Problem
Chroma subsampling makes saturated red graphics bleed into adjacent text after compression.
Solution
Root Cause / Diagnostic:
Video codecs (H.264, H.265, ProRes 422) use 4:2:0 or 4:2:2 chroma subsampling, halving color resolution horizontally and vertically to save bandwidth. Saturated pure red (RGB: 255, 0, 0) possesses extreme color energy combined with low perceived luminance. When subsampled and compressed through lossy discrete cosine transform (DCT) algorithms, the red chroma boundaries smear across adjacent high-contrast white text, producing fuzzy, bleeding edges.
Actionable Fix:
1. Desaturate pure graphic reds slightly (reduce saturation by 10-15%) and mix in a subtle amount of green and blue (e.g., RGB 225, 25, 25) to prevent color clipping.
2. Place a thin 1-pixel dark neutral border or drop shadow around red text elements to separate them from contrasting background elements.
3. Export using 10-bit 4:2:2 intermediate masters (ProRes 422 HQ) and inspect compressed YouTube test uploads to confirm sharp, bleed-free graphic edges.
Pro Tip:
Avoid pure 100% saturated primary colors (especially pure red and pure blue) in on-screen lower thirds and graphics; broadcast-safe graphics adhere strictly to 75% color saturation limits.
Video codecs (H.264, H.265, ProRes 422) use 4:2:0 or 4:2:2 chroma subsampling, halving color resolution horizontally and vertically to save bandwidth. Saturated pure red (RGB: 255, 0, 0) possesses extreme color energy combined with low perceived luminance. When subsampled and compressed through lossy discrete cosine transform (DCT) algorithms, the red chroma boundaries smear across adjacent high-contrast white text, producing fuzzy, bleeding edges.
Actionable Fix:
1. Desaturate pure graphic reds slightly (reduce saturation by 10-15%) and mix in a subtle amount of green and blue (e.g., RGB 225, 25, 25) to prevent color clipping.
2. Place a thin 1-pixel dark neutral border or drop shadow around red text elements to separate them from contrasting background elements.
3. Export using 10-bit 4:2:2 intermediate masters (ProRes 422 HQ) and inspect compressed YouTube test uploads to confirm sharp, bleed-free graphic edges.
Pro Tip:
Avoid pure 100% saturated primary colors (especially pure red and pure blue) in on-screen lower thirds and graphics; broadcast-safe graphics adhere strictly to 75% color saturation limits.