HLS VOD — CMAF Init Segment (init_0.m4s)
A CMAF initialisation segment: the moov box carrying codec configuration and track metadata, with no media samples. A player must fetch this before any media segment of the same rendition, and switching renditions mid-stream means fetching the new rendition's init first — the step ABR implementations most often get wrong.
Rendered preview of the m4s file (830 B). Download above for the original.
Specifications
- Protocol
- HLS
- Packaging
- CMAF / fMP4
- Segment Duration
- 1s
- Ladder
- 320x180 at 300 kbps, 480x270 at 700 kbps, 640x360 at 1400 kbps
- Generated By
- ffmpeg hls muxer
- Served Inline
- yes — /files/stream/
- Cors
- Access-Control-Allow-Origin: *
What is a .m4s file?
M4S is a CMAF/fragmented-MP4 media segment: a moof header plus an mdat payload covering a few seconds of one rendition. It is not a complete file — the codec configuration lives in a separate initialisation segment, so an .m4s on its own cannot be decoded and most players will refuse it outright.
How to use this file
Use example .m4s segments to test adaptive-streaming clients, segment fetchers and CMAF parsers. Load the matching init segment first, then append segments in order; a client that can play a segment without its init is not doing CMAF correctly.
How to use this file for testing
“HLS VOD — CMAF Init Segment (init_0.m4s)” is a deterministic Novus Examples fixture for Streaming manifests, Video codecs, Video QA. HLS playlists and DASH MPDs covering multi-bitrate ladders, byte-range addressing, and segment templates. Served inline with permissive CORS under /files/stream/, so a player can load them from any origin without re-hosting.
Documented properties for this file: M4S · 830 bytes. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Related files
- m4sDASH VOD — Init Segment (init-stream0.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- m4sDASH VOD — Init Segment (init-stream1.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- m4sDASH VOD — Init Segment (init-stream2.m4s)A DASH initialisation segment carrying codec configuration for one representation. Named by the manifest's $RepresentationID$ template, so this file also exercises whether a client resolves template variables correctly rather than pattern-matching filenames.
- mpdDASH VOD — Manifest (Playable Package)A complete, playable MPEG-DASH manifest for the same 320x180 at 300 kbps, 480x270 at 700 kbps, 640x360 at 1400 kbps ladder as the HLS package, produced from the same encoder run — so the two can be compared directly as packaging rather than as content. Every segment it references exists in this group. Served inline as application/dash+xml with permissive CORS, so dash.js can load it cross-origin.
- m4sDASH VOD — Media Segment (chunk-stream0-00001.m4s)A one-second DASH media segment, addressed by the manifest's $Number$ template. The same underlying CMAF structure as the HLS segments in the sibling package — which is the whole point of CMAF, and something a fixture set should let you verify rather than take on trust.
- m4sDASH VOD — Media Segment (chunk-stream0-00002.m4s)A one-second DASH media segment, addressed by the manifest's $Number$ template. The same underlying CMAF structure as the HLS segments in the sibling package — which is the whole point of CMAF, and something a fixture set should let you verify rather than take on trust.
Generated by generation/video_streaming_wave.py. Free for any use, no attribution required — license.