Andrea: Thanks for the manual updates - I was secretly hoping you would do this !

I certainly was unaware that "cuda" was a pixel format but when doing "ffmpeg -pix_fmts" it shows up.  No idea what it does.  When we get back to cuda/driver upgrade, I will have gg try it.  That could be fun.

The new "Format" button of the Render window as seen under the Video wrench shows "private" options that can be passed to an underlying muxer.  When you click on the Format button, you also have to click on the subsequent "view" button that popups to see them and like the view option in the Preset menu, when you highlight one of them, a yellow tooltip shows up in the lower right hand corner with 1 line of information if available. I believe most can be used on the ffmpeg command line if you ran from a window.  For example, one of these for mp4 is "moov_size" and that is effective.  If you look at section 21.18.1 in     http://ffmpeg.org/ffmpeg-all.html   these are the ones you will see for mp4.   Or for mp3 of that url in section 5.3 as:

        "For example to write an ID3v2.3 header instead of a default ID3v2.4 to an MP3 file, use the id3v2_version private option of the MP3 muxer"

In other words, these muxer/private options are all over the place to try and learn about them.

This should be documented in the manual (so I don't have to try to figure it out when I forget!)