156 lines
3.5 KiB
PHP
156 lines
3.5 KiB
PHP
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<?php
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/**
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* Base class for streaming segment readers
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*
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* @file
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* @ingroup HLS
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*/
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namespace MediaWiki\TimedMediaHandler\HLS;
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use Exception;
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/**
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* Base class for reading a media file and segmenting it.
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*/
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abstract class Segmenter {
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protected string $filename;
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protected array $segments;
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public function __construct( string $filename, ?array $segments = null ) {
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$this->filename = $filename;
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if ( $segments ) {
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$this->segments = $segments;
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} else {
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$this->segments = [];
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$this->parse();
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}
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}
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/**
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* Fill the segments from the underlying file
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*/
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abstract protected function parse(): void;
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/**
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* Consolidate adjacent segments to approach the target segment length.
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*/
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public function consolidate( float $target ): void {
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$out = [];
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$n = count( $this->segments );
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$init = $this->segments['init'] ?? false;
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if ( $init ) {
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$n--;
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$out['init'] = $init;
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}
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if ( $n < 2 ) {
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return;
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}
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$first = $this->segments[0];
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$start = $first['start'];
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$size = $first['size'];
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$timestamp = $first['timestamp'];
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$duration = $first['duration'];
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$i = 1;
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while ( $i < $n ) {
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// Append segments until we get close
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while ( $i < $n - 1 && $duration < $target ) {
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$segment = $this->segments[$i];
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$total = $duration + $segment['duration'];
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if ( $total >= $target ) {
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$after = $total - $target;
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$before = $target - $duration;
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if ( $before < $after ) {
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// Break segment early
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break;
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}
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}
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$duration += $segment['duration'];
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$size += $segment['size'];
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$i++;
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}
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// Save out a segment
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$out[] = [
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'start' => $start,
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'size' => $size,
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'timestamp' => $timestamp,
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'duration' => $duration,
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];
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if ( $i < $n ) {
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$segment = $this->segments[$i];
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$start = $segment['start'];
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$size = $segment['size'];
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$timestamp = $segment['timestamp'];
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$duration = $segment['duration'];
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$i++;
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}
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}
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$out[] = [
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'start' => $start,
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'size' => $size,
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'timestamp' => $timestamp,
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'duration' => $duration,
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];
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$this->segments = $out;
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}
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/**
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* Modify the media file and segments in-place to insert any
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* tweaks needed for the file to stream correctly.
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*
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* This is used by MP3Segmenter to insert ID3 timestamps.
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*/
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public function rewrite(): void {
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// no-op in default; fragmented .mp4 can be left as-is
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}
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public function playlist( float $target, string $filename ): string {
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$lines = [];
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$lines[] = "#EXTM3U";
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$lines[] = "#EXT-X-VERSION:7";
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$lines[] = "#EXT-X-TARGETDURATION:$target";
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$lines[] = "#EXT-MEDIA-SEQUENCE:0";
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$lines[] = "#EXT-PLAYLIST-TYPE:VOD";
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$url = urlencode( $filename );
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$init = $this->segments['init'] ?? false;
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if ( $init ) {
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$lines[] = "#EXT-X-MAP:URI=\"{$url}\",BYTERANGE=\"{$init['size']}@{$init['start']}\"";
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}
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$n = count( $this->segments ) - 1;
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for ( $i = 0; $i < $n; $i++ ) {
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$segment = $this->segments[$i];
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$lines[] = "#EXTINF:{$segment['duration']},";
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$lines[] = "#EXT-X-BYTERANGE:{$segment['size']}@{$segment['start']}";
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$lines[] = "{$url}";
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}
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$lines[] = "#EXT-X-ENDLIST";
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return implode( "\n", $lines );
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}
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public static function segment( string $filename ): Segmenter {
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$ext = strtolower( substr( $filename, strrpos( $filename, '.' ) ) );
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switch ( $ext ) {
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case '.mp3':
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return new MP3Segmenter( $filename );
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case '.mp4':
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case '.m4v':
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case '.m4a':
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case '.mov':
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case '.3gp':
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return new MP4Segmenter( $filename );
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default:
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throw new Exception( "Unexpected streaming file extension $ext" );
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}
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}
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}
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