photo/app/Media/MSVideo.php

<?php

namespace App\Media;

use Illuminate\Support\Collection;

use App\Media\MSVideo\Container;
use App\Media\MSVideo\Containers\rlist\{avih, isft, movi, strh};
use App\Media\MSVideo\Containers\Unknown;

// https://www.jmcgowan.com/avi.html

class MSVideo extends Base
{
	private const LOGKEY = 'MFM';

	protected string $debug;

	private const container_classes = 'App\\Media\\MSVideo\\Containers\\';

	public function __construct(string $filename,string $type)
	{
		parent::__construct($filename,$type);

		$this->size = $this->filesize;
		$this->offset = 0;
		$this->containers = collect();

		$this->fopen();

		$format = $this->fread(4);
		switch ($format) {
			case 'RIFF': // AVI, WAV, etc
			case 'SDSS': // SDSS is identical to RIFF, just renamed. Used by SmartSound QuickTracks (www.smartsound.com)
			case 'RMP3': // RMP3 is identical to RIFF, just renamed. Used by [unknown program] when creating RIFF-MP3s
				$be = FALSE; // Big Endian ints
				$data = unpack('Vsize/a4subtype',$this->fread(8));

				// RMP3 is identical to WAVE, just renamed. Used by [unknown program] when creating RIFF-MP3s
				if ($data['subtype'] === 'RMP3')
					$data['subtype'] = 'WAVE';

				// AMV files are RIFF-AVI files with parts of the spec deliberately broken, such as chunk size fields hardcoded to zero (because players known in hardware that these fields are always a certain size
				if ($data['subtype'] !== 'AMV ') {
					// Handled separately in ParseRIFFAMV()
					$this->containers = $this->get_containers(self::container_classes,Unknown::class,$x=$this->ftell(),$this->filesize-$x,$be);
				}

				break;

			default:
				$data = unpack('Nsize/a4subtype',$this->fread(8));
				dump($data);
				throw new \Exception('Cannot handle this RIFF file format yet: '.$format);
		}

		$this->fclose();
	}

	public function __get(string $key): mixed
	{
		switch ($key) {
			case 'audio_channels':
				return $this->getAudioAtoms()
					->count();

			case 'audio_codec':
			case 'audio_samplerate':
			return $this->getAudioAtoms()
				->map(fn($item)=>$item->{$key})
				->join(',');

			// Signatures are calculated by the sha of the MDAT atom.
			case 'signature':
				$container = $this->find_containers(movi::class,1);

				return $container?->{$key};

			// Creation Time is in the MOOV/MVHD atom
			case 'creation_date':
				return NULL;	// I dont think create date is in an AVI file

			case 'duration':
				return $this->getVideoAtoms()
					->map(fn($item)=>$item->{$key})
					->join(',');

			// Height/Width is in the rlist/avih container
			case 'height':
			case 'width':
				$container = $this->find_containers(avih::class,1);

				return $container?->{$key};

			case 'gps_altitude':
			case 'gps_lat':
			case 'gps_lon':
				return NULL;	// No GPFS details in an AVI file?

			case 'make':
			case 'model':
				return NULL;	// Make/Model of camera not in an avi file

			case 'software':
				$container = $this->find_containers(isft::class,1);

				return $container?->software;

			case 'time_scale':
				$container = $this->find_containers(avih::class,1);

				return $container?->time_scale;

			case 'type':
				return parent::__get($key);

			case 'video_codec':
			case 'video_framerate':
				return $this->getVideoAtoms()
					->map(fn($item)=>$item->{$key})
					->join(',');

			default:
				throw new \Exception('Unknown key: '.$key);
		}
	}

	protected function get_containers(string $class_prefix,string $unknown,int $offset,int $size,bool $be=TRUE,string $bytes=NULL,string $passthru=NULL,\Closure $callback=NULL): Collection
	{
		$rp = 0;
		if (! $bytes) {
			$fh = fopen($this->filename,'r');
			fseek($fh,$offset);
		}

		$result = collect();

		while ($rp < $size) {
			$read = $bytes ? substr($bytes,$rp,8) : fread($fh,8);
			$rp += 8;

			$header = unpack(sprintf('a4name/%ssize',($be ? 'N' : 'V')),$read);

			if (strlen($header['name'] < 4))
				throw new \Exception(sprintf('Name is less than 4 chars: [%s]',$header['name']));

			if (($header['size'] === 0) && ($header['name'] !== 'JUNK'))
				throw new \Exception(sprintf('Chunk [%s] is unexpectedly zero',$header['name']));

			// all structures are packed on word boundaries
			if (($header['size']%2) != 0)
				$header['size']++;

			// We cant have a php function named 'list', so we change it to rlist
			if ($header['name'] === 'LIST')
				$header['name'] = 'RLIST';

			// Load our class for this supplier
			$class = $class_prefix.$header['name'];

			$data = $bytes
				? substr($bytes,$rp,$header['size'])
				: ($header['size'] && ($header['size'] <= self::record_size) ? fread($fh,$header['size']) : NULL);

			if ($header['size'] >= 8) {
				$o = class_exists($class)
					? new $class($offset+$rp,$header['size'],$this->filename,$be,$data,$passthru)
					: new $unknown($offset+$rp,$header['size'],$this->filename,$header['name'],$be,$data);

				$result->push($o);

				$rp += $header['size'];

				// Only need to seek if we didnt read all the data
				if ((! $bytes) && ($header['size'] > self::record_size))
					fseek($fh,$offset+$rp);

			} else {
				dd([get_class($this) => $data]);
			}

			// Work out if data from the last container next to be passed onto the next one
			if ($callback)
				$passthru = $callback($o);
		}

		if (! $bytes) {
			fclose($fh);
			unset($fh);
		}

		return $result;
	}

	/**
	 * Find all the video track atoms
	 *
	 * @return Collection
	 * @throws \Exception
	 */
	public function getAudioAtoms(): Collection
	{
		return $this->find_containers(strh::class)
			->filter(fn($item)=>$item->type==='auds');
	}

	/**
	 * Find all the video track atoms
	 *
	 * @return Collection
	 * @throws \Exception
	 */
	public function getVideoAtoms(): Collection
	{
		return $this->find_containers(strh::class)
			->filter(fn($item)=>$item->type==='vids');
	}

	/**
	 * Recursively look through our object hierarchy of containers looking for a specific one
	 *
	 * @param string $subcontainer
	 * @param int|NULL $expect
	 * @param int $depth
	 * @return Collection|Container|NULL
	 * @throws \Exception
	 */
	protected function find_containers(string $subcontainer,?int $expect=NULL,int $depth=100): Collection|Container|NULL
	{
		if (! isset($this->containers) || ($depth < 0))
			return NULL;

		$subcontainero = $this->containers->filter(fn($item)=>get_class($item)===$subcontainer);

		$subcontainero = $subcontainero
			->merge($this->containers->map(fn($item)=>$item->find_containers($subcontainer,NULL,$depth-1))
				->filter(fn($item)=>$item ? $item->count() : NULL)
				->flatten());

		if (! $subcontainero->count())
			return $subcontainero;

		if ($expect && ($subcontainero->count() !== $expect))
			throw new \Exception(sprintf('! Expected %d sub containers of %s, but have %d',$expect,$subcontainer,$subcontainero->count()));

		return ($expect === 1) ? $subcontainero->pop() : $subcontainero;
	}
}