Re: [alsa-devel] Problem with aloop
Gustavo da Silva Serra wrote:
I am developing an application that captures sound and send it through a network, just like a sound server. To test it I am using kaffeine with alsa output plugin. After some time playing continuously, or if I keep moving the position slider backward and forward, I get choppy sound. If I close and reopen the capture stream opened by my sound server, the sound is restored to good quality. Sometimes I have to reopen many times before I get a good sound. When I use kaffeine oss output plugin I don't have this issue. I don't have an audio sound card, so I don't know if this is an *aloop* issue.
Here are some details:
- RedHat EL 4 kernel 2.6.9.55-ELsmp 64bit
- Alsa 1.0.16
- Xinelib 1.1.12
Hi all,
I'm experiencing the same problem as Gustavo. In my case I have a SIP client calling to another PC and I'm injecting audio with aplay (or amarok, no difference there) into that SIP call. About 8/10 times everything goes well, the other two times the audio that comes out at the other PC sounds really choppy. Both PC's are on the same local network so that is probably not the problem.
What I found out is that if I patch aloop-kernel.c in the 'static struct snd_pcm_hardware snd_card_loopback_info' to have ".formats = (SNDRV_PCM_FMTBIT_S8 )," this problem goes away. But then I'm stuck with 8 bit audio. It sounds a bit like the aloop device sometimes doesn't properly synchronise the 16 bit (or 32bit, tried that as well) samples on both PCM devices and things get mis-aligned. I'm quite new to ALSA so please don't laugh too hard if I'm missing something here :)
Any input is greatly appreciated!
Kind regards, Benjamin van den Hout
Benjamin van den Hout escreveu:
Gustavo da Silva Serra wrote:
I am developing an application that captures sound and send it through a network, just like a sound server. To test it I am using kaffeine with alsa output plugin. After some time playing continuously, or if I keep moving the position slider backward and forward, I get choppy sound. If I close and reopen the capture stream opened by my sound server, the sound is restored to good quality. Sometimes I have to reopen many times before I get a good sound. When I use kaffeine oss output plugin I don't have this issue. I don't have an audio sound card, so I don't know if this is an *aloop* issue.
Here are some details:
- RedHat EL 4 kernel 2.6.9.55-ELsmp 64bit
- Alsa 1.0.16
- Xinelib 1.1.12
Hi all,
I'm experiencing the same problem as Gustavo. In my case I have a SIP client calling to another PC and I'm injecting audio with aplay (or amarok, no difference there) into that SIP call. About 8/10 times everything goes well, the other two times the audio that comes out at the other PC sounds really choppy. Both PC's are on the same local network so that is probably not the problem.
What I found out is that if I patch aloop-kernel.c in the 'static struct snd_pcm_hardware snd_card_loopback_info' to have ".formats = (SNDRV_PCM_FMTBIT_S8 )," this problem goes away. But then I'm stuck with 8 bit audio. It sounds a bit like the aloop device sometimes doesn't properly synchronise the 16 bit (or 32bit, tried that as well) samples on both PCM devices and things get mis-aligned. I'm quite new to ALSA so please don't laugh too hard if I'm missing something here :)
Any input is greatly appreciated!
Kind regards, Benjamin van den Hout _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
__________ NOD32 3088 (20080509) Information __________
This message was checked by NOD32 antivirus system. http://www.eset.com
Well, I discovered that only xinelib has this problem. Xmms and alsaplayer, for example, don't have this issue. I am testing VLC and it seems to work fine. I am not surprised, since the xine source code that deals with alsa is huge and ugly, it must be very hard to mantain that.
participants (2)
-
Benjamin van den Hout -
Gustavo da Silva Serra