Open Source Fraunhofer AAC Encoder (fdk-aac) Options

[D404]

Android 4.1 has included an AAC encoding library by Fraunhofer, and Libav/FFmpeg support for this library is in the works (that is, in a day or two, it will be official.)

From the release announcement:

As part of the Android Jelly Bean source code released recently, a new AAC
library was released as well, developed by Fraunhofer:
https://android.googlesource.com/platform/external/aac

To ease using this library on platforms other than Android, I have added
an autotools based build system and done a minor portability fix, and
released this code as fdk-aac 0.1.0 today.

This project is hosted at sourceforge, under the opencore-amr project,
acting as an umbrella project for these codecs that are repackaged from
Android as standalone libraries, just as opencore-amr, vo-amrwbenc and
vo-aacenc before this one.

The release file is available at
http://sourceforge.net/projects/opencore-amr/files/fdk-aac/
and the code is available in git at
git://opencore-amr.git.sourceforge.net/gitroot/opencore-amr/fdk-aac.

This library is licensed under a custom copyleft style license:
http://opencore-amr.git.sourceforge.net/gi...a=blob;f=NOTICE

I in general intend to limit this project to minor tweaks and portability
fixes - for anything larger than that, I'd prefer if it first is
contributed upstream, to keep the difference between the upstream code and
this library as small as possible.

Edit: Obvious patent violation removed.

It can be used as such:

Bitrate Mode

CODE

avconv -i <input> -c:a libfdk_aac -b:a <bitrate> -afterburner 1 <output>

VBR Mode

CODE

aconv -i <input> -c:a libfdk_aac -flags +qscale -global_quality [1-5] -afterburner 1 <output>

VBR modes 1-5 correspond to roughly:

1. about 32 kbps/channel
2. about 40 kbps/channel
3. about 48-56 kbps/channel
4. about 64 kbps/channel
5. about 80-96 kbps/channel

-afterburner 1 enabkes "improved quality" mode.

Cheers.

Edit: This should be moved to the Tech forum.

This post has been edited by Garf: Jul 11 2012, 19:30

[pps83]

Hello HA,

I'm a pro developer and I've worked on some audio related projects as well (using ffmpeg and aac libs). I didn't use fdk yet, but I used the one from vo. I short, the one from vo looks like a joke. They basically took the 3gpp source and dropped the sbr part. I guess the logic was to drop HE part from AAC-HE to get AAC encoder The funny thing is that the AAC part runs before sbr and the AAC part allocates buffer for the bitstream. It writes aac part in the buffer and then sbr part appends into that same buffer. They dropped the sbr part and as a result the voaac generates bitstream full of zeros. You can easily see that it's full of nullshit in a hex editor. Otherwise, it's similar to libaacplus I guess, but it has some minor cpu optimizations (pretty badly done as well). Google could have hired a good dev and that voaac could have been fixed in a couple of months (some bestest dudes from ffmpeg could have done that in a couple of weeks I guess). Overall, all pv or vo codecs that google bought from packetvideo or visual on are clear ripoffs from 3gpp code and they aren't even well done. Looks like some graduates from china worked on the 3gpp code.

About patents. Some view source code as explanation of the patent itself, that is, source code that implements patented technology infringes on it as much as the patent description. Source code might be converted to a tool that uses patented technology using a compiler. Patent description might be converted just the same way to a tool that uses patented technology using a developer with a compiler. But source code does not use patented technology. I think there were cases of successful defense that source code implementation cannot be blocked on grounds of free speech, something like: you can't prevent me to express this technology using some computer language. There is one guy who went to us court against the US and he was pretty successful representing himself without having any background in law training. I've stumbled upon this dude by reading his one of the fastest fft algorithms. I think he is also the person who wrote qmail. I don't know why I wrote the paragraph I just realized that binaries were blocked from HA, not the source code...

I'm no sound expert, but why don't you guys start pushing OPUS all over the place? Personally, from my code review and study of the codec it's not worse that AAC. It's just insane how it's impossible to get any license to all that AAC bs, plus the price is ridiculous. My personal opinion is that they invent new crap not because there is a need, but because they want to prevent from new players coming into the big game. If you look at HEVC git history: all of the commits by employees from all these well known companies (rim, qualcomm, sony etc etc). They simply put a few developers full time on codec development project and a legal team that checks daily on progress and patents every incarnation of the bubble sort with the only intention to increase number of the patents related to the "new" technology so that it would practically be impossible to prove anything before all these patents actually expire. Just the idea that all these companies suddenly collaborate on a publicly available BSD licensed library is really fishy. To me it's clear what their intentions are. It's not only my guesses, I kind of worked on similar project by similar company and biggest expense was not the developers but the legal team that was working with us along the way. Their job was to check with us if there is something new was created and explore all angles from where they could patent it as an "invention". It all looked like dirty scam from inside, and from outside it's presented as research with all bells and marketing whistles.

(usual mambo-jumbo that i'm no legal expert is omitted).

[db1989]

Overall, all pv or vo codecs that google bought from packetvideo or visual on are clear ripoffs from 3gpp code and they aren't even well done. Looks like some graduates from china worked on the 3gpp code.

from china

Does this actually have any relevance, or is it just a daft stereotype with potential to be very offensive?

I'm no sound expert, but why don't you guys start pushing OPUS all over the place?

I’m sure that plenty of people are and that even more people will be once it’s seen a stable release. You should realise, though, that AAC’s popularity is due in no small part to its adoption and consequent aggressive promotion by Apple, Nero, et al.. You’ll excuse me if I’m pessimistic and suspect that all the open initiatives in the world and all of their enthusiastic supporters at the grassroots can’t eclipse corporate power. Vorbis is an illustrative example of this for numerous reasons.

I guess that ties into your fourth paragraph, at least as far as I’m capable of decoding it.

[pps83]

from china

Does this actually have any relevance, or is it just a daft stereotype with potential to be very offensive?

Nothing against china. Not sure why I have that in mind, probably because in comments (of the code) or somewhere I saw chinese names and decided that some part of that work was done in china where it's ok to take 3gpp code and then sell the code after making some minor changes and adding different interface.

I’m sure that plenty of people are and that even more people will be once it’s seen a stable release. You should realize, though, that AAC’s popularity is due in no small part to its adoption and consequent aggressive promotion by Apple, Nero, et al.. You’ll excuse me if I’m pessimistic and suspect that all the open initiatives in the world and all of their enthusiastic supporters at the grassroots can’t eclipse corporate power. Vorbis is an illustrative example of this for numerous reasons.

I guess that ties into your fourth paragraph, at least as far as I’m capable of decoding it.

The thing with apple is pretty clear I guess: they are one of the major patent holders for aac probably (am I right?); they are major patent holder in h264 video at least. They can easily release facetime client that uses h264 video and others might be in gray zone if they try to compete with them because for this type of app entry fee for the players is ridiculous: you might be charged a dollar per download by mpeg-la or you need to cover yourself with buyout license (which is millions of dolaz). So, they are pushing it.

About opus. It's already finished bistream format. It's now standard as it has been approved by IETF on July 2, 2012. Even a year ago tests by nokia confirmed that it was one of the best codecs for real time voice when compared to some state of the art codecs like amr-wb etc. There are also other tests that compare OPUS to codecs for general music. All that info on opus-codec.org.

Honestly, ppl get harassed for posting something that is considered to be illegal by HA. Instead, I think AAC should be considered illegal here instead
When working for some big guys' projects, I learned that they wanted to squeeze every drop possible for quality and performance. But they absolutely under no circumstances could even accept possibility that a non patent-incumbered codec could be used. So, I guess it's some kind of scam going on behind the scenes.

[Garf]

The thing with apple is pretty clear I guess: they are one of the major patent holders for aac probably (am I right?);

I don't think so. They weren't involved in AAC's development at all.

Honestly, ppl get harassed for posting something that is considered to be illegal by HA. Instead, I think AAC should be considered illegal here instead

Some companies licensed encoders and made those free to download. Winamp And Nero are two of them. You're free to discuss those as well as source implementations.