Ogg Support: Next Steps

Purpose of the 1.0.5 release was to get a decent feature set to Extras repository before the Maemo Summit. There are still some bigger issues to be fixed in the future releases.

Bugs

There’s a product for Ogg Support at the Maemo Extras Bugzilla. I’ve added the major issues there but do report any other issues you find.

Tags

Media Player and File Manager depend heavily on the open source Tracker for the meta data. Tracker has different meta data extractors for different mime types. GStreamer extractor is used by default for all audio/* and video/* mime types. The gstreamer extractor uses tagreadbin for getting the meta data from the media files.

For better efficiency tagreadbin uses only parsers for getting the meta data. Decoders may need e.g. separate DSP hardware, so using decoders for getting the meta data could be a very slow and heavy process.

Unfortunately Vorbis and Flac tags are not in the container and need a decoder for parsing them. Tracker provides a separate extractor for Vorbis that’s now packaged separately for Maemo by Ivan Frade. That’s not “product quality” and shouldn’t be used, so a proper solution will replace that one. The work for getting a tag parser for Vorbis and Flac to be used with tagreadbin has already been started. Hopefully the patch will be attached to the Gnome bugzilla at some point.

Gstreamer’s playbin(2) element reports tags while playing the media file and this already works with Vorbis and Flac. MP and FM need to know the meta data before they start to play the file but e.g. the Media Widget on the Desktop seems to get the tags from the playbin2 as it shows the tags for Flac as well.

Performance

The Vorbis decoder from xiph.org isn’t as fast as the FFmpeg’s Vorbis decoder on the n900.

There weren’t any GStreamer plugins for the FFmpeg’s Vorbis decoder until Felipe implemented one. The gst-av is still missing some features that need to be implemented before it can be taken into use, mainly tags and streaming.

If you are interested in the topic, I’m sure Felipe would be more than happy to apply patches :)

I’ll report numbers about performance comparisons between MP3 and Ogg later.

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