Kirika

Collection of audio utilities for decoding/encoding/processing files and streams.

• Not based on ffmpeg/libav/libavcodec/libavformat and alike
• Channel-based audio consumption/filter chain
• Raw decoded samples exposed
• AnalyzerChannel channels / mergers / splitters / trimmers
• Audio resampler
• Audio downmixing to stereo/mono
• Multi-codec decoder and encoder
• Multi-format packetizers
• ReplayGain 2.0 track/album calculator

Codecs supported

Codec	Containers	Decoder	Sample Analyzer	Sample Format	Encoder	Notes
FLAC	FLAC, Ogg	✅	✅	int32	✅	Adjustable encoding compression level and block size. Decoding/encoding by libFLAC via goflac. If goflac codec is disabled, flacgo decoder/encoder will be used.
TTA	TTA	✅	✅	int32	✅	Decoding/encoding via S.O.N.G/go-tta.
MP3	MP3	✅	❌	float32	✅	Adjustable encoding bitrate and mode. Decoding via S.O.N.G/minimp3, encoding by LAME via go-lame.
Opus	Ogg	✅	❌	float32	✅	Adjustable encoding bitrate. Decoding/encoding by libopus via go-pus. Linked Ogg streams of different channel count are not supported.
Vorbis	Ogg	✅	❌	float32	✅	Decoding/encoding by libvorbis via go-vorbis. If go-vorbis is disabled, jfreymuth/vorbis via jfreymuth/oggvorbis decoder will be used. Linked Ogg streams of different channel count are not supported.
AAC	ADTS, ADIF*, MP4**	✅	❌	int16	✅	Adjustable encoding bitrate and mode (LC, HEv1, HEv2). Decoding/encoding by FDK-AAC via go-fdkaac. If go-fdkaac codec is disabled, VisualOn AAC encoder will be used for limited encoding support. *ADIF only supported on encoding. **MP4 only supported on encoding, and fragmented MP4 currently.
ALAC	MP4*	✅	✅	int32	✅	Decoding/encoding by libalac via go-alac. Disabled by default. *MP4 encoding only supported on fragmented MP4 currently.

Container packetizers supported

Only output from Kirika's own encoders is supported.

Container	Packetizer	Keep Mode	Sample Numbers	Offset	Notes
FLAC	✅	✅	✅	✅	Uses custom Kirika packetizer.
TTA	❌	-	-	-
MP3	✅	✅	✅	✅	Uses sssgun/mp3 as a frame parser.
Ogg	✅	✅	✅*	✅	Uses custom Kirika packetizer. *Sample numbers (absolute granule position in Ogg) depend on underlying codec implementing it. Has been tested as working for Opus, FLAC
ADTS	✅	✅	✅	✅	Uses Eyevinn/mp4ff for its ADTS frame parser.
MP4	❌	-	-	-
ADIF	❌	-	-	-

Filters

Filter	Native Sample Format	Notes
Resample	float32	Changes input source sample rate to a different sample rate. If source sample rate equals sampleRate, returns source.
Source Format	float32 int16 int32	Changes input source to a different format.
Buffer	float32 int16 int32	Makes output source a buffered channel of the specified size.
Block Size	float32 int16 int32	Adjusts input source blocks to a normalized block size.
Real Time	float32 int16 int32	Outputs enough samples per second equal to the source sample rate.
Volume	float32 int16 int32	Adjusts volume of all samples equally. If adjustement equals 1.0, returns source.
Stereo	float32 int16 int32	Makes input stereo. If source channels equals 2, returns source.
Mono	float32 int16 int32	Makes input mono. If source channels equals 1, returns source.
ReplayGain	float32 int16 int32	Creates a Volume filter with the specified ReplayGain parameters.
Normalization	float32	Automatically adjusts volume according to short term audio loudness.

Filter Chain

Allows chaining different filters together where one's output is the next one input.

Hashers

Several audio Analyzer hashers are implemented. List of current ones:

• CRC32
• SHA256
• SHA1
• MD5
• AccurateRipV1
• AccurateRipV1 (Start mode)
• AccurateRipV2
• AccurateRipV2 (Start mode)

Dependencies

Go >= 1.20

libFLAC (required by goflac)

sudo apt install libflac-dev

libopus and libopusfile (required by go-pus)

sudo apt install libopus-dev libopusfile-dev

libopusenc (required by go-pus)

git clone --depth 1 https://gitlab.xiph.org/xiph/libopusenc.git
cd libopusenc
./autogen.sh
./configure --prefix /usr
make
sudo make install

libvorbis (required by go-vorbis)

sudo apt install libvorbis-dev

FDK AAC Codec Library (required by go-fdkaac)

sudo apt install libfdk-aac-dev

Alternatively if package cannot be found under your distribution:

git clone --depth 1 https://github.com/mstorsjo/fdk-aac.git
cd fdk-aac
./autogen.sh
./configure --prefix /usr
make -j$(nproc)
sudo make install

libalac (required by go-alac)

git clone --depth 1 https://git.gammaspectra.live/S.O.N.G/alac.git
cd alac
autoreconf -fi
./configure --prefix /usr
make -j$(nproc)
sudo make install

LAME (required by go-lame)

sudo apt install libmp3lame-dev

libsamplerate (required by gosamplerate)

sudo apt install libsamplerate0-dev

libebur128 (required by go-ebur128)

sudo apt install libebur128-dev

Build tags

Several Golang build tags exist to change which features are included in the project.

CGO_ENABLED=0

This tag disables CGO support, and disables any formats/codecs that require it. Some other features will degrade or be less performant, or alternative decoders be used.

Additionally, libebur128 (used for normalization) will be disabled.

Some tests cannot be completed in this mode.

Codecs supported, CGO_ENABLED=0

Codec	Containers	Decoder	Sample Analyzer	Sample Format	Encoder	Notes
FLAC	FLAC	✅	✅	int32	✅*	Decoding/encoding by flacgo. *Encoder only supports Verbatim / Constant frame prediction modes, offering almost no compression.
TTA	TTA	✅	✅	int32	✅	Decoding/encoding by S.O.N.G/go-tta.
MP3	MP3	✅	❌	2ch. float32	❌	Decoding by S.O.N.G/go-mp3.
Opus	-	❌	-	-	❌
Vorbis	Ogg	✅	❌	float32	❌	Decoding by jfreymuth/vorbis via jfreymuth/oggvorbis.
AAC	-	❌	-	-	❌
ALAC	-	❌	-	-	❌

disable_format_[format]

This tag disables support for the specified format/codec. This does not affect packetizers.

Current implemented [format]: aac, alac, flac, mp3, opus, tta, vorbis. Disabling flac will break tests.

disable_codec_libfdk-aac

This tag disables the libfdk-aac support for decoding/encoding AAC. This is available for specific problems with the FDK license that conflicts with your needs or policy.

If this tag is enabled, yet aac support remains enabled, an AAC encoder (but not decoder) will be built with the VisualOn AAC encoder bindings, which are vastly worse.

disable_codec_libflac

This tag disables the libFLAC support for decoding/encoding FLAC.

If this tag is enabled, yet flac support remains enabled, flacgo FLAC decoder/encoder will be used.

disable_codec_libvorbis

This tag disables the libvorbis support for decoding/encoding Vorbis.

If this tag is enabled, yet vorbis support remains enabled, jfreymuth/vorbis via jfreymuth/oggvorbis Vorbis decoder will be used.

disable_codec_lame

This tag disables the LAME support for encoding MP3. This is available for specific problems with the LGPL v2 license that conflicts with your needs or policy.

MP3 decoding is not affected by this tag.

disable_codec_tta

This tag disables the TTA support for decoding/encoding TTA. This is available for specific problems with the LGPL v3 license that conflicts with your needs or policy.

This is equivalent to disable_format_tta.

enable_codec_libalac

This tag enables the libalac support for decoding/encoding ALAC.

This library has vast security issues, enable on your own risk. An alternate codec for decoding might be added in the future.

Utilities

cmd/decode

Example application that decodes files and provides some general information about the decoded streams, and produces an MD5 hash of the sample data. Run via $ go run git.gammaspectra.live/S.O.N.G/Kirika/cmd/decode -input "resources/samples/cYsmix - Haunted House/11. The Great Rigid Desert.flac"

Example output:

2023/01/29 12:58:27 File: resources/samples/cYsmix - Haunted House/11. The Great Rigid Desert.flac
2023/01/29 12:58:27 Available decoders:
2023/01/29 12:58:27     flac: reference libFLAC 1.3.3 20190804 (S.O.N.G/goflac) (analyzer)
2023/01/29 12:58:27 Decoding as int32 24-bit @ 44100Hz 2 channel(s)
2023/01/29 12:58:27 Decoded 17323031 sample(s)
2023/01/29 12:58:27 Processed 4230 blocks(s) (avg 4095.28 sample(s) per block)
2023/01/29 12:58:27 Duration 6m32.812494331s
2023/01/29 12:58:27 MD5 hash: c1a62472ca433e6c4b02e842a8348660
2023/01/29 12:58:27     Check via $ ffmpeg -hide_banner -loglevel error -i "resources/samples/cYsmix - Haunted House/11. The Great Rigid Desert.flac" -vn -c:a pcm_s24le -f md5 -
2023/01/29 12:58:27 Took 385.02864ms

Licenses

Kirika

Copyright (c) 2022 Kirika Contributors All rights reserved.

Redistribution and use in source and binary forms, with or without modification,are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Dependencies

Subdependencies that are not cgo-based are denoted in cursive.

Dependency	Language	License	Notes
S.O.N.G/go-alac	Go	BSD 2-Clause
S.O.N.G/alac	C++/C	Apache 2.0	Can be linked by cgo as a shared library.
S.O.N.G/go-ebur128	Go	BSD 2-Clause
jiixyj/libebur128	C	MIT	Can be linked by cgo as a shared library.
S.O.N.G/go-fdkaac	Go	MIT
mstorsjo/fdk-aac	C++/C	FDK License, BSD-like	Does not include patent grants. Considered free by Red hat, Fedora, GNU, FSF; and non-free by Debian. Can be linked by cgo as a shared library.
S.O.N.G/go-pus	Go	MIT
xiph/opus	C	BSD 3-Clause	Read extra license details on the official site. Can be linked by cgo as a shared library.
xiph/opusfile	C	BSD 3-Clause	Can be linked by cgo as a shared library.
xiph/ogg	C	BSD 3-Clause	Can be linked by cgo as a shared library.
xiph/libopusenc	C	BSD 3-Clause	Can be linked by cgo as a shared library.
S.O.N.G/go-vorbis	Go	BSD 2-Clause
xiph/vorbis	C	BSD 3-Clause	Can be linked by cgo as a shared library.
S.O.N.G/go-tta	Go	LGPL v3
S.O.N.G/goflac	Go	BSD 3-Clause
xiph/flac	C	BSD 3-Clause	Read extra license details on the official site. Can be linked by cgo as a shared library.
dh1tw/gosamplerate	Go	BSD 2-Clause
libsndfile/libsamplerate	C	BSD 2-Clause	Can be linked by cgo as a shared library.
Eyevinn/mp4ff	Go	MIT
S.O.N.G/voaac-go	Go	Apache 2.0
mstorsjo/vo-aacenc	C	Apache 2.0	Subdependency and included as part of S.O.N.G/voaac-go.
S.O.N.G/go-mp3	Go	Apache 2.0
jfreymuth/oggvorbis	Go	MIT
jfreymuth/vorbis	Go	MIT	Subdependency of jfreymuth/oggvorbis.
S.O.N.G/minimp3	Go	MIT
lieff/minimp3	C	CC0 1.0	Subdependency and included as part of S.O.N.G/minimp3.
S.O.N.G/flacgo	Go	The Unlicense
icza/bitio	Go	Apache 2.0 or LGPL v2.1	Subdependency of S.O.N.G/flacgo.
sssgun/mp3	Go	MIT
viert/go-lame	Go	MIT
LAME	C	LGPL v2	Can be linked by cgo as a shared library.