procedure shouldn't work.

Normally, I apply the Sony Levels FX as the final Event FX - making sure the footage conforms to the 16-235 color space as seen with the Sony Video Scopes. Which, of course, means that it would not be applied as the "Video Output FX" on the preview window.

As far as the bonus question is concerned, I think the key is to limit the color space to the 16-235 range and you should be fine.

...Jerry

[Ray Turcotte]

Thanks Jerry

Recently I shot and posted a music video for my brother George, which you can view here.

George-Painted Corners Video.mp4 - YouTube

I followed all of the steps above & used the handbrake better method of rendering the video to the web.

However, upon playback from youtube or on facebook, the video is darker and the "darks" darker than how it was shot and how it was edited. I even applied some luminance gain on the output, to where the light reflections off of the cymbals and dobro in the background just started to clip.

However, playing back on youtube the experience is darker than what I edited in Vegas, even played back on the monitor it was edited on.. So, I am not sure where the problem is.

Thanks

[Mike Kujbida]

Ray, it looks fine on my 24" Dell.

[Jerry Amende]

Ray,

Triplets!!! I think that looks very nice as well. What camera did you use?

...Jerry

Edit: Thinking a little about your "dilemma" - did you try adding the cRGB->sRGB Levels FX template (rather than adjusting the sliders to conform to 16-235)? In other words, if you applied the sRGB->cRGB correction to your external monitor, in order to reverse the process try applying the cRGB->sRGB to your footage in Vegas. (if I understand what you're doing).

[Ray Turcotte]

Jerry

I used my HDR-AX2000. I shot it in 1920x1080/24p FH mode and down sized it via handbrake. I added some luminance and saturation via the HSL FX on the output, then applied the Sony level FX with the Computer RGB to Studio RGB preset last. Also under the project settings I selected the "32bit floating point video levels" for the pixel format.


Reviewing the RGB parade vector scope the dark pixels start at about value 38 and there are only a few pixels in 235-240. range.

Thanks everyone for the feedback.

P.S. While editing I realized 24p was too slow a frame rate - Musicians hands & feet move surprisingly fast