Bryston SP3, Manual

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SP3 PREAMP / PROCESSOR
APPENDIX D
HDMI NOTES
HDMI Notes, Part 1 Page 1 of 4
SP3 – HDMI Notes (1)
2-Aug-2012,
Stan Bleszynski, Bryston Ltd .
HDMI Handshaking
When SP3 selects HDMI input port as its audio signal source, it acts as an HDMI
repeater, placed in between HDMI signal source (DVD player, BD player etc) and HDMI
signal “sink” (TV screen, TV projector etc). Every class of the devices on the HDMI
chain has to respond to the HDMI handshake procedure, initiated by the signal source,
that is by a player. The handshake is initiated normally on power up, on disk
reinsertions, or on other events. In order to make the initial handshake proceed
optimally, the HDMI devices should preferably be powered up beginning with the “sink”
(TV screen), then the repeater (SP3) then the player. That way the main signal source
will be immediately able to poll (handshake) the rest of the HDMI chain which will
already be powered up and ready to respond.
Using more than 1 HDMI sources (players)
If two HDMI sources are connected to SP3 HDMI inputs, then SP3 will select only one
link at a time, leaving the other link “dead ended”. This may break the established
handshake status between the player that is not currently active, and the TV screen
resulting in a possible change of the player output signal format. This behaviour is
strongly player-dependent and copy-protection dependent on the media being played.
Some DVD or BD players maintain the last signal sample rate and format that was played
previously to an interruption (or disconnect)
1
, some other players tend to immediately
downgrade the output stream from multichannel audio to stereo or from encoded streams
such as DTS or Dolby Digital to PCM. Some players may also downgrade the sample
rate of audio and downgrade the video resolution.
This may cause various artefacts or somewhat unpredictable behaviour (loss of audio etc)
when switching away from one HDMI source to another source and then back. If the
drive switched the format while being disconnected and would not restore the previous
one, then pressing HDMI button again to switch it off to analog
2
and then on again may
force the drive to re-handshake and restore the original.
If that does not restore the correct HDMI status then reinserting the disk or re-powering
the player may be necessary.
1
As long as the disk is in.
2
HDMI button toggles between HDMI active and Analog mode, while the actual HDMI chain link from
the source to the TV screen remains unbroken. As long as the main source selection remains unchanged.
This feature allows passing the video signal through HDMI while using analog for audio. At the same
time since the HDMI chain remains unbroken while toggling the HDMI active on/off , it allows the player
to re-handshake with the TV screen re-establishing the original channel format.