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[0/2] Introduce HDMI Video Guard Band test pattern

Message ID 20220513125307.3494442-1-hverkuil-cisco@xs4all.nl
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Series Introduce HDMI Video Guard Band test pattern | expand

Message

Hans Verkuil May 13, 2022, 12:53 p.m. UTC 
These patches add support for a specific test pattern to test HDMI
receivers.

Four pixels of the RGB color 0xab55ab are inserted at the left hand side of
the image. This is only done for 3 or 4 byte RGB pixel formats. The HDMI
TMDS encoding of this pixel value equals the Video Guard Band value as
defined by HDMI (see section 5.2.2.1 in the HDMI 1.3 Specification) that
preceeds the first actual pixel of a video line. If an HDMI receiver
doesn't handle this correctly, then it might keep skipping these Video
Guard Band patterns and end up with a shorter video line. So this is a
nice pattern to test with.

And yes, this does cause one receiver we tested with to lose sync :-)

Regards,

	Hans

Hans Verkuil (2):
  media: v4l2-tpg: add HDMI Video Guard Band test pattern
  media: vivid: add HDMI Video Guard Band control

 drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 38 +++++++++++++++++++
 .../media/test-drivers/vivid/vivid-ctrls.c    | 14 +++++++
 include/media/tpg/v4l2-tpg.h                  | 16 ++++++++
 3 files changed, 68 insertions(+)