YouTube downloading MP4, Webm and FLV? Options

[Mark the Man]

Hi I am new here and I don't know much about codecs and stuff so I came here to get somethings straight.

So I am downloading couple of videos from youtube via keepvid and I have a couple of option I don't know which to choose from, one of the videos I am downloading is available in FLV 480p, MP4(480p Max) and Webm 480p...

The MP4 one is about (173MB), the FLV (240MB) and Webm about (330MB) my question is webm best since Webm has the largest file size?


Accourding to Wikipedia here: http://en.wikipedia.org/wiki/YouTube#Video_technology , the webm has the highest video bitrate which is 1 and FLV is 0.8-1...

I want to know which has the highest quality in terms of video and audio.

[CoRoNe]

Between MP4 and FLV: FLV for 360p and 480p (there's no MP4 at 480p). MP4 for 720p and up.
For MP4 vs. Webm it all comes down to codecs. H.264 vs. VP8 to be precise. Numerous tests have shown VP8 to be inferior to H.264. But in your case, the 330MB Webm file might even be the one of highest video quality due to the higher bitrate.
Although AAC has a slight edge, 128Kbps AAC and 128Kbps Vorbis are quite on par with eachother according to recent listeningtests.
Webm[VP9+Opus] would be really interesting in the near future.