[vlc-devel] [PATCH 0/3] Maintain vsync phase sync in mmal vout

Julian Scheel julian at jusst.de
Fri Aug 29 09:25:18 CEST 2014

To ensure that no frames are dropped or duplicated due to frame draws
happening very close to vsync time and jittering around it, the drawing of a
picture shall ideally happen with a safe delay after a vsync.
With mmal there two mechanisms involved. The first is the so called latency
target, which tries to synchronise the HDMI clock to the frame rendering
interval by slightly adjusting the HDMI pixel clock. The second mechanisms is
determining the actual phase offset and doing an initial shift to place the
renderings in a safe time slot.
For this to work I propose a vout core extension which allows vouts to request
a phase offset at the core, which will be applied to the picture timestamps by
the core.

Julian Scheel (3):
  mmal/vout: Configure latency target
  vout: Allow vout plugins to request phase offset
  mmal/vout: Request phase offset at core

 include/vlc_vout_display.h      | 10 ++++++
 modules/hw/mmal/vout.c          | 79 ++++++++++++++++++++++++++++++++++++++++-
 src/video_output/display.c      |  8 +++++
 src/video_output/video_output.c |  1 +
 4 files changed, 97 insertions(+), 1 deletion(-)


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