Newsletter #43 - March 5, 2005
Movie
Maker 2 and Photo Story
Encoder Screen Capture
Session - World Wind
The current issue of Wired
magazine has a page devoted to NASA's World Wind software...
after a 179 MB download, installation, and some playing with it, I had
to check how best to use it in a Movie Maker
project.
The software includes a
screenshot feature... that's too easy. Let's go for a video, using either the
Windows Media Encoder doing a screen capture, or a camcorder shooting the laptop
screen.
My first test was a capture
session. That resulted in this 33 second, 2.4 MB file on neptune. It shows you
where World Wind starts... a global view of earth.
World Wind was using 80 to 90%
of my laptop's CPU (2.4 Ghz), and I know that a screen capture session
needs a good bit of CPU energy for smooth video.
My next quick test was my
camcorder shooting the laptop screen as I zoomed from an altitude of
44,645.93 km to 600 meters above my daughter's house. It's too crude a
video to showcase, but it was fun and gives you an idea of what you can do with
the software. The file is 320x240, 7.7 MB, with a 2 minute
duration:
Zoom like that into anyplace
on earth... or glide over the planet like you see in flight
simulation games... but these use actual photos taken from
space.
In this issue,
we'll use the Windows Media Encoder to
capture an area of the screen to get a video clip for Movie Maker,
using the World Wind app. It'll be a mini-tutorial about one feature
of the Encoder.
... before getting
into it, a couple notes...
What's Happening?
My library workshop schedule is being finalized all the way
through next February... alternating between introducing Movie Maker
to beginners and covering advanced topics. I'll add the dates to the bottom
section of the newsletters when they are available.
Pegson's Windows
Movie Maker Archive is a new website (about a month old now).
It's a library of the custom transitions and effects that have been
developed by those who have put a lot of effort into developing them... figuring
out how to tweak various settings to achieve all kinds of neat things. Their
tweaking of XML files is even moving into text clip features. There's been
lots of posts, but Pegson's site is the first to collect all the info and
present it in an easy way for viewing, complete with graphics to illustrate
them.
NASA's World
Wind
A free download, the
NASA World Wind app
comes right from NASA, with an assist from the community of those
involved in the open source software project...
Open World Wind
After a 180 MB download, an installation
that included a couple prerequisite pieces of software, here's the opening
view of the world.
The goal of this newsletter is to use the Encoder to
capture some video from it. The fewer pixels being dynamically displayed
and captured, the theory is the easier it will be to play and capture
smooth movement. For the sake of testing, let me set the bar high and go
for full DVD quality at 640x480. I'll lower the bar if I need to.
Move the World Wind window so it snugs up to the upper
left corner of your computer monitor. It's too big a window when first opened,
but let it sit there as we open the encoder... we'll adjust the size
of the World Wind window to align with an Encoder 640x480 capture
area.
the Windows Media
Encoder
It's a package of utilities, but we'll focus on the encoder
itself, a video processing studio with all kinds of neat features.
With a default installation, the path to the encoder
is C:\Program Files\Windows Media Components\Encoder\wmenc.exe. You'll have
it in your startup menu.
When you open the Encoder, there's a wizard to guide you...
... the first choice is easy - the Capture
screen option
Region of the Screen
If you were putting together an animated tutorial about how to
use Movie Maker, capturing the selected window would be appropriate.
A full screen capture would be used for something like a
video game (if the screen resolution wasn't set too high - I run my laptop at
1600x1200 and never tried a full screen capture... too many pixels for smooth
capturing if there's lots of motion.
The region of the screen is a good
choice for the World Wind app. You can position and size the area so the
capture results in a standard sized video clip - 640x480 or 320x240.
If you were narrating a capture as it went along, you would
opt to include the audio. I'd rather add the narration later in Movie Maker and
let more of the computer's energy go into making a smooth capture.
Set the Area to be
Captured
In this next page of the screen capture wizard, you pick the
area of the screen. 
I did some testing to find the right numbers to enter
when working with World Wind. The coordinates of the top left corner are 10 and
55, and the width x height are 640x480 for a normal DVD sized video.
You can use 320x240 if that's the video size you want. For
this tutorial and some testing I'll start with 640x480.
Opt to have the encoder flash the border of the
capture area during the session... at least during the first test capture
to be sure things are aligned. Beyond that it's
optional.
File Name/Location
In the next page of the wizard, pick a folder location
and give it the name of the video file you'll be creating.
Settings Selection
On the next page of the wizard you'll pick from Low,
Medium and High quality... but it has a tip that you can view (and adjust) the
settings later, after you finish getting started. Let's opt for Medium, not
knowing what settings that means.
Display Information
A wizard page for optional info... title, author,
copyright, rating, and description...
Settings Review
This final page of the wizard summarizes the choices you
made in the wizard, and has an important little checkbox at the lower left -
leaving it checked will kick off the capture session when you click the Finish
button... lets leave it checked and see what happens.
Finish
Here's what happens:
-
It thinks a few seconds
.
-
It gives you this message... an interesting one in that it has
an option to go forward but not to cancel or go back.... so we say OK and go
forward.
-
If you have a file of the same name, it gives you another
message to confirm you want to overwrite it.
-
Going forward, the encoder minimizes itself and you can
tell it's recording the screen area because there's a red flashing border
around the capture area you defined... here's why we wanted that border for
the initial test capture.
This screen shot captured the initial size of
my World Wind window with the red flashing border set to capture
the 640x480 area. What we need to do is resize the window to
align with the red border...
Grab the lower right corner of the window and
resize it... the encoder will continue to record as you make the change.
The red border and pixels it covers are not included in the
captured file, just the area inside the red border.
Capture Session Settings
When you start encoding the Encoder window minimizes and
the area being captured is bounded by the slowly blinking red frame.
When you maximize the encoder, the capturing pauses... and you're no longer
in the wizard. You're in the encoder's main working window. Press the
Properties button to change the
session settings.
There are 9 tabs of settings... note that, at this point,
all settings are grayed out and you can't change them. That's because
you've only paused the encoding; you haven't completed or cancelled
the session.
Click the green Start Encoding
button to continue the capturing and add more footage to the file in
progress. Click the red Stop button to finish the
session. As this was a test encoding to setup the area to be captured,
I'll Stop it.
Once stopped, the encoder will give you a window showing
the Encoding Results for the capture session... info such
as the duration of the capture, the bit rate, frames per second, etc. It's
interesting that it expected an average of 5 frames per second but got only
0.63... so a 2 minute capture ended up with a total of 75 frames, the number
we'd expect in a 2-1/2 second movie at 30 frames per second. I'll be using
those reports during the testing later on.
I had many other programs running during the
setup phase, things that took the computer's energy away from the
session, so it's not a fair assessment...
Let's go into the actual test phase. Press the Close
button for the capture session and all of the grayed options will be
un-grayed, open for changes.
Save the Encoding
Session
An Encoding session is similar to a Movie Maker
project... it's time to save the session file for the first time. Session
files have an extension of .wme (Windows Media Encoder). I named this
one World Wind.wme.
A saved session lets you reopen it the next time
and start where you left off... no need to step through the wizard or do the
positioning settings again. It also let's me put a .wme file on my website
and make it available for downloading, similar to a .prx profile for a
movie.
Close the encoder after saving the session
file... the next time you open the encoder, cancel the wizard window and
use File > Open or select one of your recent session files... in this case
World Wind.wme.
Before opening it again, I'll get ready for some test
captures. My goal is a good looking, smooth playing wmv video clip
when viewed in the Windows Media Player... a standard size to
incorporate into a movie... non-standard would make for a
noticeably egg-shaped world.
Prep for the Capturing
My laptop has a 2.4 Ghz CPU, not low but not high by
today's standards.
Here's what the Performance tab of the Task
Manager shows: World Wind is using 20 to 43% of the
CPU while it's just sitting there with no motion of the earth,
the encoder is open, capturing, and showing the blinking frame...
and using 51 to 67% of the CPU. And 4 other processes are using some CPU
energy.
It's time to turn off other things that
are using or might use some CPU during the capture sessions... we want to give
it all to World Wind and the Encoder, and balance the settings of the 2 apps as
best we can.
I'll turn off (if I can) things I see
using some CPU:
- msimn.exe - I write my newsletters using Outlook
Express. I'll close it and keep test notes on a yellow pad.
- taskmgr.exe - the Task Manager was
running just to get the CPU stats. It won't run during
testing.
- explorer.exe - a basic process that I'll
leave running.
- lsass.exe - a security process that I can't turn
off.
I'll turn off some other stuff to save a bit more
or avoid interruptions:
- the flashing red border of the Encoder during
a capture session was helpful when positioning the world, but not needed
once it's in place.
- switch the WiFi antenna off on the laptop to
disconnect it from the internet and our home network, so it's not
interrupted by instant messages or auto updates.
- shut down the Microsoft AntiSpyware app
running in the background
- close or disable Norton anti-virus
Session
Properties
Going across the tabs of the properties:
-
The Sources are fine... a screen capture with
the 640x480 area defined.
-
The Output file has an appropriate name and
folder location.
-
The Compression tab needs a bit of work. By
opting for medium quality in the wizard, we didn't know we were saying we
wanted 5 frames per second with a video bit rate of 100Kbps. Press the
Edit button and you'll be into something that looks like the
profile editor... because that's what it is.
-
The other 5 tabs don't need any setting changes.
It's time to run some tests to see
what settings work best.
Test Captures at
Various Compression Settings
The worlds been sitting still during
the setup... it's time to give it a nudge so it rotates through the capture
session tests. Press the keyboard's left arrow key a few times to get it going
in the usual direction.
You don't have to play the output file to
see how well you did with your capture session. As soon as you stop a
session, you see this window tallying up the results. That's what I used to
assess the 36 test captures.
The figure shows what you would like to
see... the average bitrate meeting the expected, the average frames per second
meeting the expected, and zero frame dropped.... a perfect score.
The scores I saw were far from perfect. For
this screen shot, I ran a session without World Wind running, just to see a
perfect scoresheet for a 640x480, 29.97 fps, uncompressed video.
Test
Results
When capturing at the
640x480 size, the best was an average
of 4.53 frames per second when I was asking for 29.97. It
was with the V7 codec with a setting of 1000Kbps and a smoothness setting of 85.
Although the best, it wasn't good.
The lowest actual frame rate at that size
was 0.59, using the Video 9 screen capture codec.
I next tried the 320x240
size and did another 14 test captures. The
best averaged 14.55 frames per
second when capturing to an uncompressed file.
The worst at the reduced size was 4.74
fps using the video 9 codec, CBR85, 2000 Kbps bitrate.
The patterns that
emerged were:
-
Capturing at 640x480 didn't give results worth
using. Go with 320x240 when capturing from World
Wind.
-
Uncompressed was clearly better.
Forget trying to find the right codec or the right settings. In 6 tests
without compression, the worst case was 8.90 fps when I gave it a target of 15
fps... interesting that I got better results when I gave it higher
targets of 30 or 60 frames per second.
-
The newer the codec, the lower the actual
frame rate. V7 codecs did better than V8, and V8 better than
V9.
-
A setting of 100 for smoothness versus a lower
target of 95, or a normal setting of 85, didn't seem to make much
difference...
-
The only sessions which resulted
in dropped frames were those using the V9 codec
with a smoothness setting of 100. And the lower the bitrate target
in that group of 6 tests, the worse the performance. The lowest target
bitrate I tried was 100 Kbps, and it reported more frames
dropped than captured.
After looking over the results
and patterns, I did my last and biggest capture test for this
newsletter. 320x240 with lots of world motion, uncompressed, and for a
longer time - 3 minutes, 55 seconds. The saved file was 306+ MB. The
actual frame rate averaged 11.29 and there were no dropped frames. I ran it
through Movie Maker to get a more reasonably sized (13 MB) compressed file and
put a copy on the website to show you... here's the link to
the:
It's the best I could get from World Wind
using the Encoder... but its insufficient frame rate makes it
still not good enough.
Closing
World Wind is a great software package... and so is the
Encoder. But, if I want decent quality video clips from World Wind, I'll setup
my camcorder on a tripod and shoot
footage from my laptop's screen.
The test clip shown in the opening of this newsletter,
taken with the camcorder, was shot in daylight hours, with lots of reflections
going on in the laptop screen... it's best to do it in the dark so
the light source is only the laptop monitor.
Even if you don't get video skimming over your
neighborhood using World Wind and the Encoder, I hope you've gotten
something from the exercise. Get your camcorder ready.
Have a great week...
PapaJohn
