I was thinking about writing data to the output and recording it on the input and calculating the time it takes.  This would be done on bluetooth and a non- bluetooth device (regular speakers).  With those two values, get the ratio of bluetooth to non-bluetooth and just multiplying that by the latency from pulseaudio.  This value would be used as the delay to sync audio/video. Wondering if this would help in lip sync and where this value should go?  "pcm_pulse.c" in alsa-plugins has the function pulse_delay() which returns the delay.  Can this be modified to reflect this newly acquired delay?  If not, then where?  Thanks Baek Chang  <div class="gmail_quote"> On Thu, Jan 22, 2009 at 1:00 PM, Lennart Poettering <<a href="mailto:lennart@poettering.net">lennart@poettering.net</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> <div><div></div><div class="Wj3C7c">On Wed, 21.01.09 13:44, Baek Chang (<a href="mailto:baeksan@ccrma.stanford.edu">baeksan@ccrma.stanford.edu</a>) wrote: > How is the latency obtained when using bluetooth in pulseaudio.  By latency > I mean something similar to snd_pcm_delay().  Since bluetooth doesn't use > alsa, how is the time delay calculated from writing data to actually hearing > it out of the dac? </div></div>AFAIK Bluetooth doesn't really offer a sensible way to query the current delay, not even a2dp. In fact a2dp doesn't even offer flow control. The clocking part in the PA BT module is currently lacking. I just bought myself a bit of BT hardware so that I can hack on this and try to work around the limitations of BT a bit. Lip-sync audio/video with a BT headset is probably not going to happen, though. And that is not a limitation of PA but of BT. Lennart -- Lennart Poettering                        Red Hat, Inc. lennart [at] poettering [dot] net         ICQ# 11060553 <a href="http://0pointer.net/lennart/" target="_blank">http://0pointer.net/lennart/</a>           GnuPG 0x1A015CC4 _______________________________________________ pulseaudio-discuss mailing list <a href="mailto:pulseaudio-discuss@mail.0pointer.de">pulseaudio-discuss@mail.0pointer.de</a> <a href="https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss" target="_blank">https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss</a> </blockquote></div> -- Baek Chang <a href="mailto:baeksan@ccrma.stanford.edu">baeksan@ccrma.stanford.edu</a> 407-267-6701