webrtc: add raw payload support

This commit adds support for raw payloads such as L24 audio to `webrtcsink` &
`webrtcsrc`.

Most changes take place within the `Codec` helper structure:

* A `Codec` can now advertise a depayloader. This also ensures that a format
  not only can be decoded when necessary, but it can also be depayloaded in the
  first place.
* It is possible to declare raw `Codec`s, meaning that their caps are compatible
  with a payloader and a depayloader without the need for an encoder and decoder.
* Previous accessor `has_decoder` was renamed as `can_be_received` to account
  for codecs which can be handled by an available depayloader with or without
  the need for a decoder.
* New codecs were added for the following formats:
  * L24, L16, L8 audio.
  * RAW video.

The `webrtc-precise-sync` examples were updated to demonstrate streaming of raw
audio or video.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1501>

Cargo.lock

@@ -3051,6 +3051,7 @@ dependencies = [
  "gstreamer-webrtc",
  "http 1.1.0",
  "human_bytes",
+ "itertools 0.12.1",
  "livekit-api",
  "livekit-protocol",
  "once_cell",

docs/plugins/gst_plugins_cache.json

@@ -10183,7 +10183,7 @@
                 "kind": "object",
                 "properties": {
                     "audio-caps": {
-                        "blurb": "Governs what audio codecs will be proposed",
+                        "blurb": "Governs what audio codecs will be proposed. Valid values: [audio/x-opus; audio/x-raw, format=(string)S24BE, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]; audio/x-raw, format=(string)S16BE, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]; audio/x-raw, format=(string)U8, layout=(string)interleaved, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ]]",
                         "conditionally-available": false,
                         "construct": false,
                         "construct-only": false,
@@ -10366,7 +10366,7 @@
                         "writable": true
                     },
                     "video-caps": {
-                        "blurb": "Governs what video codecs will be proposed",
+                        "blurb": "Governs what video codecs will be proposed. Valid values: [video/x-vp8; video/x-h264; video/x-vp9; video/x-h265; video/x-av1; video/x-raw, format=(string){ RGB, RGBA, BGR, BGRA, AYUV, UYVY, I420, Y41B, UYVP }, width=(int)[ 1, 32767 ], height=(int)[ 1, 32767 ]]",
                         "conditionally-available": false,
                         "construct": false,
                         "construct-only": false,
@@ -10498,7 +10498,7 @@
                 "kind": "object",
                 "properties": {
                     "audio-codecs": {
-                        "blurb": "Names of audio codecs to be be used during the SDP negotiation. Valid values: [OPUS]",
+                        "blurb": "Names of audio codecs to be be used during the SDP negotiation. Valid values: [OPUS, L24, L16, L8]",
                         "conditionally-available": false,
                         "construct": false,
                         "construct-only": false,
@@ -10578,7 +10578,7 @@
                         "writable": true
                     },
                     "video-codecs": {
-                        "blurb": "Names of video codecs to be be used during the SDP negotiation. Valid values: [VP8, H264, VP9, H265, AV1]",
+                        "blurb": "Names of video codecs to be be used during the SDP negotiation. Valid values: [VP8, H264, VP9, H265, AV1, RAW]",
                         "conditionally-available": false,
                         "construct": false,
                         "construct-only": false,

net/webrtc/Cargo.toml

@@ -25,6 +25,7 @@ anyhow = "1"
 chrono = "0.4"
 thiserror = "1"
 futures = "0.3"
+itertools = "0.12"
 tokio = { version = "1", features = ["fs", "macros", "rt-multi-thread", "time"] }
 tokio-native-tls = "0.3.0"
 tokio-stream = "0.1.11"

net/webrtc/examples/README.md

@@ -34,6 +34,13 @@ mode and an example based on RTSP instead of WebRTC.
 The examples can also be used for [RFC 7273] NTP or PTP clock signalling and
 synchronization.
 
+Finally, raw payloads (e.g. L24 audio) can be negotiated.
+
+Note: you can have your host act as an NTP server, which can help the examples
+with clock synchronization. For `chrony`, this can be configure by editing
+`/etc/chrony.conf` and uncommenting / editing the `allow` entry. The examples
+can then be launched with `--ntp-server _ip_address_`.
+
 [RFC 6051]: https://datatracker.ietf.org/doc/html/rfc6051
 [RFC 7273]: https://datatracker.ietf.org/doc/html/rfc7273
 [Instantaneous RTP synchronization...]: https://coaxion.net/blog/2022/05/instantaneous-rtp-synchronization-retrieval-of-absolute-sender-clock-times-with-gstreamer/
@@ -44,7 +51,7 @@ The example uses the default WebRTC signaller. Launch it using the following
 command:
 
 ```shell
-cargo run --bin gst-webrtc-signalling-server
+cargo run --bin gst-webrtc-signalling-server --no-default-features
 ```
 
 ### Receiver
@@ -53,14 +60,14 @@ The receiver awaits for new audio & video stream publishers and render the
 streams using auto sink elements. Launch it using the following command:
 
 ```shell
-cargo r --example webrtc-precise-sync-recv
+cargo r --example webrtc-precise-sync-recv --no-default-features
 ```
 
 The default configuration should work for a local test. For a multi-host setup,
 see the available options:
 
 ```shell
-cargo r --example webrtc-precise-sync-recv -- --help
+cargo r --example webrtc-precise-sync-recv --no-default-features -- --help
 ```
 
 E.g.: the following will force `avdec_h264` over hardware decoders, activate
@@ -70,7 +77,8 @@ specified address:
 ```shell
 GST_PLUGIN_FEATURE_RANK=avdec_h264:MAX \
 WEBRTC_PRECISE_SYNC_RECV_LOG=debug \
-cargo r --example webrtc-precise-sync-recv -- --server 192.168.1.22
+cargo r --example webrtc-precise-sync-recv --no-default-features -- \
+  --server 192.168.1.22
 ```
 
 ### Sender
@@ -79,7 +87,7 @@ The sender publishes audio & video test streams. Launch it using the following
 command:
 
 ```shell
-cargo r --example webrtc-precise-sync-send
+cargo r --example webrtc-precise-sync-send --no-default-features
 ```
 
 The default configuration should work for a local test. For a multi-host setup,
@@ -87,7 +95,7 @@ to set the number of audio / video streams, to enable rapid synchronization or
 to force the video encoder, see the available options:
 
 ```shell
-cargo r --example webrtc-precise-sync-send -- --help
+cargo r --example webrtc-precise-sync-send --no-default-features -- --help
 ```
 
 E.g.: the following will force H264 and `x264enc` over hardware encoders,
@@ -97,7 +105,7 @@ specified address:
 ```shell
 GST_PLUGIN_FEATURE_RANK=264enc:MAX \
 WEBRTC_PRECISE_SYNC_SEND_LOG=debug \
-cargo r --example webrtc-precise-sync-send -- \
+cargo r --example webrtc-precise-sync-send --no-default-features -- \
   --server 192.168.1.22 --video-caps video/x-h264
 ```
 
@@ -120,16 +128,49 @@ commands such as:
 #### Receiver
 
 ```shell
-cargo r --example webrtc-precise-sync-recv -- --expect-clock-signalling
+cargo r --example webrtc-precise-sync-recv --no-default-features -- \
+  --expect-clock-signalling
 ```
 
 #### Sender
 
 ```shell
-cargo r --example webrtc-precise-sync-send -- --clock ntp --do-clock-signalling \
+cargo r --example webrtc-precise-sync-send --no-default-features -- \
+  --clock ntp --do-clock-signalling \
   --video-streams 0 --audio-streams 2
 ```
 
+### Raw payload
+
+The sender can be instructed to send raw payloads. Note that raw payloads
+are not activated by default and must be selected explicitly.
+
+This command will stream two stereo L24 streams:
+
+```shell
+cargo r --example webrtc-precise-sync-send --no-default-features -- \
+  --video-streams 0 \
+  --audio-streams 2 --audio-codecs L24
+```
+
+Launch the receiver with:
+
+```shell
+cargo r --example webrtc-precise-sync-recv --no-default-features -- \
+  --audio-codecs L24
+```
+
+This can be used to stream multiple RAW video streams using specific CAPS for
+the streams and allowing fallback to VP8 & OPUS if remote doesn't support raw
+payloads:
+
+```shell
+cargo r --example webrtc-precise-sync-send --no-default-features -- \
+  --video-streams 2 --audio-streams 1 \
+  --video-codecs RAW --video-codecs VP8 --video-caps video/x-raw,format=I420,width=400 \
+  --audio-codecs L24 --audio-codecs OPUS --audio-caps audio/x-raw,rate=48000,channels=2
+```
+
 ## Android
 
 ### `webrtcsrc` based Android application

net/webrtc/examples/webrtc-precise-sync-recv.rs

@@ -43,6 +43,18 @@ struct Args {
     #[clap(long, help = "RTP jitterbuffer latency (ms)", default_value = "40")]
     pub rtp_latency: u32,
 
+    #[clap(
+        long,
+        help = "Force accepted audio codecs. See 'webrtcsrc' 'audio-codecs' property (ex. 'OPUS'). Accepts several occurrences."
+    )]
+    pub audio_codecs: Vec<String>,
+
+    #[clap(
+        long,
+        help = "Force accepted video codecs. See 'webrtcsrc' 'video-codecs' property (ex. 'VP8'). Accepts several occurrences."
+    )]
+    pub video_codecs: Vec<String>,
+
     #[clap(long, help = "Signalling server host", default_value = "localhost")]
     pub server: String,
 
@@ -123,6 +135,14 @@ fn spawn_consumer(
         webrtcsrc.set_property("do-retransmission", false);
     }
 
+    if !args.audio_codecs.is_empty() {
+        webrtcsrc.set_property("audio-codecs", gst::Array::new(&args.audio_codecs));
+    }
+
+    if !args.video_codecs.is_empty() {
+        webrtcsrc.set_property("video-codecs", gst::Array::new(&args.video_codecs));
+    }
+
     bin.add(&webrtcsrc).context("Adding webrtcsrc")?;
 
     let signaller = webrtcsrc.property::<gst::glib::Object>("signaller");

net/webrtc/examples/webrtc-precise-sync-send.rs

@@ -1,7 +1,9 @@
-use anyhow::{bail, Context};
+use anyhow::{anyhow, bail, Context};
 use futures::prelude::*;
 use gst::prelude::*;
 use gst_rtp::prelude::*;
+use gstrswebrtc::utils::Codecs;
+use itertools::Itertools;
 use tracing::{debug, error, info};
 use url::Url;
 
@@ -45,7 +47,28 @@ struct Args {
     )]
     pub video_streams: usize,
 
-    #[clap(long, help = "Force video caps (ex. 'video/x-h264')")]
+    #[clap(
+        long,
+        help = "Audio codecs that will be proposed in the SDP (ex. 'L24', defaults to ['OPUS']). Accepts several occurrences."
+    )]
+    pub audio_codecs: Vec<String>,
+
+    #[clap(
+        long,
+        help = "Use specific audio caps (ex. 'audio/x-raw,rate=48000,channels=2')"
+    )]
+    pub audio_caps: Option<String>,
+
+    #[clap(
+        long,
+        help = "Video codecs that will be proposed in the SDP (ex. 'RAW', defaults to ['VP8', 'H264', 'VP9', 'H265']). Accepts several occurrences."
+    )]
+    pub video_codecs: Vec<String>,
+
+    #[clap(
+        long,
+        help = "Use specific video caps (ex. 'video/x-raw,format=I420,width=400')"
+    )]
     pub video_caps: Option<String>,
 
     #[clap(long, help = "Use RFC 6051 64-bit NTP timestamp RTP header extension.")]
@@ -135,6 +158,8 @@ impl App {
     }
 
     async fn prepare(&mut self) -> anyhow::Result<()> {
+        use std::str::FromStr;
+
         debug!("Preparing");
 
         self.pipeline = Some(gst::Pipeline::new());
@@ -217,6 +242,26 @@ impl App {
             });
         }
 
+        if !self.args.audio_codecs.is_empty() {
+            let mut audio_caps = gst::Caps::new_empty();
+            for codec in self.args.audio_codecs.iter() {
+                audio_caps.merge(
+                    Codecs::audio_codecs()
+                        .find(|c| &c.name == codec)
+                        .ok_or_else(|| {
+                            anyhow!(
+                                "Unknown audio codec {codec}. Valid values are: {}",
+                                Codecs::audio_codecs().map(|c| c.name.as_str()).join(", ")
+                            )
+                        })?
+                        .caps
+                        .clone(),
+                );
+            }
+
+            webrtcsink.set_property("audio-caps", audio_caps);
+        }
+
         for idx in 0..self.args.audio_streams {
             let audiosrc = gst::ElementFactory::make("audiotestsrc")
                 .property("is-live", true)
@@ -226,10 +271,64 @@ impl App {
                 .context("Creating audiotestsrc")?;
             self.pipeline().add(&audiosrc).context("Adding audiosrc")?;
 
+            if let Some(ref caps) = self.args.audio_caps {
+                audiosrc
+                    .link_pads_filtered(
+                        None,
+                        &webrtcsink,
+                        Some("audio_%u"),
+                        &gst::Caps::from_str(caps).context("Parsing audio caps")?,
+                    )
+                    .context("Linking audiosrc")?;
+            } else {
                 audiosrc
                     .link_pads(None, &webrtcsink, Some("audio_%u"))
                     .context("Linking audiosrc")?;
             }
+        }
+
+        if !self.args.video_codecs.is_empty() {
+            let mut video_caps = gst::Caps::new_empty();
+            for codec in self.args.video_codecs.iter() {
+                video_caps.merge(
+                    Codecs::video_codecs()
+                        .find(|c| &c.name == codec)
+                        .ok_or_else(|| {
+                            anyhow!(
+                                "Unknown video codec {codec}. Valid values are: {}",
+                                Codecs::video_codecs().map(|c| c.name.as_str()).join(", ")
+                            )
+                        })?
+                        .caps
+                        .clone(),
+                );
+            }
+
+            webrtcsink.set_property("video-caps", video_caps);
+        }
+
+        let raw_video_caps = {
+            let mut raw_video_caps = if let Some(ref video_caps) = self.args.video_caps {
+                gst::Caps::from_str(video_caps).context("Parsing video caps")?
+            } else {
+                gst::Caps::new_empty_simple("video/x-raw")
+            };
+
+            // If no width / height are specified, set something big enough
+            let caps_mut = raw_video_caps.make_mut();
+            let s = caps_mut.structure_mut(0).expect("created above");
+            match (s.get::<i32>("width").ok(), s.get::<i32>("height").ok()) {
+                (None, None) => {
+                    s.set("width", 800i32);
+                    s.set("height", 600i32);
+                }
+                (Some(width), None) => s.set("height", 3 * width / 4),
+                (None, Some(height)) => s.set("width", 4 * height / 3),
+                _ => (),
+            }
+
+            raw_video_caps
+        };
 
         for idx in 0..self.args.video_streams {
             let videosrc = gst::ElementFactory::make("videotestsrc")
@@ -247,13 +346,7 @@ impl App {
                 .expect("adding video elements");
 
             videosrc
-                .link_filtered(
+                .link_filtered(&video_overlay, &raw_video_caps)
-                    &video_overlay,
-                    &gst::Caps::builder("video/x-raw")
-                        .field("width", 800i32)
-                        .field("height", 600i32)
-                        .build(),
-                )
                 .context("Linking videosrc to timeoverlay")?;
 
             video_overlay
@@ -261,10 +354,6 @@ impl App {
                 .context("Linking video overlay")?;
         }
 
-        if let Some(ref video_caps) = self.args.video_caps {
-            webrtcsink.set_property("video-caps", &gst::Caps::builder(video_caps).build());
-        }
-
         Ok(())
     }
 

net/webrtc/src/utils.rs

@@ -427,7 +427,7 @@ impl Clone for DecodingInfo {
 
 #[derive(Clone, Debug)]
 struct EncodingInfo {
-    encoder: gst::ElementFactory,
+    encoder: Option<gst::ElementFactory>,
     payloader: gst::ElementFactory,
     output_filter: Option<gst::Caps>,
 }
@@ -437,6 +437,7 @@ pub struct Codec {
     pub name: String,
     pub caps: gst::Caps,
     pub stream_type: gst::StreamType,
+    pub is_raw: bool,
 
     payload_type: Option<i32>,
     decoding_info: Option<DecodingInfo>,
@@ -449,16 +450,27 @@ impl Codec {
         stream_type: gst::StreamType,
         caps: &gst::Caps,
         decoders: &glib::List<gst::ElementFactory>,
+        depayloaders: &glib::List<gst::ElementFactory>,
         encoders: &glib::List<gst::ElementFactory>,
         payloaders: &glib::List<gst::ElementFactory>,
     ) -> Self {
         let has_decoder = Self::has_decoder_for_caps(caps, decoders);
+        let has_depayloader = Self::has_depayloader_for_codec(name, depayloaders);
+
+        let decoding_info = if has_depayloader && has_decoder {
+            Some(DecodingInfo {
+                has_decoder: AtomicBool::new(has_decoder),
+            })
+        } else {
+            None
+        };
+
         let encoder = Self::get_encoder_for_caps(caps, encoders);
         let payloader = Self::get_payloader_for_codec(name, payloaders);
 
         let encoding_info = if let (Some(encoder), Some(payloader)) = (encoder, payloader) {
             Some(EncodingInfo {
-                encoder,
+                encoder: Some(encoder),
                 payloader,
                 output_filter: None,
             })
@@ -470,12 +482,52 @@ impl Codec {
             caps: caps.clone(),
             stream_type,
             name: name.into(),
+            is_raw: false,
             payload_type: None,
+            decoding_info,
+            encoding_info,
+        }
+    }
 
-            decoding_info: Some(DecodingInfo {
+    pub fn new_raw(
-                has_decoder: AtomicBool::new(has_decoder),
+        name: &str,
-            }),
+        stream_type: gst::StreamType,
+        depayloaders: &glib::List<gst::ElementFactory>,
+        payloaders: &glib::List<gst::ElementFactory>,
+    ) -> Self {
+        let decoding_info = if Self::has_depayloader_for_codec(name, depayloaders) {
+            Some(DecodingInfo {
+                has_decoder: AtomicBool::new(false),
+            })
+        } else {
+            None
+        };
 
+        let payloader = Self::get_payloader_for_codec(name, payloaders);
+        let encoding_info = payloader.map(|payloader| EncodingInfo {
+            encoder: None,
+            payloader,
+            output_filter: None,
+        });
+
+        let mut caps = None;
+        if let Some(elem) = Codec::get_payloader_for_codec(name, payloaders) {
+            if let Some(tmpl) = elem
+                .static_pad_templates()
+                .iter()
+                .find(|template| template.direction() == gst::PadDirection::Sink)
+            {
+                caps = Some(tmpl.caps());
+            }
+        }
+
+        Self {
+            caps: caps.unwrap_or_else(gst::Caps::new_empty),
+            stream_type,
+            name: name.into(),
+            is_raw: true,
+            payload_type: None,
+            decoding_info,
             encoding_info,
         }
     }
@@ -488,33 +540,15 @@ impl Codec {
         self.payload_type = Some(pt);
     }
 
-    pub fn new_decoding(
+    pub fn can_be_received(&self) -> bool {
-        name: &str,
-        stream_type: gst::StreamType,
-        caps: &gst::Caps,
-        decoders: &glib::List<gst::ElementFactory>,
-    ) -> Self {
-        let has_decoder = Self::has_decoder_for_caps(caps, decoders);
-
-        Self {
-            caps: caps.clone(),
-            stream_type,
-            name: name.into(),
-            payload_type: None,
-
-            decoding_info: Some(DecodingInfo {
-                has_decoder: AtomicBool::new(has_decoder),
-            }),
-
-            encoding_info: None,
-        }
-    }
-
-    pub fn has_decoder(&self) -> bool {
         if self.decoding_info.is_none() {
             return false;
         }
 
+        if self.is_raw {
+            return true;
+        }
+
         let decoder_info = self.decoding_info.as_ref().unwrap();
         if decoder_info.has_decoder.load(Ordering::SeqCst) {
             true
@@ -599,6 +633,40 @@ impl Codec {
         })
     }
 
+    fn has_depayloader_for_codec(
+        codec: &str,
+        depayloaders: &glib::List<gst::ElementFactory>,
+    ) -> bool {
+        depayloaders.iter().any(|factory| {
+            factory.static_pad_templates().iter().any(|template| {
+                let template_caps = template.caps();
+
+                if template.direction() != gst::PadDirection::Sink {
+                    return false;
+                }
+
+                template_caps.iter().any(|s| {
+                    s.has_field("encoding-name")
+                        && s.get::<gst::List>("encoding-name").map_or_else(
+                            |_| {
+                                if let Ok(encoding_name) = s.get::<&str>("encoding-name") {
+                                    encoding_name == codec
+                                } else {
+                                    false
+                                }
+                            },
+                            |encoding_names| {
+                                encoding_names.iter().any(|v| {
+                                    v.get::<&str>()
+                                        .map_or(false, |encoding_name| encoding_name == codec)
+                                })
+                            },
+                        )
+                })
+            })
+        })
+    }
+
     pub fn is_video(&self) -> bool {
         matches!(self.stream_type, gst::StreamType::VIDEO)
     }
@@ -608,11 +676,13 @@ impl Codec {
     }
 
     pub fn build_encoder(&self) -> Option<Result<gst::Element, Error>> {
-        self.encoding_info.as_ref().map(|info| {
+        self.encoding_info.as_ref().and_then(|info| {
-            info.encoder
+            info.encoder.as_ref().map(|encoder| {
+                encoder
                     .create()
                     .build()
-                .with_context(|| format!("Creating encoder {}", info.encoder.name()))
+                    .with_context(|| format!("Creating encoder {}", encoder.name()))
+            })
         })
     }
 
@@ -655,13 +725,17 @@ impl Codec {
     }
 
     pub fn encoder_factory(&self) -> Option<gst::ElementFactory> {
-        self.encoding_info.as_ref().map(|info| info.encoder.clone())
+        self.encoding_info
+            .as_ref()
+            .and_then(|info| info.encoder.clone())
     }
 
     pub fn encoder_name(&self) -> Option<String> {
-        self.encoding_info
+        self.encoding_info.as_ref().and_then(|info| {
+            info.encoder
                 .as_ref()
-            .map(|info| info.encoder.name().to_string())
+                .map(|encoder| encoder.name().to_string())
+        })
     }
 
     pub fn set_output_filter(&mut self, caps: gst::Caps) {
@@ -753,7 +827,7 @@ impl Codecs {
         Self(codecs.values().cloned().collect())
     }
 
-    pub fn find_for_encoded_caps(&self, caps: &gst::Caps) -> Option<Codec> {
+    pub fn find_for_payloadable_caps(&self, caps: &gst::Caps) -> Option<Codec> {
         self.iter()
             .find(|codec| codec.caps.can_intersect(caps) && codec.encoding_info.is_some())
             .cloned()
@@ -766,6 +840,11 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
         gst::Rank::MARGINAL,
     );
 
+    let depayloaders = gst::ElementFactory::factories_with_type(
+        gst::ElementFactoryType::DEPAYLOADER,
+        gst::Rank::MARGINAL,
+    );
+
     let encoders = gst::ElementFactory::factories_with_type(
         gst::ElementFactoryType::ENCODER,
         gst::Rank::MARGINAL,
@@ -782,14 +861,19 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
             gst::StreamType::AUDIO,
             &OPUS_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
+        Codec::new_raw("L24", gst::StreamType::AUDIO, &depayloaders, &payloaders),
+        Codec::new_raw("L16", gst::StreamType::AUDIO, &depayloaders, &payloaders),
+        Codec::new_raw("L8", gst::StreamType::AUDIO, &depayloaders, &payloaders),
         Codec::new(
             "VP8",
             gst::StreamType::VIDEO,
             &VP8_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
@@ -798,6 +882,7 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
             gst::StreamType::VIDEO,
             &H264_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
@@ -806,6 +891,7 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
             gst::StreamType::VIDEO,
             &VP9_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
@@ -814,6 +900,7 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
             gst::StreamType::VIDEO,
             &H265_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
@@ -822,9 +909,11 @@ static CODECS: Lazy<Codecs> = Lazy::new(|| {
             gst::StreamType::VIDEO,
             &AV1_CAPS,
             &decoders,
+            &depayloaders,
             &encoders,
             &payloaders,
         ),
+        Codec::new_raw("RAW", gst::StreamType::VIDEO, &depayloaders, &payloaders),
     ])
 });
 
@@ -836,36 +925,16 @@ impl Codecs {
             .cloned()
     }
 
-    pub fn video_codecs() -> Vec<Codec> {
+    pub fn video_codecs<'a>() -> impl Iterator<Item = &'a Codec> {
         CODECS
             .iter()
             .filter(|codec| codec.stream_type == gst::StreamType::VIDEO)
-            .cloned()
-            .collect()
     }
 
-    pub fn audio_codecs() -> Vec<Codec> {
+    pub fn audio_codecs<'a>() -> impl Iterator<Item = &'a Codec> {
         CODECS
             .iter()
             .filter(|codec| codec.stream_type == gst::StreamType::AUDIO)
-            .cloned()
-            .collect()
-    }
-
-    pub fn video_codec_names() -> Vec<String> {
-        CODECS
-            .iter()
-            .filter(|codec| codec.stream_type == gst::StreamType::VIDEO)
-            .map(|codec| codec.name.clone())
-            .collect()
-    }
-
-    pub fn audio_codec_names() -> Vec<String> {
-        CODECS
-            .iter()
-            .filter(|codec| codec.stream_type == gst::StreamType::AUDIO)
-            .map(|codec| codec.name.clone())
-            .collect()
     }
 
     /// List all codecs that can be used for encoding the given caps and assign
@@ -909,9 +978,9 @@ impl Codecs {
     }
 }
 
-pub fn is_raw_caps(caps: &gst::Caps) -> bool {
+pub fn has_raw_caps(caps: &gst::Caps) -> bool {
-    assert!(caps.is_fixed());
+    caps.iter()
-    ["video/x-raw", "audio/x-raw"].contains(&caps.structure(0).unwrap().name().as_str())
+        .any(|s| ["video/x-raw", "audio/x-raw"].contains(&s.name().as_str()))
 }
 
 pub fn cleanup_codec_caps(mut caps: gst::Caps) -> gst::Caps {

net/webrtc/src/webrtcsink/imp.rs

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MPL-2.0
 
-use crate::utils::{cleanup_codec_caps, is_raw_caps, make_element, Codec, Codecs, NavigationEvent};
+use crate::utils::{
+    cleanup_codec_caps, has_raw_caps, make_element, Codec, Codecs, NavigationEvent,
+};
 use anyhow::Context;
 use gst::glib;
 use gst::prelude::*;
@@ -13,6 +15,7 @@ use gst_webrtc::{WebRTCDataChannel, WebRTCICETransportPolicy};
 use futures::prelude::*;
 
 use anyhow::{anyhow, Error};
+use itertools::Itertools;
 use once_cell::sync::Lazy;
 use std::collections::HashMap;
 
@@ -513,12 +516,12 @@ impl Default for Settings {
 
         Self {
             video_caps: Codecs::video_codecs()
-                .into_iter()
+                .filter(|codec| !codec.is_raw)
-                .flat_map(|codec| codec.caps.iter().map(|s| s.to_owned()).collect::<Vec<_>>())
+                .flat_map(|codec| codec.caps.iter().map(ToOwned::to_owned))
                 .collect::<gst::Caps>(),
             audio_caps: Codecs::audio_codecs()
-                .into_iter()
+                .filter(|codec| !codec.is_raw)
-                .flat_map(|codec| codec.caps.iter().map(|s| s.to_owned()).collect::<Vec<_>>())
+                .flat_map(|codec| codec.caps.iter().map(ToOwned::to_owned))
                 .collect::<gst::Caps>(),
             stun_server: DEFAULT_STUN_SERVER.map(String::from),
             turn_servers: gst::Array::new(Vec::new() as Vec<glib::SendValue>),
@@ -884,7 +887,12 @@ impl PayloadChainBuilder {
             codec = self.codec,
         );
 
-        let needs_encoding = is_raw_caps(&self.input_caps);
+        let needs_encoding = if self.codec.is_raw {
+            !self.codec.caps.can_intersect(&self.input_caps)
+        } else {
+            has_raw_caps(&self.input_caps)
+        };
+
         let mut elements: Vec<gst::Element> = Vec::new();
 
         let (raw_filter, encoder) = if needs_encoding {
@@ -898,6 +906,9 @@ impl PayloadChainBuilder {
             let raw_filter = self.codec.raw_converter_filter()?;
             elements.push(raw_filter.clone());
 
+            let encoder = if self.codec.is_raw {
+                None
+            } else {
                 let encoder = self
                     .codec
                     .build_encoder()
@@ -905,7 +916,10 @@ impl PayloadChainBuilder {
                 elements.push(encoder.clone());
                 elements.push(make_element("capsfilter", None)?);
 
-            (Some(raw_filter), Some(encoder))
+                Some(encoder)
+            };
+
+            (Some(raw_filter), encoder)
         } else {
             (None, None)
         };
@@ -3431,7 +3445,7 @@ impl BaseWebRTCSink {
     ) -> Result<gst::Structure, Error> {
         let pipe = PipelineWrapper(gst::Pipeline::default());
 
-        let has_raw_input = is_raw_caps(&input_caps);
+        let has_raw_input = has_raw_caps(&input_caps);
         let src = discovery_info.create_src();
         let mut elements = vec![src.clone().upcast::<gst::Element>()];
         let encoding_chain_src = if codec.is_video() && has_raw_input {
@@ -3616,29 +3630,7 @@ impl BaseWebRTCSink {
         output_caps: gst::Caps,
         codecs: &Codecs,
     ) -> Result<(), Error> {
-        let futs = if let Some(codec) = codecs.find_for_encoded_caps(&discovery_info.caps) {
+        let futs = if has_raw_caps(&discovery_info.caps) {
-            let mut caps = discovery_info.caps.clone();
-
-            gst::info!(
-                CAT,
-                imp = self,
-                "Stream is already encoded with codec {}, still need to payload it",
-                codec.name
-            );
-
-            caps = cleanup_codec_caps(caps);
-
-            vec![self.run_discovery_pipeline(
-                &name,
-                &discovery_info,
-                codec,
-                caps,
-                &output_caps,
-                ExtensionConfigurationType::Auto,
-            )]
-        } else {
-            let sink_caps = discovery_info.caps.clone();
-
             if codecs.is_empty() {
                 return Err(anyhow!(
                     "No codec available for encoding stream {}, \
@@ -3648,10 +3640,12 @@ impl BaseWebRTCSink {
                 ));
             }
 
+            let sink_caps = discovery_info.caps.clone();
+
             let is_video = match sink_caps.structure(0).unwrap().name().as_str() {
                 "video/x-raw" => true,
                 "audio/x-raw" => false,
-                _ => anyhow::bail!("Unsupported caps: {}", discovery_info.caps),
+                _ => anyhow::bail!("expected audio or video raw caps: {sink_caps}"),
             };
 
             codecs
@@ -3668,6 +3662,28 @@ impl BaseWebRTCSink {
                     )
                 })
                 .collect()
+        } else if let Some(codec) = codecs.find_for_payloadable_caps(&discovery_info.caps) {
+            let mut caps = discovery_info.caps.clone();
+
+            gst::info!(
+                CAT,
+                imp = self,
+                "Stream is already in the {} format, we still need to payload it",
+                codec.name
+            );
+
+            caps = cleanup_codec_caps(caps);
+
+            vec![self.run_discovery_pipeline(
+                &name,
+                &discovery_info,
+                codec,
+                caps,
+                &output_caps,
+                ExtensionConfigurationType::Auto,
+            )]
+        } else {
+            anyhow::bail!("Unsupported caps: {}", discovery_info.caps);
         };
 
         let mut payloader_caps = gst::Caps::new_empty();
@@ -3949,12 +3965,20 @@ impl ObjectImpl for BaseWebRTCSink {
             vec![
                 glib::ParamSpecBoxed::builder::<gst::Caps>("video-caps")
                     .nick("Video encoder caps")
-                    .blurb("Governs what video codecs will be proposed")
+                    .blurb(&format!("Governs what video codecs will be proposed. Valid values: [{}]",
+                        Codecs::video_codecs()
+                            .map(|c| c.caps.to_string())
+                            .join("; ")
+                    ))
                     .mutable_ready()
                     .build(),
                 glib::ParamSpecBoxed::builder::<gst::Caps>("audio-caps")
                     .nick("Audio encoder caps")
-                    .blurb("Governs what audio codecs will be proposed")
+                    .blurb(&format!("Governs what audio codecs will be proposed. Valid values: [{}]",
+                        Codecs::audio_codecs()
+                            .map(|c| c.caps.to_string())
+                            .join("; ")
+                    ))
                     .mutable_ready()
                     .build(),
                 glib::ParamSpecString::builder("stun-server")
@@ -4397,7 +4421,8 @@ impl ElementImpl for BaseWebRTCSink {
                     gst::CapsFeatures::new([D3D11_MEMORY_FEATURE]),
                 );
 
-            for codec in Codecs::video_codecs() {
+            // Ignore specific raw caps from Codecs: they are covered by video/x-raw & audio/x-raw
+            for codec in Codecs::video_codecs().filter(|codec| !codec.is_raw) {
                 caps_builder = caps_builder.structure(codec.caps.structure(0).unwrap().to_owned());
             }
 
@@ -4412,7 +4437,7 @@ impl ElementImpl for BaseWebRTCSink {
 
             let mut caps_builder =
                 gst::Caps::builder_full().structure(gst::Structure::builder("audio/x-raw").build());
-            for codec in Codecs::audio_codecs() {
+            for codec in Codecs::audio_codecs().filter(|codec| !codec.is_raw) {
                 caps_builder = caps_builder.structure(codec.caps.structure(0).unwrap().to_owned());
             }
             let audio_pad_template = gst::PadTemplate::with_gtype(

net/webrtc/src/webrtcsrc/imp.rs

@@ -9,6 +9,7 @@ use anyhow::{Context, Error};
 use gst::glib;
 use gst::subclass::prelude::*;
 use gst_webrtc::WebRTCDataChannel;
+use itertools::Itertools;
 use once_cell::sync::Lazy;
 use std::borrow::BorrowMut;
 use std::collections::{HashMap, HashSet};
@@ -94,14 +95,18 @@ impl ObjectImpl for BaseWebRTCSrc {
                 gst::ParamSpecArray::builder("video-codecs")
                     .flags(glib::ParamFlags::READWRITE | gst::PARAM_FLAG_MUTABLE_READY)
                     .blurb(&format!("Names of video codecs to be be used during the SDP negotiation. Valid values: [{}]",
-                        Codecs::video_codec_names().into_iter().collect::<Vec<String>>().join(", ")
+                        Codecs::video_codecs()
+                            .map(|c| c.name.as_str())
+                            .join(", ")
                     ))
                     .element_spec(&glib::ParamSpecString::builder("video-codec-name").build())
                     .build(),
                 gst::ParamSpecArray::builder("audio-codecs")
                     .flags(glib::ParamFlags::READWRITE | gst::PARAM_FLAG_MUTABLE_READY)
                     .blurb(&format!("Names of audio codecs to be be used during the SDP negotiation. Valid values: [{}]",
-                        Codecs::audio_codec_names().into_iter().collect::<Vec<String>>().join(", ")
+                        Codecs::audio_codecs()
+                            .map(|c| c.name.as_str())
+                            .join(", ")
                     ))
                     .element_spec(&glib::ParamSpecString::builder("audio-codec-name").build())
                     .build(),
@@ -271,12 +276,12 @@ impl Default for Settings {
             signaller: signaller.upcast(),
             meta: Default::default(),
             audio_codecs: Codecs::audio_codecs()
-                .into_iter()
+                .filter(|codec| !codec.is_raw)
-                .filter(|codec| codec.has_decoder())
+                .cloned()
                 .collect(),
             video_codecs: Codecs::video_codecs()
-                .into_iter()
+                .filter(|codec| !codec.is_raw)
-                .filter(|codec| codec.has_decoder())
+                .cloned()
                 .collect(),
             enable_data_channel_navigation: DEFAULT_ENABLE_DATA_CHANNEL_NAVIGATION,
             do_retransmission: DEFAULT_DO_RETRANSMISSION,
@@ -630,7 +635,13 @@ impl Session {
             }
             srcpad.set_target(Some(&ghostpad)).unwrap();
         } else {
-            gst::debug!(CAT, obj = element, "Unused webrtcbin pad {webrtcbin_pad:?}");
+            gst::debug!(
+                CAT,
+                obj = element,
+                "Unused webrtcbin pad {} {:?}",
+                webrtcbin_pad.name(),
+                webrtcbin_pad.current_caps(),
+            );
         }
         ghostpad
     }
@@ -1326,11 +1337,13 @@ impl BaseWebRTCSrc {
 impl ElementImpl for BaseWebRTCSrc {
     fn pad_templates() -> &'static [gst::PadTemplate] {
         static PAD_TEMPLATES: Lazy<Vec<gst::PadTemplate>> = Lazy::new(|| {
+            // Ignore specific raw caps from Codecs: they are covered by VIDEO_CAPS & AUDIO_CAPS
+
             let mut video_caps_builder = gst::Caps::builder_full()
                 .structure_with_any_features(VIDEO_CAPS.structure(0).unwrap().to_owned())
                 .structure(RTP_CAPS.structure(0).unwrap().to_owned());
 
-            for codec in Codecs::video_codecs() {
+            for codec in Codecs::video_codecs().filter(|codec| !codec.is_raw) {
                 video_caps_builder =
                     video_caps_builder.structure(codec.caps.structure(0).unwrap().to_owned());
             }
@@ -1339,7 +1352,7 @@ impl ElementImpl for BaseWebRTCSrc {
                 .structure_with_any_features(AUDIO_CAPS.structure(0).unwrap().to_owned())
                 .structure(RTP_CAPS.structure(0).unwrap().to_owned());
 
-            for codec in Codecs::audio_codecs() {
+            for codec in Codecs::audio_codecs().filter(|codec| !codec.is_raw) {
                 audio_caps_builder =
                     audio_caps_builder.structure(codec.caps.structure(0).unwrap().to_owned());
             }