From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric B. Mitchell" Date: Tue, 22 Sep 1998 22:49:57 +0000 Subject: Re: compression tools Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sound@vger.kernel.org There is an implementation of the adpcm algorithms available in the Speak Freely package: http://www.fourmilab.ch/speakfree/ Off topic: Although, I'm wonder if anyone has implemented the adaptive audio compression algorithms from Dr. Dobbs a few months ago... Chris Bagwell wrote: > > I can only speak from the point of view of *free*. Best quality is only > going to come with buying something from the likes of RealAudio. > > Besides that, I've had good luck with various ADPCM formats. Both IMA > ADPCM and Microsoft ADPCM can convert 16-bit audio into 4-bit audio > which results in a considerable compression. Plus realtime > compression/decompression is easy on even limited machines (even 386s). > Sound quality holds up remarkably well. Right now its probably easiest > to convert your samples into .wav files under windows as it includes > codecs for both of those versions. > > I've implemented the decoder portion into sox but haven't gotten around > to adding the encoder (although the algorithms are readily available). > You could use that to listen to the streaming audio. IMA ADPCM was > designed to support streaming (recovery from lost blocks of data) > although I haven't seen any decoders take advantage of this. You can > grab a copy of sox with this support from: > > http://home.sprynet.com/sprynet/cbagwell/projects.html > > There is also a RAW IMA ADPCM encoder/decoder available on the net that > compiles under most versions of unix. Do a search for adpcm.shar. > > Hope it helps, > Chris > > Florin Andrei wrote: > > > > I need some real-time compression tools, wich can provide a reasonable > > sound quality and a good compression ratio. [snip] > > Any suggestions? > > Florin Andrei > > -- > Chris Bagwell | Fujitsu Network Communications > mailto:cbagwell@tddtx.fujitsu.com | Richardson, Texas -- +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+ | Eric B. Mitchell mailto:ericmit@ix.netcom.com | +=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+