Re: [Alsa-user] pcm_min.c trouble with modification
Michał Kowalczyk wrote: SND_PCM_FORMAT_U8, //changing this type for any other gives an error in the output: segmentation fault. U8 has one byte per sample; if you try to use a bigger sample format, you have to enlarge the buffer accordingly. 1, //argument responsible for channels; if I change it to 2(stereo) program gives an segmentation fault error. Using two channels would double the buffer size, too. 48000, //sampling rate; works good but if I modify this to lower value the time of generating noise will be longer, don't know why. If the sample rate is lower, you need more timer to play the same number of samples. frames = snd_pcm_writei(handle, buffer, sizeof(buffer)); The last parameter is measued in frames, not in bytes. When you use another sample format than U8/S8 or more then one channel, you have to divide the buffer size by the number of bytes per frame. HTH Clemens -- Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] pcm_min.c trouble with modification
MK wrote: I want to write a simple ALSA application. I have downloaded pcm_min.c from ALSA documentation and try to do some modifications in code like change channels to stereo or sampling rate to 44100Hz. But every time program fails. Can anybody explain me why this is happening? Please show your changes. Best regards, Clemens -- Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] pcm_min.c trouble with modification
On Thu, 9 Apr 2009 18:02:56 -0600 s. keeling keel...@nucleus.com wrote: You'd think grep + sed would be good for the initial change, then you're left with tracking down every instance where that didn't work. At least, that's how I write code (or maintain others' cruft). Too many cooks in the kitchen, working by their own rules? :-P No, I don't think grep + sed would be enough. There are cases when literal 44100, 48000 are legitimate - when there is a table describing card capabilities WRT sampling rate. And, AFAIR, in dmix there is just 48000 instead of DEFAULT_SAMPLE_RATE to be introduced. To me it all looked really a mess, so, I think, you'll need to go over the code in much more detail than I did, to formulate for yourself the structure of #define statement, etc. I was probably supposed to file a bug report regarding all this, but somehow I'm feel hopeless and was very tired when I was doing this auditing. Regards, Sergei. -- This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
[Alsa-user] pcm_min.c trouble with modification
Hello. I want to write a simple ALSA application. I have downloaded pcm_min.c from ALSA documentation and try to do some modifications in code like change channels to stereo or sampling rate to 44100Hz. But every time program fails. Can anybody explain me why this is happening? -- This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] pcm_min.c trouble with modification
On Thu, 09 Apr 2009 23:32:59 +0200 MK matern...@o2.pl wrote: Hello. I want to write a simple ALSA application. I have downloaded pcm_min.c from ALSA documentation and try to do some modifications in code like change channels to stereo or sampling rate to 44100Hz. But every time program fails. Can anybody explain me why this is happening? -- This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user Regarding the sample rate - I once audited ALSA source to see how sample rate is dealt with. My naive expectation was ALSA as a whole was written with single point of change in mind. Alas, according to my observation, it's not the case, i.e. it is not possible to change ALSA code in just _one_ place to change default sample rate. I even wrote an Email to this list with single point of change in the subject - I know the developers monitor the list. This Email apparently remains unanswered. Look for single point of change in the list archive. Regards, Sergei. -- This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] pcm_min.c trouble with modification
Incoming from Sergei Steshenko: On Thu, 09 Apr 2009 23:32:59 +0200 MK matern...@o2.pl wrote: I want to write a simple ALSA application. I have downloaded pcm_min.c from ALSA documentation and try to do some modifications in code like change channels to stereo or sampling rate to 44100Hz. But every time program fails. Can anybody explain me why this is happening? Regarding the sample rate - I once audited ALSA source to see how sample rate is dealt with. Thankyou. My naive expectation was ALSA as a whole was written with single point of change in mind. Alas, according to my observation, it's not the case, i.e. it is not possible to change ALSA code in just _one_ place to change default sample rate. Wow. Isn't that what the #include directive is for? You'd think grep + sed would be good for the initial change, then you're left with tracking down every instance where that didn't work. At least, that's how I write code (or maintain others' cruft). Too many cooks in the kitchen, working by their own rules? :-P -- Any technology distinguishable from magic is insufficiently advanced. (*) Please don't Cc: me. - - -- This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
