<?php
/*
 * ffmpeg.php
 * A barebones ffmpeg based webm implementation for vichan.
 */

function get_webm_info($filename) {
	global $board, $config;
	$filename = escapeshellarg($filename);
	$ffprobe = $config['webm']['ffprobe_path'];
	$ffprobe_out = array();
	$webminfo = array();

	exec("$ffprobe -v quiet -print_format json -show_format -show_streams $filename", $ffprobe_out);
	$ffprobe_out = json_decode(implode("\n", $ffprobe_out), 1);
	$webminfo['error'] = is_valid_webm($ffprobe_out);
	if(empty($webminfo['error'])) {
		$webminfo['width'] = $ffprobe_out['streams'][0]['width'];
		$webminfo['height'] = $ffprobe_out['streams'][0]['height'];
		$webminfo['duration'] = $ffprobe_out['format']['duration'];
	}
	return $webminfo;
}
function is_valid_webm($ffprobe_out) {
	global $board, $config;
	if (empty($ffprobe_out))
		return array('code' => 1, 'msg' => $config['error']['genwebmerror']);
	$extension = pathinfo($ffprobe_out['format']['filename'], PATHINFO_EXTENSION);
	if ($extension === 'webm' && !stristr($ffprobe_out['format']['format_name'], 'mp4')) {
		if ($ffprobe_out['format']['format_name'] != 'matroska,webm')
			return array('code' => 2, 'msg' => $config['error']['invalidwebm']."error 1");
	} elseif ($extension === 'mp4' || stristr($ffprobe_out['format']['format_name'], 'mp4')) {
		if ($ffprobe_out['streams'][0]['codec_name'] != 'h264' && $ffprobe_out['streams'][1]['codec_name'] != 'aac')
			return array('code' => 2, 'msg' => $config['error']['invalidwebm']."error 2");
	} else {
		return array('code' => 1, 'msg' => $config['error']['genwebmerror']."error 3");  
	}
	if ((count($ffprobe_out['streams']) > 1) && (!$config['webm']['allow_audio']))
		return array('code' => 3, 'msg' => $config['error']['webmhasaudio']."error 4");
	if ((empty($ffprobe_out['streams'][0]['width']) || (empty($ffprobe_out['streams'][0]['height']))) && !$config['webm']['allow_audio']) {
		return array('code' => 2, 'msg' => $config['error']['invalidwebm']."error 5");
	}
	if ($ffprobe_out['format']['duration'] > $config['webm']['max_length'])
		return array('code' => 4, 'msg' => sprintf($config['error']['webmtoolong'], $config['webm']['max_length'])."error 6");
}
function make_webm_thumbnail($filename, $thumbnail, $width, $height, $duration) {
	global $board, $config;
	$filename = escapeshellarg($filename);
	$thumbnailfc = escapeshellarg($thumbnail); // Should be safe by default but you
	// can never be too safe.
	$width = escapeshellarg($width);
	$height = escapeshellarg($height); // Same as above.
	$ffmpeg = $config['webm']['ffmpeg_path'];
	$ret = 0;
	$ffmpeg_out = array();
	exec("$ffmpeg -strict -2 -ss " . floor($duration / 2) . " -i $filename -v quiet -an -vframes 1 -f mjpeg -vf scale=$width:$height $thumbnailfc 2>&1", $ffmpeg_out, $ret);
	// Work around for https://trac.ffmpeg.org/ticket/4362
	if (filesize($thumbnail) === 0) {
		// try again with first frame
		exec("$ffmpeg -y -strict -2 -ss 0 -i $filename -v quiet -an -vframes 1 -f mjpeg -vf scale=$width:$height $thumbnailfc 2>&1", $ffmpeg_out, $ret);
		clearstatcache();
		// failed if no thumbnail size even if ret code 0, ffmpeg is buggy
		if (filesize($thumbnail) === 0) {
			$ret = 1;
		}
	}
	return $ret;
}