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Topic Title: overcast on Wirecast
Topic Summary: Why is black not black with Wirecast?
Created On: 12/19/2010 12:28 AM
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 12/19/2010 12:28 AM
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spotduster

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After careful comparison for several years of every version of Wirecast so far, we have noticed one persistent issue. When broadcasting or recording to disk black is really a grey, and many colors appear somewhat washed out.

We have also noticed that after using Flash Media Live Encoder with the same devices, in both broadcast and record to disk black is much closer to black. And many colors appear more vivid.

Why is this? Is this a Wirecast issue, a Qucktime issue?

Here are two sample videos we just made from the same VFW device (NewTek VT5 card) using H264 video and aac audio of a simple black screen coming out of our video system capture card. Both clips are created on the same machine, using the same bitrates, etc. And technically we've noticed that doesn't really matter either. Black is not black in a wirecast broadcast or recording no matter what settings you play with. Whether WMV or MP4.

Wirecast: Wirecast.mp4
FMLE: FMLE.mp4

Using VLC for impartial playback testing you will notice that the FMLE encoded file is much darker than the Wirecast encoded file. (This can also be verified in Sony Vegas as well.) From both the black issue and the seemingly washed out colors issue that also is present we are wondering if anything can be done. Could it also be a color space difference?

Incidentally both files were directly recorded by the Wowza Media Server and written to mp4 outside of Wirecast to avoid any programs partiality or differences in writing to disk. Although this can also be verified in record to disk files with both programs as well.

Please help.

Edited: 12/19/2010 at 5:22 AM by spotduster
 12/19/2010 6:46 PM
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benjaminhigginbotham

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I'm not a Telestream engineer but I downloaded the two clips and did a quick analysis of the blacks in Photoshop. It looks like Wirecast is following the proper 7.5 IRE format whereas FMLE is incorrectly crushing the blacks at 0 IRE. There is a bit more information here: http://www.glennchan.info/arti.../setup/75IREsetup.html but in the US there is actually no such thing is pure black with video. It is all very close to black, but not actually black.

In some systems you can crush the blacks to get a 'Super Black' of 0 IRE but you will lose detail in the image when that happens. Not sure if this is what is going on, but based on my screenshots that's what it looks like.

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Benjamin Higginbotham
benjamin@spacevidcast.com
http://www.spacevidcast.com
 12/19/2010 7:07 PM
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spotduster

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Thanks. We are familiar with the IRE numbers. We have VT5 setup with the 7.5 IRE setting. On the surface that might seem to be the answer, and it may even be. My only question to your observation is why do the colors look so much more vivid in the broadcasts from FMLE? Maybe I should run some SMTMPE color bars through and post them too?
 12/20/2010 2:36 PM
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CraigS

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Please to check with test signal and make sure source and settings are exactly the same. Both Wirecast and FMLE are using the same MainConcept H.264 codec for Flash encoding.

Given that Wirecast is decoding for compositing since, unlike FMLE, Wirecast is also a switcher, check the levels in Wirecast preview as well.

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CraigS
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 12/20/2010 2:52 PM
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benjaminhigginbotham

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That's a really good suggestion. I would love to see some test patterns come back from each encoder to see what is really going on. While both systems use the same encoder, that's certainly not the whole picture. Any image pre-processing or pushing in/out of the GPU can distort the picture which may be why we see a variance here. Would love to see what those test patterns look like.

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Benjamin Higginbotham
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 12/20/2010 3:45 PM
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webstream

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I'll jump in here because I have been noticing Windows Media is pretty blown out and soft on Wirecast vs Windows Media Encoder. Here is a black and color bar comparison between the two, this is with a Digital Rapids DRC-500 card, no change other than the app difference.





Edited: 12/20/2010 at 3:57 PM by webstream
 12/20/2010 4:04 PM
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CraigS

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OK if people are seeing this with both Windows Media and Flash that would be in the issue is in the decode and processing. Fill out the form and link to the forum thread so the engineers can see the examples and links. I wonder if Wirecast is moving 0-255 to 16-235 range which is typical of USA NTSC Broadcast.
http://www.telestream.net/tele...st/contact-support.htm

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CraigS
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 12/21/2010 4:48 PM
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spotduster

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Thanks webstream. We have noticed this problem actually since the early days of version 3.0. We just thought it was "normal" until we closely compared with other products such as FMLE and WME.

@ Craig. The settings we used were identical in FMLE and Wirecast. This information is actually in my original post. I am now starting another post here with much more detailed info comparing all the encoders.

 12/21/2010 5:56 PM
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webstream

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no problem, I actually did the comparison because I had clients complaining about windows media looking flat and blown out and I tended to always blame it based on the windows media codec. Seeing this post led me to do a direct comparison and there is a noticeable difference. I have submitted the issue to the engineers.
 12/21/2010 6:13 PM
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CraigS

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Thanks for that. We're investigating at what stage it's happening (clearly before the encode).

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CraigS
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 12/21/2010 8:38 PM
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spotduster

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Ok, so here is the result of some thorough testing we've done on this issue. I believe this shows there is definitely a problem.

We used the SMPTE bars downloaded from Wikipedia. Calibrated our NewTek VT5 system to them via it's proc amps. All screenshots from encoders were brought back into VT5 on the same DDR and proc amp settings for scope comparison, thus comparing a perfect original with encoder output.

Here we have created a control group directly out of VT5 complete with video scope shots:

Notes: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it. Normally this line would be 7.5 IRE, but for the purposes of testing I calibrated the small black line in the lower part of the test pattern to 7.5 IRE black. You can verify this by looking closely at the Waveform-Y scope. You can see that color saturation, hue, brightness and contrast are all dead on in this group. This test setup is used to pass through all the test encoders and comes from the VT5 card's internal VFW capture drivers.

Test results Wirecast uncompressed MOV to disk (the best performance from Wirecast encoders):

Notes: It can be quickly observed that color saturation, brightness and contrast have all dropped significantly. White is now about 91 IRE and black about 10 IRE. This completely demonstrates what I was explaining verbally in my first post.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results of Wirecast h264 encode to disk:

Notes: As we begin to compress in Wirecast we see that brightness, contrast and color saturation begin to suffer even further. White is now about 92 IRE and black is now about 12 IRE! Yuck.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results of Wirecast with internal WME Encoder to disk:

Notes: WME inside Wirecast performs slightly worse than h264. One area it seems to do a little better is in black. White is about 91 IRE and black is about 10 again (Almost as good as uncompressed black actually.) The WME from Wirecast is where we noticed the "overcast" or washed out video originally about two years ago.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results of WME (Windows Media Encoder) for Windows (outside Wirecast) to disk:

Notes: WME outside Wirecast performs much better than uncompressed MOV from Wirecast! Brightness and contrast are essentially right on, color saturation also shows very little loss with results at least falling in the targets on the Waveform-Y scope. This should be what WME inside Wirecast looks like.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results for FMLE h264 mp4 (local broadcast) to disk (lossless from original to file through Wowza Developer Edition):

Notes: As you can see FMLE h264 currently has the best performance in this test. Brightness and contrast are right on, as well as color saturation. The only thing at variance from the original is black is a hair darker, coming in at about 6 IRE. And if you are going to err, I would think you'd want to to be at 7.5 IRE or a bit darker. Does the 7.5 IRE really apply to webcasts anyway?
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Observations:
    The video scopes tell the story. Wirecast definitely is doing something to all its output that is reducing brightness, contrast and color saturation.

    It appears in all records to disk and broadcasts alike, it also appears with every source we've tested and can remember.

    It does not appear to be showing much of this problem on the live or preview screens though. It seems to be something happening more in the encode hand off for everything.

    Also, on careful inspection there appears to be subtle differences in the SMPTE test bars even between the live and preview screens. White's and off whites are the most noticeably different with this sub-problem.

    We have noticed this problem even on a clean install of Windows/Wirecast.


Unknowns:
    Is this a 0-255 to 16-235 range setting issue like Craig mentioned? I know when I override all player settings with the 16-235 settings on our Nvidia card it makes the files look a lot better, but then everything else is off the scale wrong.

    Is this only a Wirecast windows problem, or does it affect Mac also?





Ok, part two. Now for the black compares directly.

Control group, VT5 black proc amped to 7.5 IRE.

Notes: Black is right on the line. 7.5 IRE in this output from VT5 to disk directly.

Test results Wirecast uncompressed MOV to disk (the best performance from Wirecast encoders):

Notes: Black is about 12-13 IRE. Obviously not acceptable.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.


Test results of Wirecast h264 encode to disk:

Notes: Black is about 10-11 IRE. Still not acceptable.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results of Wirecast with internal WME Encoder to disk:

Notes: Black is about 10-11 IRE. Still not acceptable.
Remember: Lower black line on Waveform-Y is not part of the test pattern, but is a slim background area, disregard it.

Test results of WME (Windows Media Encoder) for Windows (outside Wirecast) to disk:

Notes: WME is showing here a little darker than the 7.5 IRE input. Excellent.


Test results for FMLE h264 mp4 (local broadcast) to disk (loss less from original to file through Wowza Developer Edition):

Notes: FMLE h264 is showing here a little darker than the 7.5 IRE input. Excellent also.



System specs are:
Windows 7 x64
AMD Phenom 9950 Quad-Core Processor (appr. 10.4Ghz or 2.6Ghz per core)(Black Edition - Not currently overclocked)
ASUS M3N-HT Deluxe motherboard (w/mempipe)
4GB System RAM
NVIDIA GeForce 9800 GT w/1GB onboard ram (112 stream processors)(2 DVI, 1 s-video)(driver version CUDA 190.38)
NVIDIA nForce 780a SLI (8 stream processors)(onboard GPU w/512MB shared system ram) (1 HDMI, 1 VGA)
1 -24' Hannspree monitor (1080p)
2 - 22' Proview monitors
1 - NewTek VT5 video mixer/VFW capture card/SX-84 24 camera input breakout box
1 - Sony HVR-A1U 1080i down-converted to s-video for input into NewTek SX-84 video router
1 - Sony HDR-HC1 1080i down-converted to s-video for input into NewTek SX-84 video router
1 - Sony HDR-HC1 1080i down-converted to s-video for input into NewTek SX-84 video router
1 - Onboard Nvidia Gigabit network card for broadcast traffic & internet
1 - Creative Labs X-Fi Pro sound card
1 - 250GB SATA primary windows hard drive
5 - 1TB SATA secondary (recording and post production) hard drives
1 - TLC-6 USB based Tally Light Controller & system for VT5
3 - DVD-R recorders for system redundancy on main cameras
System can broadcast output directly to FMLE, Wirecast and WME via VFW capture drivers.
Lots of other cool goodies.



Hope all that helps you guys find this problem! I'm guessing this is a simple fix. Probably harder to locate the problem than fix it.
 12/21/2010 8:41 PM
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spotduster

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Oh yeah, please feel free to send us a free copy of Wirecast for all our hard work.
 12/21/2010 9:33 PM
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CraigS

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Originally posted by: spotduster
Oh yeah, please feel free to send us a free copy of Wirecast for all our hard work.


So you like the effect of raising black and lowering whites?

Thanks for testing. I will test on Mac as well.



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CraigS
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 12/22/2010 12:23 PM
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spotduster

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Well I meant once the prob is fixed. I'm all for affirmative action, just not in video software. BTW, I did send in a report to support as well.
 12/22/2010 12:41 PM
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CraigS

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The engineers are investigating the cause and how it might be fixed.
BTW maybe you should submit a request to be added to the beta tester list if you haven't already.

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CraigS
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 12/23/2010 2:31 PM
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spotduster

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Where would I do such a thing?
 12/23/2010 2:52 PM
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CraigS

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Find the secret email address. It should still be good as development is always ongoing.
http://blogs.telestream.net/wi...he-word-on-wirecast-4/

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CraigS
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 1/2/2011 9:02 AM
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HiltonT

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Originally posted by: benjaminhigginbotham
I'm not a Telestream engineer but I downloaded the two clips and did a quick analysis of the blacks in Photoshop. It looks like Wirecast is following the proper 7.5 IRE format whereas FMLE is incorrectly crushing the blacks at 0 IRE. There is a bit more information here: http://www.glennchan.info/arti.../setup/75IREsetup.html but in the US there is actually no such thing is pure black with video. It is all very close to black, but not actually black.


NTSC = Never The Same Color (or sometimes No True Skin Color)



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Regards,

Hilton Travis
http://blog.hiltontravis.com/

My Wirecast Config
 1/3/2011 11:34 AM
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CraigS

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Black levels shouldn't change. Also once in the digital world it's not really NTSC analog.

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CraigS
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 2/7/2011 5:12 PM
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spotduster

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Is there any chance there is an update to this issue?

Also, did not ever receive anything after submitting to beta testing email. Thanks.
 2/7/2011 5:28 PM
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CraigS

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For issues use the form below not beta form.
http://www.telestream.net/tele...st/contact-support.htm
They will respond back with a case number and you can ask for an update. They are looking at it but I can't speak to details at the moment.

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CraigS
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 2/8/2011 11:09 AM
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SynchPoint

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I solved something similar to this. Check that you GFX card is using the full range of colour 0-255. I have an nVidia card and in the control panel after I set this my levels were fine.

See my thread - http://forum.telestream.net/fo...did=6581&enterthread=y
 2/8/2011 1:24 PM
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CraigS

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Thanks for pointing to that thread. Do consider making a video tutorial showing how you adjusted your GPU.

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CraigS
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 2/8/2011 6:36 PM
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michael61341

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SynchPoint:

Can you give us the proceedure?
Control panel/ then what?

Michael

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 2/8/2011 7:17 PM
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CraigS

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See SynchPoint, people want to know. Let clamor for a tutorial.

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CraigS
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 2/9/2011 7:44 AM
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michael61341

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Found this:

http://www.ehow.co.uk/how_6872...color-video-cards.html

If you adjust the monitor colors, do you adjust Wirecast by default?

Michael

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ASUS P6T SE
2 64GB SSD Raid 0 OS
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 2/9/2011 11:35 AM
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CraigS

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Keep in mind that people reporting the issue are seeing two levels of black depending on how they're checking, using one GPU setting.

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CraigS
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 2/10/2011 7:45 AM
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SynchPoint

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Hi all

Here is the setting you need to change. By default the nVidia cards dynamic range is set to - limited 16-235. Change this to - full 0-255.



With one of my PCs the nVidia driver had this feature, but I did have to find an older nVidia driver for another PC that didn't have this option. Be aware that some nVidia drivers have the option but changing it doesn't change the video levels. You may just need to try different drivers.

Let me know if you get stuck and I'll look at what drivers/nVidia cards I am using.

Hope that helps

 2/10/2011 11:36 AM
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CraigS

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Those that make the change please post back the results.

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CraigS
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 3/14/2011 6:06 AM
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Guille

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It works. All these years blaming Osprey because of the poor color shown by the 700e and after all it was configuration issue. You should warn about this in documentation.

The next step is to improve the mainconcept codec implementation.

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