Add metadata to audio files - feature

README.md

@@ -328,6 +328,27 @@ method. It only accepts audio filters.
 You can build your own filters and some are bundled in PHP-FFMpeg - they are
 accessible through the `FFMpeg\Media\Audio::filters` method.
 
+#### Metadata
+
+Add metadata to audio files. Just pass an array of key=value pairs of all
+metadata you would like to add. If no arguments are passed into the filter
+all metadata will be removed from input file. Currently supported data is
+title, artist, album, artist, composer, track, year, description, artwork
+
+```php
+$audio->filters()->addMetadata(["title" => "Some Title", "track" => 1]);
+
+//remove all metadata and video streams from audio file
+$audio->filters()->addMetadata();
+```
+
+Add artwork to the audio file
+```php
+$audio->filters()->addMetadata(["artwork" => "/path/to/image/file.jpg"]);
+```
+NOTE: at present ffmpeg (version 3.2.2) only supports artwork output for .mp3
+files
+
 ###### Resample
 
 Resamples an audio file.

src/FFMpeg/Filters/Audio/AddMetadataFilter.php

@@ -0,0 +1,42 @@
+<?php
+namespace FFMpeg\Filters\Audio;
+
+use FFMpeg\Filters\Audio\AudioFilterInterface;
+use FFMpeg\Format\AudioInterface;
+use FFMpeg\Media\Audio;
+
+class AddMetadataFilter implements AudioFilterInterface
+{	
+	/** @var Array */
+	private $metaArr;
+
+	function __construct($data = null)
+	{
+		$this->metaArr = $data;
+	}
+
+	public function getPriority()
+	{
+		//must be of high priority in case theres a second input stream (artwork) to register with audio
+		return 9;
+	}
+
+	public function apply(Audio $audio, AudioInterface $format)
+	{
+		if (is_null($this->metaArr))
+			return ['-map_metadata', '-1', '-vn'];
+
+		$metadata = [];
+
+		if (array_key_exists("artwork", $this->metaArr)) {
+			array_push($metadata, "-i", $this->metaArr['artwork'], "-map", "0", "-map", "1");
+			unset($this->metaArr['artwork']);
+		}
+
+		foreach ($this->metaArr as $k => $v) {
+			array_push($metadata, "-metadata", "$k=$v");
+		}
+
+		return $metadata;
+	}
+}

src/FFMpeg/Filters/Audio/AudioFilters.php

@@ -2,6 +2,7 @@
 
 namespace FFMpeg\Filters\Audio;
 
+use FFMpeg\Filters\Audio\AddMetadataFilter;
 use FFMpeg\Media\Audio;
 
 class AudioFilters
@@ -26,4 +27,25 @@ class AudioFilters
 
         return $this;
     }
+
+    /**
+     * Add metadata to an audio file. If no arguments are given then filter
+     * will remove all metadata from the audio file
+     * @param Array|Null $data  If array must contain one of these key/value pairs:
+     *    - "title": Title metadata
+     *    - "artist": Artist metadata
+     *    - "composer": Composer metadata
+     *    - "album": Album metadata
+     *    - "track": Track metadata
+     *    - "artwork": Song artwork. String of file path
+     *    - "year": Year metadata
+     *    - "genre": Genre metadata
+     *    - "description": Description metadata
+     */
+    public function addMetadata($data = null)
+    {
+        $this->media->addFilter(new AddMetadataFilter($data));
+
+        return $this;
+    }
 }

tests/Unit/Filters/Audio/AudioMetadataTest.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Tests\FFMpeg\Unit\Filters\Audio;
+
+use FFMpeg\Filters\Audio\AudioFilters;
+use Tests\FFMpeg\Unit\TestCase;
+
+class AudioMetadataTest extends TestCase
+{
+    public function testAddMetadata()
+    {
+        $capturedFilter = null;
+
+        $audio = $this->getAudioMock();
+        $audio->expects($this->once())
+            ->method('addFilter')
+            ->with($this->isInstanceOf('FFMpeg\Filters\Audio\AddMetadataFilter'))
+            ->will($this->returnCallback(function ($filter) use (&$capturedFilter) {
+                $capturedFilter = $filter;
+            }));
+        $format = $this->getMock('FFMpeg\Format\AudioInterface');
+
+        $filters = new AudioFilters($audio);
+        $filters->addMetadata(array('title' => "Hello World"));
+        $this->assertEquals(array(0 => "-metadata", 1 => "title=Hello World"), $capturedFilter->apply($audio, $format));
+    }
+
+    public function testRemoveMetadata()
+    {
+        $capturedFilter = null;
+
+        $audio = $this->getAudioMock();
+        $audio->expects($this->once())
+            ->method('addFilter')
+            ->with($this->isInstanceOf('FFMpeg\Filters\Audio\AddMetadataFilter'))
+            ->will($this->returnCallback(function ($filter) use (&$capturedFilter) {
+                $capturedFilter = $filter;
+            }));
+        $format = $this->getMock('FFMpeg\Format\AudioInterface');
+
+        $filters = new AudioFilters($audio);
+        $filters->addMetadata();
+        $this->assertEquals(array(0 => "-map_metadata", 1 => "-1", 2 => "-vn"), $capturedFilter->apply($audio, $format));
+    }
+}