The 29.97 Master and the 23.976 Interview
Marco is assembling a 52-minute documentary. The sequence is 1920x1080 at 29.97 fps because the broadcaster requires a 29.97 master. Camera A, the main interview, was shot at 23.976; cameras B and C at 29.97. Sound was recorded double-system at 48 kHz, but one music bed is a 44.1 kHz MP3 and one screen-recording clip is variable frame rate. Marco used Scale to Frame Size on the 23.976 clips, and a 140% push-in on the interview now looks soft. After he nested three scenes to apply a look, the B-cam audio drifts about 4 frames late by the end of the second nest. He has one week.
1. Is 29.97 the right sequence frame rate here? Explain what happens to the 23.976 footage and how you would protect quality.
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The 29.97 master is a delivery requirement, not an editing requirement. The judgement is where the conversion happens.
- If the whole show could live at 23.976, you would edit there and add pulldown at export: A-cam stays pristine, and B/C lose roughly one frame in five, which is invisible on talking heads and cutaways.
- Here B and C are 29.97 and carry most of the coverage, so a 23.976 sequence would drop frames from the majority of the material. Keep the 29.97 sequence and accept that the 23.976 A-cam is conformed by frame duplication.
What you must not do is postpone the decision. Change the sequence frame rate after cutting and every cut point, keyframe and audio edit shifts relative to the new frame grid - on a 52-minute show that is a day of repair. Lock the rate before the first cut, and if the broadcaster later asks for a 23.976 version, conform at export from the finished 29.97 master rather than re-editing.
2. Why does the 140% push-in look soft, and how does Marco fix it without rebuilding the edits?
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What happened: Scale to Frame Size is applied at import and rasterizes the clip to the sequence raster immediately. Scaling 100→140 then magnifies a 1080-line image to roughly 1512 lines - pixels that no longer exist. Set to Frame Size behaves differently: it writes the value into Motion > Scale and keeps the full source raster available.
Fix, fastest first:
- Select the affected clips, right-click, uncheck Scale to Frame Size, then check Set to Frame Size. The Motion > Scale value resets so the source fills the frame properly.
- Re-check the push. From a 4K source there is now real headroom before softness appears.
- Re-time the move: Bezier ease-out on the final keyframe so it settles instead of stopping dead - softness reads far worse on a hard stop.
- If any clip was Render and Replaced after the bad scaling, redo it; the render baked the softness into new media.
3. Diagnose the 4-frame audio drift that appears after nesting, and say what you would check first.
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One of three causes, and the order matters.
- Frame-rate mismatch inside the nest. Each nested sequence conforms its contents to its own frame rate. If a nest is 23.976 while the master is 29.97, the nest is retimed on the way in and audio/video can separate at the tail. Open Sequence > Sequence Settings on the nest itself and compare.
- Variable frame rate screen capture. VFR has no constant frame duration, so conforming is an approximation that accumulates error. Right-click > Properties and look at the real frame rate; if it drifts, transcode to constant frame rate before it enters a nest.
- Sample-rate misinterpretation. The 44.1 kHz MP3 resampled to 48 kHz is normally clean, but a clip whose Interpret Footage is set to 48 kHz when the file is 44.1 plays about 8.8% fast - far more than 4 frames over a scene.
Four frames over one scene points at #1 or #2, not #3. Check the nest's sequence settings before touching the audio.