Video Metadata

I’ve been playing around with extracting some metadata from videos in Ruby on Rails, particularly using RVideo (an ffmpeg wrapper) and a Mediainfo wrapper I found on github. Initially I was excited about RVideo, because it has some support for transcoding and stuff, but the version I found on the Google code page didn’t work well with my ffmpeg install, and using ffmpeg to get information about a video isn’t the cleanest technique to begin with.

Installing mediainfo on Debian is pretty straightforward.

wget http://downloads.sourceforge.net/zenlib/libzen0_0.4.2-1_i386.Debian_5.deb

wget http://downloads.sourceforge.net/mediainfo/libmediainfo0_0.7.16-1_i386.Debian_5.deb

wget http://downloads.sourceforge.net/mediainfo/mediainfo_0.7.16-1_i386.Debian_5.deb

sudo dpkg -i libzen0_0.4.2-1_i386.Debian_5.deb

sudo dpkg -i libmediainfo0_0.7.16-1_i386.Debian_5.deb

sudo dpkg -i mediainfo_0.7.16-1_i386.Debian_5.deb

sudo gem install greatseth-mediainfo

Then, I added a line to enviroment.rb, right before Initializer.run block:

require ‘mediainfo’

I think I should be able to use config.gem ‘mediainfo’ or something like that, but I couldn’t get it to work.
Now, I can do something like

@file = Mediainfo.new @video.base_path + @video.public_filename

and something like

@file.height

to get much needed information.

If you haven’t install a gem from github before, you might need this page: http://gems.github.com/

Logo & Branding

I was a bit tired of the name “Open Source Video Managment System” and “Digital Video Server” doesn’t sound much better. Both of those do a much better job describing what my project does, and don’t really establish an identify for it. Kind of like “Digital Signage”, the first name we worked on the Concerto project…. describing what our system does, yes… but not really establishing an identity for it.

So I asked Katie Boudreau, one of the more graphically inclined people I know, to come up with a logo and name for my project that was a little more unique than I might come up with. You can check out the logo at the top of this page, I think it came out pretty great!

Now I need to come up with an answer if people ask “Why did you choose the name Bonsai video?”.

Week 2 Slides

Here are the slides I presented this week at the RCOS meeting. I got some good feedback about the meta data and search functionality. I broke rails on my development server this morning (accidentally chowned /var) so I’ve got to spend another 2-3 hours fixing that. I suspect I’ll have some code committed to git next week when I’ve got some basic upload stuff working.

To database or not to database

For the past week or so I’ve been thinking about the storage of video files, and how to implement a storage system that is fast, effecient, secure, and reliable. My big question here is to use a database or not to use a database. I’m likely using MySQL for everything else, but video files are a bit larger than you VARCHAR(255) or even larger than a photo gallery image I’d store in a database. I’m concerned that throwing video files, ranging from 100MB to 5GB in a database might start to slow things down… which I really don’t want to happen. On the other hand, I can’t afford to have video files laying around in violation of a database foreign constraint, which might happen if a user deletes a video and the file delete fails (maybe its in use).

I’ve done some work storing large datasets in MySQL, but no work storing >25MB in a single field. Of course there would have to be a seperate media table, to prevent a stray ‘SELECT * FROM videos’ fr0m crashing the whole thing. but that still doesn’t convince me it will be as fast as it needs to be.

Another nice plus on the filesystem side is the mod_flv and mod_h264 streaming plugins for Apache. I know you can write a version of the flv streaming module in PHP, but I don’t see it having the speed of an Apache plugin.

I think ideally I’d like to store videos in the database or using something besides the regular flat file approach. Using Ruby on Rails might make this a moot point from a programming perspective, attachment_fu easily handles both file and database datastores.

If you have any experience storing large files in a database, I’d love to hear about it.

Week 1 Slides

Here are some slides detailing the project objectives and timeline. I’m unsure if I’m going to be able to make it to the Friday meeting, but I’ll be continuing to make progress over the weekend. Hopefully mid/late next week there will be some code pushed to git for all to see!

Greetings.

Hi everyone! I recently heard back from the RCOS leaders and my proposal has been accepted for development of an open source digital video server. In the next few days I’m going to be working out a rough schedule and getting my hands dirty with some code. As soon as I’ve got more to share I’ll post it here!