Problem
An alpha-channel export loses transparency because the selected codec does not support the required alpha format.
Solution
Root Cause / Diagnostic:
Common distribution video containers and codecs (such as standard H.264/MP4, standard ProRes 422, and standard DNxHD) are structurally architected to encode three color channels (RGB or YUV 4:2:0/4:2:2) with zero auxiliary channel data. If an editor selects an MP4 or ProRes 422 preset to export transparent lower-thirds or motion graphics overlays, the encoder discards the 32-bit alpha channel entirely and automatically fills transparent regions with solid black.
Actionable Fix:
1. Change the export format to a codec that natively supports 32-bit RGBA channels: Apple ProRes 4444 (or ProRes 4444 XQ), GoPro CineForm (RGB 12-bit with Alpha), or DNxHR HQX with Alpha.
2. In the video export settings, ensure 'Depth' is explicitly set to '8 bpc + alpha' or '16 bpc + alpha' (or 'Millions of Colors+').
3. Re-import the exported file into the NLE and place it over a brightly colored background clip to verify that underlying video shows through transparent regions flawlessly.
Pro Tip:
If web delivery requires transparent video for web browsers, export WebM with VP9 alpha support or convert ProRes 4444 files to HEVC with alpha targeting Apple QuickTime web players.
Common distribution video containers and codecs (such as standard H.264/MP4, standard ProRes 422, and standard DNxHD) are structurally architected to encode three color channels (RGB or YUV 4:2:0/4:2:2) with zero auxiliary channel data. If an editor selects an MP4 or ProRes 422 preset to export transparent lower-thirds or motion graphics overlays, the encoder discards the 32-bit alpha channel entirely and automatically fills transparent regions with solid black.
Actionable Fix:
1. Change the export format to a codec that natively supports 32-bit RGBA channels: Apple ProRes 4444 (or ProRes 4444 XQ), GoPro CineForm (RGB 12-bit with Alpha), or DNxHR HQX with Alpha.
2. In the video export settings, ensure 'Depth' is explicitly set to '8 bpc + alpha' or '16 bpc + alpha' (or 'Millions of Colors+').
3. Re-import the exported file into the NLE and place it over a brightly colored background clip to verify that underlying video shows through transparent regions flawlessly.
Pro Tip:
If web delivery requires transparent video for web browsers, export WebM with VP9 alpha support or convert ProRes 4444 files to HEVC with alpha targeting Apple QuickTime web players.