For any given bit rate, the quality will go down as the resolution goes up. Likewise, for any given resolution, the quality will up as the bit rate goes up.
A common misunderstanding is that the size of the player (what people view) is related to the size of output stream. This is simply not the case. The size of the player is set by the player values. How much information is in that player is set by the output resolution.
A good example would be "HD Video". Broadcast TV HD video is transmitted at some 20 Mbps, far beyond what most networks can support and completely unnecessary. In fact, popular web TV systems like Netflix routinely deliver "HD" video at 1 to 2 Mbps.
Here are some guidelines:
- 20 Kbps to 100 Kbps -- use 320 x 240 or 320 x 180 output resolution
- 100 Kbps to 800 Kbps -- use 640 x 480 or 640 x 360 output resolution
- 800 Kbps to 1500 Kbps -- use 1024 x 640 (or use the same as above) resolution
- 1500 Kbps and above -- use 1280 x 720 (or use the same as above) resolution
You may be surprised at how good a high quality 640 x 360 output resolution, streamed at 800 Kbps, will look even when the video player is full screen.