Problem
Interlaced source footage shows combing because field interpretation was assigned incorrectly.
Solution
Root Cause / Diagnostic:
Interlaced video formats (1080i, 50i, 59.94i) capture temporal motion across alternating horizontal scan lines (odd lines in Field 1, even lines in Field 2) separated by a fractional time offset. If an NLE interprets an interlaced clip as progressive, or inverts the field dominant order (e.g., Upper Field First interpreted as Lower Field First), both temporal fields are displayed simultaneously on progressive screens. This results in severe horizontal jagged streaks (combing artifacts) across all moving edges.
Actionable Fix:
1. Right-click the interlaced source clip in the project bin, select 'Modify' -> 'Interpret Footage', and set Field Order to 'Upper Field First' (or match camera specification).
2. If delivering to web or mobile progressive platforms (YouTube), apply a high-quality de-interlacing filter (YADIF or motion-adaptive de-interlacing) or set sequence output to Progressive.
3. Inspect fast lateral movement on a progressive computer monitor to confirm that horizontal combing lines are completely eliminated.
Pro Tip:
For legacy archive restoration, de-interlace interlaced 59.94i footage to 59.94p (progressive 60 fps) rather than 29.97p; doubling frame rate preserves all original temporal motion fluidness without losing field information.
Interlaced video formats (1080i, 50i, 59.94i) capture temporal motion across alternating horizontal scan lines (odd lines in Field 1, even lines in Field 2) separated by a fractional time offset. If an NLE interprets an interlaced clip as progressive, or inverts the field dominant order (e.g., Upper Field First interpreted as Lower Field First), both temporal fields are displayed simultaneously on progressive screens. This results in severe horizontal jagged streaks (combing artifacts) across all moving edges.
Actionable Fix:
1. Right-click the interlaced source clip in the project bin, select 'Modify' -> 'Interpret Footage', and set Field Order to 'Upper Field First' (or match camera specification).
2. If delivering to web or mobile progressive platforms (YouTube), apply a high-quality de-interlacing filter (YADIF or motion-adaptive de-interlacing) or set sequence output to Progressive.
3. Inspect fast lateral movement on a progressive computer monitor to confirm that horizontal combing lines are completely eliminated.
Pro Tip:
For legacy archive restoration, de-interlace interlaced 59.94i footage to 59.94p (progressive 60 fps) rather than 29.97p; doubling frame rate preserves all original temporal motion fluidness without losing field information.