====== Vorbis speech compression ======

[[https://xiph.org/vorbis/|Vorbis audio format]] is suitable for effective speech compression (note that this will also downmix it from stereo to mono).

''oggenc'' (command line tool) //parameters// for speech compression with best size/quality ratio:

<code>
smallest file, lower quality:
-q 0 --resample 22050 -S 1 --downmix --advanced-encode-option lowpass_frequency=6

small file, better quality:
-q 1 --resample 22050 -S 1 --downmix --advanced-encode-option lowpass_frequency=8
</code>

''oggenc'' is part of package [[https://packages.debian.org/stable/vorbis-tools|vorbis-tools]].

__Sidenote__: [[https://opus-codec.org/|Opus audio format]] is generally more effective for both music and speech, but player support is a bit worse compared to Vorbis.