Supported Codecs

Symphonia provides pure Rust implementations of popular audio codecs. Each codec is provided by a separate crate and can be enabled using feature flags.

Feature Flags

By default, Symphonia only enables royalty-free open standard codecs. Additional codecs can be enabled using feature flags:

symphonia = { version = "0.5", features = ["aac", "mp3", "alac"] }

All codecs can be enabled at once with the all-codecs feature flag. All MPEG audio codecs (MP1, MP2, MP3) can be enabled with the mpa feature flag.

The following table shows all supported audio codecs, their development status, gapless playback support, and associated feature flags:

Codec	Status	Gapless	Feature Flag	Default	Crate
AAC-LC	Great	No	`aac`	No	`symphonia-codec-aac`
ADPCM	Good	Yes	`adpcm`	Yes	`symphonia-codec-adpcm`
ALAC	Great	Yes	`alac`	No	`symphonia-codec-alac`
HE-AAC (AAC+, aacPlus)	-	-	`he-aac`	No	`symphonia-codec-aac`
HE-AACv2 (eAAC+, aacPlus v2)	-	-	`he-aac-v2`	No	`symphonia-codec-aac`
FLAC	Excellent	Yes	`flac`	Yes	`symphonia-bundle-flac`
MP1	Great	No	`mp1`, `mpa`	No	`symphonia-bundle-mp3`
MP2	Great	No	`mp2`, `mpa`	No	`symphonia-bundle-mp3`
MP3	Excellent	Yes	`mp3`, `mpa`	No	`symphonia-bundle-mp3`
Opus	-	-	`opus`	Yes	`symphonia-codec-opus`
PCM	Excellent	Yes	`pcm`	Yes	`symphonia-codec-pcm`
Vorbis	Excellent	Yes	`vorbis`	Yes	`symphonia-codec-vorbis`
WavPack	-	-	`wavpack`	Yes	`symphonia-codec-wavpack`

A symphonia-bundle-* package is a combination of a decoder and a native demuxer.

Status Classifications

Excellent

All media streams decode correctly. No audible or inaudible glitches. All required features are supported.This status is only assigned after passing all compliance tests, or if Symphonia’s output matches a reference implementation over a large test corpus.

Great

Most media streams decode correctly. Inaudible glitches may be present. Most common features are supported.This status indicates that major development is complete and the codec is acceptable for most applications.

Good

Many media streams decode. Some streams may panic, error, or produce audible glitches. Some features may not be supported.This status indicates active development or known limitations.

- (In Progress)

In work or not started yet. Not recommended for production use.

Codec Details

AAC-LC (Advanced Audio Coding - Low Complexity)

Status: Great
Gapless: No
Crate: symphonia-codec-aac
Most common AAC profile
Widely used in MP4 containers
Good quality at moderate bitrates
Decoder contributed by Kostya Shishkov

ADPCM (Adaptive Differential Pulse Code Modulation)

Status: Good
Gapless: Yes
Crate: symphonia-codec-adpcm
Simple lossy compression
Multiple variants (IMA, MS)
Commonly found in WAV files
Enabled by default

ALAC (Apple Lossless Audio Codec)

Status: Great
Gapless: Yes
Crate: symphonia-codec-alac
Lossless compression
Native to Apple ecosystem
Typically in MP4/M4A containers
Supports up to 32-bit audio

FLAC (Free Lossless Audio Codec)

Status: Excellent
Gapless: Yes
Crate: symphonia-bundle-flac
Industry-standard lossless codec
Excellent compression efficiency
Wide platform support
Enabled by default

MP1, MP2, MP3 (MPEG Audio Layer I, II, III)

MP1 Status: Great (Gapless: No)
MP2 Status: Great (Gapless: No)
MP3 Status: Excellent (Gapless: Yes)
Crate: symphonia-bundle-mp3
MP3 is the most common lossy audio format
Enable all MPEG audio codecs with mpa feature
MP3 decoder passes compliance tests

PCM (Pulse Code Modulation)

Status: Excellent
Gapless: Yes
Crate: symphonia-codec-pcm
Uncompressed audio
Multiple bit depths (8, 16, 24, 32-bit)
Integer and floating-point formats
Enabled by default

Vorbis

Status: Excellent
Gapless: Yes
Crate: symphonia-codec-vorbis
Free, open-source lossy codec
Typically in OGG containers
Superior to MP3 at equivalent bitrates
Enabled by default

Gapless Playback

Gapless playback eliminates silence or gaps between tracks during continuous playback. The following codecs support gapless playback:

ADPCM - Yes
ALAC - Yes
FLAC - Yes
MP3 - Yes
PCM - Yes
Vorbis - Yes

Gapless playback requires support from both the codec (decoder) and the container format (demuxer). See Supported Formats for format-specific gapless support.

Usage Example

use symphonia::core::codecs::DecoderOptions;
use symphonia::core::formats::FormatOptions;
use symphonia::core::io::MediaSourceStream;
use symphonia::core::meta::MetadataOptions;
use symphonia::core::probe::Hint;
use std::fs::File;

// Open and probe the media file
let file = Box::new(File::open("audio.flac")?);
let mss = MediaSourceStream::new(file, Default::default());
let mut hint = Hint::new();
hint.with_extension("flac");

let probed = symphonia::default::get_probe()
    .format(&hint, mss, &FormatOptions::default(), &MetadataOptions::default())?;

let mut format = probed.format;

// Find the first audio track
let track = format.default_track().unwrap();

// Create a decoder for the track's codec
let mut decoder = symphonia::default::get_codecs()
    .make(&track.codec_params, &DecoderOptions::default())?;

// Decode packets
let track_id = track.id;
loop {
    let packet = format.next_packet()?;
    if packet.track_id() == track_id {
        let decoded = decoder.decode(&packet)?;
        // Process decoded audio samples
    }
}

For complete examples, see the Examples page.

Get Started

Core Concepts

Guides

Resources

Supported Codecs

Feature Flags