I've evaluated TVTOOL and have mixed feelings about it.
I'm very happy with the composite video output of the Gainward PowerPack G3 Ti200 Golden Sample, which uses the Conexant CX25871-13 chip. I've watched videos in the 2.2k-2.6k bps streaming rate on my TV and they are clean and very clear.
The only problem I have with Expertool from Gainward is that you have to pass through several steps to switch the output.
With TVTOOL, you have the ability to do this on the fly using hot keys, but the video quality for me was unstable. Maybe it is that the software has a lot of settings, and maybe I missed something (I played with the settings for a couple of hours), or that I was using version 5.5.3 and not the new 6.01 beta (supposed to fix a lot of GF3 issues). I dunno.
I would like to switch the video, and control the CX25871-13 chip via a script, or C++ or C#, but I've yet to find a driver class for it.
That's my 2 cents worth.
Hop