A defining characteristic of DASH implementations using M4S is the separation of tracks. Typically, the player downloads two distinct sets of M4S files:
To download these streams effectively, you generally need software that can interpret the manifest and merge the fragments into a single MP4: m4s downloader
: This is the industry standard for command-line downloading. It can automatically detect .mpd manifest links and merge M4S fragments into a playable MP4 file. You can find it on GitHub. A defining characteristic of DASH implementations using M4S
Since the audio and video were downloaded as separate streams (often saved as video.m4s and audio.m4s ), they are not synchronized in a single file. The final step is muxing . The downloader utilizes multimedia frameworks (such as FFmpeg) to interleave the audio and video tracks into a single container, typically .mp4 or .mkv . You can find it on GitHub