Video

Basic support for adding videos to slides is included in Slidie via the video magic text value.

Warning

Video support in Slidie is relatively limited and comes with far more caveats than other features.

The author would feel worse about this if not for the fact that every other presentation tool seems to fumble video handling in their own unique ways.

Embedded videos are only supported in the XHTML viewer. The user-defined placeholder will be shown in other output formats.

Note

Whilst PDF technically includes support for embedding videos, it is not usable in practice. For example, viewer support is extremely limited and often very unreliable. Implementing video embeddings which happen to be compatible with the already-small pool of capable viewers is also horrendous and involves things like Flash(!) and undocumented Javascript APIs. In short, I’m afraid the author eventually concluded that they did not want to go there, despite serious good-faith efforts to do so.

Inserting a video

To insert a video into a slide, insert a placeholder rectangle or image grouped with a magic text box with one of the following forms:

@@@
video = "<video URL here>"  # Short form

@@@
# Long form
[video]
url = "<video URL here>"
start = 0.0  # Start offset, seconds (optional)
loop = false  # Repeatedly play video (optional)
mute = false  # Mute audio (optional)

Video URLs may point to online resources or be relative URLs to files stored adjacently to the rendered XHTML viewer.

Warning

Slidie does not attempt to embed videos within the generated XHTML output due to browser limitations on data URL lengths. Care must be taken to ensure that local video files are stored and distributed together with the generated XHTML output in the correct relative location.

Warning

Some browsers refuse to play video from plain HTTP (non-HTTPS) URLs when the viewer is loaded from a file:// URL.

The optional start time controls the point at which the video will play.

If loop is true, the video will be restart from the beginning when it reaches the end (even if start is set to a non-zero value).

If mute is true, audio will be muted.

Warning

Due to browser autoplay restrictions, videos placed on the first slide in the show will not play until you first move to another slide and then back again. Videos on other slides should play correctly, however.

Note

Slidie currently does not include any mechanism for controling playback: media will always automatically start from the specified offset upon entering the slide and play to completion (or slide exit, if loop is set). This may be addressed in a future release. In the meantime, some browsers allow you to right-click and choose ‘show controls’.

Automatic video placeholder generation

The slidie-video-stills command will automatically extract a still frame from embedded videos and insert it as the placeholder image for the video.

Usage:

$ slidie-video-stills path/to/slide.svg

Using slidie-video-stills, you can quicly lay out videos your slides using simple rectangle placeholders and later replace them automatically with stills for the benefit of thumbnails and non-XHTML output formats.