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View Full Version : Helix Fixed-point open source HE-AAC decoder

karl_lillevold
3rd March 2005, 20:23
Yesterday, the RealNetworks Codec Team released an open source optimized High-Efficiency AAC (aacPlus) decoder to the Helix Community.

The Helix Fixed-point HE-AAC decoder provides an optimized 32-bit fixed-point implementation, which will be dual-licensed under RCSL/RPSL. No extra copyright license is required beyond the standard Helix license terms, although patent licenses are not included and must be acquired from the appropriate AAC licensors.

The Helix AAC decoder is highly optimized for ARM processors and meets or exceeds the performance of other commercial implementations. It also features one of the first widely available fixed-point implementations of SBR.

The following features are currently supported:
· MPEG-2 and MPEG-4 low complexity decoding (intensity stereo, MS, TNS, PNS)
· spectral band replication (SBR), high-quality mode
· mono, stereo, and multichannel modes
· ADTS, ADIF, and raw data block decoding
· MP4, RM, and other file formats supported via Helix client


https://datatype.helixcommunity.org/2005/aacfixptdec
bond
4th March 2005, 12:14
wow, thanks a lot, real, for that :)
Capirossi
23rd March 2005, 19:40
thanks real :cool:
Kurtnoise
11th July 2005, 16:23
Hi,

Is there a way to have a binary/short compile to test this decoder, Karl ?

Thanks...
karl_lillevold
11th July 2005, 17:40
No, I am afraid I do not have one. But I know that with the source code it is possible to build a cmd line unit test executable that decodes .aac files to PCM or .wav. Other than that, you might consider asking on the helix community, probably the datatype mailing list or forum.
karl_lillevold
13th July 2005, 19:02
By the way, one can easily obtain the source code via the CVS web based browser:
https://helixcommunity.org/viewcvs/cgi/viewcvs.cgi/datatype/aac/codec/fixpt/decoder/
without setting up the somewhat complicated secure CVS checkout procedure. It should be possible to create a standalone build environment too, without using the Helix ribosome build system, but this I am sure entirely sure about.
Kurtnoise
20th July 2005, 12:03
Finally cml, Enig123's friend, has build a win32 binary (http://www.hydrogenaudio.org/forums/index.php?showtopic=35695&hl=) for this decoder. I haven't tested yet...


:thanks:
Sirber
11th October 2005, 13:02
included in "ffdshow audio".
dimzon
11th October 2005, 13:39
included in "ffdshow audio".
don't support PS