diff --git a/app/Album.php b/app/Album.php
index 26858b76..f72ee9ca 100644
--- a/app/Album.php
+++ b/app/Album.php
@@ -23,19 +23,17 @@ namespace Poniverse\Ponyfm;
 use Exception;
 use Helpers;
 use Illuminate\Database\Eloquent\Model;
-use Illuminate\Database\Eloquent\ModelNotFoundException;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Foundation\Bus\DispatchesJobs;
 use Auth;
 use Cache;
-use File;
+use Poniverse\Ponyfm\Traits\TrackCollection;
 use URL;
-use Poniverse\Ponyfm\Jobs\EncodeTrackFile;
 use Poniverse\Ponyfm\Traits\SlugTrait;
 
 class Album extends Model
 {
-    use SoftDeletes, SlugTrait, DispatchesJobs;
+    use SoftDeletes, SlugTrait, DispatchesJobs, TrackCollection;
 
     protected $dates = ['deleted_at'];
 
@@ -85,6 +83,10 @@ class Album extends Model
         return $this->hasMany('Poniverse\Ponyfm\Track')->orderBy('track_number', 'asc');
     }
 
+    public function trackFiles() {
+        return $this->hasManyThrough(TrackFile::class, Track::class, 'album_id', 'track_id');
+    }
+
     public function comments()
     {
         return $this->hasMany('Poniverse\Ponyfm\Comment')->orderBy('created_at', 'desc');
@@ -277,68 +279,6 @@ class Album extends Model
         }
     }
 
-    public function countDownloadableTracks()
-    {
-        $trackCount = 0;
-
-        foreach ($this->tracks as $track) {
-            if ($track->is_downloadable == true) {
-                $trackCount++;
-            } else {
-                continue;
-            }
-        }
-
-        return $trackCount;
-    }
-
-    public function countCachedTrackFiles($format)
-    {
-        $cachedCount = 0;
-
-        foreach ($this->tracks as $track) {
-            /** @var $track Track */
-
-
-            if ($track->is_downloadable == false) {
-                continue;
-            }
-
-            try {
-                $trackFile = $track->trackFiles()->where('format', $format)->firstOrFail();
-            } catch (ModelNotFoundException $e) {
-                throw $e;
-            }
-
-            if ($trackFile->expires_at != null && File::exists($trackFile->getFile())) {
-                $cachedCount++;
-            }
-        }
-
-        return $cachedCount;
-    }
-
-    public function encodeCacheableTrackFiles($format)
-    {
-        foreach ($this->tracks as $track) {
-            /** @var $track Track */
-
-            if ($track->is_downloadable == false) {
-                continue;
-            }
-
-            try {
-                $trackFile = $track->trackFiles()->where('format', $format)->firstOrFail();
-            } catch (ModelNotFoundException $e) {
-                throw $e;
-            }
-
-            if (!File::exists($trackFile->getFile()) && $trackFile->is_in_progress != true) {
-                $this->dispatch(new EncodeTrackFile($trackFile, true));
-            }
-        }
-    }
-
     public function syncTrackIds($trackIds)
     {
         $trackIdsInAlbum = [];
diff --git a/app/Http/Controllers/Api/Web/AlbumsController.php b/app/Http/Controllers/Api/Web/AlbumsController.php
index 67b0b98d..71f986b2 100644
--- a/app/Http/Controllers/Api/Web/AlbumsController.php
+++ b/app/Http/Controllers/Api/Web/AlbumsController.php
@@ -91,7 +91,9 @@ class AlbumsController extends ApiControllerBase
     {
         // Validation
         try {
+            /** @var Album $album */
             $album = Album::with('tracks.trackFiles')->findOrFail($id);
+
         } catch (ModelNotFoundException $e) {
             return $this->notFound('Album not found!');
         }
@@ -100,14 +102,10 @@ class AlbumsController extends ApiControllerBase
             return $this->notFound('Format not found!');
         }
 
-        $trackCount = $album->countDownloadableTracks();
-        try {
-            $cachedCount = $album->countCachedTrackFiles($format);
-        } catch (ModelNotFoundException $e) {
-            return $this->notFound('Track file in album not found!');
-        }
+        $trackCount = $album->countDownloadableTracks($format);
+        $availableFilesCount = $album->countAvailableTrackFiles($format);
 
-        if ($trackCount === $cachedCount) {
+        if ($trackCount === $availableFilesCount) {
             $url = $album->getDownloadUrl($format);
         } else {
             $album->encodeCacheableTrackFiles($format);
diff --git a/app/Http/Controllers/Api/Web/PlaylistsController.php b/app/Http/Controllers/Api/Web/PlaylistsController.php
index 246d2724..aac920b3 100644
--- a/app/Http/Controllers/Api/Web/PlaylistsController.php
+++ b/app/Http/Controllers/Api/Web/PlaylistsController.php
@@ -116,6 +116,7 @@ class PlaylistsController extends ApiControllerBase
     {
         // Validation
         try {
+            /** @var $playlist Playlist */
             $playlist = Playlist::with('tracks.trackFiles')->findOrFail($id);
         } catch (ModelNotFoundException $e) {
             return $this->notFound('Playlist not found!');
@@ -129,14 +130,10 @@ class PlaylistsController extends ApiControllerBase
             return $this->notFound('Format not found!');
         }
 
-        $trackCount = $playlist->countDownloadableTracks();
-        try {
-            $cachedCount = $playlist->countCachedTrackFiles($format);
-        } catch (ModelNotFoundException $e) {
-            return $this->notFound('Track file in playlist not found!');
-        }
+        $trackCount = $playlist->countDownloadableTracks($format);
+        $availableFilesCount = $playlist->countAvailableTrackFiles($format);
 
-        if ($trackCount === $cachedCount) {
+        if ($trackCount === $availableFilesCount) {
             $url = $playlist->getDownloadUrl($format);
         } else {
             $playlist->encodeCacheableTrackFiles($format);
diff --git a/app/Playlist.php b/app/Playlist.php
index e68eb981..b30cc7b2 100644
--- a/app/Playlist.php
+++ b/app/Playlist.php
@@ -20,21 +20,19 @@
 
 namespace Poniverse\Ponyfm;
 
-use File;
 use Helpers;
 use Illuminate\Database\Eloquent\Model;
-use Illuminate\Database\Eloquent\ModelNotFoundException;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Foundation\Bus\DispatchesJobs;
 use Auth;
 use Cache;
+use Poniverse\Ponyfm\Traits\TrackCollection;
 use URL;
-use Poniverse\Ponyfm\Jobs\EncodeTrackFile;
 use Poniverse\Ponyfm\Traits\SlugTrait;
 
 class Playlist extends Model
 {
-    use SoftDeletes, SlugTrait, DispatchesJobs;
+    use SoftDeletes, SlugTrait, DispatchesJobs, TrackCollection;
 
     protected $table = 'playlists';
 
@@ -158,6 +156,12 @@ class Playlist extends Model
             ->orderBy('position', 'asc');
     }
 
+    public function trackFiles()
+    {
+        $trackIds = $this->tracks->lists('id');
+        return TrackFile::whereIn('track_id', $trackIds);
+    }
+
     public function users()
     {
         return $this->hasMany('Poniverse\Ponyfm\ResourceUser');
@@ -204,63 +208,6 @@ class Playlist extends Model
         return URL::to('p' . $this->id . '/dl.' . Track::$Formats[$format]['extension']);
     }
 
-    public function countDownloadableTracks()
-    {
-        $trackCount = 0;
-
-        foreach ($this->tracks as $track) {
-            if ($track->is_downloadable == true) {
-                $trackCount++;
-            } else {
-                continue;
-            }
-        }
-
-        return $trackCount;
-    }
-
-    public function countCachedTrackFiles($format)
-    {
-        $cachedCount = 0;
-
-        foreach ($this->tracks as $track) {
-            /** @var $track Track */
-
-            if ($track->is_downloadable == false) {
-                continue;
-            }
-
-            $trackFile = $track->trackFiles()->where('format', $format)->firstOrFail();
-
-            if ($trackFile->expires_at != null && File::exists($trackFile->getFile())) {
-                $cachedCount++;
-            }
-        }
-
-        return $cachedCount;
-    }
-
-    public function encodeCacheableTrackFiles($format)
-    {
-        foreach ($this->tracks as $track) {
-            /** @var $track Track */
-
-            if ($track->is_downloadable == false) {
-                continue;
-            }
-
-            try {
-                $trackFile = $track->trackFiles()->where('format', $format)->firstOrFail();
-            } catch (ModelNotFoundException $e) {
-                throw $e;
-            }
-
-            if (!File::exists($trackFile->getFile()) && $trackFile->is_in_progress != true) {
-                $this->dispatch(new EncodeTrackFile($trackFile, true));
-            }
-        }
-    }
-
     public function getFilesize($format)
     {
         $tracks = $this->tracks;
diff --git a/app/Traits/TrackCollection.php b/app/Traits/TrackCollection.php
new file mode 100644
index 00000000..2be06db0
--- /dev/null
+++ b/app/Traits/TrackCollection.php
@@ -0,0 +1,127 @@
+<?php
+
+/**
+ * Pony.fm - A community for pony fan music.
+ * Copyright (C) 2015 Peter Deltchev
+ * Copyright (C) 2015 Kelvin Zhang
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace Poniverse\Ponyfm\Traits;
+
+
+use File;
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\Relations\Relation;
+use Poniverse\Ponyfm\Jobs\EncodeTrackFile;
+use Poniverse\Ponyfm\TrackFile;
+
+
+/**
+ * Class TrackCollection
+ * @package Poniverse\Ponyfm\Traits
+ *
+ * Contains common logic between albums and playlists. They share some functionality
+ * because they're both a form of downloadable track collection.
+ */
+trait TrackCollection
+{
+    /**
+     * This relation represents all tracks contained by the collection.
+     *
+     * @return Relation
+     */
+    abstract public function tracks();
+
+    /**
+     * This relation represents all track files belonging to this collection's
+     * tracks.
+     *
+     * @return Relation
+     */
+    abstract public function trackFiles();
+
+
+    /**
+     * Returns the number of tracks that are available in the given format.
+     *
+     * @param string $format
+     * @return int the number of downloadable tracks in this collection
+     */
+    public function countDownloadableTracks($format) {
+        return $this->downloadableTrackFiles($format)->count();
+    }
+
+
+    /**
+     * Returns the number of currently-available track files (master files +
+     * currently cached files) for this collection in the given format.
+     *
+     * @param string $format
+     * @return int
+     */
+    public function countAvailableTrackFiles($format) {
+        $trackFiles = $this->downloadableTrackFiles($format);
+        $availableCount = 0;
+
+        foreach ($trackFiles as $trackFile) {
+            /** @var TrackFile $trackFile */
+
+            if (
+                $trackFile->is_master ||
+                ($trackFile->expires_at != null && File::exists($trackFile->getFile()))
+            ) {
+                $availableCount ++;
+            }
+        }
+
+        return $availableCount;
+    }
+
+
+    /**
+     * Kicks off the encoding of any cacheable files in this collection that
+     * do not currently exist.
+     *
+     * @param $format
+     */
+    public function encodeCacheableTrackFiles($format) {
+        $trackFiles = $this->downloadableTrackFiles($format);
+
+        foreach ($trackFiles as $trackFile) {
+            /** @var TrackFile $trackFile */
+
+            if (!File::exists($trackFile->getFile()) && $trackFile->is_in_progress != true) {
+                $this->dispatch(new EncodeTrackFile($trackFile, true));
+            }
+        }
+    }
+
+
+    /**
+     * Returns an Eloquent collection of downloadable TrackFiles for this {@link TrackCollection}.
+     * A {@link TrackFile} is considered downloadable if its associated {@link Track} is.
+     *
+     * @param $format
+     * @return Collection
+     */
+    protected function downloadableTrackFiles($format) {
+        return $this->trackFiles()->with([
+            'track' => function ($query) {
+                $query->where('is_downloadable', true);
+            }
+        ])->where('format', $format)->get();
+    }
+}