wwp@yahoogroups.com:
Re: file size and a significant loss of resolution
Markus Altendorff 2006-Jul-01 10:19:00
northwest_omnipresence wrote:
> Seems I have this problem at every event. I make these huge
> cylindrical panos, (not equirect and not cubic) then spend days trying
> to fit a 32 MB jpeg and a 6-7 MB qtvr into a 700 Kb file. I do not use
> a complicated set up - I shoot with a Nikon Coolpix 3700, in jpg (no
> raw settings as far as I know), stitch it (most times with assistance
> as in this case, thank you very much Bo Lorentzen) and then convert it
> to qtvr, within the size requirements for the WWP.
>
> My pictures always seem to turn out fuzzy when I do it, and then when
> more generous souls in the community offer to help, the photos turn
> out sharp and clear. There are obviously steps I am missing, but I am
> at a loss as to what those steps might be.
Hi Sean,
do you run the original high-res file through your QTVR
converter? I couldn't find the step of "make a resized copy
and create the QTVR from that" - which may be the reason why
it didn't work out for you? Using a 32 MB JPEG as source
requires both a lot of computation on the visitor's machine
and quite low quality in the compression to reach the target
sizes.
For comparison, my own workflow is like that:
1) stitch pano (i'm using Stitcher and 37 shots, but that's
just my config. - yours may very well vary ;)
2) result is an 18000x9000 picture @ 400something MB TIF.
Load it into Photoshop.
3) edit the imperfections of stitching, if necessary (and
maybe patching the floor tile of those fancy spherical panos ;)
4) Save as "raw/uncorrected master file" (JPEG, maximum
quality - for the archive)
5) Edit color, brightness, saturation, running the
pseudo-HDR (Jook's method) - not necessarily in that order.
6) Sharpen excessively :) - most of the time, 300 % strength
and 0.5 (rarely up to 1) pixels radius.
7) Save as "publishable master file" (JPEG, quality 11 of 12
- also, for the archive)
Now prepare for web/WWP delivery:
8) rescale to 6000 wide (x3000) pixels - this reduces pixel
noise, since it's averaging 3x3 = 9 pixels into 1 final pixel
9) sharpen again, see above - for "crisp" look on the web
10) Save as (whatever) - this is only an intermediate file
11) create pano from the 6000x3000 image - choosing cube
face size of 1600x1600 in CubicConverter, with 5x5 tiling
and JPEG quality of 35-50. This creates the "fullscreen" MOV
file.
12) change cube face size to 800 x 800, tiling to 2x2, JPEG
as in 11). This is the "small" MOV file.
I'm not adding a low-res preview. With the tiling, and the
"grid" display, i'm hoping there's enough feedback of
"please wait, download in progress" for the visitor to stay
tuned... also, i'm an occasional ST-TNG watcher [holodeck,
anyone? ;) ]
To reach the target file sizes, i tweak either the JPEG
compression (starting at 50 and going worse, if necessary)
or the cube faces (1600 may become 1500, and 800 could go
down to 500 - but not much less).
Well, that's my workflow. It has worked out well so far.
It's not mandatory, though - and i'm open to suggestions ;)
-Markus