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Av0101
Participating Frequently
January 27, 2025
Answered

PAL video fields playback problem with AJA IO X3

  • January 27, 2025
  • 3 replies
  • 620 views
Premiere 25.1/ OS X Sonoma 14.6.1
 
PAL Video fields display incorrectly on an SDI monitor from an AJA IO X3 interface.
Both fields appear to be displayed simultaneously causing a blurred effect.
This is most apparent on interlaced credit rolls and fast motion video.
This fault occurs both in the clip viewer and in a PAL sequence. 
 
Sequence settings:
Broadcast 25i 4 mono discrete
 
Custom settings:
Frame size 720x576 4x3
Pixel Aspect Ratio  D1/DV PAL 1.0940
Fields: Upper Field First
 
Note: PAL interlaced clips do display field motion correctly to an external video monitor when edited into a  1080i25 sequence, or when played from AJA Control Room.
The issue also occurs in OSX Premiere 23.6.9.
 
Computer specs:
  Model Name: Mac mini   M2 Pro
  Chip: Apple M2 Pro
  Total Number of Cores: 12
  Memory: 32 GB
 
AJA Control Panel and drivers version 17.1.3
 
PAL interlaced Credit roll test clip supplied.
    Correct answer Ben Insler

    Hi @Av0101 - we spent some time diving deeper into this issue. I suspect the experiencing you are having has to do with field dominance.  Usually when we encounter issues with fields displaying incorrectly, incorrect field dominance is the culprit.

     

    I've tested what you reported with an AJA Io|4K Plus, using your provided PAL 576i25 4x3 Credit roll.mov.  I notice that I get smoother external monitor playback when the field dominance of the sequence is inverted from the field dominance assigned in the source clip itself, i.e. the source clip is imported into Premiere Pro with an upper field dominance, but I force the sequence containing the clip to lower field dominance.

     

    I would suggest checking the method for the way this clip was created/transcoded to ensure that its field order is correct.  We have seen issues in the past where transcodes were made between formats of differeing field dominance (for example HD UFF to SD LFF), but the field dominance from the source format was preserved, causing an incorrect field dominance and field playback judder for the resulting transcoded clip.

     

    You can also always choose to manually reinterpret the source clip's field dominance (Clip > Modify > Interpret Footage... > Field Order) and add that reinterpreted clip back to your edit sequence and see if the field issue is resolved, which would also indicate a field dominance issue on the source clip.  Note: when you manually reinterpret a source clip's field dominance in Premiere Pro, this change only applies to new uses of the clip in a sequence.  Any existing uses of the clip in sequences will remain unaltered.

    3 replies

    B
    Community Manager
    Ben InslerCommunity ManagerCorrect answer
    Community Manager
    March 4, 2025

    Hi @Av0101 - we spent some time diving deeper into this issue. I suspect the experiencing you are having has to do with field dominance.  Usually when we encounter issues with fields displaying incorrectly, incorrect field dominance is the culprit.

     

    I've tested what you reported with an AJA Io|4K Plus, using your provided PAL 576i25 4x3 Credit roll.mov.  I notice that I get smoother external monitor playback when the field dominance of the sequence is inverted from the field dominance assigned in the source clip itself, i.e. the source clip is imported into Premiere Pro with an upper field dominance, but I force the sequence containing the clip to lower field dominance.

     

    I would suggest checking the method for the way this clip was created/transcoded to ensure that its field order is correct.  We have seen issues in the past where transcodes were made between formats of differeing field dominance (for example HD UFF to SD LFF), but the field dominance from the source format was preserved, causing an incorrect field dominance and field playback judder for the resulting transcoded clip.

     

    You can also always choose to manually reinterpret the source clip's field dominance (Clip > Modify > Interpret Footage... > Field Order) and add that reinterpreted clip back to your edit sequence and see if the field issue is resolved, which would also indicate a field dominance issue on the source clip.  Note: when you manually reinterpret a source clip's field dominance in Premiere Pro, this change only applies to new uses of the clip in a sequence.  Any existing uses of the clip in sequences will remain unaltered.

    Bruce Bullis
    Bruce Bullis
    Legend
    February 7, 2025

    Working with AJA, we figured out this is our issue. 🙂

    We'll have a look!

    Bruce Bullis
    Bruce Bullis
    Legend
    January 27, 2025

    We recommend contacting AJA about this issue.

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