I will try to explain what you need to do to get best possible quality for You tube 3D videos .
From beggining my advice is, do not go lower than 720P ( 1280X720 ) resolution.
I don't know when but You tube changed the bitrates and now HD looks little better.
FullHD 1080P ( 1920X1080 ) is AVC 6000+ Kbps with audio 152 Kbps.
I recomend to encode video to 6500 Kbps with audio 160Kbps.
This way you will have best possible quality after You tube reprocess the video.
You can make 720P ( 1280X720 ). Format is the same.
Only diference is video, reprocessed to 2800+ Kbps.
But i would not recomend it. Let me explain why.
3D video requires 2 cameras. One for the left and one for the right eye.
So, if you want FullHD 3D that means that we will have video that is big 3840X1080 pixels.
You tube do not support that format and now, what we need to do?
We need to split FullHD format in half.
There is 2 option, Over/Under or Left/Right.
Personally I choose Over/Under simply because i have 3D camera that records interlaced video.
Interlaced video is only 1920x540 pixels. By that logic i do not "lose" any pixels.
Only higher compression on You tube.
You can go with any of this 2 formats you prefer.
Some pictures and examples:
Formats:
Side L/R
Over/Under
Bit rates:
And video for example:
