Symphonia

Symphonia is a pure Rust audio decoding and media demuxing library supporting AAC, ALAC, FLAC, MP3, MP4, OGG, Vorbis, and WAV.

Features

Decode support for the most popular audio codecs
Demux the most common media container formats
Read most metadata and tagging formats
Automatic format and decoder detection
Provides a set of 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

Format and Codec Support Roadmap

Support for individual audio codecs and media formats is provided by separate crates. By default, Symphonia enables support for FOSS codecs and formats, but others may be enabled via the features option.

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

Status	Meaning
-	No work started or planned yet.
In Work	Is in work or will be started next.
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 freely available, then a status of excellent will be assigned if Symphonia's implementation matches the quality of a reference implementation, or ffmpeg.

Formats (Demuxers)

Format	Status	Feature Flag	Default	Crate
ISO/MP4	Great	`isomp4`	No	`symphonia-format-isomp4`
MKV/WebM	In Work	`mkv`	Yes	`symphonia-format-mkv`
OGG	Great	`ogg`	Yes	`symphonia-format-ogg`
Wave	Excellent	`wav`	Yes	`symphonia-format-wav`

Codecs (Decoders)

Codec	Status	Feature Flag	Default	Crate
AAC-LC	Good	`aac`	No	`symphonia-codec-aac`
ALAC	Great	`alac`	No	`symphonia-codec-alac`
HE-AAC (AAC+, aacPlus)	-	`aac`	No	`symphonia-codec-aac`
HE-AACv2 (eAAC+, aacPlus v2)	-	`aac`	No	`symphonia-codec-aac`
FLAC	Excellent	`flac`	Yes	`symphonia-bundle-flac`
MP1	-	`mp3`	No	`symphonia-bundle-mp3`
MP2	-	`mp3`	No	`symphonia-bundle-mp3`
MP3	Excellent	`mp3`	No	`symphonia-bundle-mp3`
Opus	In Work	`opus`	Yes	`symphonia-codec-opus`
PCM	Excellent	`pcm`	Yes	`symphonia-codec-pcm`
Vorbis	Great	`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.

Tags (Readers)

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

Format	Status
ID3v1	Great
ID3v2	Great
ISO/MP4	Great
RIFF	Great
Vorbis comment (FLAC)	Perfect
Vorbis comment (OGG)	Perfect

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 or better in performance to popular open-source C-based implementations. Currently, Symphonia's decoders are generally +/-15% the performance of ffmpeg. The exact amount will depend strongly on the codec, and which features of the codec are leveraged in the encoding.

Benchmarks (as of September 2019)

These benchmarks compare the single-threaded decoding performance of both Symphonia and FFmpeg with various audio files.

The benchmarks were executed on an Arch Linux system with a Core i7 4790k and 32GB of RAM, for a minimum of 20 runs each. Hyperfine was used to execute the test. The full benchmark script is as follows:

#!/bin/bash
IN="${1@Q}"
hyperfine -m 20 "ffmpeg -threads 1 -benchmark -v 0 -i ${IN} -f null -" "symphonia-play --decode-only ${IN}"

MP3, 192kbps @ 44.1kHz

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Symphonia	306.2 ± 3.0	301.8	312.5	1.1
FFmpeg	272.7 ± 4.3	267.6	285.3	1.0

MP3, 320kbps @ 44.1kHz

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Symphonia	355.1 ± 8.4	348.2	376.2	1.1
FFmpeg	316.0 ± 3.5	308.8	322.8	1.0

FLAC, 24-bit @ 96kHz

Decoder	Mean [ms]	Min [ms]	Max [ms]	Relative
Symphonia	453.6 ± 2.9	449.3	462.4	1.0
FFmpeg	501.9 ± 4.3	496.4	512.7	1.1

FLAC, 24-bit @ 48kHz

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Symphonia	324.0 ± 8.9	315.4	346.3	1.0
FFmpeg	331.0 ± 7.4	323.6	354.5	1.0

WAVE, S32LE @ 44.1kHz

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Symphonia	84.5 ± 1.8	81.8	89.1	1.0
FFmpeg	129.8 ± 3.4	123.4	136.1	1.5

Example Usage

Basic usage examples may be found in symphonia/examples.

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 ffmpeg.

Authors

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 an open-source project and contributions are very welcome! If you would like to make a large contribution, please raise an issue ahead of time to make sure your efforts fit into the project goals, and that there's no duplication of effort. Please be aware that all contributions must also be licensed under the MPL v2.0 license to be accepted.

When submitting a pull request, be sure you have included yourself in the CONTRIBUTORS file!

Be-ing / Symphonia