The SMPTE-352 Link Number refers to a value present in the SDI output of a 4K UHD quad 3G-SDI output. There are four outputs, and each of these outputs can have an associated link number so that the connected device (our AVP HEVC Encoder in this case) can work out what 3G-SDI has been connected to which spigot on the HEVC Card.

If the SMPTE-352 Link Numbers are present (and this only seems to be available in 2SI mode, not in square division (quad) mode) then the AVP can correctly de-interleave the content regardless of the order that the inputs were presented.

You can view the link numbers (if present) by connecting to the AVP host card via SSH:

  SSH <jpaddress>
  
  login:
  
  root
  viper

Once logged in, telnet to the card in the correct slot (slot 1 to 6) in the case of the HEVC card it's normally slot 1 (if it's a single card)

  telnet slot1
  
  login:
  
  root
  (no password)

Now enter the command RepConsole

  RepConsole, you will now see the prompt change to REP>

To see the SMPTE-352 Link Numbers, enter the following command:

  video status
  
  The output will be similar to the following:
  
  SDI input 0 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  SDI input 1 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 1)
  SDI input 2 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 2)
  SDI input 3 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 3)
  UHD input remapping: none
  Video set to 2160p (interleaved format) at 59.94 frames/s
  Video source is SDI (video locked)
  Action on video loss is freeze frame without ident text
  Front panel video monitor source is output 0 to NARA

We can see in the above example that the SMPTE-352 link numbers are 0-0, 1-1, 2-2 and 3-3, so they are in the correct order. For this reason the line UHD input remapping is set to none, as no remapping is required.

In the next example, the 3G-SDI inputs have been connected in an incorrect order:

  SDI input 0 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  SDI input 1 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 1)
  SDI input 2 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 3)
  SDI input 3 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 2)
  UHD input remapping: SDI 0 -> UHD 0, SDI 1 -> UHD 1, SDI 2 -> UHD 3, SDI 3 -> UHD 2
  Video set to 2160p (interleaved format) at 59.94 frames/s
  Video source is SDI (video locked)
  Action on video loss is freeze frame without ident text
  Front panel video monitor source is output 0 to NARA

Here we can see that the SMPTE-352 order is 0,1,3,2. So the last two inputs are swapped. Although the AVP HEVC card can cope with this, and the encode will look fine (because the SMPTE-352 link numbers are present) we can see that the UHD input remapping is now reporting SDI 0 → UHD 0, SDI 1 → UHD 1, SDI 2 → UHD 3, SDI 3 → UHD 2 to let us know that the AVP is dealing with a mis-plugged input.

I tested this in Quad mode (the AJA Ki Pro allows you to select either Sqare or 2SI output) and got the following:

  SDI input 0 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  SDI input 1 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  SDI input 2 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  SDI input 3 locked to 1080p at 59.94 frames/s (SMPTE-352 link number 0)
  UHD input remapping: none
  Video set to 2160p (interleaved format) at 59.94 frames/s
  Video source is SDI (video locked)
  Action on video loss is freeze frame without ident text
  Front panel video monitor source is output 0 to NARA

Here we can see that there are no SMPTE-352 Link numbers present, so perhaps SMPTE-352 Link numbers are only part of the interleaved specification.