wwp@yahoogroups.com:
Re: compression WAS Re: i'm in! feedback please...
Hans Nyberg 2005-Mar-27 10:25:00
On Mar 27, 2005, at 10:27 AM, pedro_silva58 wrote:
> for example, to the left of the
> initial view of my pano there's a small tower with a window.
> comparing my big pano with your (smaller) version, yours has lots of
> compression artifacts not present in mine.? many more elsewhere.
> sure, yours is much smaller, but optimal?
> i look forward to further enlightening from the experts ("religious"
> wars aside).
Optimal is always a subjective evaluation you have to do depending on
the way an image is seen.
A QTVR is seen in a short glimpse by the viewer when he pans around. He
does not look into details like you do in a still image.
Also remember that you should try to restrict the view to your actual
resolution.
It is not possible to do that exactly on a fullscreen which adapts to
the screen resolution but many people just let the viewers zoom in to
sizes 3-4 times larger than your actual resolution. You can see
artifacts much more when you do that. You would never look at a still
image in 300%
Remember that the movie I made was a recompression of your already
compressed movie.
You probably also used jpg from the camera.
If you use your original panorama you will see much less artifacts at
the same compression as I used.
It also means that your movie will be slightly larger at the same
compression, thats why I said your optimal size is 700-800kb
40% compression (whatever it is on panocube scale) is from my
experience (10 years digital) the optimal compression for a QTVR
without visible artifacts from most images if you start with an
uncompressed image.
But remember using JPG from the camera always reduces this quality.
Each time you compress you increase artifacts.
Hans
Hans Nyberg
commercial photographer
hans nyberg fotografi
hasselvej 6 DK-8550 ryomgaard denmark
<http://www.hans-nyberg.dk>
<http://www.qtvr.dk>
<http://www.panoramas.dk> Panoramas.dk - Features Fullscreen QTVR
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