Experimental NDI output.

src/config/ndi_option.disabled.ml

@@ -0,0 +1,2 @@
+let detected = "no (requires ctypes-foreign)"
+let enabled = false

src/config/ndi_option.enabled.ml

@@ -0,0 +1 @@
+noop.enabled.ml

src/core/dune

@@ -143,6 +143,7 @@
   lang_fdkaac
   lang_flac
   lang_mp3
+  lang_ndi
   lang_ogg
   lang_opus
   lang_source
@@ -178,6 +179,8 @@
   mutex_utils
   native_audio_converter
   native_video_converter
+  ndi_format
+  ndi_encoder
   noblank
   noise
   normalize
@@ -644,6 +647,14 @@
  (optional)
  (modules stereotool_op))
 
+(library
+ (name liquidsoap_ndi)
+ (libraries ndi liquidsoap_core)
+ (library_flags -linkall)
+ (wrapped false)
+ (optional)
+ (modules ndi_out))
+
 (library
  (name liquidsoap_theora)
  (libraries theora theora.decoder liquidsoap_core liquidsoap_ogg)
@@ -732,6 +743,7 @@
   lo_option
   mad_option
   memtrace_option
+  ndi_option
   ogg_option
   opus_option
   osc_option
@@ -897,6 +909,11 @@
    from
    (liquidsoap_portaudio -> portaudio_option.enabled.ml)
    (-> portaudio_option.disabled.ml))
+  (select
+   ndi_option.ml
+   from
+   (liquidsoap_ndi -> ndi_option.enabled.ml)
+   (-> ndi_option.disabled.ml))
   (select
    posix_time_option.ml
    from

src/core/encoder/encoder.ml

@@ -25,6 +25,7 @@
 type format =
   | WAV of Wav_format.t
   | AVI of Avi_format.t
+  | NDI of Ndi_format.t
   | Ogg of Ogg_format.t
   | MP3 of Mp3_format.t
   | Shine of Shine_format.t
@@ -61,6 +62,12 @@ let type_of_format f =
     | AVI a -> audio_video_type a.Avi_format.channels
     | MP3 m -> audio_type (if m.Mp3_format.stereo then 2 else 1)
     | Shine m -> audio_type m.Shine_format.channels
+    | NDI { audio = false; video = false } -> assert false
+    | NDI { audio = true; video = false } ->
+        audio_type (Lazy.force Frame.audio_channels)
+    | NDI { audio = true; video = true } ->
+        audio_video_type (Lazy.force Frame.audio_channels)
+    | NDI { audio = false; video = true } -> video_type ()
     | Flac m -> audio_type m.Flac_format.channels
     | Ffmpeg m ->
         List.fold_left
@@ -138,6 +145,7 @@ let string_of_format = function
   | AVI w -> Avi_format.to_string w
   | Ogg w -> Ogg_format.to_string w
   | MP3 w -> Mp3_format.to_string w
+  | NDI w -> Ndi_format.to_string w
   | Shine w -> Shine_format.to_string w
   | Flac w -> Flac_format.to_string w
   | Ffmpeg w -> Ffmpeg_format.to_string w

src/core/encoder/encoder.mli

@@ -25,6 +25,7 @@
 type format =
   | WAV of Wav_format.t
   | AVI of Avi_format.t
+  | NDI of Ndi_format.t
   | Ogg of Ogg_format.t
   | MP3 of Mp3_format.t
   | Shine of Shine_format.t

src/core/encoder/encoders/ndi_encoder.ml

@@ -0,0 +1,43 @@
+(*****************************************************************************
+
+  Liquidsoap, a programmable stream generator.
+  Copyright 2003-2024 Savonet team
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details, fully stated in the COPYING
+  file at the root of the liquidsoap distribution.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+
+ *****************************************************************************)
+
+(** NDI encoder. This encoder does nothing and can only by used with `output.ndi` *)
+
+let encoder ~pos _ =
+  let error () =
+    Runtime_error.raise
+      ~pos:(match pos with Some p -> [p] | None -> [])
+      ~message:"The NDI encoder can only be used with `output.ndi`!" "invalid"
+  in
+  {
+    Encoder.insert_metadata = (fun _ -> error ());
+    header = error;
+    hls = Encoder.dummy_hls (fun _ -> error ());
+    encode = (fun _ -> error ());
+    stop = error;
+  }
+
+let () =
+  Plug.register Encoder.plug "ndi"
+    ~doc:"NDI encoder. Only used with `output.ndi`." (function
+    | Encoder.NDI m -> Some (fun ?hls:_ ~pos _ _ -> encoder ~pos m)
+    | _ -> None)

src/core/encoder/formats/ndi_format.ml

@@ -0,0 +1,29 @@
+(*****************************************************************************
+
+  Liquidsoap, a programmable stream generator.
+  Copyright 2003-2024 Savonet team
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details, fully stated in the COPYING
+  file at the root of the liquidsoap distribution.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+
+ *****************************************************************************)
+
+type t = { audio : bool; video : bool }
+
+let to_string { audio; video } =
+  Printf.sprintf "%%ndi(%s)"
+    (String.concat ","
+       ((if audio then "%audio" else "%audio.none")
+       :: (if video then ["%video"] else ["%video.none"])))

src/core/encoder/lang/lang_ndi.ml

@@ -0,0 +1,62 @@
+(*****************************************************************************
+
+  Liquidsoap, a programmable stream generator.
+  Copyright 2003-2024 Savonet team
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details, fully stated in the COPYING
+  file at the root of the liquidsoap distribution.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
+
+ *****************************************************************************)
+
+open Ndi_format
+
+let type_of_encoder p =
+  match
+    List.fold_left
+      (fun (audio, video) -> function
+        | `Encoder ("audio", []) -> (true, video)
+        | `Encoder ("audio.none", []) -> (false, video)
+        | `Encoder ("video", []) -> (audio, true)
+        | `Encoder ("video.none", []) -> (audio, false)
+        | _ -> (audio, video))
+      (true, true) p
+  with
+    | true, true -> Encoder.audio_video_type ~pcm_kind:Content.Audio.kind 2
+    | false, true -> Encoder.video_type ()
+    | true, false -> Encoder.audio_type ~pcm_kind:Content.Audio.kind 2
+    | _ -> Lang_encoder.raise_error ~pos:None "Invalid %%ndi encoder parameter!"
+
+let make params =
+  let defaults = { audio = true; video = true } in
+  let ndi =
+    List.fold_left
+      (fun ndi -> function
+        | `Encoder ("audio", []) -> { ndi with audio = true }
+        | `Encoder ("audio.none", []) -> { ndi with audio = false }
+        | `Encoder ("video", []) -> { ndi with video = true }
+        | `Encoder ("video.none", []) -> { ndi with video = false }
+        | `Labelled (_, v) ->
+            Lang_encoder.raise_error ~pos:(Value.pos v) "Invalid parameter!"
+        | _ ->
+            Lang_encoder.raise_error ~pos:None
+              "Invalid %%ndi encoder parameter!")
+      defaults params
+  in
+  if (not ndi.audio) && not ndi.video then
+    Lang_encoder.raise_error ~pos:None
+      "%%ndi encoder needs at least one audio or video field!";
+  Encoder.NDI ndi
+
+let () = Lang_encoder.register "ndi" type_of_encoder make

src/core/outputs/icecast2.ml

@@ -80,6 +80,8 @@ module Icecast = struct
             samplerate = Some (Lazy.force m.Fdkaac_format.samplerate);
             channels = Some m.Fdkaac_format.channels;
           }
+      | Encoder.NDI _ ->
+          { quality = None; bitrate = None; samplerate = None; channels = None }
       | Encoder.External m ->
           {
             quality = None;