Enable id3v2 tags in HLS for all encoders. (#3604)

doc/content/hls_output.md

@@ -32,8 +32,8 @@ not recommended for listener-facing setup but can be useful to sync up with a ca
 
 HLS outputs supports metadata in two ways:
 
-- Through a `timed_id3` metadata logical stream with the `mpegts` format.
-- Through regular ID3 frames, as requested by the [HLS specifications](https://datatracker.ietf.org/doc/html/rfc8216#section-3.4) for `adts`, `mp3`, `ac3` and `eac3` formats.
+- Using the `%ffmpeg` encoder, through a `timed_id3` metadata logical stream with the `mpegts` format.
+- Through regular ID3 frames, as requested by the [HLS specifications](https://datatracker.ietf.org/doc/html/rfc8216#section-3.4) for `adts`, `mp3`, `ac3` and `eac3` formats with the `%ffmpeg` encoder and also natively using the `%mp3`, `%shine` or `%fdkaac` encoders.
 - There is currently no support for in-stream metadata for the `mp4` format.
 
 Metadata parameters are passed through the record methods of the streams' encoders. Here's an example

src/core/dune

@@ -96,6 +96,7 @@
   echo
   encoder
   encoder_formats
+  encoder_utils
   error
   external_decoder
   external_encoder

src/core/encoder/encoder_utils.ml

@@ -0,0 +1,66 @@
+(*****************************************************************************
+
+  Liquidsoap, a programmable audio stream generator.
+  Copyright 2003-2023 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
+
+ *****************************************************************************)
+
+(* See: https://datatracker.ietf.org/doc/html/rfc8216#section-3.4 *)
+let render_mpeg2_timestamp =
+  let mpeg2_timestamp_unit = 90000. in
+  let frame_len =
+    lazy
+      (Int64.of_float
+         (Frame.seconds_of_main (Lazy.force Frame.size) *. mpeg2_timestamp_unit))
+  in
+  fun ~frame_position ~sample_position () ->
+    let buf = Buffer.create 10 in
+    let frame_position =
+      Int64.mul (Lazy.force frame_len) (Int64.of_int frame_position)
+    in
+    let sample_position =
+      Int64.of_float
+        (Frame.seconds_of_main sample_position *. mpeg2_timestamp_unit)
+    in
+    let position = Int64.add frame_position sample_position in
+    let position = Int64.unsigned_rem position 0x1ffffffffL in
+    Buffer.add_int64_be buf position;
+    Buffer.contents buf
+
+let mk_hls_id3 ?(id3_version = 3) ~frame_position ~sample_position m =
+  let timestamp =
+    Printf.sprintf "com.apple.streaming.transportStreamTimestamp\000%s"
+      (render_mpeg2_timestamp ~frame_position ~sample_position ())
+  in
+  let m = ("PRIV", timestamp) :: m in
+  Utils.id3v2_of_metadata ~version:id3_version m
+
+let mk_id3_hls ~pos encoder =
+  let id3_version_ref = ref None in
+  let init ?id3_enabled ?id3_version () =
+    id3_version_ref := id3_version;
+    if id3_enabled = Some false then
+      Lang_encoder.raise_error ~pos "Format requires ID3 metadata!";
+    true
+  in
+  let insert_id3 ~frame_position ~sample_position m =
+    Some
+      (mk_hls_id3 ?id3_version:!id3_version_ref ~frame_position ~sample_position
+         m)
+  in
+  Encoder.{ (dummy_hls encoder) with init; insert_id3 }

src/core/encoder/encoders/fdkaac_encoder.ml

@@ -111,7 +111,7 @@ let encoder ~pos aac =
   {
     Encoder.insert_metadata = (fun _ -> ());
     header = (fun () -> Strings.empty);
-    hls = Encoder.dummy_hls encode;
+    hls = Encoder_utils.mk_id3_hls ~pos encode;
     encode;
     stop;
   }

src/core/encoder/encoders/ffmpeg_encoder_common.ml

@@ -24,28 +24,6 @@
 
 let log = Ffmpeg_utils.log
 
-(* See: https://datatracker.ietf.org/doc/html/rfc8216#section-3.4 *)
-let render_mpeg2_timestamp =
-  let mpeg2_timestamp_unit = 90000. in
-  let frame_len =
-    lazy
-      (Int64.of_float
-         (Frame.seconds_of_main (Lazy.force Frame.size) *. mpeg2_timestamp_unit))
-  in
-  fun ~frame_position ~sample_position () ->
-    let buf = Buffer.create 10 in
-    let frame_position =
-      Int64.mul (Lazy.force frame_len) (Int64.of_int frame_position)
-    in
-    let sample_position =
-      Int64.of_float
-        (Frame.seconds_of_main sample_position *. mpeg2_timestamp_unit)
-    in
-    let position = Int64.add frame_position sample_position in
-    let position = Int64.unsigned_rem position 0x1ffffffffL in
-    Buffer.add_int64_be buf position;
-    Buffer.contents buf
-
 type encoder = {
   mk_stream : Frame.t -> unit;
   encode : Frame.t -> int -> int -> unit;
@@ -242,16 +220,11 @@ let encoder ~pos ~mk_streams ffmpeg meta =
       | Some "adts" | Some "mp3" | Some "ac3" | Some "eac3" ->
           if id3_enabled = Some false then
             Lang_encoder.raise_error ~pos "Format requires ID3 metadata!";
-          let id3_version = Option.value ~default:3 id3_version in
           encoder.insert_id3 <-
             (fun ~frame_position ~sample_position m ->
-              let timestamp =
-                Printf.sprintf
-                  "com.apple.streaming.transportStreamTimestamp\000%s"
-                  (render_mpeg2_timestamp ~frame_position ~sample_position ())
-              in
-              let m = ("PRIV", timestamp) :: m in
-              Some (Utils.id3v2_of_metadata ~version:id3_version m));
+              Some
+                (Encoder_utils.mk_hls_id3 ?id3_version ~frame_position
+                   ~sample_position m));
           true
       | Some _ when id3_enabled = Some true ->
           Lang_encoder.raise_error ~pos

src/core/encoder/encoders/lame_encoder.ml

@@ -75,7 +75,7 @@ let () =
     Lame.init_params enc;
     enc
   in
-  let mp3_encoder mp3 metadata =
+  let mp3_encoder ~pos mp3 metadata =
     let enc = create_encoder mp3 in
     let channels = if mp3.Mp3_format.stereo then 2 else 1 in
     (* Lame accepts data of a fixed length.. *)
@@ -118,12 +118,13 @@ let () =
     let stop () = Strings.of_string (Lame.encode_flush enc) in
     {
       insert_metadata = (fun _ -> ());
-      hls = Encoder.dummy_hls encode;
+      hls = Encoder_utils.mk_id3_hls ~pos encode;
       encode;
       header = (fun () -> Strings.empty);
       stop;
     }
   in
   Plug.register Encoder.plug "lame" ~doc:"LAME mp3 encoder." (function
-    | Encoder.MP3 mp3 -> Some (fun ?hls:_ ~pos:_ _ meta -> mp3_encoder mp3 meta)
+    | Encoder.MP3 mp3 ->
+        Some (fun ?hls:_ ~pos _ meta -> mp3_encoder ~pos mp3 meta)
     | _ -> None)

src/core/encoder/encoders/shine_encoder.ml

@@ -27,7 +27,7 @@ open Shine_format
 let create_encoder ~samplerate ~bitrate ~channels =
   Shine.create { Shine.channels; samplerate; bitrate }
 
-let encoder shine =
+let encoder ~pos shine =
   let channels = shine.channels in
   let samplerate = Lazy.force shine.samplerate in
   let enc = create_encoder ~samplerate ~bitrate:shine.bitrate ~channels in
@@ -67,13 +67,13 @@ let encoder shine =
   {
     Encoder.insert_metadata = (fun _ -> ());
     header = (fun () -> Strings.empty);
-    hls = Encoder.dummy_hls encode;
+    hls = Encoder_utils.mk_id3_hls ~pos encode;
     encode;
     stop;
   }
 
 let () =
   Plug.register Encoder.plug "shine" ~doc:"SHINE fixed-point mp3 encoder."
     (function
-    | Encoder.Shine m -> Some (fun ?hls:_ ~pos:_ _ _ -> encoder m)
+    | Encoder.Shine m -> Some (fun ?hls:_ ~pos _ _ -> encoder ~pos m)
     | _ -> None)

tests/streams/hls_id3v2.liq

@@ -26,6 +26,9 @@ output.file.hls(
       %ffmpeg(format = "mpegts", %audio(codec = "aac")).{id3_version=4}
     ),
     ("ts", %ffmpeg(format = "mpegts", %audio(codec = "aac")).{id3=false}),
+    ("shine", %shine),
+    ("lame", %mp3),
+    ("fdkaac", %fdkaac),
     (
       "mp4",
       %ffmpeg(
@@ -39,17 +42,30 @@ output.file.hls(
   s
 )
 
-to_check = ref({aac=null(), ts_with_meta=null(), ts=null(), mp4=null()})
+to_check =
+  ref(
+    {
+      aac=null(),
+      shine=null(),
+      lame=null(),
+      fdkaac=null(),
+      ts_with_meta=null(),
+      ts=null(),
+      mp4=null()
+    }
+  )
 
 def check_done() =
-  let {aac, ts_with_meta, ts, mp4} = to_check()
+  let {aac, shine, lame, fdkaac, ts_with_meta, ts, mp4} = to_check()
+
   if
     null.defined(ts)
   then
     test.fail(
       "ts shouldn't have metadata!"
     )
   end
+
   if
     null.defined(mp4)
   then
@@ -59,10 +75,12 @@ def check_done() =
   end
 
   if
-    null.defined(aac) and null.defined(ts_with_meta)
+    null.defined(aac) and null.defined(fdkaac) and null.defined(ts_with_meta)
   then
     aac = null.get(aac)
+    fdkaac = null.get(fdkaac)
     ts_with_meta = null.get(ts_with_meta)
+
     if
 
         aac["title"] ==
@@ -72,6 +90,13 @@ def check_done() =
       aac["album"] == "foolol"
     and
 
+        fdkaac["title"] ==
+          "test title"
+
+    and
+      fdkaac["album"] == "foolol"
+    and
+
         ts_with_meta["title"] ==
           "test title"
 
@@ -95,6 +120,49 @@ aac =
   )
 
 output.dummy(fallible=true, aac)
+
+#< FFMPEG seems to be unable to parse id3v2 metadata
+inside mp3 streams..
+shine = input.hls("#{tmp_dir}/shine.m3u8")
+shine =
+source.on_metadata(
+shine,
+fun (m) ->
+begin
+if m["title"] != "" then to_check := to_check().{shine=m} end
+check_done()
+end
+)
+
+output.dummy(fallible=true, shine)
+
+lame = input.hls("#{tmp_dir}/lame.m3u8")
+lame =
+source.on_metadata(
+lame,
+fun (m) ->
+begin
+if m["title"] != "" then to_check := to_check().{lame=m} end
+check_done()
+end
+)
+
+output.dummy(fallible=true, lame)
+>#
+
+fdkaac = input.hls("#{tmp_dir}/fdkaac.m3u8")
+fdkaac =
+  source.on_metadata(
+    fdkaac,
+    fun (m) ->
+      begin
+        if m["title"] != "" then to_check := to_check().{fdkaac=m} end
+        check_done()
+      end
+  )
+
+output.dummy(fallible=true, fdkaac)
+
 ts_with_meta = input.hls("#{tmp_dir}/ts_with_meta.m3u8")
 ts_with_meta =
   source.on_metadata(
@@ -131,4 +199,4 @@ mp4 =
   )
 
 output.dummy(fallible=true, mp4)
-clock.assign_new(sync="none", [s, aac, ts_with_meta, ts, mp4])
+clock.assign_new(sync="none", [s, aac, fdkaac, ts_with_meta, ts, mp4])