How to determine video duration via link by downloading 7% of the file, and why the MP4 header can be zero

The author examines the technical challenge of determining the duration of MP4 video files. The focus is on scenarios where standard tools fail to read metadata and the file header contains a zero duration value. The article provides a detailed explanation of the internal structure of the MP4 container and how metadata is stored. The author proposes an efficient solution: retrieving the necessary information using just three HTTP Range requests, which avoids the need to download the entire video file. This method is particularly useful for optimizing services that process media content, as it allows data extraction by downloading only about 7% of the file. The article is valuable for developers working with streaming data and video processing, as it offers an alternative to heavy libraries like ffmpeg, demonstrating a deep understanding of network protocols and file formats.