From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp1.sscnet.ucla.edu ([128.97.229.231]:35926 "EHLO smtp1.sscnet.ucla.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751925AbZIOFQ4 (ORCPT ); Tue, 15 Sep 2009 01:16:56 -0400 Message-ID: <4AAF232F.9060204@cogweb.net> Date: Mon, 14 Sep 2009 22:16:31 -0700 From: David Liontooth MIME-Version: 1.0 To: hermann pitton CC: linux-media@vger.kernel.org Subject: Audio drop on saa7134 References: <4AAEFEC9.3080405@cogweb.net> <20090915000841.56c24dd6@pedra.chehab.org> <4AAF11EC.3040800@cogweb.net> <1252988501.3250.62.camel@pc07.localdom.local> In-Reply-To: <1252988501.3250.62.camel@pc07.localdom.local> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: hermann pitton wrote: > Am Montag, den 14.09.2009, 21:02 -0700 schrieb David Liontooth: > >> >> We've been using saa7135 cards for several years with relatively few >> incidents, but they occasionally drop audio. >> I've been unable to find any pattern in the audio drops, so I haven't >> reported it -- I have no way to reproduce the error, but it happens >> regularly, affecting between 3 and 5% of recordings. Audio will >> sometimes drop in the middle of a recording and then resume, or else >> work fine on the next recording. >> > > Hi Dave, > > hmm, losing audio on three to five percent of the recordings is a lot! > > When we started to talk to each other, we had only saa7134 PAL/SECAM > devices over here. > > That has changed a lot, but still no System-M here. > > The kernel thread detecting audio on saa7133/35/31e behaves different > from the one on saa7134. > > But if you let it run with audio_debug=1, you should have something in > the logs when losing the audio. The kernel audio detection thread must > have been started without success or id find the right thing again. I > would assume caused by a weaker signal in between. > > Do you know about the insmod option audio_ddep? > > It is pretty hidden and I almost must look it up myself in the code. > > Cheers, > Hermann > > OK, I'll try running with audio_debug=1. Could you clarify what you mean by "The kernel audio detection thread must have been started without success or id find the right thing again"? An audio drop can be initiated at any point in the recording. A weak signal is a good guess, but I've never noticed a correlation with video quality. I didn't know about audio_ddep -- what does it do? I'm not seeing it in modinfo. It would be fantastic to get this problem solved -- we've had to record everything in parallel to avoid loss, and still very occasionally lose sound. Cheers, Dave