HLS, Intentionally Corrupt: Missing #EXTM3U Signature
An intentionally corrupt HLS playlist with the mandatory #EXTM3U signature removed. Everything else is valid. The specification requires the first line to be exactly #EXTM3U and that clients reject anything else, so this separates conforming parsers from lenient ones that sniff for EXT tags instead.
#EXT-X-VERSION:7
#EXT-X-TARGETDURATION:4
#EXT-X-PLAYLIST-TYPE:VOD
#EXTINF:4.000,
seg-00001.m4s
#EXTINF:4.000,
seg-00002.m4s
#EXT-X-ENDLIST
Specifications
- Corruption
- missing mandatory #EXTM3U first line
- Otherwise Valid
- yes
- Segments
- 2
- Alt Text
- An intentionally corrupt HLS playlist with the mandatory #EXTM3U signature removed
- Alt Text Source
- description
Testing contract
Expected to fail- Scenario
- Load the playlist in an HLS client and check whether the first line is validated.
- Expected result
- The mandatory `#EXTM3U` first line has been removed; everything else, including both segment entries, is valid. RFC 8216 requires a client to reject a playlist whose first line is not exactly `#EXTM3U`, so a conforming client refuses the file while a lenient one sniffs for EXT tags and plays 2 segments.
What is a .m3u8 file?
M3U8 (.m3u8) is a UTF-8 M3U playlist, most importantly the backbone of HTTP Live Streaming (HLS). An HLS media playlist lists timed media segments with #EXTINF tags and directives like #EXT-X-TARGETDURATION, and a master playlist points to alternate bitrate renditions.
How to use this file
Use an example .m3u8 file to test HLS parsers and players, segment and directive extraction, and adaptive-streaming tooling, or as a plain UTF-8 M3U playlist.
How to use this file for testing
“HLS, Intentionally Corrupt: Missing #EXTM3U Signature” is a deterministic Testaroo fixture for Streaming manifests, 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: M3U8 · 139 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.
Code examples
# manifests resolve their own segments, so pass the URL, not a local copy
ffprobe -v error -show_entries stream=codec_name,width,height no-extm3u.m3u8
ffplay no-extm3u.m3u8Generated by generation/video_timedtext.py. Free for any use, no attribution required, license.
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.
