Crystal Vision
Data packet management
TANDEM-200 User Manual R1.7
20
13/02/2008
Trading process speed for robustness
SONY and SMPTE embed/de-embed modes for the TANDEM-200:
Embed modes
Card edge (Statesman)
Speed >>
Robustness >>
SONY1 (Sony audio fifo min)
* * * * * * * * *
* *
SONY2 (Sony audio fifo short)
* * * * * * * *
* * *
SONY3 (Sony audio fifo medium)
* * * * * * *
* * * *
SONY4 (Sony)
* * * * * *
* * * * *
SMPTE1 (SMPTE audio fifo min)
* * * * *
* * * * * * *
SMPTE2 (SMPTE audio fifo short)
* * * *
* * * * * * * *
SMPTE3 (SMPTE audio fifo medium)
* * *
* * * * * * * * *
SMPTE4 (SMPTE)
* *
* * * * * * * * * *
De-embed modes
Card edge (Statesman)
Speed >>
Robustness >>
SONY1 (Sony audio fifo min)
* * * * * * * * *
* *
SONY2 (Sony audio fifo short)
* * * * * * * *
* * *
SONY3 (Sony audio fifo medium)
* * * * * * *
* * * *
ALL (SMPTE/Sony)
* *
* * * * * * * * * *
Note:
The text in brackets is used by the Statesman PC interface and is the equivalent of the
preceding text displayed at the card edge.
The fastest de-embedding processing results from using SONY1. The slowest and safest
of the de-embedding modes is ‘ALL’, and is recommended when the input cannot be
guaranteed to be always in SONY format.
The fastest embedding mode is also SONY1, since the buffer memory required is the
smallest. SMPTE modes require some extra audio data to be held in a longer queue to
bridge over the vertical switch point gaps. SMPTE4 is the slowest but also the most
robust mode.
If de-embed is set to ANY SONY mode, and the incoming SDI has SMPTE format
embedded audio, it will automatically change to ‘ALL’ de-embed mode within a fraction
of a second. However, there could be some corruption of audio, especially with SONY1
or SONY2 de-embed selected, during a second or two while de-embed mode
automatically changes over. It is strongly recommended NOT to select any SONY de-
embed mode if there is a chance of SMPTE mode inputs, except if the changeover always
occur whilst ‘off-air’.
SONY1 or SONY2 embed and de-embed formats (or SMPTE1 and SMPTE2 formats)
should be avoided if there is likely to be corruption of signals as may occur during SDI or
AES source switching. SONY4 is the most robust, SONY3 is a good compromise
between speed and robustness, and SONY2 is a tighter compromise where speed is of
high importance.
