diff --git a/audio-decoder.rkt b/audio-decoder.rkt
index f92c3d8..49c510f 100644
--- a/audio-decoder.rkt
+++ b/audio-decoder.rkt
@@ -2,6 +2,9 @@
 
   (require "flac-decoder.rkt"
            "mp3-decoder.rkt"
+           "ffmpeg-decoder.rkt"
+           "audio-sniffer.rkt"
+           "private/utils.rkt"
            racket/contract
            racket/string
            racket/path
@@ -52,12 +55,38 @@
                                 mp3-stop
                                 'ao))
 
+  ;; FFmpeg decodere
+  (hash-set! audio-readers
+             'ffmpeg
+             (make-audio-reader '("ogg" "oga" "opus"
+                                  "m4a" "mp4" "m4b"
+                                  "aac"
+                                  "wav"
+                                  "aiff" "aif" "aifc"
+                                  "wma"
+                                  "webm" "mkv" "mka")
+                                ffmpeg-valid?
+                                ffmpeg-open
+                                ffmpeg-read
+                                ffmpeg-seek
+                                ffmpeg-stop
+                                'ao))
+
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;; Known extensions
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
   (define known-extensions
-    '("flac" "mp3"))
+    '("flac"   ; FLAC decoder
+      "mp3"    ; mp3 decoder
+      "ogg" "oga" "opus"
+      "m4a" "mp4" "m4b"
+      "aac"
+      "wav"
+      "aiff" "aif" "aifc"
+      "wma"
+      "webm" "mkv" "mka" ; FFMPEG decoder
+      ))
 
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;; Register audio reader
@@ -92,7 +121,11 @@
     (set! ext (format "~a" ext))
     (when (string-prefix? ext ".")
       (set! ext (substring ext 1)))
-    (not (null? (filter (λ (e) (string-ci=? ext e)) known-extensions)))
+    (if (not (null? (filter (λ (e) (string-ci=? ext e)) known-extensions)))
+        #t
+        (begin
+          (warn-sound "extension '~a' not in known-extensions '~a'" ext known-extensions)
+          #f))
     )
 
   (define/contract (audio-file-valid? file)
@@ -189,17 +222,33 @@
   (define (right-reader? reader ext)
     (not (null? (filter (λ (e) (string-ci=? ext e)) (audio-reader-exts reader)))))
 
+  (define reader-for-kind
+    (make-hash '((mp3 . ffmpeg)            ; ffmpeg does a better job on gapless playback...
+                 (flac . flac)
+                 (ogg . ffmpeg)
+                 (vorbis . ffmpeg)
+                 (opus . ffmpeg)
+                 (wav . ffmpeg)
+                 (aiff . ffmpeg)
+                 (mp4 . ffmpeg)
+                 (aac . ffmpeg)
+                 (alac . ffmpeg)
+                 (ac3 . ffmpeg)
+                 (ape . ffmpeg)
+                 (wavpack . ffmpeg)
+                 (wma . ffmpeg)
+                 (matroska . ffmpeg))))
+
+
   (define (find-reader audio-file)
-    (let* ((f (build-path audio-file))
-           (ext (substring (format "~a" (path-get-extension audio-file)) 1)))
-      (letrec ((f (λ (keys)
-                    (if (null? keys)
-                        #f
-                        (let ((reader (hash-ref audio-readers (car keys))))
-                          (if (right-reader? reader ext)
-                              (list (car keys) reader)
-                              (f (cdr keys))))))))
-        (f (hash-keys audio-readers))
+    ; First try to sniff the format
+    (let ((format (audio-sniff-format/extension audio-file)))
+      (let ((reader-kind (hash-ref reader-for-kind format #f)))
+        (if (eq? reader-kind #f)
+            #f
+            (let ((reader (hash-ref audio-readers reader-kind)))
+              (list reader-kind reader))
+            )
         )
       )
     )
diff --git a/audio-sniffer.rkt b/audio-sniffer.rkt
index 250dfe8..589c424 100644
--- a/audio-sniffer.rkt
+++ b/audio-sniffer.rkt
@@ -2,7 +2,9 @@
 
 (require racket/contract
          racket/path
-         racket/string)
+         racket/string
+         racket/runtime-path
+         )
 
 (provide audio-format?
          audio-sniff-format
@@ -333,4 +335,24 @@
 
 (define/contract (audio-format-matches? file formats)
   (-> path-string? (listof symbol?) boolean?)
-  (audio-format-matches?* file formats))
\ No newline at end of file
+  (audio-format-matches?* file formats))
+
+(define-runtime-path audio-tests "tests")
+
+(define (sniff-test)
+  (for-each (λ (ext)
+              (let* ((dir (build-path audio-tests))
+                     (ext* (format ".~a" ext))
+                     (files (map (λ (f)
+                                   (build-path audio-tests f))
+                                 (filter (λ (f)
+                                           (string-suffix? (format "~a" f) ext*))
+                                         (directory-list dir))))
+                     )
+                (for-each (λ (f)
+                            (displayln (format "~a: ~a" f (audio-sniff-format/extension f))))
+                          files)
+                )
+              )
+            '(aac adts flac mp3 ogg ts ac3 aiff m4a mp4 ogx wav wv mp2))
+  )
diff --git a/ffmpeg-decoder.rkt b/ffmpeg-decoder.rkt
index aa05db3..b0229e0 100644
--- a/ffmpeg-decoder.rkt
+++ b/ffmpeg-decoder.rkt
@@ -1,7 +1,7 @@
 (module ffmpeg_decoder racket/base
 
   (require ffi/unsafe
-           "ffmpeg_ffi.rkt"
+           "ffmpeg-ffi.rkt"
            "private/utils.rkt"
            (prefix-in fin: finalizer)
            )
diff --git a/ffmpeg-ffi.rkt b/ffmpeg-ffi.rkt
index 3d9f528..b44cf63 100644
--- a/ffmpeg-ffi.rkt
+++ b/ffmpeg-ffi.rkt
@@ -118,6 +118,16 @@
   (define-ffmpeg-audio fmpg_timecode
     (_fun _fmpg_instance -> _double))
 
+  (define-ffmpeg-audio fmpg_ffmpeg_version
+    (_fun -> _string*/utf-8))
+
+  (define-ffmpeg-audio fmpg_int_version2string
+    (_fun _int -> _string*/utf-8))
+
+  (define-ffmpeg-audio fmpg_compatible_ffmpeg
+    (_fun -> _int))
+  
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Our interface for decoding to racket
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/libao-async-ffi.rkt b/libao-async-ffi.rkt
index ae0a295..543e49c 100644
--- a/libao-async-ffi.rkt
+++ b/libao-async-ffi.rkt
@@ -8,6 +8,7 @@
          )
 
 (provide ao_create_async
+         ao_real_output_bits_async
          ao_stop_async
          ao_play_async
          ao_is_at_music_id_async
@@ -66,6 +67,10 @@
 ;extern void *ao_create_async(int bits, int rate, int channel, int byte_format);
 (define-libao-async ao_create_async(_fun _int _int _int _Endian_t _string/utf-8 -> _libao-async-handle-pointer))
 
+;extern int ao_real_output_bits(void *handle)
+(define-libao-async ao_real_output_bits_async
+  (_fun _libao-async-handle-pointer -> _int))
+
 ;extern void ao_stop_async(void *handle);
 (define-libao-async ao_stop_async(_fun _libao-async-handle-pointer -> _void))
 
diff --git a/libao.rkt b/libao.rkt
index c2f15d0..4a65671 100644
--- a/libao.rkt
+++ b/libao.rkt
@@ -10,6 +10,7 @@
          )
 
 (provide ao-open-live
+         ao-device-bits
          ao-open-file
          ao-play
          ao-close
@@ -35,6 +36,8 @@
 (define-struct ao-handle (handle-num
                           [bits #:auto #:mutable]
                           [bytes-per-sample #:auto #:mutable]
+                          [dev-bits #:auto #:mutable]
+                          [dev-bytes-per-sample #:auto #:mutable]
                           [byte-format #:auto #:mutable]
                           [channels #:auto #:mutable]
                           [rate #:auto #:mutable]
@@ -113,15 +116,17 @@
                   (err-sound "ao-open-live - cannote create player")
                   (set-ao-handle-closed! handle #t)
                   handle)
-                (begin
-                  (info-sound "ao-open-live - created player")
+                (let ((out-bits (ffi:ao_real_output_bits_async player)))
+                  (info-sound "ao-open-live - created player at ~a bits" out-bits)
+                  (set-ao-handle-dev-bits! handle out-bits)
+                  (set-ao-handle-dev-bytes-per-sample! handle (/ out-bits 8))
                   (set-ao-handle-closed! handle #f)
                   handle
                   )
                 )
             )
       )
-      )
+    )
                     
 
 (rc:define/contract (ao-close handle)
@@ -143,6 +148,10 @@
 (define (any? x)
   #t)
 
+(rc:define/contract (ao-device-bits handle)
+  (rc:-> ao-handle? integer?)
+  (ao-handle-dev-bits handle))
+
 (rc:define/contract (ao-play handle music-id at-time-in-s music-duration-s buffer buf-len buf-type)
   (rc:-> ao-handle? integer? number? number? any? integer? ao-supported-music-format? void?)                    
   (let* ((bytes-per-sample (ao-handle-bytes-per-sample handle))
diff --git a/play-test.rkt b/play-test.rkt
index cd3b633..79db44d 100644
--- a/play-test.rkt
+++ b/play-test.rkt
@@ -4,10 +4,13 @@
          simple-log
          "private/utils.rkt"
          racket-sprintf
+         racket/runtime-path
          ;data/queue
   ;racket-sound
          )
 
+(define-runtime-path tests "tests")
+
 (define test-file3 #f)
 (define test-file4 #f)
 (define test-file3-id 3)
@@ -15,8 +18,9 @@
 (let ((os (system-type 'os)))
   (when (eq? os 'unix)
     ;(set! test-file3 "/muziek/Klassiek-Viool/Alina Ibragimova/Paganini_24 Caprices (2021)/24. 24 Caprices, Op 1 - No. 24 in A minor- Tema con variazioni. Quasi presto.flac")
-    (set! test-file3 "/tmp/test.mp3")
-    (set! test-file4 "/tmp/test1.mp3")
+    ;(set! test-file3 "/tmp/test.mp3")
+    (set! test-file3 (build-path tests "mahler-1.mp3"))
+    (set! test-file4 (build-path tests "mahler-2.mp3"))
     )
   (when (eq? os 'windows)
     ;(set! test-file3 "C:\\Muziek\\Klassiek-Strijkkwartet\\Quatuor Zaïde\\Franz\\01 Erlkönig, D. 328 (Arr. For String Quartet by Eric Mouret).flac")
@@ -34,6 +38,10 @@
 (define current-file-id -1)
 (define current-audio-h #f)
 
+(define current-bits -1)
+(define current-rate -1)
+(define current-channels -1)
+
 (sl-log-to-display)
 (define wav-output-file #f)
 (define seeked #f)
@@ -51,12 +59,43 @@
                       (when (= (round current-seconds) 10)
                         (when (and (= current-file-id 3) (not seeked))
                           (set! seeked #t)
-                          (audio-seek current-audio-h 97.0)))))
+                          (let ((perc (exact->inexact (* (/ (- duration 15) duration) 100.0))))
+                            (info-sound "Seeking to ~a%" perc)
+                            (audio-seek current-audio-h perc))))))
          )
+
+    (when (not (eq? ao-h #f))
+      (when (not (and
+                  (= current-bits bits-per-sample)
+                  (= current-rate rate)
+                  (= current-channels channels)))
+        (ao-close ao-h)
+        (set! ao-h #f)))
+    
     ;(displayln buf-info)
     (when (eq? ao-h #f)
-      (set! ao-h (ao-open-file bits-per-sample rate channels 'native-endian wav-output-file)))
+      
+      (info-sound "Opening ao handle")
+      (info-sound "bits-per-sample: ~a" bits-per-sample)
+      (info-sound "rate           : ~a" rate)
+      (info-sound "channels       : ~a" channels)
+      (info-sound "endian         : ~a" 'native-endian)
+      (info-sound "(optional) file: ~a" wav-output-file)
+      (sync-log-sound)
+      
+      (set! ao-h (ao-open-file bits-per-sample rate channels 'native-endian wav-output-file))
+
+      (set! current-bits bits-per-sample)
+      (set! current-rate rate)
+      (set! current-channels channels)
+      (info-sound "ao bits per sample: ~a" (ao-device-bits ao-h))
+      (sync-log-sound)
+      )
+    
     ;(displayln 'ao-play)
+    ;(dbg-sound "Playing audio at ~a" second)
+    ;(sync-log-sound)
+               
     (ao-play ao-h current-file-id second duration buffer buf-len ao-type)
     (set! duration (inexact->exact (round duration)))
     ;(displayln 'done)
diff --git a/private/utils.rkt b/private/utils.rkt
index cc6c946..1315e6d 100644
--- a/private/utils.rkt
+++ b/private/utils.rkt
@@ -18,6 +18,7 @@
            err-sound
            warn-sound
            fatal-sound
+           sync-log-sound
            )
 
   (sl-def-log racket-sound sound)
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