I’ve just fixed some missing links on the LCA video site, so all the talks are now online – yay!
It’s been an interesting experience, which is still not finished. I’m working on collecting all the slides for the talks and putting them into a common format (probably both pdf and odf). Jean-Marc is still working on transcoding the videos to speex (speech-only). And then there are all the annotations that we received through the irc channel, which I’d like to publish onto a cmmlwiki together with the videos.
It will all come in good time. The hardest and most important task were the videos.
I think we found a good formula this year to make the videos happen. DV tapes are impossible to handle. Recording to DVD provides a good backup straight away and a simple storage means. It could be further simplified if recording was done straight to disk and everything handled as files only, which is the way in which the DebConfs were done. But then – I am a big fan of having physical, high-quality backups.
Here’s a little FAQ for those annoying recurring questions:
- Why are there not all miniconf talks present?
We did not aim to record Monday and Tuesday, but rather used them as testing days for the equipment and the team. Therefore, having any video at all from the miniconfs is a bonys.
- The sound is rather quiet on some videos – can you fix that?
Unfortunately, some days came out really quiet and it will take a lot of post-processing to fix this. We don’t have the time and people to undertake this. So, just turn up your speakers, the volume on your desktop and on the application.
- What software did you use to transcode and publish?
We are only publishing the video in the open and free Ogg Theora format. Since we recorded straight to DVD, all we had to do thus was to rip the DVDs using
"vobcopy"(with the “-l” option in order to get all the pieces on the DVD stiched together). If the resulting vob file consisted of multiple sessions, then the timing restarted in the middle which confuses transcoding. So, we used
"avidemux"to recreate a correct MPEG_TS (transport stream). The resulting vob file was transcoded to Ogg Theora using a
ffmpeg2theorascript and finally uploaded to the server using
"scp"with the “-l” option. On a fast machine and a fast connection, each of these steps is faster than realtime (i.e. takes less time than the duration of the video). My slowest process was the upload, which I had to do over night in batch from my home ADSL connection.
- How much space do the published Ogg Theora files use?
Using the “-p preview” option of ffmpeg2theora provides you with 384×288 video at 25 fps for PAL recordings. The size in bytes varies a lot between the files. Our largest file is about 257MB and is from a 1:23 hrs long talk. Our shortest file is about 10MB and is from a 6 min long talk. Overall we’re using 11.9GB of disk space for 141 files. That comprises only the Ogg Theora video files. The vob files are a bit more than 10 times the size of a Ogg Theora file, so we don’t keep them on the server.