Formats and conversion tools

recordmydesktop saves exclusively to Free formats (Theora for video and Vorbis for audio).

A general tool to convert from one format to another is ffmpeg. You can use it like this:

ffmpeg -i input-file.ogm -vcodec libx264 -b 2000k -t 5 output.mp4

Note that the -ss option does not seem to work with Theora encode streams.

Avidemux is a nice application to split and edit streams, with a GUI. It cannot read Theora encoded videos yet though.

To split or generally work with Theora videos, the applications are in the Gentoo package liboggz. Extracting part of a Theora video does not reset the time counter to 0 which is strange. Also, mplayer does not read well "non-canonical" Theora videos (for example ones extracted and that do not start with a keyframe). VLC is better, but generally speaking, support for Theora is quite buggy in a lot of tools.

Applications for video edition

Kdenlive seems to be a very good application. It can export to a lot of different formats, and take any format as input.
Reading from Theora seems to be buggy.
A very important concept in Kdenlive are the project profiles. Here you define the target resolution, Pixel Aspect Ratio and Display Aspect Ratio.

If you want to import a video or audio file, use "Project -> Add clip". But the project settings (profile) should be correctly chosen first (resolution, number of frames per second) and they should usually match the source clip. If they don't you can expect distortions (either on the resolution or the time span of the rendered file).
Once the clip is added, it's very important to drag it to the V1 or the V2 track in the project bin! You can start to work on the movie only once this step is done.
There is a "clip monitor" preview that I don't really understand and don't find useful. You can hide it in "View -> Clip Monitor". I use only the Project Monitor as a preview.
Removing part of a video file (or audio file) is easy, you can use the razor tool (X). Click on the start point on the video track, then on the end point. You can then delete the item between those two markers (choose the select tool, right click then Delete item), and then use "Remove space" if you want to shorten the rendered file.

When exporting to Flash video from Kdenlive, it is crucial to create a project profile that has the exact same data as the original source. Eg, PAR, DAR and resolution should exactly match those of the original source. This is because Flash video are not anamorphic (eg, rescaling is not possible to adapt to some given size).

The best way seems to be to use ffmpeg -i filename.avi. It gives you lots of useful data, such as resolution, DAR and PAR.

Youtube limits the duration of a video to 10 minutes and upload size to 1Gb. You can add fmt=22 as a parameter to the URL to get the video in HD. When embedding you need to use "&ap=%2526fmt%3D22" in the URL.

blip.tv seems a very good service. There is an upload counter when you upload a video, which is very nice, and they accept Theora videos.