Encoding Videos

To create a video, make an .xaf file first (the easiest way to do this is to use the record function in the File menu). Then you need to render the animation. XaoS can output sequences of ordinary PNG images that can later be used by a video encoder.

Generating Images

To generate an image sequence, choose Render Animation from the File menu. You can also use the following command on the command line:

xaos -render [filename] -size 352x240 -antialiasing -renderframerate 24
-basename [basename]

File to render ([filename]) is the name of the .xaf file, Basename ([basename]) is the name used as the base filename for rendered images. This should also include the path where you want to save the images. XaoS adds a sequence number and .png extension to this name automatically.

You might also want to change the resolution. Make sure that the resolution you choose is supported by the video codec you wish to use.

The framerate can also be altered. Make sure you choose a framerate that is supported by the video codec you wish to use.

Antialiasing (-antialiasing) is used to produce smoother images. It takes a much longer time and much more memory to calculate them, but resulting images are better for video compression and they result in a much smaller video file.

On the other hand, the other XaoS rendering option Always Recalculate (-alwaysrecalc), which disables XaoS's zooming optimizations, is not recommended. If that's used, the sequence of animation then contains quite a lot of extra information, which increases size of video file, but because of the codec's lossy compression it is hard to see any difference, so it's not worth it.

Once you start it, XaoS will generate thousands of frames. They take quite some time to calculate and save, and consume plenty of disk space.

All images are named [basename]framenum.png. For example intro0001.png is the first frame of the animation intro. If consecutive frames are the same, XaoS will either create a symlink (on Unix or Mac OS X) or save another copy (on Windows).

Encoding Videos

Once XaoS has generated the .png files for each frame of the animation, you can use a third-party video encoder to convert the sequence of images into a video file. We currently recommend the following encoders, which support a wide variety of video codecs and file formats:

• ffmpeg; Instructions
• mencoder from mplayer; Instructions