diff --git a/.github/scripts/build-posix.sh b/.github/scripts/build-posix.sh
index 70f67880ea..e35d81a46c 100755
--- a/.github/scripts/build-posix.sh
+++ b/.github/scripts/build-posix.sh
@@ -41,6 +41,10 @@ echo "::group::Setting up specific dependencies"
 
 opam install -y xml-light
 
+git clone https://github.com/savonet/ocaml-xiph.git
+cd ocaml-xiph
+opam install -y .
+
 cd /tmp/liquidsoap-full/liquidsoap
 
 ./.github/scripts/checkout-deps.sh
diff --git a/CHANGES.md b/CHANGES.md
index e6bdda0518..2b22641a28 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -26,6 +26,7 @@ Fixed:
 
 - Fixed request resolution loop when enabling both `autocue`
   and `replaygain` metadata resolvers (#4245, fixed in #4246)
+- Fixed `flac` encoding segfault (#4286, #4274)
 - Fixed source `last_metadata` not being properly updated (#4262)
 - Convert all ICY (icecast) metadata from `input.http` to `utf8`.
 - Fixed `inotify` unwatching due to GC cleanup (#4275)
diff --git a/dune-project b/dune-project
index 2a47da480d..dfe24e7bce 100644
--- a/dune-project
+++ b/dune-project
@@ -117,7 +117,7 @@
     (fdkaac (< 0.3.1))
     (ffmpeg (< 1.2.0))
     (ffmpeg-avutil (< 1.2.0))
-    (flac (< 0.3.0))
+    (flac (< 1.0.0))
     (frei0r (< 0.1.0))
     (inotify (< 1.0))
     (ladspa (< 0.2.0))
@@ -125,7 +125,7 @@
     (lo (< 0.2.0))
     (mad (< 0.5.0))
     (magic (< 0.6))
-    (ogg (< 0.7.4))
+    (ogg (< 1.0.0))
     (opus (< 0.2.0))
     (portaudio (< 0.2.0))
     (posix-time2 (< 2.0.2))
@@ -133,13 +133,13 @@
     (samplerate (< 0.1.5))
     (shine (< 0.2.0))
     (soundtouch (< 0.1.9))
-    (speex (< 0.4.0))
+    (speex (< 1.0.0))
     (srt (< 0.3.0))
     (ssl (< 0.7.0))
     (tls (< 1.0.2))
     (sdl-liquidsoap (< 2))
-    (theora (< 0.4.0))
-    (vorbis (< 0.8.0))
+    (theora (< 1.0.0))
+    (vorbis (< 1.0.0))
     (xmlplaylist (< 0.1.3)))
   (synopsis "Liquidsoap core library and binary"))
 
diff --git a/liquidsoap-core.opam b/liquidsoap-core.opam
index 6a75736720..39767caf15 100644
--- a/liquidsoap-core.opam
+++ b/liquidsoap-core.opam
@@ -83,7 +83,7 @@ conflicts: [
   "fdkaac" {< "0.3.1"}
   "ffmpeg" {< "1.2.0"}
   "ffmpeg-avutil" {< "1.2.0"}
-  "flac" {< "0.3.0"}
+  "flac" {< "1.0.0"}
   "frei0r" {< "0.1.0"}
   "inotify" {< "1.0"}
   "ladspa" {< "0.2.0"}
@@ -91,7 +91,7 @@ conflicts: [
   "lo" {< "0.2.0"}
   "mad" {< "0.5.0"}
   "magic" {< "0.6"}
-  "ogg" {< "0.7.4"}
+  "ogg" {< "1.0.0"}
   "opus" {< "0.2.0"}
   "portaudio" {< "0.2.0"}
   "posix-time2" {< "2.0.2"}
@@ -99,13 +99,13 @@ conflicts: [
   "samplerate" {< "0.1.5"}
   "shine" {< "0.2.0"}
   "soundtouch" {< "0.1.9"}
-  "speex" {< "0.4.0"}
+  "speex" {< "1.0.0"}
   "srt" {< "0.3.0"}
   "ssl" {< "0.7.0"}
   "tls" {< "1.0.2"}
   "sdl-liquidsoap" {< "2"}
-  "theora" {< "0.4.0"}
-  "vorbis" {< "0.8.0"}
+  "theora" {< "1.0.0"}
+  "vorbis" {< "1.0.0"}
   "xmlplaylist" {< "0.1.3"}
 ]
 build: [
diff --git a/src/core/decoder/liq_flac_decoder.ml b/src/core/decoder/liq_flac_decoder.ml
index 5a7ff869a6..506d92dc27 100644
--- a/src/core/decoder/liq_flac_decoder.ml
+++ b/src/core/decoder/liq_flac_decoder.ml
@@ -45,11 +45,14 @@ let create_decoder input =
       | Some f -> Some (fun () -> Int64.of_int (f ()))
       | None -> None
   in
-  let dummy_c =
-    Flac.Decoder.get_callbacks ?seek ?tell ?length read (fun _ -> ())
+  let write_ref = ref (fun _ -> ()) in
+  let write v =
+    let fn = !write_ref in
+    fn v
+  in
+  let decoder, info, _ =
+    Flac.Decoder.create ?seek ?tell ?length ~read ~write ()
   in
-  let decoder = Flac.Decoder.create dummy_c in
-  let decoder, info, _ = Flac.Decoder.init decoder dummy_c in
   let samplerate, _ =
     (info.Flac.Decoder.sample_rate, info.Flac.Decoder.channels)
   in
@@ -60,33 +63,29 @@ let create_decoder input =
         let duration = Frame.seconds_of_main ticks in
         let samples = Int64.of_float (duration *. float samplerate) in
         let pos = Int64.add !processed samples in
-        let c =
-          Flac.Decoder.get_callbacks ?seek ?tell ?length read (fun _ -> ())
-        in
-        let ret = Flac.Decoder.seek decoder c pos in
+        let ret = Flac.Decoder.seek decoder pos in
         if ret = true then (
           processed := pos;
           ticks)
         else (
-          match Flac.Decoder.state decoder c with
+          match Flac.Decoder.state decoder with
             | `Seek_error ->
-                if Flac.Decoder.flush decoder c then 0
+                if Flac.Decoder.flush decoder then 0
                 else
                   (* Flushing failed, we are in an unknown state.. *)
                   raise End_of_stream
             | _ -> 0));
     decode =
       (fun buffer ->
-        let c =
-          Flac.Decoder.get_callbacks ?seek ?tell ?length read (fun data ->
-              let len = try Audio.length data with _ -> 0 in
-              processed := Int64.add !processed (Int64.of_int len);
-              buffer.Decoder.put_pcm ~samplerate data)
-        in
-        match Flac.Decoder.state decoder c with
+        (write_ref :=
+           fun data ->
+             let len = try Audio.length data with _ -> 0 in
+             processed := Int64.add !processed (Int64.of_int len);
+             buffer.Decoder.put_pcm ~samplerate data);
+        match Flac.Decoder.state decoder with
           | `Search_for_metadata | `Read_metadata | `Search_for_frame_sync
           | `Read_frame ->
-              Flac.Decoder.process decoder c
+              Flac.Decoder.process decoder
           | _ -> raise End_of_stream);
     eof = (fun _ -> ());
     close = (fun _ -> ());
@@ -118,7 +117,7 @@ let file_type filename =
     ~finally:(fun () -> Unix.close fd)
     (fun () ->
       let write _ = () in
-      let h = Flac.Decoder.File.create_from_fd write fd in
+      let h = Flac.Decoder.File.create_from_fd ~write fd in
       let info = h.Flac.Decoder.File.info in
       let rate, channels =
         (info.Flac.Decoder.sample_rate, info.Flac.Decoder.channels)
@@ -161,7 +160,7 @@ let get_tags ~metadata:_ ~extension ~mime file =
     ~finally:(fun () -> Unix.close fd)
     (fun () ->
       let write _ = () in
-      let h = Flac.Decoder.File.create_from_fd write fd in
+      let h = Flac.Decoder.File.create_from_fd ~write fd in
       match h.Flac.Decoder.File.comments with Some (_, m) -> m | None -> [])
 
 let metadata_decoder_priority =
@@ -191,7 +190,7 @@ let dresolver ~metadata:_ file =
     ~finally:(fun () -> Unix.close fd)
     (fun () ->
       let write _ = () in
-      let h = Flac.Decoder.File.create_from_fd write fd in
+      let h = Flac.Decoder.File.create_from_fd ~write fd in
       let info = h.Flac.Decoder.File.info in
       match info.Flac.Decoder.total_samples with
         | x when x = Int64.zero -> raise Not_found
diff --git a/src/core/decoder/ogg_flac_duration.ml b/src/core/decoder/ogg_flac_duration.ml
index 339c3d642e..fa14de0d34 100644
--- a/src/core/decoder/ogg_flac_duration.ml
+++ b/src/core/decoder/ogg_flac_duration.ml
@@ -37,22 +37,14 @@ let dresolver ~metadata:_ file =
         let serial = Ogg.Page.serialno page in
         let os = Ogg.Stream.create ~serial () in
         Ogg.Stream.put_page os page;
-        let packet = Ogg.Stream.get_packet os in
+        let packet = Ogg.Stream.peek_packet os in
         (* Test header. Do not catch anything, first page should be sufficient *)
         if not (Flac_ogg.Decoder.check_packet packet) then raise Not_found;
         let fill () =
           let page = Ogg.Sync.read sync in
           if Ogg.Page.serialno page = serial then Ogg.Stream.put_page os page
         in
-        let callbacks = Flac_ogg.Decoder.get_callbacks os (fun _ -> ()) in
-        let dec = Flac.Decoder.create callbacks in
-        let rec info () =
-          try Flac.Decoder.init dec callbacks
-          with Ogg.Not_enough_data ->
-            fill ();
-            info ()
-        in
-        info ()
+        Flac_ogg.Decoder.create ~fill ~write:(fun _ -> ()) os
       in
       (* Now find a flac stream *)
       let rec init () = try test_flac () with Not_found -> init () in
@@ -64,7 +56,7 @@ let dresolver ~metadata:_ file =
       samples /. float info.Flac.Decoder.sample_rate)
 
 let () =
-  Plug.register Request.dresolvers "ogg/flac" ~doc:""
+  Plug.register Request.dresolvers "ogg_flac" ~doc:""
     {
       dpriority = (fun () -> Liq_ogg_decoder.priority#get);
       file_extensions = (fun () -> Liq_ogg_decoder.file_extensions#get);
diff --git a/src/core/encoder/encoders/flac_encoder.ml b/src/core/encoder/encoders/flac_encoder.ml
index 343ca83cd9..855c7ecf40 100644
--- a/src/core/encoder/encoders/flac_encoder.ml
+++ b/src/core/encoder/encoders/flac_encoder.ml
@@ -44,8 +44,7 @@ let encoder flac meta =
   in
   let buf = Strings.Mutable.empty () in
   let write chunk = Strings.Mutable.add_bytes buf chunk in
-  let cb = Flac.Encoder.get_callbacks write in
-  let enc = Flac.Encoder.create ~comments p cb in
+  let enc = Flac.Encoder.create ~comments ~write p in
   let enc = ref enc in
   let encode frame =
     let b = AFrame.pcm frame in
@@ -55,11 +54,11 @@ let encoder flac meta =
         (dst_freq /. src_freq) b 0 len
     in
     let b = Audio.sub b start len in
-    Flac.Encoder.process !enc cb b;
+    Flac.Encoder.process !enc b;
     Strings.Mutable.flush buf
   in
   let stop () =
-    Flac.Encoder.finish !enc cb;
+    Flac.Encoder.finish !enc;
     Strings.Mutable.flush buf
   in
   {
diff --git a/src/core/encoder/encoders/ogg_encoder.ml b/src/core/encoder/encoders/ogg_encoder.ml
index 0e1508b812..0e296b6428 100644
--- a/src/core/encoder/encoders/ogg_encoder.ml
+++ b/src/core/encoder/encoders/ogg_encoder.ml
@@ -132,8 +132,7 @@ let encoder ~pos { Ogg_format.audio; video } =
     and ogg_stop () =
       let f track = track.id <- None in
       List.iter f tracks;
-      if Ogg_muxer.state ogg_enc = Ogg_muxer.Streaming then
-        Ogg_muxer.end_of_stream ogg_enc
+      Ogg_muxer.end_of_stream ogg_enc
     and stop () =
       ogg_stop ();
       Ogg_muxer.get_data ogg_enc
diff --git a/src/core/ogg_formats/ogg_flac_encoder.ml b/src/core/ogg_formats/ogg_flac_encoder.ml
index 86849ffe55..b8128c5531 100644
--- a/src/core/ogg_formats/ogg_flac_encoder.ml
+++ b/src/core/ogg_formats/ogg_flac_encoder.ml
@@ -51,7 +51,7 @@ let create_encoder ~flac ~comments () =
       | None ->
           let x =
             Flac_ogg.Encoder.create ~comments ~serialno:(Ogg.Stream.serialno os)
-              p write_cb
+              ~write:write_cb p
           in
           enc := Some x;
           x
@@ -80,8 +80,8 @@ let create_encoder ~flac ~comments () =
       (data.Ogg_muxer.data, data.Ogg_muxer.offset, data.Ogg_muxer.length)
     in
     let b = Array.map (fun x -> Array.sub x ofs len) b in
-    let { Flac_ogg.Encoder.encoder; callbacks } = get_enc os in
-    Flac.Encoder.process encoder callbacks b;
+    let { Flac_ogg.Encoder.encoder } = get_enc os in
+    Flac.Encoder.process encoder b;
     List.iter write_page (flush_pages ())
   in
   let end_of_page p =
@@ -90,12 +90,12 @@ let create_encoder ~flac ~comments () =
     else Ogg_muxer.Time (Int64.to_float granulepos /. float samplerate)
   in
   let end_of_stream os =
-    let { Flac_ogg.Encoder.encoder; callbacks } = get_enc os in
+    let { Flac_ogg.Encoder.encoder } = get_enc os in
     (* Assert that at least some data was encoded.. *)
     if not !started then (
       let b = empty_data () in
-      Flac.Encoder.process encoder callbacks b);
-    Flac.Encoder.finish encoder callbacks;
+      Flac.Encoder.process encoder b);
+    Flac.Encoder.finish encoder;
     set_stream_eos os;
     flush_pages ()
   in
diff --git a/src/core/ogg_formats/ogg_muxer.ml b/src/core/ogg_formats/ogg_muxer.ml
index 759257223a..2f95be87fa 100644
--- a/src/core/ogg_formats/ogg_muxer.ml
+++ b/src/core/ogg_formats/ogg_muxer.ml
@@ -219,9 +219,7 @@ let register_track ?fill encoder track_encoder =
 
 (** Start streams, set state to Streaming. *)
 let streams_start encoder =
-  if Hashtbl.length encoder.tracks = 0 then
-    log#info "%s: Starting stream with no ogg track.." encoder.id;
-  log#info "%s: Starting all streams" encoder.id;
+  log#info "%s: Starting %d track(s)" encoder.id (Hashtbl.length encoder.tracks);
 
   (* Add skeleton information first. *)
   begin
diff --git a/tests/regression/dune.inc b/tests/regression/dune.inc
index dc606c4403..e6a72ef33e 100644
--- a/tests/regression/dune.inc
+++ b/tests/regression/dune.inc
@@ -975,6 +975,22 @@
   (:run_test ../run_test.exe))
  (action (run %{run_test} external-encoder.liq liquidsoap %{test_liq} external-encoder.liq)))
   
+(rule
+ (alias citest)
+ (package liquidsoap)
+ (deps
+  fallible_ogg.liq
+  ../media/all_media_files
+  ../../src/bin/liquidsoap.exe
+  ../streams/file1.png
+  ../streams/file1.mp3
+  ./theora-test.mp4
+  (package liquidsoap)
+  (source_tree ../../src/libs)
+  (:test_liq ../test.liq)
+  (:run_test ../run_test.exe))
+ (action (run %{run_test} fallible_ogg.liq liquidsoap %{test_liq} fallible_ogg.liq)))
+  
 (rule
  (alias citest)
  (package liquidsoap)
diff --git a/tests/regression/fallible_ogg.liq b/tests/regression/fallible_ogg.liq
new file mode 100644
index 0000000000..8db15c5273
--- /dev/null
+++ b/tests/regression/fallible_ogg.liq
@@ -0,0 +1,9 @@
+port = 9301
+
+s = playlist("../media")
+
+output.icecast(fallible=true, port=port, mount="test.flac", %ogg(%flac), s)
+
+s = input.harbor("test.flac", buffer=1., port=port)
+
+output.dummy(on_start=test.pass, fallible=true, s)