Just an update on this issue to complete the thread. I tracked down the bug in the emu10k1 driver. Seems it gets triggered when the clock is synchronized to SPDIF or ADAT. Here is a link to the bug report and a patch which I used to fix the problem (though some work is still required for a proper fix): https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4287 Best regards, Josh Green On Sat, 2008-12-13 at 16:32 -0800, Josh Green wrote: > Hello ALSA users, > > I'm working on an audio archiving project for a non-profit radio > station. For this I have setup an Ubuntu 8.10 system using the provided > ALSA 1.0.17. We would like to record an AES/EBU stream connected to the > digital input of an EMU 0404 PCI card. > > I have figured out how to record the digital stream, but the audio > stream consists of valid audio samples interleaved with 0 samples. This > results in a stream which plays back at half speed with some other > regular clicking artifacts (assuming that is because the timing is > different). > > Example stereo audio stream (Left, Right, 0, 0, Left, Right, 0, 0, ...): > 0x12341234 0x12341234 0x00000000 0x00000000 > 0x56785678 0x56785678 0x00000000 0x00000000 > 0x9ABC9ABC 0x9ABC9ABC 0x00000000 0x00000000 > ... > > Audio was captured with the following arecord commands: > > # Native capture (8 channels of 48KHz 32 bit) > arecord -D hw:0,2 -f S32_LE -c 8 -r 48000 test.wav > > # Using plughw to capture a 24 bit stereo stream > arecord -D plughw:0,2 -f S24_LE -c 2 -r 48000 test.wav > > > In both cases the previously described problem is observed. > > Documentation on using this device in Linux seems rather sparse, but > from various blogs and emails on the Internet I discovered: > > There are 3 capture devices. 1st is for analog capture, 2nd is for Mic > capture and 3rd is for Multichannel capture (the one which we want and > will allow recording from the digital input). > > I set the 'Clock Internal Rate' mixer setting using amixer to "SPDIF" to > sync to external AES/EBU clock. > > I routed DSP 0 and DSP 1 capture sources to "0202 SPDIF Left" and "0202 > SPDIF Right" respectively. > > > I suspect this is a bug in the driver. Has anyone had success with this > card and recording AES/EBU from the digital input? Any ideas what is > wrong? Thanks in advance! > > Best regards, > Josh Green > > > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > Alsa-user mailing list > Alsa-user@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/alsa-user > ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
