Return-Path: Subject: Re: [RFC/PATCH] sbc: new filtering function for 8 band fixed point encoding From: Jaska Uimonen To: ext Jelle de Jong Cc: linux-bluetooth@vger.kernel.org In-Reply-To: <492FFF3B.7000702@powercraft.nl> References: <1227879337.20555.12.camel@esdhcp03999.research.nokia.com> <1227881932.31311.2.camel@violet.holtmann.net> <492FFF3B.7000702@powercraft.nl> Content-Type: text/plain Date: Fri, 28 Nov 2008 17:20:06 +0200 Message-Id: <1227885606.20555.37.camel@esdhcp03999.research.nokia.com> Mime-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi, I did the git clone this morning and made the patch on top of that. Johan already came to tell me that I have whitespace instead of tabs in the changed parts. Sorry about that, I'll fix it. He said it will take 1 minutes to fix that but it was at least 1/2 hour with emacs :) br, Jaska On Fri, 2008-11-28 at 15:24 +0100, ext Jelle de Jong wrote: > Marcel Holtmann wrote: > > Hi Jaska, > > > >> I did some testing on the current 8 band fixed point > >> encoding and it seems to attenuate frequencies below 800Hz > >> and above 18kHz. There might be some other stuff happening > >> also, because at least to me the bass seemed to lack some > >> "definition". > >> > >> I didn't quite understand how the current tables are calculated > >> and how the filtering works so I wrote a new filtering function > >> and calculated new filter tables for it. It is written > >> using 16 bit fixed point without any platform specific optimizations. > >> I only unrolled some loops etc. I tried to follow the > >> flow chart in MPEG-1 annex c. > >> > >> With this new filtering the low and high frequencies are there, but > >> I haven't done any more thorough testing. At least it sounds > >> a little bit better to my ears :) > > > > thanks for looking at it. I am seriously lost when it comes to audio > > codecs and my ears normally don't count for much. > > > > So do you think we should throw all away any you start over providing a > > correct implementation with fixed point integer and then we start > > optimizing step by step (while testing against SBC conformance) or how > > should we continue. For sure we have to fix our codec. > > > > Regards > > > > Marcel > > Hi Jaska, Thank you so much for improving the codecs :-D it was on my > long standing wish list. You want to receive a few Dutch stroopwafels > for your efforts :-D > > Is the patch you provided working against the latest git? Marcel would > you be willing to review the patch for code style, hidden issues etcetera. > > I would love to test this patch this weekend and apply it to the latest git. > > I am an heavy stereo bluetooth user and will notice glitches and quality > distortions on my bluetooth speakers and headsets. > > Best regards, > > Jelle