I then reviewed their file size, for some reason I saw little
difference in them. For example:
Video set to 50kbps max:
http://www.andycarvin.com/video/demo-3ivx50.mov
video set to 25 max:
http://www.andycarvin.com/video/demo-3ivx25.mov
But the difference in file size was marginal: 1.6 vs. 1.4 megs.
Meanwhile, if I didn't set a max bit rate, the file was only 1.8 megs.
I tried to spend some time figuring out what was behind this, but it
started eating up my entire day, so I decided to drop it and post what
I'd already figured out (not to mention the fact that I'm supposedly
launching a new blog on Thursday and should be working on that).
Perhaps the issue is that the files were so small already that setting
a max bit rate offers marginal change at best? Maybe I should do this
again with larger files so the bit rate difference is more noticeable?
thanks
andy
--- In [email protected], "Michael Verdi" <[EMAIL PROTECTED]> wrote:
>
> Hey Andy,
> I just looked at your post quickly and noticed that you didn't seem
to limit
> the bit rate on any of those clips. By limiting the bit rate you can get
> very similar results at much much lower bit rates.
> For example - take your smallest clip. You compressed it using 3ivx
at 160 X
> 120 pixels, 15fps but the bit rate is 420kbits/sec - about 8X too big to
> progressive download over a dialup modem.
> Here's a video that I did last year as a test to see what what
videoblogging
> would look like on dialup. I used 3ivx, 160 X 120 pixels, 8fps and I
limited
> the bit rate to something like 33 kbits/sec.
> The result is my 45 sec video comes in at 271K (48.77kbits/sec)
while your 5
> sec video comes in at 285K (420.28kbits/sec).
>
> I think the idea of doing a compression matrix with a single test
clip at
> set bit rates is a great idea. I'd love to help put one together using
> mpeg4, 3ivx, h.264, windows media 9, and Flash 8 - using single and
double
> pass where available.
>
> -Verdi
>
> On 4/25/06, Andy Carvin <[EMAIL PROTECTED]> wrote:
> >
> > Hi everyone,
> >
> > One of my vlog viewers asked me for an explanation of various
quicktime
> > compression techniques. I've just published my response:
> >
> > http://www.andycarvin.com/archives/2006/04/andys_video_blogging.html
> >
> > In this demonstration, I start with a 10 megabyte video shot in avi
> > format, 30 frames per second, 640x480 pixels, 16 bit stereo. I then
> > produced seven compressed versions of it, including ones that utilize
> > varying frame rates, screen sizes, compression codecs, and audio
> > compression. The most compressed version I created is 97% smaller
than
> > the original avi video, and is potentially quite suitable for video
> > blogging in low-bandwidth situations around the world. Some examples:
> >
> > Original uncompressed video (10 megs):
> > http://www.andycarvin.com/video/demo-nocompression.avi
> >
> > Significant compression (1.8 megs, 82% reduction):
> > http://www.andycarvin.com/video/demo-3ivx.mov
> >
> > Extreme compression (292 bits, 97% reduction):
> > http://www.andycarvin.com/video/demo-3ivx8bit160.mov
> >
> > Here's a chart featuring all of the videos and their settings:
> >
> > http://www.andycarvin.com/compressiontable.html
> >
> > Hope this is useful,
> > andy
> >
> >
> > --
> > ------------------------------
> > Andy Carvin
> > acarvin (at) edc . org
> > andycarvin (at) yahoo . com
> >
> > http://www.digitaldivide.net
> > http://www.andycarvin.com
> > ------------------------------
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
>
>
> --
> Me: http://michaelverdi.com
> R&D: http://evilvlog.com
> Learn to videoblog: http://freevlog.org
> Learn to videoblog in person: http://node101.org
>
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