Extend OpenSubsonic support with Transcode Offset extension

api/funkwhale_api/music/models.py

@@ -916,14 +916,14 @@ class Upload(models.Model):
         # Not using reverse because this is slow
         return self.listen_url + "&download=false"
 
-    def get_transcoded_version(self, format, max_bitrate=None):
+    def get_transcoded_version(self, format, max_bitrate=None, time_offset=None):
         if format:
             mimetype = utils.EXTENSION_TO_MIMETYPE[format]
         else:
             mimetype = self.mimetype or "audio/mpeg"
             format = utils.MIMETYPE_TO_EXTENSION[mimetype]
 
-        existing_versions = self.versions.filter(mimetype=mimetype)
+        existing_versions = self.versions.filter(mimetype=mimetype, time_offset=time_offset)
         if max_bitrate is not None:
             # we don't want to transcode if a 320kbps version is available
             # and we're requestiong 300kbps
@@ -936,18 +936,24 @@ class Upload(models.Model):
             # we found an existing version, no need to transcode again
             return existing_versions[0]
 
-        return self.create_transcoded_version(mimetype, format, bitrate=max_bitrate)
+        return self.create_transcoded_version(mimetype, format, bitrate=max_bitrate, time_offset=time_offset)
 
     @transaction.atomic
-    def create_transcoded_version(self, mimetype, format, bitrate):
+    def create_transcoded_version(self, mimetype, format, bitrate, time_offset):
         # we create the version with an empty file, then
         # we'll write to it
         f = ContentFile(b"")
         bitrate = min(bitrate or 320000, self.bitrate or 320000)
-        version = self.versions.create(mimetype=mimetype, bitrate=bitrate, size=0)
+        version = self.versions.create(mimetype=mimetype, bitrate=bitrate, time_offset=time_offset, size=0)
+
+        if time_offset is not None:
+            time_offset_filename = "-" + str(time_offset)
+        else:
+            time_offset_filename = ""
+
         # we keep the same name, but we update the extension
         new_name = (
-            os.path.splitext(os.path.basename(self.audio_file.name))[0] + f".{format}"
+            os.path.splitext(os.path.basename(self.audio_file.name))[0] + time_offset_filename + f".{format}"
         )
         version.audio_file.save(new_name, f)
         utils.transcode_audio(
@@ -955,6 +961,7 @@ class Upload(models.Model):
             output=version.audio_file,
             output_format=utils.MIMETYPE_TO_EXTENSION[mimetype],
             bitrate=str(bitrate),
+            time_offset=time_offset,
         )
         version.size = version.audio_file.size
         version.save(update_fields=["size"])
@@ -1002,10 +1009,11 @@ class UploadVersion(models.Model):
     accessed_date = models.DateTimeField(null=True, blank=True)
     audio_file = models.FileField(upload_to=get_file_path, max_length=255)
     bitrate = models.PositiveIntegerField()
+    time_offset = models.IntegerField(null=True, blank=True)
     size = models.IntegerField()
 
     class Meta:
-        unique_together = ("upload", "mimetype", "bitrate")
+        unique_together = ("upload", "mimetype", "bitrate", "time_offset")
 
     @property
     def filename(self) -> str:

api/funkwhale_api/music/utils.py

@@ -108,7 +108,10 @@ def transcode_file(input, output, input_format=None, output_format="mp3", **kwar
     return transcode_audio(audio, output, output_format, **kwargs)
 
 
-def transcode_audio(audio, output, output_format, **kwargs):
+def transcode_audio(audio, output, output_format, time_offset=None, **kwargs):
+    if time_offset is not None:
+        audio = audio[time_offset:]
+
     with output.open("wb"):
         return audio.export(output, format=output_format, **kwargs)
 

api/funkwhale_api/music/views.py

@@ -501,7 +501,7 @@ def get_file_path(audio_file):
         return path.encode("utf-8")
 
 
-def should_transcode(upload, format, max_bitrate=None):
+def should_transcode(upload, format, max_bitrate=None, time_offset=None):
     if not preferences.get("music__transcoding_enabled"):
         return False
     format_need_transcoding = True
@@ -552,7 +552,7 @@ def record_downloads(f):
 
 @record_downloads
 def handle_serve(
-    upload, user, format=None, max_bitrate=None, proxy_media=True, download=True
+    upload, user, format=None, max_bitrate=None, time_offset=None, proxy_media=True, download=True
 ):
     f = upload
     # we update the accessed_date
@@ -593,8 +593,8 @@ def handle_serve(
         file_path = get_file_path(f.source.replace("file://", "", 1))
     mt = f.mimetype
 
-    if should_transcode(f, format, max_bitrate=max_bitrate):
-        transcoded_version = f.get_transcoded_version(format, max_bitrate=max_bitrate)
+    if should_transcode(f, format, max_bitrate=max_bitrate, time_offset=time_offset):
+        transcoded_version = f.get_transcoded_version(format, max_bitrate=max_bitrate, time_offset=time_offset)
         transcoded_version.accessed_date = now
         transcoded_version.save(update_fields=["accessed_date"])
         f = transcoded_version

api/funkwhale_api/subsonic/views.py

@@ -189,7 +189,10 @@ class SubsonicViewSet(viewsets.GenericViewSet):
     )
     def get_open_subsonic_extensions(self, request, *args, **kwargs):
         data = {
-            "openSubsonicExtensions": [{"name": "formPost", "versions": [1]}],
+            "openSubsonicExtensions": [
+                {"name": "formPost", "versions": [1]},
+                {"name": "transcodeOffset", "versions": [1]}
+            ],
         }
         return response.Response(data, status=200)
 
@@ -309,6 +312,15 @@ class SubsonicViewSet(viewsets.GenericViewSet):
         if max_bitrate:
             max_bitrate = max_bitrate * 1000
 
+        time_offset = data.get("timeOffset")
+        try:
+            time_offset = int(time_offset) or None
+        except (TypeError, ValueError):
+            time_offset = None
+
+        if time_offset:
+            time_offset = time_offset * 1000
+
         format = data.get("format") or None
         if max_bitrate and not format:
             # specific bitrate requested, but no format specified
@@ -323,6 +335,7 @@ class SubsonicViewSet(viewsets.GenericViewSet):
             user=request.user,
             format=format,
             max_bitrate=max_bitrate,
+            time_offset=time_offset,
             # Subsonic clients don't expect 302 redirection unfortunately,
             # So we have to proxy media files
             proxy_media=True,

changes/changelog.d/opensubsonic.feature

@@ -1 +1,2 @@
 Extend Subsonic API with OpenSubsonic support (#2270)
+Extend OpenSubsonic support with Transcode Offset extension