quicktime .mov files and youtube

Ken Moffat zarniwhoop at ntlworld.com
Wed Sep 7 08:27:28 PDT 2011


On Wed, Sep 07, 2011 at 11:32:19AM +0800, littlebat wrote:
> 
> I haven't converted video for youtube, but can give you some clues:
> 
> 1, download a video from youtube and check its media information with
> "ffmpeg -i filename", get its video codec and audio codec, fps,
> resolution, etc... Maybe, youtube website has the suggestion.
> 
 Thanks, I'd not thought of this!  Got too hung-up on the "maintain
the quality" suggestions on the recent youtube pages (supposedly,
everything gets recoded for html5).  Some things I've downloaded
(with the youtube_dl Python prog/script) show all sorts of different
codecs, but the video bitrates are typically 3000k or less, and audio
never exceeds 125k bits.  My original .mov files are typically
31000k video and 512k audio (but only 16KHz sampling frequency).

 What I'm doing now is to use ffmpeg to convert .mov to .mp4 with
lower bitrates.  When ffmpeg is told to produce .mov or .mp4 it
converts the input mjpeg with mp3 to mpeg and aac.  Both xine and
totem play these output files correctly.  Maybe I'll even do this in
future for initial review, the outputs are more sensible sizes.

 Still experimenting with bitrates : -b 3000k -ab 64k is as good as
I need [ 3000k+ video bits, nominal 64k audio bits ] but I'm still
playing with the numbers.  Will need to upload an example at what I
think is a good compromise size (my upload is *slow*), then see what
results.

> 2, then, convert your video with the parameters above. If your want the
> close quality as original video, try: 
> ffmpeg -i originalfile -sameq resultfile.avi

 Actually, I did try -sameq when I got the camera, but it wasn't
useful : ISTR the quality was very degraded on the version of ffmpeg
I'm using.

 Cheers.

ĸen
-- 
das eine Mal als Tragödie, das andere Mal als Farce



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