I need an Android-side solution that lets me play pre-existing MP4 files so they appear to the other party as the live camera feed inside an ongoing WhatsApp video call. The goal is smooth, full-screen presentation sharing rather than casual “watch-together” viewing, so video quality and audio sync must stay as close to real time as WhatsApp’s limits allow. Key points • My MP4s are already prepared; the job is purely about the streaming mechanism. • This has to work on standard, non-rooted phones running recent Android versions (13/14 preferred). • I am open to any practical approach—virtual camera, screen capture overlay, MediaProjection API, or other tactics—as long as it survives WhatsApp’s camera hand-off and keeps frame drops minimal. • A lightweight control UI to pick and start a file is welcome, but polished design is not the priority; reliability is. Deliverables 1. An installable APK (or Android Studio project) that injects the chosen MP4 into a live WhatsApp video call. 2. Clear step-by-step setup instructions I can hand to less technical colleagues. 3. Source code with concise comments highlighting the key hooks (camera substitution, audio routing, permission handling). 4. A short test report showing latency and frame-rate results on at least one mainstream handset model. Acceptance criteria • Recipient sees and hears the MP4 in real time for the duration of the call with no manual camera toggling required. • Playback length up to 10 minutes verified without crashes or audio desync >200 ms. • Solution stays functional after a phone reboot and across WhatsApp re-installs (within normal permission prompts). If you’ve already tackled virtual camera feeds, MediaProjection, or similar real-time video substitution tricks, this should be a quick win. Let’s discuss your proposed approach and timeline so I can start presenting seamlessly on WhatsApp.