Author Archives: Multimedia Mike

64-bit Builds Are A Go

Please join me in welcoming the newest member of the FATE build farm: a 64-bit Ubuntu Linux session for pure 64-bit builds. The machine is actually a Mac Mini Core 2 Duo 2.0 GHz running VMware Fusion. Ideally, it would be nice to use the same machine for Mac OS X autobuilding and testing. Per my understanding, however, the base FFmpeg tree is not immediately build ready due to a conflict with the gcc version shipped with Apple’s default Xcode environment.


Apple Mac Mini

A pristine, dignified, stylized piece of Mac hardware, and what do I have it doing? Farm work. I also got the Mac Mini to try to delve into this Mac OS environment and see if it could possibly win me over as a full time user. That part isn’t looking too hopeful at this point, but I’m sort of committed to the FATE Server aspect now.

Rejected Ideas

People have provided a lot of useful and constructive feedback, both publicly and privately, regarding the developing FATE Server. I’m not taking every idea seriously, however. For example, several people have suggested that the build machines should trigger off of emails to the mailing list that monitors FFmpeg SVN commit messages and only check out new code and kick off new build/test cycles in response to such mails. Since the SVN server is responsible for sending the emails, the flow looks something like this:


A complicated protocol loop

Really, this post is merely an excuse to make more illustrations using OpenOffice’s Draw component. Anyway, the current FATE system operates by polling the SVN server periodically for updated revisions (where period=15min); it also checks again immediately after completing a full build/test cycle. In this case, I can’t justify adding the coding, debugging, and maintenance complexities of having the script poll the server somehow (or even have emails pushed via IMAP), parse the emails, and determine when to ask SVN for new source, when the periodic poll process performs peachy. Thus, one box and two arrows are eliminated from the drawing entirely.

One person who has a lot more experience in web database apps than I do was appalled that I was going the simple route by using the Python MySQLdb module to access the FATE Server’s MySQL database directly and insert new build records and test results. Hey, it’s the simplest solution, and my web provider allows me to do it.


Straight MySQL Protocol

Apparently, it’s trendier for modern apps to travel along a more circuitous route. This means, rather than use the most direct protocol, package the data in some intermediate format — often an XML-based format — and send it along an HTTP transport. Common candidates for the task include XML-RPC, REST and SOAP. Ad-hoc protocols are also possible.


A more roundabout protocol

At first, this went right into the ‘reject’ bin as well. I may need to rethink that, though. I am lining up helpful souls who wish to lend their own custom hardware resources to this effort so that FATE (and FFmpeg, in turn) can enjoy broader platform support. It turns out that Python-MySQLdb does not work equally well on all operating systems. Hopefully, Python’s built-in HTTP libraries will work well enough that I could build my own ad-hoc protocol (no XML, thanks) if need be.

Working With Git

I want to be responsible and organized as I develop the FATE Server. To that end, I thought it would be good to get all of the project source code into a source control system. Since Git is building momentum, I thought this would be a great opportunity to get my feet wet (similar to how this exercise has been a good reason to learn Python).


Git logo

I’m pleased to report that Git is performing admirably. It’s important to remember, however, that I have low standards when it comes to source control. Indeed, any SCM is equally adequate when you’re working by yourself on one machine. Git still keeps the easy things easy: git init, git add, git commit, git diff, git log; that’s as deep as I have delved thus far. At least I will have a baseline of experience for when I get actively involved with a project that uses Git, which is where many would like FFmpeg to go one day.

Clientside MySQL Compression

I figured out yesterday’s problem and the upshot is that x86_32 builds using gcc 2.95.3 have been reinstated for the FATE Server. So the nostalgic, sentimentalist users of FFmpeg should be happy to know the test suite is still being run through the old school compiler.

For reference, this is how to compress data using Python so that it will be suitable for insertion into a MySQL table (and so that MySQL will be able to decompress it with its built-in UNCOMPRESS() function):

It can make an impressive difference, particularly with highly redundant text as is seen with compiler output. For example: