Tuesday, 23 September 2008

Getting ffmpeg to work under ubuntu

I had a fair whack of trouble getting ffmpeg to compile on ubuntu. These are the steps I took that finally got it working for me.

Firstly - I'm going to assume you've downloaded and installed the appropriate libraries (codecs?) for the various audio/video formats that you are going to use (eg lame). I'm just going to cover making ffmpeg actually compile and run.

The usual set of steps will be

  • Downloading ffmpeg: svn checkout svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg
  • cd ffmpeg
  • Configuring appropriately to your build. Eg: ./configure --enable-libmp3lame --disable-vhook --disable-mmx --enable-nonfree --enable-gpl --enable-shared --enable-libamr-nb --enable-libfaad --enable-libx264 --enable-encoder=x264 --prefix=/opt/local --extra-ldflags=-L/opt/local/lib --extra-cflags=-I/opt/local/include
  • make
  • sudo make install

If that all works for you, then brilliant, but for me it fell over while trying to make, telling me it couldn't find x264. For some reason it's necessary to add --enable-pthreads to make it work on ubuntu.

The next big hurdle for me was that a bug appears in the v4l2 library for ubuntu. It doesn’t properly load some of the basic linux types. This is apparently a well-known bug in some of the older linux headers, and will stall the compilation of ffmpeg with a whole slew of bogus error messages, that essentially boil down to the __u64 and __s64 types failing to be defined appropriately.

To make a temporary fix, you can open up asm/types.h (I used find to find it) and figure out where the asm types are located on your distro (for me they’re in asm-i386/types.h).

Now, copy the two lines that define __u64 and __s64 and paste them into:
/usr/include/linux/videodev2.h just above their first use to help define v4l2_std_id

Note - this is an ugly, quick hack, but it should get the compilation going again. For a more permanent solution - I'd suggest chatting to the ubuntu people... or maybe it's time for me to get around to upgrading from feisty ;)

That will generally get you compiled and installed, but I then fell over a run-time bug that boiled down to an error message: “cannot find libavdevice.so.52”. This problem had me stalled for weeks. Google returns a lot of talk about the problem, but very few solutions, but eventually I stumbled across the answer: you need to add a library path to your environment thus:
export LD_LIBRARY_PATH=/usr/local/lib/

Finally ffmpeg safely up and running on ubuntu. Yay!

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