Crystal Vision
Introduction
SYNNER-E 3G User Manual R1.2
6
10/09/2012
Delays
SYNNER-E 3G’s design approach has been to provide the user with a full set of controls to
set and/or bypass the delays – especially the various audio delays - as required. This has
benefits in at least two areas:
Maximum flexibility
It simplifies the interaction between the different delays
SYNNER-E 3G delays
Video Delays
The video delay can be considered as being in three parts although the action of these delays
will depend on if the SYNNER-E 3G is set to synchronise or delay mode.
(1)
Fixed video delays of several frame lengths, 0, 1, or 2. This is 'bulk' video delay for (i)
matching other big video delays in the system (ii) allowing the audio to be advanced
relative to the video, to compensate for slippage elsewhere.
(2)
A fixed video delay of 0 or 0.5 frames. This interacts differently with delays on different
types of audio. PCM audio is delayed by the same amount as the video, maintaining
lipsync. Dolby E is not directly affected by this delay, so the Dolby E can be made earlier,
relative to the video, prior to the alignment process. Without this delay, the alignment
process will always delay the Dolby E relative to the video, by between 0 and 1 frame.
With the 0.5 frame delay in the video path, the alignment process can change the Dolby E
timing by +/- 0.5 frames relative to the video. This allows repeated embed/de-embed
cycles with less risk of the Dolby E getting progressively later relative to the video.
(3)
A synchroniser delay, this automatically adjusts over a range 0 to 1 frame to provide the
desired output timing.
Note:
The 'frames' used for describing delays are Dolby E frames. For interlaced video, a Dolby
E frame is the same length as a video frame. For the relevant progressive video standards,
a Dolby E frame is the same length as two video frames.
The fundamental difference in "delay" mode is that the "video synchroniser" delay is set
directly by user controls rather than automatically, by the relative timing of the input and the
reference.
