black levels changing with avi output

crocdoc wrote on 7/20/2011, 4:17 PM

I'm putting together some video clips for a PowerPoint presentation and, as PP is very limited in the number of codecs it recognises, am rendering them as avi files using the default avi setting in Vegas. It should be lossless, right? However, the resulting clips are very dark and high in contrast. If I put any of the clips through AE to add an effect, they get darker with each step.

It reminded me of this thread, here: http://www.sonycreativesoftware.com/forums/ShowMessage.asp?MessageID=771045&Replies=4 but in this instance it isn't a Cineform issue .

Anyone have any idea what is going on? Is there another codec I should be looking at which isn't going to alter brightness/contrast/black levels with each step?

Comments

musicvid10 wrote on 7/20/2011, 4:43 PM

MPEG-2 or even MPEG-1 will work much better in Powerpoint than uncompressed RGB. If you are going through AE, I suggest using DNxHD as an intermediate.

crocdoc wrote on 7/20/2011, 5:26 PM

Thanks.

I originally started using mpeg but PP doesn't seem to recognise progressive scan mpeg-2, for it comes up as a blank box. I've just tried again, with the same results. I must be missing something?

Since my first post, I managed to get a good result using Cineform avi without everything going dark and contrasty. I didn't think PP would be able to cope with Cineform avi files, which is why I went to the default .avi, but I must have made some error with my earlier attempt as it is now working fine.

However, I will try DNxHD coming out of AE as well, for comparison.

musicvid10 wrote on 7/20/2011, 5:50 PM

PP doesn't seem to recognise progressive scan mpeg-2
Progressive MPEG-2 and MPEG-1 both work fine in Powerpoint, have done it dozens of times for educational presentations.

However, I will try DNxHD coming out of AE as well, for comparison.
Also, I was suggesting DNxHD as an intermediate BETWEEN Vegas and AE, not as a delivery format. Best of luck.

crocdoc wrote on 7/20/2011, 6:19 PM

Yes, I gathered you meant DNxHD as an intermediate rather than as a delivery format.

Now I'm perplexed as to why the mpegs I am rendering are not being recognised by PP. The only changes I have made from the default rendering setting is making them progressive scan and fixed bit rate, rather than variable. I've just tried it again, with the same result. I can open the file and view it in media player classic, but when I embed the file into PP it comes up as a black box which, when clicked on (as I would do in the presentation) as a white box. The sound, however, seems to work.

robwood wrote on 7/21/2011, 6:14 AM

try rendering to WMV format.

farss wrote on 7/21/2011, 6:54 AM

"Now I'm perplexed as to why the mpegs I am rendering are not being recognised by PP"

PPT uses an embedded version of WMP and if you're using mpeg-2 it will not be able to decode it by default. If you've got a DVD playing app installed on the same PC then the mpeg-2 codec that got installed with that will probably also enable WMP to play it.

Your problem with AVI files is quite understandable. The problem is not that the uncompressed codec is expanding levels at all. I've used uncompressed AVI files from time to time and there is no problem with the levels, if there was many here would be screaming.
The problem is that Vegas's preview monitor incorrectly displays video in the first place. This causes you to assume your video looks one way, then you play it out through another player that displays it correctly and you see something different and assume it is wrong.

Bob.

crocdoc wrote on 7/21/2011, 7:29 AM

Seriously? Vegas' preview monitor displays video incorrectly? That's a bit scary. Do you output to another monitor when you're editing?

I'm guessing that you're right about the mpeg-2 codec, as I'm pretty sure that I don't have a specific DVD playing app on this computer.

So far PPT seems to be coping with Cineform AVI files and on the days I'm giving my presentation I'll make sure it's the only app running, to free up RAM.

Robwood - I've never been happy with the look of WMV files in the past, so I've avoided that route, but thanks anyway.

farss wrote on 7/21/2011, 7:49 AM

"Do you output to another monitor when you're editing?"
Absolutely. I used to use a CRT based monitor but now use a quite good LCD monitor as my Secondary Display with Vegas setup to convert StudioRGB to ComputerRGB.
In the absense of such a device apply a plugin to the Preview Monitor that converts from Studio RGB to Computer RGB using the fx icon in the monitor. Make certain to disable the plugin before rendering as that FX is actually being applied to the Video Buss and as a result your rendered output will have its level shifted.

Bob.

crocdoc wrote on 7/21/2011, 8:20 AM

Thank you for that. I do work with an LCD monitor as a secondary display but haven't been converting the preview to ComputerRGB. Is there a plugin within Vegas that does that, or do I need to search for a third party fx?

edit: I think I've found the answer - unticking the 7.5 IRE and Studio RGB boxes in video scopes?

farss wrote on 7/21/2011, 2:16 PM

" Is there a plugin within Vegas that does that, or do I need to search for a third party fx?"

Several FXs have presets for doing that, the simplest being the Sony Levels plugin.

" I think I've found the answer - unticking the 7.5 IRE and Studio RGB boxes in video scopes"

Changing the video scopes settings will not change the Preview Monitor. To get the Video Scopes to read correctly you should uncheck the 7.5 setup box and check the Studio box.

If you're using the Secondary Preview monitor then in its setup tick the Studio checkbox as shown here:

Bob.

crocdoc wrote on 7/21/2011, 3:43 PM

Thanks again.