[vlc-devel] question: Can modules influence the presentation time?
defusix at defusix.net
Sat Aug 22 23:56:24 CEST 2015
I have a question related to module development. I don't know if it's
appropriate to ask it here, but I got no answer on #videolan on
Freenode, and I can't find an active forum for VLC development
I have a ledstrip controlled by an embedded Linux computer. I want to
develop a visualization module for VLC that sends data (based on the
audio) over UDP to that embedded computer. The issue is: Synchronizing
the led visuals with the played audio. Because there will be some delay
between the transmission of the graphics and the time it displays, I
thought it would be best to let the module send frames including the
presentation timestamp. (I will use PTP to sync the clocks of both
systems, so the timestamps created by VLC will be usable by the embedded
Linux computer). Looking at the source code of VLC, modules that process
audio or video blocks get a PTS. My question is: Can the presentation
time be delayed by a module in order to create enough headroom? The
headroom I need will be about 8ms to 15ms.
If this is not possible, the only solution I can think of is having the
module just buffer audio blocks, thereby delaying the audio. But it will
get out of sync with the video then.
With kind regards,
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