[opus] Opus Radio Stream
giles at thaumas.net
Thu Dec 26 17:43:23 UTC 2019
On 2019-12-26 9:07 a.m., Jeron Lau wrote:
> I tried looking at the Icecast source
> code, with no luck - it doesn't seem to depend on any of the opus
> libraries, but implements it itself (Although, I might be wrong).
IIRC icecast reimplements the few packet inspection functions it needs
to avoid adding libopus as a dependency. It doesn't need to actually
encode or decode so it saves a lot of unnecessary code in the deployed
application. You can of course use the `opus_packet_*` functions from
Icecast-style streaming encapsulates Opus packets in a Ogg container
stream (like .opus files) according to
https://tools.ietf.org/html/rfc7845.html which is then streamed over http.
Some browsers can play .opus streams directly in an HTML Audio element.
Others only support mp4 or webm encapsulation through the
MediaSourceExtensions API; for those you can fetch the stream manually
decoding you'll also have to decode in js. But if you've tried the
dir.xiph.org streams, presumedly you have that part working ok.
Icecast treats .opus streams pretty much the same as .ogg streams,
copying out the most recent encapsulation pages it has received to
connected clients. You can see some optimizations for better buffering
in the libshout client library for uploading streams to the icecast server.
A simpler C client is available at https://r-w-x.org/r/oggfwd.git
Hope that helps,
More information about the opus