Crystal Vision
Introduction
SYNNER-E 3G User Manual R1.2
9
10/09/2012
User Controls
Each stereo audio channel has the same set of controls, which determine whether it bypasses
various delays or processes.
The TAD selection determines whether a stereo channel passes through the appropriate TAD
(6) or (9), or bypasses it with minimum delay. This also affects the operation of the Dolby E
alignment delay (7). If Dolby E goes through the TAD, then the output of (7) is aligned with
the input video, ready to be synchronised. If Dolby E bypasses the TAD, the output of (7) is
aligned with the output video, ready to be embedded.
The Frame delays selection determines whether a stereo channel passes through the 0, 1, or 2
frame audio delay (4), or bypasses it with minimum delay.
The user delay determines the whether a stereo channel passes through the "user" audio delay,
or bypasses it with minimum delay. The "user" delay for Dolby E is (8), for other audio it is
(5).
The Resample Enable control affects how the audio data is manipulated to change the PCM
delays. On resampled channels (resample enabled) the audio will be continuously resampled
allowing seamless changes in audio delay. On non-resampled channels (resample not enabled)
samples will be passed unchanged through the signal path: if the delay has to change, single
audio samples will be dropped or repeated as required. This control has no effect on channels
containing Dolby E.
The Dolby-E align control allows the user to send Dolby E through delay (7) to produce the
correct relationship with the video timing, or to bypass delay (7), passing the Dolby E to the
next stage with minimum delay.
There are two global controls PCM Audio Delay and Dolby E Delay. The PCM Audio Delay
control has a range of -20 to 80ms and will increase the tracking delay by the required amount.
If a delay elsewhere in the signal path is non-zero the overall audio delay can be shortened by
up to 20ms by setting the PCM Audio Delay in its negative range.
The Dolby E delay has a range of -10 to +40 Dolby E samples. The 0 to 40 sample section is
straightforward; the audio is delayed by the required amount. If a delay elsewhere in the signal
path is non-zero the overall Dolby delay can be shortened by up to 10 samples by setting the
Dolby E delay in its negative range. This delay affects timing after the alignment process and
allows for Dolby E to be embedded at a fixed offset from the default guardband position.
Because this delay sits between the alignment block and the synchroniser the delay range was
chosen so that the user cannot move the Dolby E so far that it gets corrupted if the
synchroniser drops or repeats a frame.
