Asterisk Opus/VP8 patch

Since Opus and VP8 cannot, as of now, be integrated in the Asterisk repositories (learn why in this thread), we prepared a patch that adds support for both codecs (Opus transcoding, VP8 passthrough) to Asterisk 11.1.2.

Installing the patch

To support Opus, you'll need to install libopus first. No library is needed for VP8, as its support is passthrough only.

The patch was built on top of Asterisk 11.1.2: applying it on different versions may or may not work out of the box, but solving conflicts shouldn't be too hard anyway. Copy it in the Asterisk source folder and apply it:

patch -p1 -u < asterisk_opus+vp8.diff

Run the bootstrap script to regenerate the configure:

./bootstrap.sh

Configure the patched Asterisk.

./configure --prefix=/usr

Make sure that codec_opus and format_vp8 are enabled in menuselect before going on. Besides, for better results, install the slin16 versions of the Asterisk sounds, which are not enabled by default.

make menuselect

Compile and install.

make
make install

Testing

You can test Opus using the free softphone PhonerLite. Make sure you choose the beta version, as the stable one does not comply with draft-ietf-payload-rtp-opus (RTP timestamp increment). The codec_opus module also has a CLI command to enable debugging: type opus set debug for information about it.

Usage: opus set debug {status|none|normal|huge}
    Enable/Disable Opus debugging: normal only debugs setup and errors, huge debugs every single packet

For VP8 you can make use of the open source softphone Linphone, which added support for VP8 in version 3.5.0.

What is missing

SDP fmtp parameters related to Opus and defined in draft-ietf-payload-rtp-opus are parsed but currently ignored: this means that there's no interaction between chan_sip and codec_opus in that sense. Besides, there still is no ad-hoc Opus configuration file for codec defaults. VP8, as anticipated, is passthrough only: besides, there's currently no way to read VP8 files for Playback.

Help us improve the support!

Found an issue? Solved one? Added something that was missing? Help us make it better!

Developed by @meetecho