feat(models): add Source.prefer_audio_track

A per-Source CharField choice (original / default) with a data migration.
Defaults to 'original', which keeps the current combined-format matching
behaviour (added in PR #1452) unchanged. format_summary gains a
' DEFAULT-AUDIO' marker so the source list shows which sources deviate.

Refs #1468

tubesync/sync/migrations/0038_source_prefer_audio_track.py

@@ -0,0 +1,35 @@
+# Generated by Django 5.2.11 on 2026-09-07 00:00
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sync', '0037_alter_source_fallback'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='source',
+            name='prefer_audio_track',
+            field=models.CharField(
+                choices=[
+                    ('original', 'Original audio (recorded language)'),
+                    ('default', "Publisher's default audio (often an auto-dub)"),
+                ],
+                db_index=True,
+                default='original',
+                help_text=(
+                    'Which audio track to download when the source publishes more than one. '
+                    '"Original audio" is the track in the language the video was actually '
+                    'recorded in. "Publisher\'s default audio" is whichever track the uploader '
+                    'set as the default for viewers, which for many channels is an automatic '
+                    'dubbed translation. This setting has no effect when a video only offers a '
+                    'single audio track.'
+                ),
+                max_length=8,
+                verbose_name='prefer audio track',
+            ),
+        ),
+    ]

tubesync/sync/models/source.py

@@ -12,7 +12,7 @@ from django.utils.text import slugify
 from django.utils.translation import gettext_lazy as _
 from yt_dlp import DownloadError
 from ..choices import (Val,
-    SponsorBlock_Category, YouTube_SourceType, IndexSchedule,
+    AudioTrack, SponsorBlock_Category, YouTube_SourceType, IndexSchedule,
     CapChoices, Fallback, FileExtension, FilterSeconds,
     SourceResolution, SourceResolutionInteger,
     YouTube_VideoCodec, YouTube_AudioCodec,
@@ -252,6 +252,21 @@ class Source(db.models.Model):
         default=False,
         help_text=_('Where possible, prefer HDR media for this source'),
     )
+    prefer_audio_track = db.models.CharField(
+        _('prefer audio track'),
+        max_length=8,
+        db_index=True,
+        choices=AudioTrack.choices,
+        default=AudioTrack.ORIGINAL,
+        help_text=_(
+            'Which audio track to download when the source publishes more than one. '
+            '"Original audio" is the track in the language the video was actually '
+            'recorded in. "Publisher\'s default audio" is whichever track the uploader '
+            'set as the default for viewers, which for many channels is an automatic '
+            'dubbed translation. This setting has no effect when a video only offers a '
+            'single audio track.'
+        ),
+    )
     fallback = db.models.CharField(
         _('fallback'),
         max_length=1,
@@ -468,7 +483,8 @@ class Source(db.models.Model):
         ac = self.source_acodec
         f = ' 60FPS' if self.is_video and self.prefer_60fps else ''
         h = ' HDR' if self.is_video and self.prefer_hdr else ''
-        return f'{self.source_resolution} (video:{vc}, audio:{ac}){f}{h}'.strip()
+        a = '' if self.prefer_audio_track == Val(AudioTrack.ORIGINAL) else ' DEFAULT-AUDIO'
+        return f'{self.source_resolution} (video:{vc}, audio:{ac}){f}{h}{a}'.strip()
 
     @property
     def directory_path(self):