ZenConverter

ZenConverter is an offline-first file conversion tool for Android. It processes your media and documents directly on your device using native platform APIs, FFmpeg, and on-device neural networks. No cloud uploads, no ads, no trackers, and no account required. Your files never leave your phone. Key Features: Video & Audio (Powered by FFmpeg) • Convert videos to MP4, MKV, and MOV with customizable codecs, bitrates, resolutions, and frame rates. • Video merge: concatenate multiple video files into one with aspect-ratio normalization and silent audio track synthesis. • Visual trimming and multi-segment splitting for long media files. • Export video overview contact sheets (3x3, 3x4, 4x4, 5x5 grids) with video metadata headers and timestamps. • Convert videos to animated GIFs with palettegen color optimization. • Extract audio or convert audio files across MP3, M4A, WAV, FLAC, WMA, and OPUS with bitrate and sample-rate controls. On-Device AI (Tencent NCNN with Vulkan GPU) • Image Super-Resolution: Upscale raster images up to 4x using Real-ESRGAN deep-learning models with tiled inference. • Video Frame Interpolation (Experimental): Double video frame rates (e.g., 30 fps to 60 fps) using RIFE optical flow. PDF & Document Tools • Compress PDFs with presets (High Quality, Balanced, Small File) while keeping selectable text and vector layouts intact. • Merge multiple PDF files, extract selectable text to TXT / Markdown, or apply password encryption and decryption. • Convert DOCX, PPTX, and XLSX documents to PDF, TXT, or Markdown locally using device system fonts. Images, Fonts & Subtitles • Convert between JPG, PNG, WEBP, and ICO. Render PDF pages to images or pack images into a PDF. • Convert font formats between TTF, OTF, WOFF, and WOFF2. • Convert subtitle and lyrics files between SRT, VTT, LRC, and ASS with timestamp preservation and encoding fallbacks. • Metadata Safety: Inspect photo and video metadata (including HEIC/HEIF), and strip EXIF metadata from JPG files without re-encoding. Modern Android Experience • Material You dynamic theme integration that matches your system wallpaper. • System dark theme with an independent pure black toggle for OLED displays. • In-app language switching supporting English, Simplified Chinese, Traditional Chinese, and French. Notes: • ZenConverter runs on arm64-v8a devices. • Converting large video files or running AI upscaling requires adequate battery, memory, and free storage space. • ZenConverter is open-source software licensed under the AGPL-3.0.