IsoMedia final class

Minn\Media\Av\IsoMedia · public/minn/src/Minn/Media/Av/IsoMedia.php · 364 lines

MPEG-4 and QuickTime files (MP4, M4A, M4V, MOV) as the reference's media reader measures them (probe media-meta). The movie header gives the playing time and the time it was made; each track's first sample entry gives its codec. Only AAC ("mp4a") is read as audio, and it alone makes a file audio/mp4 (or video/mp4 beside a video track); anything else is video/quicktime. A video entry with a vendor is read the QuickTime way (its compressor's name, lossless false); one without, the ISO way (a named codec, and "mp4" as the format for the codecs it knows). Only H.264 and MPEG-4 video have the bitrate the audio leaves.

Uses 1

Source

Used by 1

Analyzer

Constants and properties

private	`VIDEO` = `'avc1=H.264/MPEG-4 AVC\|cvid=Cinepak\|dvc =DVC-NTSC\|dvcp=DVC-PAL\|gif =GIF\|h263=H263\|hvc1=H.265/HEVC\|jpeg=JPEG\|kpcd=PhotoCD\|mjpa=Motion JPEG-A\|mjpb=Motion JPEG-B\|mp4v=\|png =PNG\|raw =RAW\|rle =\|rpza=Video\|smc =Graphics\|SVQ1=Sorenson Video 3\|SVQ3=Sorenson Video 3 (Apple Quicktime 5)\|tiff=TIFF\|v216=\|v308=\|v408=\|v410=\|yuv2=ComponentVideo'`	Video codecs the ISO way names, and makes a file "mp4" for (code => name, empty for none).
private	`DATAFORMATS` = `array ( 'mp4v' => 'mpeg4', '3IV1' => '3ivx', '3IV2' => '3ivx', '3ivx' => '3ivx', 'DIVX' => 'divx', 'divx' => 'divx', 'DIV3' => 'divx', 'div3' => 'divx', 'XVID' => 'xvid', 'xvid' => 'xvid', )`
private	`CONTAINERS` = `array ( 0 => 'moov', 1 => 'trak', 2 => 'mdia', 3 => 'minf', 4 => 'stbl', 5 => 'udta', 6 => 'ilst', 7 => 'covr', )`
private	`EPOCH` = `2082844800`	Seconds between 1904, where the movie's clock starts, and 1970.
private	`MOOV_LIMIT` = `67108864`
private	`BOX_LIMIT` = `4096`	The most boxes read at one level (the file's, or a container's).

Public

static	`detects(string $head): bool`#	Whether a file's first bytes are an MPEG-4 or QuickTime box.
static	`read(Minn\Media\Av\Source $source): array`#	The file's analysis: format, type, playing time and bitrate, the audio and video streams, the movie header for its creation time and the cover. `@return array<string, mixed>`

Internals 13

Private and protected methods: how the class does its work. Not a contract; they change whenever the code is tidied.

private

movie(Minn\Media\Av\Source $source): array#

The movie box's bytes (null when there is none, or it is too large to read) and where the first media data begins.

@return array{moov: ?string, dataStart: ?int}

private

boxHeader(string $bytes, int $room): array#

A box's size, type and header length from its first bytes; a size of 0 runs to $room, a size of 1 is the 64-bit size that follows.

@return array{0: int, 1: string, 2: int}

private

children(string $bytes, int $start, int $end): array#

The boxes inside a run of bytes, each with its body's place.

@return list<array{type: string, start: int, end: int}>

private

find(string $bytes, array $boxes, array $path): ?array#

The first box of a type along a path of containers, or null.

`$boxes`	`list<array{type: string, start: int, end: int}>`
`$path`	`list<string>`

@return array{type: string, start: int, end: int}|null

private

movieHeader(string $bytes, array $moov): ?array#

The movie header's timescale, duration and creation time.

$moov list<array{type: string, start: int, end: int}>

@return array{timescale: int, duration: int, created: int}|null

private

track(string $bytes, array $trak): array#

A track's size (from its header) and its first sample entry, read as audio or video.

$trak array{type: string, start: int, end: int}

@return array{entry: array<string, mixed>|null}

private

aac(string $entry): array#

An AAC sample entry's stream: its rate and channels as the version 0 layout places them (whatever the version), and the average bitrate an elementary stream descriptor directly inside it gives.

@return array<string, mixed>

private

averageBitrate(string $esds): ?int#

The average bitrate an elementary stream descriptor's decoder configuration gives; null without one.

private

afterLength(string $bytes, int $at): int#

Where a descriptor's body starts, after its length of one to four bytes.

private

videoEntry(string $entry, array $trackSize): array#

A video sample entry read the QuickTime way (it names a vendor) or the ISO way.

$trackSize array{0: float, 1: float}

@return array<string, mixed>

private

cover(string $bytes, array $moov): ?array#

The cover an iTunes tag list holds: its bytes and type.

$moov list<array{type: string, start: int, end: int}>

@return array<string, mixed>|null

private

ordered(array $video): array#

A video stream's fields in the order the reference keeps them.

$video array<string, mixed>

@return array<string, mixed>

private

videoCodecs(): array#

@return array<string, string> code => name