Render "lossless"

[Chris Davis]

I'm making several short software sales videos that consist of screen captures from Camtasia. In Vegas I'm basically syncing the descriptive audio with the screen captures. I'm not applying any effects and pretty much the only manipulation of the source video is to freeze the screen (using the velocity envelope) until the audio catches up.

As I watch the preview, it is a perfect representation of the source video. However, when I render, I get a small amount of artifacts, and some of the text color (specifically red and blue) are noticeably different. It doesn't matter what format I render to, even uncompressed avi.

Is there some setting I'm missing to make the output perfectly match the input?

[Giroud Francois]

with video it is almost impossible.
any format you can put on a distributable media will be 4:2:0 in a standard user world (DV, DVD)
means you got only quarter resolution for color. very bad for computer pictures.
mpeg2 allows for better rendering (4:2:2 and even 4:4:4) but not on DVD.
all these video compression are more like lossy JPEG compression than GIF.
Additionally computer generate picture with higher resolution than video (usually starting at least with 800x600 while video stops at 720x480/576)
the codec you usually get for screen capturing are specially crafted to keep resolution intact (more like a GIF compression than like a JPEG) while displayed on computer screen.
going HD with blu-ray could be a solution.
On Apple Mac, screen capture is often enhanced by zooming on the picture.
look at this video to see what i mean (interstingly , the guy capture Windows stuff as well on the mac by running a windows emulator).
Even there, you got a flash video that is targeted for computer and you can hardly expect to get resutlts as good as this one from video.
http://www.reykroona.com/?p=41

[Chris Davis]

This will not be distributed on DVD or Blu-ray. It will be converted to flash video for use on a website or desktop application. I already have a lossless codec for flash, but it's only as good as the source video.

I'm rendering to the same resolution as the source.

[Giroud Francois]

so it seems you edit the source video under a codec that is lower quality than your source.
saving to uncompressed video would not change, since rendering would first create the temporary file under the lossy codec.

[Chris Davis]

How do you select a codec under which to edit? Perhaps this is the piece of the puzzle I'm missing.

[Giroud Francois]

i do not know vegas, but as most of NLE, you have to open a new project , defining resolution and codec you will be working with (usually the same as source).
when you edit is over, you can convert to lower size/resolution for test.
for sure, if you select any preset made for video editing, you probably are on the wrong side

[Perrone Ford]

You do not need to do this with Vegas, and you are not losing anything by dropping the source file onto the vegas timeline. Vegas does not work like Final Cut.

[Seth Bloombaum]

Originally Posted by Chris Davis

How do you select a codec under which to edit? Perhaps this is the piece of the puzzle I'm missing.

Originally Posted by Perrone Ford

You do not need to do this with Vegas, and you are not losing anything by dropping the source file onto the vegas timeline. Vegas does not work like Final Cut.

With Perrone on this one - Vegas has its own internal preview system. Matching project properties to source media produces the best preview results, but is not mandatory. This is what allows you to drop (almost) any media of any resolution on any Vegas timeline and edit. Seems like other NLEs are also now moving in this direction, but Vegas has allowed this from the beginning.

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The task at hand:

Render to AVI, go to the "custom" dialog, video tab, video codec, give a try to TSSC - this is the Camtasia codec, and should give good results for output for your flash encoder. If the initial capture was on a different machine and you don't have the TSSC codec on your vegas PC, I believe the codec is freely available from techsmith.com, either packaged with a player or standalone.

The color-shifting problems I've occasionally had with some screen-capture clips have mostly been solved by doing an intermediate re-render to the same codec. This has been kind of an uneccessarily lengthy process, but proved to be a solid workflow. See color changes in final render - go back and intermediate render 1 or 2 source clips and output final render again - repeat until done!

I've also had good luck with Camstudio, which comes with its own screen codec, similar to Camtasia's TSSC codec.

PS. perhaps you already know this; best appearance is created by working backwards from final output resolution (don't forget to make allowance for taskbar, flash player window border, flash player menu bar) and using that resolution for initial capture, for vegas project resolution, for intermediates (set render rez in the custom dialog and save it as a preset) - use it for everything and never rescale.