Hi TaaDow,
Thanks for your message.
We had to find a compromise between quality and the resources available on a regular PC. As YouTube will not accept videos over 30fps, we felt that this was a very high quality standard. To double the FPS and also support large frame sizes would not only take significantly longer to render, but the performance hit would be unacceptable on a home PC.
Please see our FAQ - Performance Considerations - for more information: http://www.trakax.com/software/pc/faq/
In regards to a custom bitrate option, we felt that this was adding an unnecessary level of complexity to the application. The bitrate changes dramatically depending on the frame size chosen and we wanted to create a quality (high-quality, average quality etc.) that was applicable and comparable to any frame size chosen. Although this is something we will take into consideration for future releases, we felt that for the ease of use for the average user, having the bitrate already set in the default levels provided would be less confusing.
I hope this answers your query and if you require any further information, please do not hesitate to contact me at any time.
Many thanks,
Catriona