PrismCore

Aether

The default playback engine on iPhone, iPad, Mac, Apple TV and Apple Vision Pro — on for every install, not behind a switch.

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It is a Swift package, not a framework you have to build. Anything that already hands a URL to AVPlayer can use it.

PrismCore is meant to be invisible: you open a film and it plays. What it buys you is everything a player that draws its own picture has to give up.

1. 1

   It reads the file instead of converting it

   FFmpeg’s demuxer opens the container — MKV, MPEG-TS, AVI — and separates what is inside into its streams: the picture, each audio language, each subtitle. Nothing is decoded and nothing is converted; the file is only being read apart.

2. 2

   The streams are repacked, untouched

   The same compressed picture and sound are placed into fragmented MP4 pieces, described by a playlist of the kind AVPlayer opens natively. It is a change of packaging, not of content — bit for bit the same video and the same audio that were in the file.

3. 3

   A local address serves it

   Those pieces are handed to AVPlayer from 127.0.0.1, the address that never leaves the device, as if the film were being streamed. That is the whole trick: Apple’s player will gladly stream something it refuses to open as a file.

4. 4

   Apple’s engine does the rest

   Hardware decoding, Atmos passthrough, the Dolby Vision handshake, the track menu, PiP and AirPlay — none of it is reimplemented, because from AVPlayer’s point of view nothing unusual is happening.

Two things cannot be repacked, and get their own treatment. Subtitles that are pictures of text rather than text (the PGS in Blu-ray rips) are read on the device by Vision’s OCR and join as ordinary subtitles. And a handful of codecs Apple never decodes at all — VP9, MPEG-2, VC-1 — take a second path where PrismCore decodes the picture itself and draws the frames; you lose the system player’s chrome there, but the film plays.

The usual choice on Apple platforms is between a player that keeps the good stuff but only opens Apple’s containers, and one that opens everything but renders its own frames and decodes audio to PCM — which is where Atmos and Dolby Vision die. PrismCore is not a player at all: it feeds AVPlayer, so there is nothing to give up.

VLCKit and libmpv draw into their own layer and hand you PCM, which is why the middle rows fail for them — a consequence of owning the render path, not an oversight. AVPlayer fails the first and last rows because it only accepts containers Apple ships support for.

Add the package, then hand it a URL. One entry point probes the source and gives back either a playlist for AVPlayer or a software pipeline, already started.

.package(url: "https://github.com/Wenzlik/PrismCore.git", from: "1.8.7")

switch try await PrismCoreEngine.open(url: mkvURL) {
case .remux(let session, let playlist):
    player.replaceCurrentItem(with: AVPlayerItem(url: playlist))
    …
    await session.stop()

case .software(let pipeline):
    hostView.layer.addSublayer(pipeline.displayLayer!)
    pipeline.play()
}

Two opt-ins are worth knowing about once the first playback works. Give the session a cache directory and a container with no index of its own harvests one as it plays, so the next play seeks like an indexed file. The same directory backs scrub-bar thumbnails, which are their own small pipeline — a separate context, decoded on the CPU, cached per keyframe — so they never stall the playback they belong to, whichever engine is on screen.

let session = try PrismCoreSession(url: mkvURL, keyframeIndexCacheDirectory: caches)

let previews = SeekPreviewService(url: mkvURL, keyframeIndexCacheDirectory: caches)
let frame: CGImage = try await previews.thumbnail(at: 42 * 60)

Platform floors are iOS 16, tvOS 17, macOS 14 and visionOS 1. FFmpeg arrives through MPVKit’s dynamic xcframeworks, so a host that already ships MPVKit adds no new binary dependencies. If your CI resolves dependencies for you, pin an exact version and keep the committed Package.resolved in step with it — otherwise a device build and a TestFlight build can quietly run different engines.