invisible layer / codec map
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experiment 31 · media api · no permissions
your codec list
identifies your hardware.
Every device decodes a different subset of audio and video formats — determined by your chip manufacturer, OS version, and installed media frameworks. The combination is specific enough to identify your hardware model without any other signal.
Which codecs your device decodes in hardware is manufacturer-specific. The exact combination narrows your phone to a handful of models. Apple Silicon, Snapdragon, and Exynos each support a different subset.
—supported
—partial
—unsupported
codec fingerprint (binary)
▶ why does codec support vary between devices?

Media decoding support is determined by a layered stack: the browser itself, the OS media framework (e.g. AVFoundation on Apple, MediaCodec on Android, DirectShow/Media Foundation on Windows), and hardware accelerators embedded in the SoC. The HTMLMediaElement.canPlayType() method queries all of these.

Results come back as empty string (no), "maybe" (container recognized, codec uncertain), or "probably" (container and codec both recognized). The distinction between "maybe" and "probably" depends on how precisely you specify the codec string — video/mp4; codecs="avc1.42E01E" is much more specific than video/mp4.

H.265 hardware decoding is present on Apple Silicon, most ARM SoCs, and newer Intel/AMD chips, but absent on many mid-range Android devices. AV1 hardware decode arrived with specific GPU generations (NVIDIA Ampere, Intel Arc, Apple M3). This makes codec support a useful differentiator even within the same OS version. Combined with GPU vendor data, it can identify the device generation to within 1-2 years.