Vegas changing colors of mts files on import. Not levels.

[banditeer]

Hi,

I have an mts source file from a TZ7 camera. When I open the file in Vegas 9 Pro, it changes the colors slightly, expecially skin tones. Its not a levels issue. I've attached two pics to illustrate. This is simply opening the file in vegas - no processing at all. When rendering the file out of vegas, these color changes are carried forward into the finished render. Anybody got a clue what's happening?

Cheers!

[jagabo]

rec.709 vs rec.601 color? Doesn't look that big though.

[banditeer]

Yes I think its to do with bt.601 vs bt.709. I think the source is bt.601 but Vegas thinks its bt.709, so soon as you import it, the color shift happens. Can't find a way round this at the moment. Yes its not a massive change, but would like to get in control of it...

[poisondeathray]

You cannot control vegas' Y'CbCr => RGB conversion to use bt.601 vs. bt.709

You can either convert to RGB using bt.601 (e.g. in avisynth) to a lossless RGB intermediate for import

or export uncompressed RGB AVI then convert bt.709 => bt.601 using aviysnth colormatrix filter (then encode to your final format goal)

[jagabo]

I AviSynth use the ColorMatrix() filter:

ColorMatrix(mode="Rec.709->Rec.601")

or

ColorMatrix(mode="Rec.601->Rec.709")

Whichever way you need to go.

[budwzr]

Vegas may be trying to match the media to the project settings, uncheck this in project properties.

[banditeer]

Thanks for your responses guys.

- budwzr - do you mean the "adjust source media to better match project or render settings" swith in the project properties?

Hmmm, looks like I'm gonna have to learn avisynth. Haven't used it before. So can I go Vegas -> Avisynth with Color matrix conversion -> Megui (or Staxrip)?

[banditeer]

After a little further digging - is the only way of frameserving out of vegas to use debugmode frameserver? This seems like a great tool but it won't work in vegas in 32bit mode...

[poisondeathray]

yes, debugmode only works in 8-bit mode for vegas

what is your final format goal?

Note a lot of the time you cannot control how a software player or hardware device chooses to convert to RGB for display. For example , youtube will convert using Rec709 , many software will use Rec601 for SD and Rec709 for HD. Some use Rec601 for everything. Vegas uses Rec709 for HD, but Adobe uses Rec601 for everything - even HD (except if you use v210) . Some will obey signal "flags"

The flags I'm talking about are --colorprim bt709 --transfer bt709 --colormatrix bt709 , which are can be used by streams encoded with x264 (or use bt601) . These are just flags that tell the player or device what matrix to use for playback - the don't change the actual data. Note, not all players/devices acknowlege the flag. Media players like popcornhour will obey if you flag a stream signal. In contrast, the avisynth colormatrix() filter changes the actual YUV data - but as you see whether or not you get playback as intended is another story and depends on many factors that are often not controllable

In general, everything HD is supposed to use Rec709 , and Rec601 for SD

[budwzr]

Why isn't it easier to just throw a +5 contrast / -5 brightness filter and move on?

Vegas has a super robust set of filters intended to address these kinds of issues. I don't understand needing to waste time in an external app for such a very minor issue.

You can chain filters to the track or the event or both. You can even keyframe the filter's output as needed.

[jagabo]

Why isn't it easier to just throw a +5 contrast / -5 brightness filter and move on?

It's not a levels problem.

[edDV]

Why would one shoot anything important on a digital camera?

Vegas and Premiere are expecting standard formats. AVCHD is assumed to be BT.709. AVCHD "Lite" is mostly a consumer marketing format not supported by standards.

[jagabo]

Why would one shoot anything important on a digital camera?

Is that a joke?
http://filmmakermagazine.com/news/2010/03/zacutos-dslr-shootout/

[budwzr]

That hasn't been proven.

Why isn't it easier to just throw a +5 contrast / -5 brightness filter and move on?

It's not a levels problem.

[edDV]

Why would one shoot anything important on a digital camera?

Is that a joke?
http://filmmakermagazine.com/news/2010/03/zacutos-dslr-shootout/

The Lumix TZ7 isn't in that class.

I'm talking about consumer level AVCHD "Lite" which is still undefined by a standard.

And I should add, not supported with Vegas or Premiere project settings.

[budwzr]

Vegas does support AVCHD Lite, which was jointly developed by Sony/Panasonic. I have an FZ35 and Vegas Pro 9e, and the files drag and drop right to the timeline.

Why would one shoot anything important on a digital camera?

Is that a joke?
http://filmmakermagazine.com/news/2010/03/zacutos-dslr-shootout/

The Lumix TZ7 isn't in that class.

I'm talking about consumer level AVCHD "Lite" which is still undefined by a standard.

And I should add, not supported with Vegas or Premiere project settings.

[edDV]

Vegas does support AVCHD Lite, which was jointly developed by Sony/Panasonic. I have an FZ35 and Vegas Pro 9e, and the files drag and drop right to the timeline.

Why would one shoot anything important on a digital camera?

Is that a joke?
http://filmmakermagazine.com/news/2010/03/zacutos-dslr-shootout/

The Lumix TZ7 isn't in that class.

I'm talking about consumer level AVCHD "Lite" which is still undefined by a standard.

And I should add, not supported with Vegas or Premiere project settings.

But there are no AVCHD "Lite" project settings so your drop is being converted to whatever the project format is.

Banditeer, what are your project settings?

[budwzr]

Hahaha, Vegas' render "presets" are just stock templates, like sample "Word" documents. You can make your own and save them in the list, it's just there as a starting point for nubes.

[edDV]

Source format, project format and "render as" format are three different things.

In the case of smart render formats like HDV or XDCAM, all three must match. For AVCHD "Lite" you need to create a custom 1280x720p 29.97 fps project format.

The 1449x879 image above is a resize from source format.

[budwzr]

Exactly, "AVCHD Lite" is simply 720p.

[poisondeathray]

you also have to "disable resample" for each clip in vegas , because of the frame repeat flag in AVCHD Lite - otherwise you get ghosting

[edDV]

FWIW - Just installed a copy of Vegas Movie Studio Platinum 10. Unlike Vegas Pro9 it does have an AVCHD project setting but AVCHD Lite is not included.



This consumer product defines the project in terms of output format. Alternately "Match Media Settings" seems to set project to source format. More later as I play with it.

[banditeer]

Thanks for the responses guys. I've been playing around with this and what it boils down to is this - I think.

Vegas is converting my mts files to RGB on import - correct? (Please correct me if I'm wrong!)

In doing so it is doing a color matrix shift of some sort. Can't get my head around which way - bt601 to bt709 or the other way. Either way its doing something in the rgb conversion.

The only way to get around this as I see it at the moment is to present Vegas with rgb in the first place hence not allow it to do this color shift. IOW, convert the mts files to uncompressed rgb first (as poisondeathray quite rightly pointed out). I've tried this out, converting the mts file to rgb uncompressed by going avs script into vdub, then out uncompressed. The resultant file upon import into vegas displays the correct color matrix (hoorah!). When I pull the original mts file into vegas next to this uncompressed rgb version, the color shift is very clear to see.

Poisondeathray, your other suggestion of coming out of vegas uncompressed the doing a 709 to 601 with avs afterwards is of course another option, but means that all previews in vegas while editing wil be inaccurate, so I think your former suggestion is the best way. I would love to be able to directly frameserve an rgb file into vegas somehow to avoid the massive intermediate uncompressed files, but I don't think thats currently possible is it??

[jagabo]

Can Vegas open AVS scripts? If so, you can convert to RGB or YUV with the correct color matrix in the script. You won't need a big intermediate file.

[banditeer]

Unfortunately jagabo I can't seem to get vegas to open avs script at all. Its a pain. Might be doing something wrong tho... not sure.

[edDV]

What are your project settings so we can duplicate your workflow? If standard def "DV-wide", it will do a 709 to 601 conversion. If you use an HD project template, it should maintain 709.

[poisondeathray]

Vegas is converting my mts files to RGB on import - correct? (Please correct me if I'm wrong!)

In doing so it is doing a color matrix shift of some sort. Can't get my head around which way - bt601 to bt709 or the other way. Either way its doing something in the rgb conversion.

Yes it is, and it's using bt.709 - I tested on some AVCHD Lite footage from another camera , and compared to conversions I know were either bt.709 vs. bt.601 done in avisynth.

Whatever your 1st screenshot was taken from ,that program converted to RGB using bt.601

Normally HD is supposed to use bt.709 for the conversion - which one is "correct" for your camera is another topic, but if you seem happy with bt.601, then you need to use one of the workarounds

I would love to be able to directly frameserve an rgb file into vegas somehow to avoid the massive intermediate uncompressed files, but I don't think thats currently possible is it??

you can use avisynth virtual file system (AVFS)
http://forum.doom9.org/showthread.php?t=133313
http://www.turtlewar.org/avfs/

[banditeer]

@edDV - I tried a whole bunch of different project templates and settings, and unfortunately it was the same result when importing the mts files. I think vegas is doing its thing with mts files as a matter of course, no matter what your project settings are.

@poisondeathray - thanks for the headsup on avfs, I'll give it a go. I also found vfapi that will create a dummy avi to feed into vegas. This seems to work as well. Is either of these methods (avfs or vfapi) destructive in any way, or purely a wrapper?

The first pic above is the mts file decoded with CoreAVC using yv12. Using bt.601 by the sounds of what you say. If I make CoreAVC use rgb rather than yv12 and force bt.709, it looks exactly the same as the mts file imported straight into vegas, so that actually all makes sense. I deduce from this that CoreAVC is actually using the wrong color matrix in yv12 mode. Subjectively, I think this looks more natural than when I force it to bt.709, but like you say, that's another topic...

[poisondeathray]

I also found vfapi that will create a dummy avi to feed into vegas. This seems to work as well. Is either of these methods (avfs or vfapi) destructive in any way, or purely a wrapper?

no, they are all frameservers , non destructive in the sense that the original file is not altered, and the frameserved image is identical to the decoded image. Another frameserver is makeavis (comes with ffdshow). Vegas is prone to crashing with all of them , except AVFS in my experience . Vegas doesn't have a dedicated avs import plugin like Premiere has

[banditeer]

Man, just when I think I've got this sussed...

Re the original mts file and how its converted to rgb: the avs script I used on the mts file was simply

DirectShowSource("filename.m2ts")

ie no conversion filters at all. So avisynth isn't doing the rgb conversion right? So where's the rgb conversion taking place? Wherever it is taking place, it must be using bt.601 and not bt.709 to show up with the colors it does in vegas...