IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Helix Fixed-point open source HE-AAC decoder, open source optimized fixed point HE-AAC
karl_lillevold
post Mar 3 2005, 20:05
Post #1


RealNetworks Sr. Codec Engineer


Group: Developer (Donating)
Posts: 89
Joined: 12-June 03
From: Seattle
Member No.: 7151



Yesterday, the RealNetworks Codec Team released an open source optimized High-Efficiency AAC (aacPlus) decoder to the Helix Community.

QUOTE
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


--------------------
Sr. Codec Engineer (video) | RealNetworks Codec Group | helixcommunity.org
This information is provided "AS IS" with no warranties, grants no rights, and reflects my personal opinion.
Go to the top of the page
+Quote Post
rjamorim
post Mar 3 2005, 20:13
Post #2


Rarewares admin


Group: Members
Posts: 7515
Joined: 30-September 01
From: Brazil
Member No.: 81



shock1.gif

Amazing!

Big thanks to RN for contributing this.


--------------------
Get up-to-date binaries of Lame, AAC, Vorbis and much more at RareWares:
http://www.rarewares.org
Go to the top of the page
+Quote Post
spoon
post Mar 4 2005, 11:22
Post #3


dBpowerAMP developer


Group: Developer (Donating)
Posts: 2723
Joined: 24-March 02
Member No.: 1615



Just what the community needs, thanks Karl.


--------------------
Spoon http://www.dbpoweramp.com
Go to the top of the page
+Quote Post
guada 2
post Mar 4 2005, 18:04
Post #4





Group: Banned
Posts: 85
Joined: 13-February 05
Member No.: 19813



Bravo.
An evolution as one likes it
Thank you Karl. smile.gif
Go to the top of the page
+Quote Post
yanchen
post Mar 6 2005, 08:27
Post #5





Group: Members
Posts: 19
Joined: 5-March 02
From: Taipei
Member No.: 1449



Great contribution for the evidence to prove the more effiective complexity design of AAC than any other codec. From the statistical number, we can see the ARM enhanced instruction cannot bring a significant improvemnent as in speech codec. It also tell us that the comparable computation power annouced by coding technology beteewn conventional AAC decoder and HE-AAC decoder is questionable.

However, from my knowledgement base, the fastest commercial AAC ARMv2 decoder in the world can reach 18 MHZ 44.1KHz stereo. But this decoder may devote much effort between memory usage and speed.

This post has been edited by yanchen: Mar 6 2005, 08:34
Go to the top of the page
+Quote Post
chelgrian
post Mar 6 2005, 21:09
Post #6





Group: Members
Posts: 316
Joined: 27-April 03
Member No.: 6228



QUOTE (yanchen @ Mar 6 2005, 08:27 AM)
Great contribution for the evidence to prove the more effiective complexity design  of AAC than any other codec. From the statistical number, we can see the ARM enhanced instruction cannot bring a significant improvemnent as in speech codec. It also tell us that the comparable computation power annouced by coding technology beteewn conventional AAC decoder and HE-AAC decoder is questionable.

However, from my knowledgement base, the fastest commercial AAC ARMv2 decoder in the world can reach 18 MHZ 44.1KHz stereo. But this decoder may devote much effort between memory usage and speed.
*


Hum they only tested it on a ARM9TDMI (v4T), ARM9E (V5TE), StrongARM (v4) and Xscale (V5TE). They didn't test on anything like a ARM1136 (v6) which has various media and SIMD extensions.

They also compiled it with ADS 1.2 rather than the latest ARM compiler RVCT 2.2 which produces significantly faster code.

The fastest ARM ACC codec was handcrafted in assembler by some guys down the corridor from me but we no longer license it commercially.
Go to the top of the page
+Quote Post
Bonzi
post Mar 7 2005, 02:31
Post #7


A/V Moderator


Group: Members
Posts: 278
Joined: 22-February 03
Member No.: 5132



Hi Karl! This is really awesome contribution to the open source community. But is the RCSL/RPSL license compatible with GPL? I ask because the it would be really nice to use this code in the iPodLinux project.
EDIT: Nevermind, according to this it is smile.gif.
Go to the top of the page
+Quote Post
The DJ
post Mar 7 2005, 18:02
Post #8





Group: Members
Posts: 1
Joined: 8-January 04
Member No.: 11057



QUOTE (Bonzi @ Mar 6 2005, 05:31 PM)
Hi Karl!  This is really awesome contribution to the open source community.  But is the RCSL/RPSL license compatible with GPL?  I ask because the it would be really nice to use this code in the iPodLinux project.
EDIT: Nevermind, according to this it is smile.gif.
*


It also says this:
1 Note: because this license contains certain reciprocal licensing terms that purport to extend to independently developed code, You may be prohibited under the terms of these otherwise compatible licenses from using code licensed under their terms with Covered Code because Covered Code may only be licensed under the RealNetworks Public Source License. Any attempt to apply non RPSL license terms, including without limitation the GPL, to Covered Code is expressly forbidden. You are responsible for ensuring that Your use of Compatible Source Licensed code does not violate either the RPSL or the Compatible Source License.


so basically RPSL is compatible with GPL, just not viceversa (according to the strict explenation of the GPL license).
Go to the top of the page
+Quote Post
HotTrance_COM
post Mar 12 2005, 09:01
Post #9





Group: Members
Posts: 2
Joined: 12-March 05
Member No.: 20552



Great! smile.gif Now we just need an open source HE-AAC ENCODER biggrin.gif

~ J
Go to the top of the page
+Quote Post
Garf
post Mar 12 2005, 12:37
Post #10


Server Admin


Group: Admin
Posts: 4853
Joined: 24-September 01
Member No.: 13



Split Nero on Linux discussion to:

http://www.hydrogenaudio.org/forums/index....showtopic=32285
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 16th April 2014 - 18:18