• Blackmagic Design

  Decklink HD Pro SPdif crackle?

  Posted by Marco Pulvirenti on April 6, 2005 at 6:17 am

  I’ve recently hooked up a Decklink HD Pro (single Link) to one of our edit systems (Dual 2.5 gb G5, 2.5 gb Ram, UL4D, Huge systems raid).
  We mainly use analog VTRs (SP Betacam). I use a AJA A-D mini-converter to convert component to SDI and a Flying Cow to convert our audio.

  Everything works perfectly except when I’m inputting. The audio (on input only) has a crackle to it. The config is: from the Decklink card RCA (SPDif) out to the SPDif in on the Flying Cow, analog out from the Cow to the VTR in, VTR out to the analog in on the cow and SPDif out back to the Decklink card.

  I have checked and replaced cables, and Flying Cows, but the crackle still persists. I have the exact setup on another system, using a Kona SD card (using AES in and out on the Flying Cow) and it has always worked perfectly. With the 2 systems setup exactly the same way, it’s been easy to swap out cables and converters. So far it seems to be a SPDif problem on the Decklink card.

  Any suggestions ? I can’t use the system to input at all. Audio out works fine. Could it be a faulty card or tether on the card ?

  TIA

  Marco

  _______________________________

  marco pulvirenti

  [rhubarb]

  durban, south africa

  Olivier Jean replied 21 years, 1 month ago 3 Members · 4 Replies
• 4 Replies

• 

  Bryan Rawles

  April 7, 2005 at 3:29 pm

  Marco,

  I have had this problem as well. I am using a Miranda VTR-100 to convert my UVW-1800 Beta Sp deck to SDI and SPdif. I have a Decklink HD Pro card into a G5 with UL4D with Huge storage as well. While capturing, I always get crackle, once the footage is captured it plays fine. I am using a Dolby digital surround decoder into a Dolby CP series distributor. I can’t figure out what the issue is. Any ideas from Blackmagic?

  -Bryan
• 

  Marco Pulvirenti

  April 11, 2005 at 12:37 pm

  Bryan

  I have solved my crackle problem. We discovered that it was a cable length issue. Apparantly, if the cable carrying a digital signal (ie. SPDIF) is over 15 metres long, normal audio cable won’t be adequate. We changed our SPDIF carrying cables to co-axial cable (similar to video BNC cables) and our problems went away.

  … not sure if this will help you though.

  Marco

  _______________________________

  marco pulvirenti

  [rhubarb]

  durban, south africa
• 

  Bryan Rawles

  April 12, 2005 at 4:42 am

  Thanks, I’ll try that.
• 

  Olivier Jean

  April 12, 2005 at 9:33 am

  Hi Marco,

  i’m glad you’ve solved your problem.
  How is the card doing otherwise ?

  Hope you had a good trip back

  Regards
  Olivier Jean
  Powermedia Systems
  Sydney Australia

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