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washed out images

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tankboy
washed out images
on Jul 27, 2007 at 12:06:04 pm

hi folks

i'm pretty sure i read in this forum a while back (although I can't seemed to find it) someone was having problems with there stuff looking washed out having come out of m100 and into FCSPro. I also seem to remember someone saying something about different colour spaces.

I've had the same problem. Stuff was shot SD on DVCAM I exported out of M100 - QT DV codec. They were encoded in studio pro single pass 6.5 bitrate and it doesn't look to bad considering its DV except on the DVD it's washed out. Almost like it's over exsposed.

Can anyone enlighten me as to why this might be and how I can avoid it. Also if anyone has a workflow (and encode settings etc) that give good results using M100 - FCSP and SD DVCAM footage that would be great to hear.

Any thoughts or comments would be greatly appreciated.

Cheers
Tankboy


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Floh
Re: washed out images
by
on Jul 27, 2007 at 12:14:09 pm

What system did you acquire on, and what codec? If you acquired in V11.x into DV codec you should be good to go. All Apple-based codecs from Media 100 use the same colorspace as Apple does in FCStudio, and no contrast problems should appear.


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cowcowcowcowcow
Arthur Dent
Re: washed out images
on Jul 27, 2007 at 1:24:58 pm

Tankboy,

I assume you've used the M100i codec in this project. If so, this codec uses color space that represents black at 16 on the RGB Value scale and white at 235 (full RGB range is 0-255). This allows for super black, and details in white above 100 IRE...

FCP


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cowcowcowcowcow
Kieran Matthew
Re: washed out images
on Jul 27, 2007 at 8:02:48 pm

Hi All,

As I understand it, the 16-235 issue is only part of the problem. In addition to the colourspace, Apple codecs work at 1.8 gamma. Compressor treats the mpegs to a brightness boost to overcome the gamma and shift it to 2.2 (the gamma of TVs) as this is where DVDs are generally seen.

The media 100i codec is already at 2.2, so the additional boost causes the already restricted colour range (with black at a distinctly grey 16 instead of 0) to be brightened further leaving the image flat and over bright.

Bitvice has a button to correct the gamma for the Apple codecs like Compressor, otherwise they come out too dark (they used to call it DV brightness IIRC). When encoding media 100i files with compressor, after sorting the range, applying a gamma adjust of 1.2 (1.8*1.2=almost 2.2) corrects the curve.

So, as Arthur mentioned, the new 100's have the export option of 0-255 range, but does it do anything about the gamma?

K


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David Issko
Re: washed out images
on Jul 27, 2007 at 10:40:46 pm

"So, as Arthur mentioned, the new 100's have the export option of 0-255 range, but does it do anything about the gamma?"

No gamma adjustments but if you encode using Compressor, there are adjustments there as you are probably well aware, however I use 11.6.2, export to QT none compression using computer 0-255 (or whatever it is) for my DVDs and I do not encounter any issues at all with the picture. I do not adust for gamma in Compressor. As Bitvice currently has 8 core issues where the program crashes just after it starts encoding, I cannot comment on it.

My experiences if it helps.

Cheers
David Issko


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Floh
Re: washed out images
by
on Jul 27, 2007 at 10:49:30 pm

[David Issko] "As Bitvice currently has 8 core issues where the program crashes just after it starts encoding, I cannot comment on it."

If you want to use BitVice with your 8Core system, you have to deactivate 4 cores before starting the encode (you can turn them on immediately after the encode starts). Search for the "CHUD Tools" on the Apple Support website; this will install a preference to turn off cores in the System Prefs.


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David Issko
Re: washed out images
on Jul 28, 2007 at 10:38:21 pm

Thanks Floh,

I am aware of the roundabout fix. I just haven't got around to trying it as I find Compressor works very fast and gives me very good results for my DVDs.

Cheers
David Issko


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tankboy
Re: washed out images
on Jul 30, 2007 at 1:26:52 am

firstly, thank you all for your responses. it has been very very helpful.

Answers to your questions. the project was aquired on a G5 quad OSX 10.4.10 M100V11.5 in the media100HD codec. I'm not sure why I think it was an oversight because it was shot sd and will be finished sd. The clips (four short films) were originally exported in QT DV Codec and have been tested in various other codecs with the same washed out problem occuring in the final DVD. I'm doing the DVD work on a Powerbook using Producer and DVDSPro 4

Okay so, I have tried the 0-255 option out of m100 but SP says it can't recognised the files and so won't import them.

So i did the gamma tweak in compressor as Kieran suggested and yeehaa! it corrected the washed out look nicely.

Now, I must clarify here I don't ususally do this stuff. I usually edit and have a guy that does all my dvd creation for me. but he's unavailable so I'm having a shot at doing it myself. So I was using the DVDStudio inbuilt encoder until I tried compressor for those tweaks.

But now I'm wondering if it is possible DVDSP could be re-encoding with inbuilt encoder during the finishing somehow because now although the pictures aren't washed out they're not as sharp and a bit jaggy. The encode settings i used in compressor are pretty much the same as the original settings used (in the inbuilt DVDSP encoder) except with the gamma tweaks.

So i guess my question this time is, does the inbuilt encoder in studio pro recognised pre-encoded files and turn itself off. Or could it be re-encoding the files (is that even possible)? As you can see I'm a bit of a dweeb at this end of things. I've read the manual and can't seem to find anything in relation to this.

I guess the change in the look of the files to softer/jaggy could be due to something else entirely (although as I say the encode settings are pretty much the same) so I'll keep testing the compressor settings. In the mean tme any more thoughts would be greatly appreciated.

sorry for the long winded post.

Cheer again
Tankboy.



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Kieran Matthew
Re: washed out images
on Jul 30, 2007 at 2:12:39 am

Hi Tankboy,

If you are bringing m2vs etc into DVDSP then it does no further encoding and just multiplexes the files.

As to the softer/jaggier look, this could be either a scaling issue, or to do with field dominance, or both.

Check that the field order coming out of your media100 matches the settings in compressor and the desired output for (NTSC?) DVD.

Also check the output frame size is correct especially the vertical height. I believe there is a problem with 480 versus 486 height - the scaling producing issues.

It could be something else entirely, but there are two things to look at initially.

HTH
K


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tankboy
Re: washed out images
on Jul 30, 2007 at 9:20:48 am

thanks for that kieran

I checked all the stuff you mentioned and that was all in order. So as part of my hit'n'miss testing strategy I tried encoding it using single pass CBR. I had previously been using VBR and hey presto it fixed it.

Cheers for all your help.

Tankboy


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