Category Archives: UltraProjector

Discussion on using the solid-state UltraProjector ( on a Mac.

UltraProjector (v1) and Mac and ffmpeg

I have previously been able to convert video files to work with the UltraProjector using an old (2006) copy of “mencoder”. I now have been able to do it using the standard “ffmpeg” command. Here are the options, and I will try to clean them up and explain later:

I downloaded the “ffmpeg” command line utility from here:

And these are the options I was using to convert an MPEG4 video file to an AVI file that plays on the UltraProjector:

ffmpeg -i creepy.mp4 -c:v libxvid -vtag XVID -r 24 -b:a 128K -ar 44100 -acodec mp2 -b:v 512k -s qvga creepy.avi

  • -c:v libxvid … use the xvid video converter
  • -vtag XVID … put “XVID” as the video tag inside the file (not sure if this is necessary)
  • -r 24 … 24 fps (higher frame rate may work for simple videos, but may play slower)
  • -b:a 128k … audio quality 128kbits
  • -ar 44100 … audio sample rate 44khz
  • -acodec mp2 … audio codec MP2 (not sure if it handles other formats or not)
  • -b:v 512K … max video bitrate. Experiment with larger numbers for better video, but at some point it will break.
  • -s qvga … output size to 320×240

UltraProjector and Mac

In 2009, I stumbled across a “coming soon” solid state digital projector called UltraProjector. It was designed for use in things like Halloween haunted house. (It was originally $149, but today is $199.) The unit, which began shipping in October that year, was a totally silent, self contained low resolution projector (320×240) with audio output. Simply convert video to the proper AVI format, copy it to the device via USB, then turn and and watch it endlessly project the video clip(s).

I evaluated one of the prototypes and made the decision to order four of them when they began shipping, and we used them in several Haunted House attractions here in Des Moines, Iowa.

BUT, I quickly found out these units were not at all Mac friendly. First, there seemed to be only one program in the known world that could convert files that would play on it, and it was only available on Windows — some AVI Creator program, available as a free download.

(UltraProjector identifies itself as “ROCK MP3” and uses a China made chipset called Rockchip.)

Some intense research showed a secondary program, ViDrop, which could create videos — maybe — and it was a graphical frontend to “mencoder,” an open source converter program that is also available for Mac.

This blog post is just a placeholder to document my attempts to convert video on a Mac to use in the UltraProjector.

A bigger problem, though, is that bogus files on the UltraProjector file system make it lock up. When you plug it up to a Mac, Spotlight takes over and creates a few hidden “dot” files on the USB file system — which then render it dead!

Here’s a quick command line to remove those files. First, open up Terminal and then change directories over to the USB UltraProjector device:

alsmb:~ allenh$ cd /Volumes/NO\ NAME/

If you list the directory there, using the “-a” option, it will show “all” files, including invisible files (files that start with a dot as their first character):

alsmb:NO NAME allenh$ ls -a

. .Trashes Storybook and Audio.avi
.. ._.Trashes
.Spotlight-V100 .fseventsd

There you can see the problem files — .Trashes, .Spotlight-V100, etc. Use the “rm” command with a few options to get rid of them. -R for recursive (so it goes in to each directory, deleting stuff), -d to tell it to remove directories, and -f to force the removal without prompting you each entry for verification:

alsmb:NO NAME allenh$ rm -R -d -f .*
rm: "." and ".." may not be removed

It’s okay that it cannot remove “.” and “..” — those are not real files, but references. “.” is the current directory (so an “ls .” shows where you are) and “..” is one directory up (“ls ..” would be “/Volumes”, in this example):

alsmb:NO NAME allenh$ ls -a
. .. Storybook and Audio.avi

You can see the dot files have been removed.

Up next … experiments with using mencoder to create proper AVI files for the device.

Stay tuned. I just wanted to get this uploaded so Google can start finding it…