Feature Name: "Smart Resume"

Go to MX Player → Settings → Decoder → Custom Codec. If it shows any existing codec, tap "Clear" or "Remove."

Custom Presets:

In unofficial Android modification communities, individual developers often share customized application packages (APKs) or custom audio/video codec zip files. "Ajeethk" is likely the handle or username of a custom uploader who compiled a "top" or optimized version of the app.

Many of these community-driven versions unlock premium features, such as "Gold" interface themes and advanced subtitle customization (shadows, borders, and custom positioning), which are usually locked behind a subscription or paywall.

Customization:

Users can adjust themes, interface buttons, and even sync out-of-order subtitles.

Pop-up Play

This is often the "killer feature." Tap the "Background play" button, and the video’s audio continues playing even when your screen is off or you switch to WhatsApp/Chrome. Furthermore, the (PIP) mode allows you to shrink the video into a floating window that stays on top of other apps.