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List:       linux-sound
Subject:    Re: Sound issue with stk1160 driver
From:       Evgeny Sagatov <sagatov () ya ! ru>
Date:       2014-02-12 20:01:11
Message-ID: 37561392235271 () web25g ! yandex ! ru
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The stk1160 driver has a problem with AC97 codec.
Look at this picture http://sagatov.net/temp/sound-wave.png
In the picture only the right audio channel connected. But for a fraction of a second \
channels are swapped. Please tell any ideas why this might happen?

This driver source code, which is responsible for the sound. It is short. May be \
specified any invalid parameter? \
http://lxr.free-electrons.com/source/drivers/media/usb/stk1160/stk1160-ac97.c Please \
help those who are understands the AC97 codec programming.

Data is not lost. But the audio channels are reversed.

03.02.2014, 17:26, "Evgeny Sagatov" <sagatov@ya.ru>:
> Dear Sirs,
> 
> I have EasyCAP device with STK1160+GM7113C+ALC101 chips.
> On my Ubuntu 12.04 with 3.11.0 kernel video capturing functioned perfectly, but \
> audio capturing have problem with sound clicks. You can hear these sounds in the \
> linked audio file (Initially both audio inputs enabled and then I mute one, then \
> both audio inputs.). http://sagatov.net/temp/audio.wav
> Clearly audible clicks in the headphones. A feeling that for a moment left and \
> right channels are swapped. I tested three devices on three computers. I also \
> tested the device on a freshly installed Ubuntu 13.10. But the result is the same \
> everywhere. In MS Windows no clicks.
> 
> I have tried to boot my Ubuntu 12.04 with the 3.2.0-58 kernel.
> Turned out that the legacy driver is already installed. Probably it is included in \
> Ubuntu distribution. I have a beautiful sound in this case without any problems.
> But I have a problem with the video :-) The video is displayed few seconds, and \
> then the gray bars (see picture in the attachment). 
> > ššWhat kind of video/audio source are you using to trigger this noise?
> > ššDo you get the noise on all captures or only on some of them?
> 
> I tried two different cameras and video player. Also I tried to leave inputs \
> unconnected. Noise is always, regardless of the source.
> 
> Noise is better heard when only one audio channel is connected. A feeling that for \
> a split second sound goes to another channel and back. 
> Earlier I have the correspondence with the developer of stk1160 driver and that the \
> information he sent to me. 
> 03.02.2014, 16:37, "Ezequiel Garcia" <elezegarcia@gmail.com>:
> 
> > ššHi,
> > 
> > ššYesterday I spent all the day debugging this issue. The noise you report
> > ššis also present on any capture I do. In fact, I noticed it in the past but \
> > never ššcared.
> > 
> > ššBad news are I still don't have a clue about it.
> > 
> > ššLet me explain you the differences between stk1160 and easycap audio.
> > ššstk1160 depends on a separate ac97-mixer driver to setup the AC97
> > ššparameters and on the snd-usb-audio driver to handle the audio stream.
> > 
> > ššeasycap does both things by itself.
> > 
> > ššSince I'm out of specific ideas, I'll try to implement the audio
> > ššhandling in stk1160 (just as easycap does) and see what happens.
> > ššHowever, it's not a simple task and it might take a few days/weeks.
> > 
> > ššFor now, you can use the easycap setting easycap_bars = 0 parameter
> > ššto avoid those bars. I'm sorry for this regression!
> > 
> > ššIn addition, you can help by taking care of the bug report. This should
> > ššbe reported to the linux-sound mailing list:
> > ššhttp://vger.kernel.org/vger-lists.html#linux-sound
> > 
> > ššThe problem must be either in snd-usb-audio or in the sound/pci/ac97/..
> > ššcode. If you can report this (put me on Cc), it would be of great help.
> > 
> > ššThanks again and sorry for this inconvenience,
> > ššEzequiel
> 
> I hope very much for your help in solving this problem.
> 
> Thank you!
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