Crate alpha2_media 

Host-independent media vocabulary and I/O contracts.

These types describe media itself, not any application built on it: source identity and color, decoded frames and audio blocks, the decoder and encoder traits that platform bindings implement, and output rate control. The renderer, the timeline model, and the platform bindings all speak them, and none of those owns them.

Structs

AudioBlock

Planar floating-point audio at the project sample rate.

AudioSpan

A provider’s answer to one request: source samples, and what the source holds on either side of them.

CancelToken

Cancellation flag shared across adapter operations.

ColorMetadata

Host-independent video color description.

DecodeRequest

One idempotent decoder request. Hosts discard results with an old generation.

DecodeResult

Result correlated to a decoder request, safe for out-of-order completion.

DecodedVideoFrame

Host-independent decoded video frame.

HostTexture

Generic image/video/text texture descriptor owned by a host.

HostTexturePixels

RGBA8 pixels returned by an image, video, or text rasterization host.

Orientation

How to show a decoded picture upright: mirror it left to right when mirror is set, then turn it clockwise by rotation.

Plane

One decoded image plane.

Rect

Rectangle inside a coded video frame.

SampleAspectRatio

Reduced pixel-width to pixel-height ratio.

SourceId

A stable media-source identifier.

SpeakerLayout

The speakers an AudioBlock’s planes feed, in plane order: 1 to MAX_AUDIO_CHANNELS of them.

StreamInfo

Platform-neutral probe result for one stream.

TextTexture

Layout facts attached to a host-rasterized text texture.

VideoRateControl

A resolved video rate control: what a sink encodes with.

YcbcrLevels

Where a YCbCr range puts a bit depth’s codes (ITU-T H.273).

YuvEncoding

How rendered RGB is written as 8-bit 4:2:0 YUV: its color coding, and where its chroma samples sit relative to the luma grid.

YuvFormat

How a planar or semi-planar YCbCr frame stores its samples.

Enums

AudioCodec

Audio codecs the engine resolves a rate for.

BitrateMode

How an encoder is asked to hold its bitrate.

ChromaLocation

Chroma sample location for subsampled YUV.

ColorMatrix

Coefficients used to decode source components.

ColorPrimaries

RGB primary chromaticities a source or export declares.

ColorRange

Nominal encoded component range.

Container

The file format an export is written in.

ContainerError

Why a container request cannot be resolved.

DecodeError

Typed decoder failure.

DecodeEvent

Decoder output and terminal states.

DecodeRequestKind

Kind of decoder cache/refill operation.

DynamicRange

Whether a signal is standard or high dynamic range. It follows the transfer: hdr exactly when the transfer is PQ or HLG, and a color whose two fields disagree is refused.

EmojiPolicy

How a text host draws emoji and other color glyphs.

EncodeError

Typed encoding failure.

EncodeEvent

One input accepted by an encoding/mux adapter.

GpuFault

What a failed GPU call says about the device it ran on, read from the platform’s own status for that call (a VkResult, HRESULT, or CVReturn) where it failed, not from any message.

IdError

An error returned when an identifier cannot be constructed.

PixelFormat

Plane organization delivered by a decoder.

Premultiplication

Alpha representation of host pixels.

QualityLevel

The five qualitative output levels.

RasterColorSpace

Generic color declaration for a host-rasterized texture.

RateControlError

Why a rate-control request is not one the engine can resolve.

Rotation

Clockwise rotation to apply when displaying a frame.

Speaker

The loudspeaker one plane of an AudioBlock feeds.

StreamKind

Media stream domain.

TextAlign

Horizontal alignment applied by a host text layout engine.

TransferFunction

Encoded transfer curve.

VideoCodec

Video codecs the engine resolves a rate for.

Constants

FRAME_RATE_EXPONENT

How bitrate grows with frame rate at equal quality: (fps / 30) ^ k.

GPU_TIMEOUT_MESSAGE

The sentence every wait on GPU work that timed out carries, wherever it was waited on (the renderer, a native interop helper, an encoder input), so a host that sees only error text tells a hung GPU from a generic failure. Hosts classify it as GPU_TIMEOUT.

MAX_AUDIO_CHANNELS

Most planes an AudioBlock carries: a 22.2 layout’s 24, the most of any layout FFmpeg names.

MAX_FRAME_DIMENSION

Largest frame edge, in pixels, anything in alpha2 decodes, renders, or composes a project at.

MAX_FRAME_PIXELS

Largest frame area, in pixels, anything in alpha2 decodes, renders, or composes a project at: a decoder refuses a larger frame before it allocates one.

MIN_VIDEO_BITRATE

No level resolves below this. Below about 300 kbps the measured encoders stopped holding their target at all (asked for 84 kbps they wrote 170 to 260), so a lower number would describe a file the encoder does not make.

REFERENCE_FPS

Frame rate the level table is stated at.

REFERENCE_PIXELS

Luma samples of the reference output the level table is stated at.

RESOLUTION_EXPONENT

How bitrate grows with pixel count at equal quality.

Traits

AudioBlockProvider

Retrieves project-rate planar audio without exposing its backing cache.

AudioBlockSink

Receives project-rate planar audio from offline or realtime graph hosts.

Decoder

Stateful media decoder implemented by a platform binding.

EncodeSink

Host encoding and muxing boundary.

Functions

codec_factor

Bits a codec needs, relative to H.264, for the same quality.

frame_size_supported

Whether a width x height frame is within MAX_FRAME_DIMENSION and MAX_FRAME_PIXELS.

level_quantizer

The constant quantizer a level resolves to for codec, where the engine has measured one.

resolve_audio_bitrate

Resolves a quality level into a stereo audio bitrate in bits per second.

resolve_export_format

The export’s container and codecs, resolved once at a host’s edge.

resolve_video_rate_control

Resolves a quality level into the rate control every sink encodes with.

sample_ticks_floor

The tick at or before sample sample at sample_rate.