@ Manual
Just use youtube-dl CMD tool so with this you can download all formats also 1080p till 4K.So from FullHD and higher you download video & audio stream separated and after this the tool will merge them together with ffmpeg (just put youtube-dl in same folder so it works automatically).Simple to use and you get what you want also very quick.
So the author of GetFLV could bundle the tools,implement & control tools into his own tool (as boxed files for exsample) so that GetFLV can also download and merge all formats.
I also don't like these brainless youtube restrictions.They want to get all but don't want to give back.
I don't understand why they not just put a simple download button on the page to make the own site more user friendly but instead they choose a other direction what is not traceable in my eyes.
greetz