# gst-meet: Integrate Jitsi Meet conferences with GStreamer pipelines

Note: gst-meet is in an **alpha** state and is under active development. The command-line options and the lib-gst-meet API are subject to change, and some important features (simulcast, RTX, TCC) are not yet fully functional.

gst-meet provides a library and tool for integrating Jitsi Meet conferences with GStreamer pipelines. You can pipe audio and video into a conference as a participant, and pipe out other participants' audio and video streams.

Thanks to GStreamer's flexibility and wide range of plugins, this enables many new possibilities.

## Installation

You will need the dependencies `glib`, `gstreamer` and `libnice`, as well as any GStreamer plugins you want to use in your pipelines, and a Rust toolchain ([rustup](https://rustup.rs/) is the easiest way to install one).

Then: `cargo install --force gst-meet` (`--force` will upgrade `gst-meet` if you have already installed it.)

To integrate gst-meet into your own application, look at `lib-gst-meet`.

## Pipeline Structure

You can pass two different pipeline fragments to gst-meet.

`--send-pipeline` is for sending audio and video. If it contains an element named `audio`, this audio will be streamed to the conference. The audio codec must be 48kHz Opus. If it contains an element named `video`, this video will be streamed to the conference. The video codec must match the codec passed to `--video-codec`, which is VP8 by default.

`--recv-pipeline-participant-template` is for receiving audio and video from other participants. This pipeline will be created once for each other participant in the conference. If it contains an element named `audio`, the participant's audio (48kHz Opus) will be sent to that element. If it contains an element named `video`, the participant's video (encoded with the codec selected by `--video-codec`) will be sent to that element. The strings `{jid}`, `{jid_user}`, `{participant_id}` and `{nick}` are replaced in the template with the participant's full JID, user part, MUC JID resource part (a.k.a. participant/occupant ID) and nickname respectively.

## Examples

A few examples of `gst-meet` usage are below. The GStreamer reference provides full details on available pipeline elements.

`gst-meet --help` lists full usage information.

Stream an Opus audio file to the conference. This is very efficient; the Opus data in the file is streamed directly without transcoding:

```
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --send-pipeline="filesrc location=sample.opus ! queue ! oggdemux name=audio"
```

Stream a FLAC audio file to the conference, transcoding it to Opus:

```
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --send-pipeline="filesrc location=shake-it-off.flac ! queue ! flacdec ! audioconvert ! audioresample ! opusenc name=audio"
```

Stream a .webm file containing VP8 video and Vorbis audio to the conference. This pipeline passes the VP8 stream through efficiently without transcoding, and transcodes the audio from Vorbis to Opus:

```
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --send-pipeline="filesrc location=big-buck-bunny_trailer.webm ! queue ! matroskademux name=demuxer
                          demuxer.video_0 ! queue name=video
                          demuxer.audio_0 ! queue ! vorbisdec ! audioconvert ! audioresample ! opusenc name=audio"
```

Stream the default video & audio inputs to the conference, encoding as VP8 and Opus, composite incoming video streams and play back incoming audio (a very basic, but completely native, Jitsi Meet conference!):

```
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --send-pipeline="autovideosrc ! queue ! videoconvert ! vp8enc buffer-size=1000 deadline=1 name=video
                          autoaudiosrc ! queue ! audioconvert ! audioresample ! opusenc name=audio" \
         --recv-pipeline-participant-template="opusdec name=audio ! autoaudiosink
                                               vp8dec name=video ! videoconvert ! autovideosink"
```

Record a .webm file for each other participant, containing VP8 video and Opus audio, without needing to do any transcoding:

```
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --recv-pipeline-participant-template="webmmux name=muxer ! filesink location={participant_id}.webm
                                               opusparse name=audio ! muxer.audio_0
                                               capsfilter caps=video/x-vp8 name=video ! muxer.video_0"
```

Play a YouTube video in the conference. By requesting Opus audio and VP9 video from YouTube, and setting the Jitsi Meet video codec to VP9, no transcoding is necessary:

```
YOUTUBE_URL="https://www.youtube.com/watch?v=vjV_2Ri2rfE"
gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
         --xmpp-domain=your.jitsi.domain \
         --room-name=roomname \
         --video-codec=vp9 \
         --send-pipeline="curlhttpsrc location=\"$(youtube-dl -g $YOUTUBE_URL -f 'bestaudio[acodec=opus]')\" ! queue ! matroskademux name=audiodemux
                          curlhttpsrc location=\"$(youtube-dl -g $YOUTUBE_URL -f 'bestvideo[vcodec=vp9]')\" ! queue ! matroskademux name=videodemux
                          audiodemux.audio_0 ! queue ! clocksync name=audio
                          videodemux.video_0 ! queue ! clocksync name=video"
```

## Debugging

It can sometimes be tricky to get GStreamer pipeline syntax and structure correct. To help with this, you can try setting the `GST_DEBUG` environment variable (for example, `3` is modestly verbose, while `6` produces copious per-packet output). You can also set `GST_DEBUG_DUMP_DOT_DIR` to the relative path to a directory (which must already exist). `.dot` files containing the pipeline graph will be saved to this directory, and can be converted to `.png` with the `dot` tool from GraphViz; for example `dot filename.dot -Tpng > filename.png`.

## License

`gst-meet`, `lib-gst-meet`, `nice` and `nice-sys` are licensed under either of

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

The dependency `xmpp-parsers` is licensed under the Mozilla Public License, Version 2.0, https://www.mozilla.org/en-US/MPL/2.0/

The dependency `gstreamer` is licensed under the GNU Lesser General Public License, Version 2.1, https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html.

## Contribution

Any kinds of contributions are welcome as a pull request.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in these crates by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

## Acknowledgements

`gst-meet` development is sponsored by [AVStack](https://www.avstack.io/). We provide globally-distributed, scalable, managed Jitsi Meet backends.