Oh, this is great information. I will study
it. Answers a lot of my questions. Thanks so much!
-Bev
----- Original Message -----
Sent: Wednesday, August 17, 2005 11:13
AM
Subject: [videoblogging] Re:
Compression
Regarding your compressed file ending up bigger than your
original:
Your camera creates footage that is already compressed, and
the settings you are using to recompress are for higher
quality/less compression than the original, hence the larger
file.
Bitrate is the key. This tells the compressor how much data space
it is allowed to use per second for the video.
I would start off by
looking at exactly what compression is used in the files your camera
creates. Load a mov that came from your camera into quicktime and go to the
window menu and select 'show movie info'.
Format, FPS and data rate are
the important ones, if you let this group know what they are, can give you
more specific advice.
Also if you see someone elses video that you like
the looks/filesize per minute of, then you can do 'show movie info' on that
and find out what bitrate etc they use. Unfortunately things can get a bit
more complex than this because theres all sorts of other options in
the compressor software, factors that can affect how good the video
looks and how much it honours other settings like the bitrate youve
chosen.
For example your camera might create videos that are mpeg 4,
320x240, 12FPS and a bitrate of 256k. If that were so, there would be no
point in recompressing at a higher resolution, framerate or bitrate,
because you wont gain anything, just end up with larger files.
The
same applies to audio, if your source footage is mono 24khz 64kb then there
would be no point recompressing to 24khz stereo 128kb
or whatever.
Regarding files being much larger than other
videoblogs:
If followed fully the guides for compression that are on
freevlog should suit most people, it shouldnt create files that are way
larger than most videoblogs out there. So if you end up with really
large files, either you made a mistake with the instructions, or theres
a bug in some part of the process (for example if you used 3ivx
to compress with qt7, it seems theres a bug so it ignores your
bitrate settings and you could end up with much larger files than you
should).
The only limitation with the guides is that they are (by
design) quite general, they have mostly been used by people using DV
cameras where the original videos are very huge (13 gigabytes per hour)
because DV isnt compressed as much as cameras that use mov, mpeg4 etc. So
pretty much whatever setting they use for recompression, it will be a
lot smaller than the original. And if they recompress with high
bitrate then the footage will look better than with low bitrate. But if
your camera only records at a low bitrate in the first place ther is
no point recompressing to a higher one, as I said earlier. This isnt
too much of a problem as the guides use a fairly low bitrate anyway,
but Id still like to know what settings your camera uses to give you
the most optimised settings for your setup.
Oh dear I hope my waffle
hasnt made things more confusing. If in doubt you could upload some really
short clips to the net and I'll happily take a
look.
Cheers
Steve of Elbows
--- In
videoblogging@yahoogroups.com, "BevSykes" <[EMAIL PROTECTED]> wrote: >
I had actually checked out that tutorial and have done some compression in
WindowsMedia (cumbersome because I have to convert from .mov, which comes
from my camera, to .avi so that it can be read in Windows Media. That
compression works but the files are then .wmv files and I note that, at
least Our Media, seems to prever Quicktime (.mov). (Though I've just
checked blip.tv and see that the preferred format seems to be .wmv) >
> -Bev > ----- Original Message -----
> From: Michael Verdi > To:
videoblogging@yahoogroups.com > Sent: Wednesday, August 17,
2005 8:32 AM > Subject: Re: [videoblogging]
Compression > > > Hi Bev, >
Check out the tutorials at: http://freevlog.org/#compress >
Sounds like you want the one for iMovie (even if you're not using
> iMovie - the QuickTime part will be the same). >
> -- > Verdi > http://michaelverdi.com >
http://freevlog.org > http://graymattergravy.com >
> > On Aug 17, 2005, at 11:24 AM, BevSykes
wrote: > > > Hi there. I'm new to the group,
new to vlogging, and am trying to > > figure out
what I'm doing. My most pressing question is about file
> > size. I just downloaded one of the reports
from Rocketboom, which > > is 4+ minutes long and
20 MB in size in Quicktime. I recorded > >
something not quite as long yesterday, in Quicktime and it was 120
> > MB in size. >
> > > I recently upgraded to Quicktime7 Pro and tried
its video > > compression utility where it
efficiently converted a 20 MB file to > > a 46 MB
file--isn't the compression supposed to go in the OTHER
> > direction???? >
> > > I know that I don't have 1/1000th the expertise
you guys do and > > don't expect to actually
contribute much to the discussion, but I'm > >
hoping to learn from you, and if I can just get the file size to be
> > reasonable, I'll be a happy camper. At present
I'm uploading > > things to OurMedia and so far
haven't had enough problem to think > > about
moving to a pay site (and until I actually produce something
> > that's worth seeing, OurMedia seems to suit my
practice videos just > >
fine). > > > > I'm one of those
senior citizens, like Steve Garfield's mom (though
> > not quite that old), who is trying to figure out the
new technology. > > > > Thanks for
your help. > > > > Bev
Sykes > > > > YAHOO! GROUPS
LINKS > > > > Visit your group
"videoblogging" on the web. > > >
> To unsubscribe from this group, send an email
to: > >
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the Yahoo! Terms of Service. > > >
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