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 On Thu, Jan 22, 2009 at 1:00 PM, Lennart Poettering <lennart at poettering.net>wrote: > On Wed, 21.01.09 13:44, Baek Chang (baeksan at ccrma.stanford.edu) 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? > > 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 > http://0pointer.net/lennart/ GnuPG 0x1A015CC4 > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at mail.0pointer.de > https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss > -- Baek Chang baeksan at ccrma.stanford.edu 407-267-6701 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20090122/67c4179e/attachment.htm>
