Date: Mon, 9 Jul 2007 21:39:10 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-hackers@freebsd.org Cc: multimedia@freebsd.org Subject: Re: Audio driver template Message-ID: <200707092139.10519.hselasky@c2i.net> In-Reply-To: <c44ca55f0707091147n48741250h588a1fcf59d1b74b@mail.gmail.com> References: <c44ca55f0707091147n48741250h588a1fcf59d1b74b@mail.gmail.com>
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On Monday 09 July 2007 20:47, Christopher Davis wrote: > http://people.freebsd.org/~cg/template.c > > Thought I would take a look at the audio driver template as > part of my task to modernize drivers, soc2007. I would simplify > the read and write functions to avoid using the bus tag and > handle, but I'm not sure what else to do to bring it up to date. > > How else can it be improved? Regarding echo cancelling, you should add some code that time-stamps the audio data, and computes the current number of bytes in the RX/TX FIFOs! Look at the exported functions in the Echo Canceller for I4B: http://www.turbocat.net/~hselasky/isdn4bsd/sources/src/sys/i4b/layer1/i4b_echo_cancel.c The echo canceller above is a work in progress. --HPS
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