Problem
Subtitle safe-area positioning conflicts with platform UI overlays on mobile playback.
Solution
Root Cause / Diagnostic:
Subtitles placed according to traditional SMPTE broadcast safe areas (80% or 90% title safe) do not account for mobile video player overlays. Platform UI elements such as scrub bars, channel handles, engagement buttons, and description banners cover the bottom 25% of mobile screens.
Actionable Fix:
1. Elevate subtitle baseline position to sit at least 15% to 20% above the bottom edge of the 1080x1920 or 1920x1080 frame canvas.
2. Apply a transparent 50% opacity bounding box or 3 px drop shadow behind text to maintain legibility against variable UI background elements.
3. Test video playback within mobile app sandbox environments or use transparent platform UI PNG overlay templates in your timeline viewer.
Pro Tip:
For YouTube Shorts and vertical platforms, keep all critical text and captions within the "central 60% safe zone" (between Y: 400 px and Y: 1500 px in a 1080x1920 canvas) to avoid player UI clipping.
Subtitles placed according to traditional SMPTE broadcast safe areas (80% or 90% title safe) do not account for mobile video player overlays. Platform UI elements such as scrub bars, channel handles, engagement buttons, and description banners cover the bottom 25% of mobile screens.
Actionable Fix:
1. Elevate subtitle baseline position to sit at least 15% to 20% above the bottom edge of the 1080x1920 or 1920x1080 frame canvas.
2. Apply a transparent 50% opacity bounding box or 3 px drop shadow behind text to maintain legibility against variable UI background elements.
3. Test video playback within mobile app sandbox environments or use transparent platform UI PNG overlay templates in your timeline viewer.
Pro Tip:
For YouTube Shorts and vertical platforms, keep all critical text and captions within the "central 60% safe zone" (between Y: 400 px and Y: 1500 px in a 1080x1920 canvas) to avoid player UI clipping.