Symphonia

Symphonia is a pure Rust audio decoding and media demuxing library supporting AAC, ADPCM, AIFF, ALAC, CAF, FLAC, MKV, MP1, MP2, MP3, MP4, OGG, Vorbis, WAV, and WebM.

Getting Started · Documentation · Examples · Benchmarks

---

Features

• Decode support for the most popular audio codecs with support for gapless playback
• Demux the most common media container formats
• Read most metadata and tagging formats
• Automatic format and decoder detection
• Basic audio primitives for manipulating audio data efficiently
• 100% safe Rust
• Minimal dependencies
• Fast with no compromises in performance!

Additionally, planned features include:

• Providing a C API for integration into other languages
• Providing a WASM API for web usage

Roadmap

Support for individual audio codecs and media formats are provided by separate crates. By default, Symphonia only enables support royalty-free open standard codecs and formats, but others may be enabled using feature flags.

Tip

All formats and codecs can be enabled with the all feature flag.

Status

The following status classifications are used to determine the state of development for each format or codec.

Status	Meaning
-	In work or not started yet.
Good	Many media streams play. Some streams may panic, error, or produce audible glitches. Some features may not be supported.
Great	Most media streams play. Inaudible glitches may be present. Most common features are supported.
Excellent	All media streams play. No audible or inaudible glitches. All required features are supported.

A status of Great indicates that major development is complete and that the feature is in a state that would be acceptable for most applications to use.

A status of Excellent is only assigned after the feature passes all compliance tests. If no compliance tests are readily available, then a status of Excellent will be assigned if Symphonia's output matches that of a reference implementation, or ffmpeg, over a large test corpus.

Formats (Demuxers)

Format	Status	Gapless*	Feature Flag	Default	Crate
AIFF	Great	Yes	aiff	No	symphonia-format-riff
CAF	Good	No	caf	No	symphonia-format-caf
ISO/MP4	Great	No	isomp4	No	symphonia-format-isomp4
MKV/WebM	Good	No	mkv	Yes	symphonia-format-mkv
OGG	Great	Yes	ogg	Yes	symphonia-format-ogg
Wave	Excellent	Yes	wav	Yes	symphonia-format-riff

* Gapless playback requires support from both the demuxer and decoder.

Tip

All formats can be enabled with the all-formats feature flag.

Codecs (Decoders)

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.

Tip

All codecs can be enabled with the all-codecs feature flag. Similarly, all MPEG audio codecs can be enabled with the mpa feature flag.

Tags (Readers)

All metadata readers are provided by the symphonia-metadata crate.

For metadata formats that are standalone and not part of the media container, a feature flag may be used to toggle support.

Format	Status	Feature Flag	Default
APEv1	Great	ape	Yes
APEv2	Great	ape	Yes
ID3v1	Great	id3v1	Yes
ID3v2	Great	id3v2	Yes
ISO/MP4	Great	N/A	N/A
RIFF	Great	N/A	N/A
Vorbis comment (FLAC)	Perfect	N/A	N/A
Vorbis comment (OGG)	Perfect	N/A	N/A

Tip

All metadata formats can be enabled with the all-meta feature flag.

Third-party Demuxers and Decoders

Symphonia is a designed around a modular framework that allows the registration of third-party demuxers and decoders. This table provides a list of crates that implement such components.

Important

This is not an endorsement of the quality, safety, or performance of these implementations. Please exercise your own judgement.

Crate	Provides
symphonia-adapter-fdk-aac	AAC-LC, HE-AAC, & HE-AACv2 via. libfdk-aac
symphonia-adapter-libopus	Opus via. libopus

Quality

In addition to the safety guarantees afforded by Rust, Symphonia aims to:

• Decode media as correctly as the leading free-and-open-source software decoders
• Prevent denial-of-service attacks
• Be fuzz-tested
• Provide a powerful, consistent, and easy to use API

Performance

Symphonia aims to be comparable to, or faster than, popular open-source C-based implementations. Currently, Symphonia's decoders are generally +/-15% the performance of FFMpeg. However, the exact range will depend strongly on the codec, which features of the codec are being leveraged in the encoding, the Rust compiler version, and the CPU architecture being compiled for.

See the benchmarks for more information.

Optimizations

All SIMD optimizations are enabled by default. SIMD support will pull in the rustfft dependency.

Instruction Set	Feature Flag	Default
SSE	opt-simd-sse	Yes
AVX	opt-simd-avx	Yes
Neon	opt-simd-neon	Yes

Tip

All SIMD optimizations can be enabled with the opt-simd feature flag.

Examples

Basic usage examples may be found here.

For a more complete application, see symphonia-play, a simple music player.

Tools

Symphonia provides the following tools for debugging purposes:

• symphonia-play for probing, decoding, validating, and playing back media streams.
• symphonia-check for validating Symphonia's decoded output against various decoders.

Minimum Supported Rust Version

The minimum supported Rust version (MSRV) for Symphonia 0.6.x releases is 1.85.

This project considers incrementing the MSRV to be a SemVer breaking change.

Author

The primary author is Philip Deljanov.

Special Thanks

• Kostya Shishkov (AAC-LC decoder contribution, see symphonia-codec-aac)

License

Symphonia is provided under the MPL v2.0 license. Please refer to the LICENSE file for more details.

Contributing

Symphonia is a free and open-source project that welcomes contributions! To get started, please read our Contribution Guidelines.