On Monday 06 February 2006 13:06, Robert McGwier wrote: > Gerald Youngblood with Flex Radio has made a multimillion dollar > business using V.19. He would be dead in the water without it being > reliable. I have used V.19 on windows, linux, etc. I converted the > gr-audio-alsa code to gr-audio-portaudio superficially and checked it > in. It will soon rise to the top of my plate. I have used portaudio on > top of jack for the new WJST development team. Joe Taylor (K1JT for you > hams) opened the source and invited a few to help. He was using > PortAudio V.19 on Windows. I have been watching PortAudio closely now > for almost two years. > > Recently: > > Eric Wachsmann of Flex Radio "finished" the windows code by getting > portaudio to run reliably on top of Windows WDM-KS. This was Flex > Radio's pay back to that community for the value it has received. This > will be lower latency than linux-2.6 with low latency and alsa or jack > in real time mode. I know as I have measured it. At this low level, > Windows allow you to preempt the kernel and just about everything else > almost without safe guards so you can get some truly tiny latencies. > > Arne Knudsen has steadily erased all problems I have experienced in > using PortAudio on top of OSS, ALSA, and Jack. > > In the last month, multiple people have gotten portaudio to run on > Coreaudio and the Mac stuff is taking off. > > I would say that this is the single best hope we have for reliable and > solid audio under Windows for GnuRadio. I will soon return to this and > help Eric, et. al. get it running and into the general cvs download and > then all of us can beat it into shape. > > I might remind Berndt and everyone else that I have NEVER used a release > version of GnuRadio. They seem to stay current for about fifteen > minutes under a major change was checked in! > > Bob > > Berndt Josef Wulf wrote: > > On Monday 06 February 2006 11:04, Eric Blossom wrote: > >> On Sun, Feb 05, 2006 at 09:12:10PM +0100, Martin Dvh wrote: > >>>> Perhaps not enough buffering? Having source/sink in threads helps > >>>> sometimes. Martin will have better insight on the topic. > >>> > >>> The code needs fixing but I haven't spend much time on optimizing it > >>> yet. I think it does has something to do with threads. Maybe another > >>> buffer layer or number of buffers (pingpong) will fix it. Put the > >>> windows_audio sink in another thread will probably help, but I don't > >>> know howto. > >>> > >>> I just copied the ideas for the windows_audio driver from other GPL'ed > >>> windows audio projects. > >>> > >>> The windows_audio driver also needs an audio_source implementation. > >>> > >>> An other solution would be to implement a direct_audio driver (directX > >>> audio) in stead of fixing this. I suspect you would have much less > >>> synchronisation issues. > >>> > >>> A quick-and-dirty solution test would indeed be to increase the > >>> audio-buffer. (You need to build from source to test this) > >>> > >>> An even more quick and dirty test is to change the default value for > >>> all buffers between blocks. (Can be done after install) > >>> change the value for self.fixed_buffer_size in > >>> C:\Python24\site-packages\gnuradio\flow_graph.py line50: > >>> self.fixed_buffer_size = 32*1024 > >>> Change this to a higher/lower value and see what it does for you. > >>> The default is 32*1024 which means 32 kByte > >>> Note that this value is for ALL blocks, so you might break things when > >>> you make it too low and slow things down when you make it too high. > >>> > >>> greetings, > >>> Martin > >> > >> I don't think changing the flow graph buffering is going to make any > >> difference. I think that the "right answer" is build a very > >> high-functioning audio sink/source using portaudio. It's on my list, > >> but if somebody else wants to do it, please do (talk to me. I've got > >> some ideas.) Using the portaudio CVS version 19 stuff, there is now > >> good support for windows, and under ALSA and jack under Linux. It's > >> also supposed to work under OS/X using CoreAudio. > > > > There hasn't been any official releases since the 30 June 2003 with > > V18.1. Do you think its a good idea to use the CVS version? > > > > No releases usually means an unacceptable status of the current work > > unfit for public release. > > > > cheerio Berndt
Wow, many thanks for a very detailed report on portaudio. It has kindled my curiosity, so much so that I've downloaded and built the V19-devel snapshot. It took only a few minor changes to get it going on NetBSD and sofar passed all test applications that I run in this short period of time. Will read the docs in greater details tonight. cheerio Berndt
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