going to happen is probably a bit of back or neck ache as you
make those small adjustments to your characters.
>> Your recording of the movie should follow this simple
procedure: Set up scene > take shot > move character/
object(s) > take shot > move character/object(s) > take
shot. This should continue until your movie is complete, or
you’re ready to take a break.
>> Because every image is saved into the same folder
with an individual file name, stopping and then restarting the
following day should not be a problem. Nothing is likely to be
overwritten, for example.
>> When you’re ready to stop recording the movie, press
Ctrl-C on your Pi’s keyboard. This terminates the stopmotion.py
program and closes the preview. With the movie complete,
it’s time to compile those hundreds or thousands of individualimages into a single movie file. Before you do that,
however, it’s a good opportunity to look for any images
that didn’t quite work out.
>> For example, if you took multiple attempts at a
particular shot, you can delete the ones you don’t want
(or move them to another directory). It’s also a good
chance to get a look at the overall movie in a sort of
“filmstrip” view. This reveals whether the lighting is
consistent, for example, or if your camera has drifted or
been obviously knocked when shooting. In some cases,
it might be possible to retake a shot if it is particularly
poor. However, it may be easier to simply drop the image,
and hope for the best.
>> When you’re ready to compile the images, browse
to the “/stopmotion” directory within the terminal (or
press F4 from within the desktop file manager to open a
terminal). Then run:
avconv -r 15 -i stopmotion/frame%03d.jpg -qscale 2
animation.h264
>> Wait while the process completes. Keep in mind
the relatively low specification of your Raspberry Pi,
and the fact that it is essentially creating a movie in high
definition. This may take a while, so go and recover—
maybe have a good shoulder rub.
>> The completed file “animation.h264” can be
run in your preferred media player. For instance,
to play in the Raspberry Pi’s omxplayer, use
omxplayer animation.h264
>> Find the video is a bit jerky? Then try altering
the frame rate and recompiling it, represented in the
avconv command with the -r 15 value. The higher
the figure, the smoother the animation. Note that the
animation also becomes shorter as you increase
the frame rate.5
SHARING WITH THE WORLD
W ith your mov ie completed, you may w ant to “um”
and “ahh” over the problems. Or you might prefer
to just get it out there to find out what people think of it.
>> Pretty much anywhere to which you can currently
upload movies is suitable. Better still, as the movie is
probably only a few seconds long, it won’t take long to
upload—so you can think about uploading the stop-
motion movie to YouTube, Facebook, Twitter, and so on.
>> Alternatively, you could upload it to your preferred
cloud storage account. From here, it should be easy to
access it from your mobile device, then upload the file
to Instagram, say.6
AUDIO!
One shortcoming that you will have noticed with
the creation of a stop-motion movie is the lack of
sound. You have two main options to get around this.
>> The first is to load up a desktop video-editing suite
on your main PC (your Raspberry Pi probably isn’t up to
it!). Import the stop-motion video and add a soundtrack.
This might be audio you already have saved to your PC,
whether that’s music or sound effects. Alternatively, you
could record some custom sound effects or dialogue to
accompany the action.
>> However, there is also the option to add audio when
you upload the video to YouTube. The Creator Studio
enables you to add sounds from YouTube’s library of
royalty-free songs. The selection is pleasingly vast, so
choose carefully!CANOTHER
PI TUTORIAL
NEXT
MONTHShadows can ruin even the best stop-motion animations,
yet this problem can be easily avoided with a bit of forward
planning. Lighting is the secret, but you need to avoid
relying on daylight or a standard ceiling light. This needn’t
cause you to break the bank, either; small LED lights
perfect for this can be bought for just a few dollars.
Positioning the lights to the left and right of the
animation “stage” enables you to cancel out any shadows
cast by you or the camera. If you’re animating with objects,
toys, or modeling clay, a third light from above also helps
to cancel out shadows.
With the shadows banished, you should also ensure
the white balance is set correctly. If you’re using the
recommended PiCamera software, auto white balance will
probably work.
You can adjust this yourself by altering the awb_mode
property, which by default is set to awb_mode=auto.
Alternatives include sunlight and cloudy , though
tungsten , fluorescent , and incandescent are set for
typical indoor lighting temperatures.
Meanwhile, you can even go as far as to disable awb_
mode with the off setting. You can then specify a precise
awb_gains setting (between 0.9 and 1.9). Consistent
lighting results in a better stop-motion movie, so take the
time to set this up accurately.LIGHTING BALANCE
58 MAXIMUMPC JUN 2019 maximumpc.com
R&D