styx-codec

Unified codec trait plus a registry for pluggable encoders/decoders. Includes MJPEG decoding and raw color converters; optional features enable FFmpeg and alternate JPEG implementations.

Documentation

• https://docs.rs/styx-codec

Install

[dependencies]
styx-codec = "0.1.0"

Codec trait

use styx_codec::prelude::*;

pub struct Passthrough {
    desc: CodecDescriptor,
}

impl Codec for Passthrough {
    fn descriptor(&self) -> &CodecDescriptor { &self.desc }
    fn process(&self, input: FrameLease) -> Result<FrameLease, CodecError> {
        if input.meta().format.code != self.desc.input {
            return Err(CodecError::FormatMismatch { expected: self.desc.input, actual: input.meta().format.code });
        }
        Ok(input)
    }
}

CodecDescriptor describes the kind (encoder/decoder), input/output FourCc, algorithm family, and implementation name.

Registry

CodecRegistry installs codecs and returns a CodecRegistryHandle for lookups:

use styx_codec::prelude::*;
use std::sync::Arc;

let registry = CodecRegistry::new();
let handle = registry.handle();
registry.register(FourCc::new(*b"MJPG"), Arc::new(MjpegDecoder::new(FourCc::new(*b"RG24"))));

let frame = /* FrameLease carrying MJPG data */;
let decoded = handle.process(FourCc::new(*b"MJPG"), frame)?;

Selection can be influenced via:

• set_policy(CodecPolicy): ordered impls, priorities, and hardware bias per FourCc.
• set_impl_priority / enable_only / disable_impl: granular control over implementations.
• lookup_preferred / process_preferred: choose by ordered impl names and hardware bias.

CodecStats tracks processed/errors/backpressure counters via the handle.

Built-in codecs

• MJPEG decoder (default feature set).
• Raw color converters: YUYV/NV12/I420 → RGB, RGBA/BGRA/BGR → RGB, passthrough.
• Optional FFmpeg (codec-ffmpeg): H264/H265/MJPEG encoders/decoders.
• Optional JPEG (codec-mozjpeg, codec-turbojpeg, codec-zune): alternate MJPEG backends.
• Optional image feature: ImageAnyDecoder and helpers for DynamicImage conversions.

See crates/styx/examples/mjpeg_decode.rs for an end-to-end registry/decode usage example.