<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=us-ascii"> <META content="MSHTML 6.00.2900.3395" name=GENERATOR></HEAD> <BODY> <DIV><SPAN class=988325016-03102008><FONT face=Arial size=2>Hi everyone,</FONT></SPAN></DIV> <DIV><SPAN class=988325016-03102008><FONT face=Arial size=2>I wonder why alsasink does not rely on the mmap() utilities provided by alsa, namely snd_pcm_mmap_begin() and snd_pcm_mmap_commit(). If my understanding is correct, the audio data provided to alsasink is first copied in a ring buffer, then passed to alsa using snd_pcm_writei(), which results in an additional copy from user to kernel space. For embedded low-power devices with dedicated internal ram for audio, this does not make a lot of sense, you want to write directly incoming data into the hardware buffer.</FONT></SPAN></DIV> <DIV><SPAN class=988325016-03102008> </SPAN></DIV> <DIV><SPAN class=988325016-03102008><FONT face=Arial size=2>I understand though that not all audio devices support mmap, but looking at the cvs repository it does look like mmap was an option in gstreamer several years ago, and it disappeared in version 1.40 of gstalsasink.c. </FONT></SPAN><SPAN class=988325016-03102008><FONT face=Arial size=2>Does anyone know why this support was removed ? And how difficult it would be to add it again ?</FONT></SPAN></DIV> <DIV><SPAN class=988325016-03102008><FONT face=Arial size=2></FONT></SPAN> </DIV> <DIV><SPAN class=988325016-03102008><FONT face=Arial size=2>Thanks for your feedback.</FONT></SPAN></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV align=left><FONT face=Arial size=2>Regards,</FONT></DIV> <DIV align=left><FONT face=Arial size=2>- Pierre</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV></BODY></HTML>