On Mon, Jun 20, 2016 at 01:08:27PM +0200, Pierre-Louis Bossart wrote: > The ALSA API provides support for 'audio' timestamps (playback/capture rate > defined by audio subsystem) and 'system' timestamps (typically linked to > TSC/ART) with one option to take synchronized timestamps should the hardware > support them.
Thanks for the info. I just skimmed Documentation/sound/alsa/timestamping.txt. That is fairly new, only since v4.1. Are then any apps in the wild that I can look at? AFAICT, OpenAVB, gstreamer, etc, don't use the new API. > The intent was that the 'audio' timestamps are translated to a shared time > reference managed in userspace by gPTP, which in turn would define if > (adaptive) audio sample rate conversion is needed. There is no support at > the moment for a 'play_at' function in ALSA, only means to control a > feedback loop. Documentation/sound/alsa/timestamping.txt says: If supported in hardware, the absolute link time could also be used to define a precise start time (patches WIP) Two questions: 1. Where are the patches? (If some are coming, I would appreciate being on CC!) 2. Can you mention specific HW that would support this? Thanks, Richard -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
