Return-Path: Message-ID: <431E5D6D.20901@xmission.com> From: Brad Midgley MIME-Version: 1.0 To: bluez-devel@lists.sourceforge.net Subject: Re: [Bluez-devel] sbc and fixed-point progress References: <001601c5b09c$df79dee0$0201a8c0@NBVICTOR> <4319C9B5.9060508@xmission.com> <002001c5b32d$7c610340$0201a8c0@NBVICTOR> In-Reply-To: <002001c5b32d$7c610340$0201a8c0@NBVICTOR> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: bluez-devel-admin@lists.sourceforge.net Errors-To: bluez-devel-admin@lists.sourceforge.net Reply-To: bluez-devel@lists.sourceforge.net List-Unsubscribe: , List-Id: BlueZ development List-Post: List-Help: List-Subscribe: , List-Archive: Date: Tue, 06 Sep 2005 21:24:29 -0600 Victor > I've checked in code for 4-subbands encoder. I've tried it only on x86, > but I do not expect any surprises on arm. Again, this is very cool... > It turned out (probably I should read the specs more carefully) that > 4-subbands with the same bitpool are actually superior to 8-subbands in > sound quality, producing 2 times higher bitrate wow, I hadn't understood that. I always thought 4 subbands sounded better just because my stereo headset is the sort of tinny in-the-ear type and I figured 4 subbands was truncating high-end frequencies just enough to make the sound less shrill. > I've added the options to specify the number of subbands and use of > joint stereo to sbcenc. ok, good. > Things to do (I'll spend some time on it): > 1. Check if joint stereo works > 2. Add command line arguments for bitpool, subbands, joint stereo, > other? (thrifty flag is a bit obscure) yes, "thrifty" was a quick hack > 4. Check/tune the error introduced by fixed point conversion (this can > be done comparing to old floating point implementation, cause current is > using int32_t for subbands, which might introduce some error in the > output stream) how is 32 bit maths selected? I assume we have to tweak the source to try it... > 5. There are still some optimizations regarding memcopies.... yes... I've been struggling with this in the decoder... Brad ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ Bluez-devel mailing list Bluez-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-devel