First implemtation of the waveform feature

src/FFMpeg/Filters/Waveform/WaveformFilterInterface.php

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+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <dev.team@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Filters\Waveform;
+
+use FFMpeg\Filters\FilterInterface;
+use FFMpeg\Media\Waveform;
+
+interface WaveformFilterInterface extends FilterInterface
+{
+    public function apply(Waveform $waveform);
+}

src/FFMpeg/Filters/Waveform/WaveformFilters.php

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+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <dev.team@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Filters\Waveform;
+
+use FFMpeg\Media\Waveform;
+
+class WaveformFilters
+{
+    private $waveform;
+
+    public function __construct(Waveform $waveform)
+    {
+        $this->waveform = $waveform;
+    }
+
+    /**
+     * Fixes the display ratio of the output frame.
+     *
+     * In case the sample ratio and display ratio are different, image may be
+     * anamorphozed. This filter fixes this by specifying the output size.
+     *
+     * @return FrameFilters
+     */
+    public function fixDisplayRatio()
+    {
+        $this->frame->addFilter(new DisplayRatioFixerFilter());
+
+        return $this;
+    }
+}

src/FFMpeg/Filters/Waveform/WaveformRatioFixerFilter.php

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+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <dev.team@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Filters\Waveform;
+
+use FFMpeg\Exception\RuntimeException;
+use FFMpeg\Media\Waveform;
+
+class WaveformRatioFixerFilter implements WaveformFilterInterface
+{
+    /** @var boolean */
+    private $downmix;
+
+    // By default, the downmix value is set to FALSE.
+    public function __construct($downmix = FALSE)
+    {
+        $this->downmix = $downmix;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getDownmix()
+    {
+        return $this->downmix;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function apply(Waveform $waveform)
+    {
+        $dimensions = null;
+        $commands = array();
+
+        foreach ($waveform->getVideo()->getStreams() as $stream) {
+            if ($stream->isVideo()) {
+                try {
+                    
+                    // Get the dimensions of the video
+                    $dimensions = $stream->getDimensions();
+                    
+                    // If the downmix parameter is set to TRUE, we add an option to the FFMPEG command
+                    if(!$this->downmix) {
+                        $commands[] = '"showwavespic=s=' . $dimensions->getWidth() . 'x' . $dimensions->getHeight().'"';
+                    }
+                    else {
+                        $commands[] = '"aformat=channel_layouts=mono,showwavespic=s=' . $dimensions->getWidth() . 'x' . $dimensions->getHeight().'"';
+                    }
+                    
+                    break;
+
+                } catch (RuntimeException $e) {
+
+                }
+            }
+        }
+
+        return $commands;
+    }
+}