add subtitles

Author: aminyazdanpanah

README.md

@@ -166,17 +166,17 @@ See **[HLS section](https://video.aminyazdanpanah.com/start?r=hls#hls)** in the
 #### Encryption(DRM)
 The encryption process requires some kind of secret (key) together with an encryption algorithm. HLS uses AES in cipher block chaining (CBC) mode. This means each block is encrypted using the ciphertext of the preceding block. [Learn more](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation)
 
-You must specify a path to save a random key to your local machine and also a URL(or a path) to access the key on your website(the key you will save must be accessible from your website). You must pass both these parameters to the `encryption` method:
+You must specify a path to save a random key to your local machine and also specify an URL(or a path) to access the key on your website(the key you will save must be accessible from your website). You must pass both these parameters to the `encryption` method:
 
 ##### Single Key
 The following code generates a key for all segment files.
 
 ```php
 //A path you want to save a random key to your local machine
-$save_to = '/home/public_html/"PATH TO THE KEY DIRECTORY"/key'
+$save_to = '/home/public_html/"PATH TO THE KEY DIRECTORY"/key';
 
-//A URL (or a path) to access the key on your website
-$url = 'https://www.aminyazdanpanah.com/?"PATH TO THE KEY DIRECTORY"/key'
+//An URL (or a path) to access the key on your website
+$url = 'https://www.aminyazdanpanah.com/?"PATH TO THE KEY DIRECTORY"/key';
 // or $url = '/"PATH TO THE KEY DIRECTORY"/key';
 
 $video->hls()
@@ -198,6 +198,26 @@ However FFmpeg supports AES encryption for HLS packaging, which you can encrypt
 
 **Besides [Apple's FairPlay](https://developer.apple.com/streaming/fps/)** DRM system, you can also use other DRM systems such as **[Microsoft's PlayReady](https://www.microsoft.com/playready/overview/)** and **[Google's Widevine](https://www.widevine.com/)**.
 
+#### Subtitles
+You can add subtitles to a HLS stream using `subtitle` method.
+```php
+use Streaming\HLSSubtitle;
+
+$persian = new HLSSubtitle('/var/subtitles/subtitles_fa.vtt', 'فارسی', 'fa');
+$persian->default();
+$english = new HLSSubtitle('/var/subtitles/subtitles_en.vtt', 'english', 'en');
+$german  = new HLSSubtitle('/var/subtitles/subtitles_de.vtt', 'Deutsch', 'de');
+$chinese = new HLSSubtitle('/var/subtitles/subtitles_zh.vtt', '中文', 'zh');
+$spanish = new HLSSubtitle('/var/subtitles/subtitles_es.vtt', 'Español', 'es');
+
+$video->hls()
+    ->subtitles([$persian, $english, $german, $chinese, $spanish])
+    ->x264()
+    ->autoGenerateRepresentations([1080, 720])
+    ->save('/var/media/hls-stream.m3u8');
+```
+**NOTE:** All m3u8 files will be generated using rules based on **[RFC 8216](https://tools.ietf.org/html/rfc8216#section-3.5)**. Only **[WebVTT](https://www.w3.org/TR/webvtt1/)** files are acceptable for now. 
+
 ### Transcoding
 A format can also extend `FFMpeg\Format\ProgressableInterface` to get realtime information about the transcoding. 
 ```php

src/File.php

@@ -127,6 +127,16 @@ public static function move(string $src, string $dst): void
         static::remove($src);
     }
 
+    /**
+     * @param string $src
+     * @param string $dst
+     * @param bool $force
+     */
+    public static function copy(string $src, string $dst, bool $force = true): void
+    {
+        static::filesystem('copy', [$src, $dst, $force]);
+    }
+
     /**
      * @param $dir
      */

src/HLS.php

@@ -53,6 +53,9 @@ class HLS extends Streaming
     /** @var array */
     private $flags = [];
 
+    /** @var array */
+    private $subtitles = [];
+
     /**
      * @return string
      */
@@ -141,6 +144,22 @@ public function encryption(string $save_to, string $url, int $key_rotation_perio
         return $this;
     }
 
+    public function subtitle(HLSSubtitle $subtitle)
+    {
+        array_push($this->subtitles, $subtitle);
+        return $this;
+    }
+
+    /**
+     * @param array $subtitles
+     * @return HLS
+     */
+    public function subtitles(array $subtitles): HLS
+    {
+        array_walk($subtitles, [$this, 'subtitle']);
+        return $this;
+    }
+
     /**
      * @return string
      */
@@ -277,6 +296,10 @@ protected function getPath(): string
         $path = $this->getFilePath();
         $reps = $this->getRepresentations();
 
+        if(!empty($this->subtitles)){
+            $this->generateSubs($path);
+        }
+
         $this->savePlaylist($path . ".m3u8");
 
         return $path . "_" . $reps->end()->getHeight() . "p.m3u8";
@@ -291,6 +314,34 @@ public function savePlaylist(string $path): void
         $mater_playlist->save($this->master_playlist ?? $path, $this->stream_des);
     }
 
+    /**
+     * @param string $path
+     */
+    private function generateSubs(string $path)
+    {
+        $this->stream_des = array_merge($this->stream_des, [PHP_EOL]);
+
+        foreach ($this->subtitles as $subtitle) {
+            if($subtitle instanceof HLSSubtitle){
+                $subtitle->generateM3U8File("{$path}_subtitles_{$subtitle->getLanguageCode()}.m3u8", $this->getDuration());
+                array_push($this->stream_des, (string)$subtitle);
+            }
+        }
+        array_push($this->stream_des, PHP_EOL);
+
+        $this->getRepresentations()->map(function (Representation $rep){
+            return $rep->setHlsStreamInfo(["SUBTITLES" => "\"" . $this->subtitles[0]->getGroupId() . "\""]);
+        });
+    }
+
+    /**
+     * @return float
+     */
+    private function getDuration():float
+    {
+        return $this->getMedia()->getFormat()->get("duration", 0);
+    }
+
     /**
      * Clear key info file if is a temp file
      */

src/HLSPlaylist.php

@@ -12,12 +12,14 @@
 namespace Streaming;
 
 
+use FFMpeg\Exception\ExceptionInterface;
+
 class HLSPlaylist
 {
     /** @var HLS */
     private $hls;
 
-    private const DEFAULT_AUDIO_BITRATE = 131072;
+    private const DEFAULT_AUDIO_BITRATE = 0; //131072;
 
     /**
      * HLSPlaylist constructor.
@@ -104,11 +106,15 @@ private function getAudioBitrate(Representation $rep): int
      */
     private function getOriginalAudioBitrate(): int
     {
-        return $this->hls
-            ->getMedia()
-            ->getStreams()
-            ->audios()
-            ->first()
-            ->get('bit_rate', static::DEFAULT_AUDIO_BITRATE);
+        try {
+            return $this->hls
+                ->getMedia()
+                ->getStreams()
+                ->audios()
+                ->first()
+                ->get('bit_rate', static::DEFAULT_AUDIO_BITRATE);
+        } catch (ExceptionInterface $e) {
+            return static::DEFAULT_AUDIO_BITRATE;
+        }
     }
 }