fdkaac(1)
NAME
fdkaac - command line frontend for libfdk-aac encoder
SYNOPSIS
fdkaac [OPTIONS] [FILE]
DESCRIPTION
fdkaac reads linear PCM audio in either WAV, raw PCM, or CAF format, and encodes it into either M4A / AAC file. If the input file is "-", data is read from stdin. Likewise, if the output file is "-", data is written to stdout if one of streamable AAC transport formats are selected by -f. When CAF input and M4A output is used, tags in CAF file are copied into the resulting M4A.
OPTIONS
-h, --help
Show command help
-o <FILE>
Output filename.
-p, --profile <n>
Target profile (MPEG4 audio object type, AOT)
2 MPEG-4 AAC LC (default)
5 MPEG-4 HE-AAC (SBR)
29 MPEG-4 HE-AAC v2 (SBR+PS)
23 MPEG-4 AAC LD
39 MPEG-4 AAC ELD
129 MPEG-2 AAC LC
132 MPEG-2 HE-AAC (SBR)
156 MPEG-2 HE-AAC v2 (SBR+PS)
-b, --bitrate <n>
Target bitrate (for CBR)
-m, --bitrate-mode <n>
Bitrate configuration mode. Available VBR quality value depends
on other parameters such as profile, sample rate, or number of
channels.
0 CBR (default)
1-5 VBR (higher value -> higher bitrate)
-w, --bandwidth <n>
Frequency bandwidth (lowpass cut-off frequency) in Hz.
Available on AAC LC only.
-a, --afterburner <n>
Configure afterburner mode. When enabled, quality is increased
at the expense of additional computational workload.
0 Off
1 On (default)
-L, --lowdelay-sbr <n>
Configure SBR activity on AAC ELD.
-1 Use ELD SBR auto configuration
0 Disable SBR on ELD (default)
1 Enable SBR on ELD
-s, --sbr-ratio <n>
Controls activation of downsampled SBR.
0 Use lib default (default)
1 Use downsampled SBR (default for ELD+SBR)
2 Use dual-rate SBR (default for HE-AAC)
Dual-rate SBR is what is normally used for HE-AAC, where AAC is
encoded at half the sample rate of SBR, hence "dual rate". On
the other hand, downsampled SBR uses same sample rate for both
of AAC and SBR (single rate), therefore downsampled SBR
typically consumes more bitrate.
Downsampled SBR is newly introduced feature in FDK encoder
library version 3.4.12. When libfdk-aac in the system doesn't
support this, dual-rate SBR will be used. When available,
dual-rate SBR is the default for HE-AAC and downsampled SBR is
the default for ELD+SBR.
Note that downsampled HE-AAC is not so common as dual-rate one.
When downsampled HE-AAC is selected, fdkaac is forced to choose
explicit hierarchical SBR signaling, which (at least) iTunes
doesn't accept.
-f, --transport-format <n>
Transport format. Tagging and gapless playback is only
available on M4A. Streaming to stdout is only available on
others.
0 M4A (default)
1 ADIF
2 ADTS
6 LATM MCP=1
7 LATM MCP=0
10 LOAS/LATM (LATM within LOAS)
-C, --adts-crc-check
Add CRC protection on ADTS header.
-h, --header-period <n>
StreamMuxConfig/PCE repetition period in the transport layer.
-G, --gapless-mode <n>
Method to declare amount of encoder delay (and padding) in M4A
container. These values are mandatory for proper gapless
playback on player side.
0 iTunSMPB (default)
1 ISO standard (edts and sgpd)
2 Both
--include-sbr-delay
When specified, count SBR decoder delay in encoder delay.
This is not iTunes compatible and will lead to gapless playback
issue on LC only decoder, but this is the default behavior of
FDK library.
Whether counting SBR decoder delay in encoder delay or not
result in incompatibility in gapless playback. You should pick
which one will work for your favorite player.
However, it's better not to choose SBR at all if you want
gapless playback. LC doesn't have such issues.
-I, --ignorelength
Ignore length field of data chunk in input WAV file.
-S, --silent
Don't print progress messages.
--moov-before-mdat
Place moov box before mdat box in M4A container. This option
might be important for some hardware players, that are known to
refuse moov box placed after mdat box.
-R, --raw
Regard input as raw PCM.
--raw-channels <n>
Specify number of channels of raw input (default: 2)
--raw-rate <n>
Specify sample rate of raw input (default: 44100)
--raw-format <spec>
Specify sample format of raw input (default: "S16L"). Spec is
as the following (case insensitive):
1st char -- type of sample
S (igned) | U (nsigned) | F (loat)
2nd part (in digits)
bits per channel
Last char -- endianness (can be omitted)
L (ittle, default) | B (ig)
--title <string>
Set title tag.
--artist <string>
Set artist tag.
--album <string>
Set album tag.
--genre <string>
Set genre tag.
--date <string>
Set date tag.
--composer <string>
Set composer tag.
--grouping <string>
Set grouping tag.
--comment <string>
Set comment tag.
--album-artist <string>
Set album artist tag.
--track <number[/total]>
Set track tag, with or without number of total tracks.
--disk <number[/total]>
Set disk tag, with or without number of total discs.
--tempo <n>
Set tempo (BPM) tag.
--tag <fcc>:<value>
Set iTunes predefined tag with explicit fourcc key and value.
See <https://code.google.com/p/mp4v2/wiki/iTunesMetadata> for
known predefined keys. You can omit first char of fcc when it
is the copyright sign.
--tag-from-file <fcc>:<filename>
Same as --tag, but set content of file as tag value.
--long-tag <name>:<value>
Set arbitrary tag as iTunes custom metadata. Stored in
com.apple.iTunes field.
--tag-from-json <filename[?dot_notation]>
Read tags from JSON. By default, tags are assumed to be direct
children of the root object in JSON. Optionally you can specify
arbitrary dot notation to locate the object containing tags.
EXAMPLES
Encode WAV file into a M4A file. MPEG4 AAC LC, VBR quality 3:
fdkaac -m3 foo.wav
Encode WAV file into a M4A file. MPEG4 HE-AAC, bitrate 64kbps:
fdkaac -p5 -b64 foo.wav
Piping from ffmpeg (you need version supporting CAF output):
ffmpeg -i foo.flac -f caf - | fdkaac -b128 - -o foo.m4a
Import tags via json:
ffprobe -v 0 -of json -show_format foo.flac >foo.json
flac -dc foo.flac | \
fdkaac - -ox.m4a -m2 --import-tag-from-json=foo.json?format.tags
NOTES
Upto 32bit integer or 64bit floating point format is supported as
input. However, FDK library is implemented based on fixed point math
and only supports 16bit integer PCM. Therefore, be wary of clipping.
You might want to dither/noise shape beforehand when your input has
higher resolution.
Following channel layouts are supported by the encoder.
1ch C
2ch L R
3ch C L R
4ch C L R Cs
5ch C L R Ls Rs
5.1ch C L R Ls Rs LFE
7.1ch (front)
C Lc Rc L R Ls Rs LFE
7.1ch (rear)
C L R Ls Rs Rls Rrs LFE
AUTHORS
nu774 <honeycomb77@gmail.com>.
November, 2013 FDKAAC(1)
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
