Action Video Lab Community

FrameFix
FrameFix
@framefix
Eminent Member
Joined: May 8, 2026
Last seen: Jul 27, 2026
Topics: 4 / Replies: 12
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RE: Timeline audio is synced, but the exported H.264 MP4 is out of sync

Play the export in at least two independent decoders, preferably on another device too. If every decoder shows the same timing error, suspect the expo...

2 months ago
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RE: Proxy video is out of sync with the original MP4 — what makes a bad proxy?

The start matches but the end is far off. I will conform the VFR source correctly before generating new proxies.

2 months ago
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RE: Why is seeking through an H.264 MP4 slow even when CPU usage is low?

How long is the GOP? If keyframes are several seconds apart, a backward jump can require a surprising amount of reconstruction even when average CPU u...

3 months ago
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RE: What is the cleanest Windows workflow for difficult MP4: decode, proxy, grade, export?

Yes. I would inspect timing first because a fast decoder cannot make broken/irregular time assumptions disappear. After that, test native decode perfo...

3 months ago
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RE: Preview is perfect, but one animated overlay flickers only in the exported MP4

Also test hardware versus software encoding and inspect the overlay's own frame rate. If the problem follows the overlay across encoders, normalize th...

3 months ago
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RE: 44.1 kHz AAC inside MP4 vs 48 kHz project audio — can that cause sync drift?

A competent editor should resample 44.1 to the project rate correctly, so the number alone does not prove the cause. It becomes more interesting when ...

3 months ago
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RE: What is the cleanest Windows workflow for difficult MP4: decode, proxy, grade, export?

VSDC fits this diagnostic order on Windows because you can test direct decode, proxies and final export without making conversion the mandatory first ...

3 months ago
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RE: Why does my MP4 look slightly different in color after export?

Compare in a color-managed environment and inspect the file's color tags. Players, browsers and OS display paths can interpret transfer characteristic...

3 months ago
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RE: MP4 plays smoothly in VLC but stutters badly on the editing timeline — why?

One detail that helped me diagnose a similar case was scrubbing with every effect bypassed and then watching the GPU's Video Decode graph. The overall...

4 months ago
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RE: Screen-recorded MP4 freezes for a moment whenever I scrub backward

A smaller proxy can feel dramatically faster even when the original is perfectly healthy. File size and editing friendliness are not the same metric.

4 months ago
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RE: What H.264 bitrate should I use for a 1080p MP4 upload?

If the platform will transcode again, avoid starving the upload master. Give its encoder a clean source rather than chasing the smallest possible uplo...

4 months ago
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RE: MP4 imports as audio only — how do I identify the missing video decoder?

Use MediaInfo and record codec, profile, level, bit depth, chroma, resolution and frame rate. 'MP4' alone is not a useful diagnosis.

4 months ago
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