[SOLVED] Youtube streaming videos

[BSPeter]

As mentioned under item (3) of my Help2help-post ...

... also make sure to mention in your post which codecs/filters BSPlayer really uses for playback: this is shown by BSPlayer (with a video file loaded!) under (Rightclick >) "Options" > "Filters" > (Advanced);

The issue you reported concerned

Originally Posted by Flesh

... trying to use Youtube streaming....

so your addition about files downloaded to your HD using other programs

Originally Posted by Flesh

...P.S. - is it possible that the issue might be that if I download video from youtube (with other programs), at 480p I get FLV aka flash file while on higher resolutions I get mp4 files.

is not directly connected, but indirectly I personally think it probably is (see item (2) below).
Why don't you use BS.Player Pro to download? (When the url is playing ... rightclick > Save as...)
(1) BS.Player also downloads HD movies as .mp4 and videos below 720p as .flv, simply since YouTube uses those video-formats/filetypes for such files.
(2) BS.Player can play both .flv as well as .mp4 videos;
what may be important is the (different) filter(s) used for playback of those different fileformats.

P.S.:
When you installed BS.Player, did you allow it to also "internally" install its preferred filters/codecs? (Internally meaning only for use by BS.Player itself and not interfering with your system's codecs/filters.)