Mikkeli Matlock
14ee5ec26c
Two failure modes cost a match silently, and neither was detectable from inside the recorder. preflight.py: the session can be dead while every local signal looks fine -- right cookie, right expiry, right profile. Only the server knows. This spends one request asking it to mint a JWT and exits non-zero if it will not, so a dead login surfaces hours before kickoff instead of at it. Reports cookies and tokens by length; it never prints a value. watchdog.py: a scheduled launch has been seen to hang at interpreter startup, alive but frozen before any of our code runs. So "is a recorder process running" is the wrong question -- the hung process answers yes. This asks whether recording is *progressing*, via a growing .ts or a freshly written log, and only intervenes when both signals are stale. A healthy capture is never interrupted. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Fr1fLMnVGNAKH5L2BmhMxn
brfc-stream-pirate
Personal time-shifting archive for Bristol Rovers video pass streams. Kickoffs land at unfriendly hours in JST; this records them unattended.
Stream is plain HLS, no DRM (StreamAMG behind Akamai). Nothing here breaks a protection measure -- it replays the same authenticated request the player makes, using your own paid session.
Pieces
| File | Job |
|---|---|
tampermonkey/brfc-stream-sniffer.user.js |
Hooks fetch/XHR in the page, captures the manifest URL verbatim, POSTs it to the catcher |
catcher.py |
Listens on 127.0.0.1:8787, hands the URL to yt-dlp, records to recordings/ |
probe.py |
Byte-exact manifest fetch + concurrency test |
The token
Manifest URLs carry an Akamai path token:
hdntl=exp=<unix>~acl=/*~id=<n>~data=hdntl~hmac=<sig>
exp-- ~24h validityacl=/*-- wildcard over the whole host, not just your matchhmac-- signature over the literal path
It is a bearer credential. Anyone holding a live URL can pull the stream until
exp. Keep it out of pastebins and issue trackers. stream-url.txt and
cookies.txt are gitignored.
Do not re-encode the path. curl normalises %2f to %2F, which
invalidates the HMAC. probe.py sends the request target verbatim.
Use Firefox for watching
yt-dlp lifts session cookies from the browser. Chrome 127+ on Windows uses app-bound cookie encryption and extraction fails. Firefox works with no fuss.
set BRFC_BROWSER=firefox # default
Workflow
pip install yt-dlp # done
python catcher.py # leave running
Install the userscript in Tampermonkey, open the match page, press play. The
sniffer catches the manifest, the catcher starts yt-dlp. Recording is MPEG-TS
(--hls-use-mpegts) so a killed process still leaves a playable file.
For a 3am kickoff: Task Scheduler opens the match page a few minutes before, the browser autoplays, the sniffer fires, the catcher records. Nobody is awake.
Concurrency check
An Akamai edge token is a stateless HMAC -- the edge validates signature and expiry and serves; it holds no session table, so it cannot count viewers. Any concurrent-stream limit lives in the entitlement API that issues tokens, upstream of the CDN. Confirm rather than assume, while the browser is playing:
python probe.py --url "<manifest from the sniffer>" --parallel 3
3/3 alongside the playing browser means four concurrent readers of one token and the edge does not care.
Findings (2026-08-29, live 2300 JST match)
Verified against a live stream. Recorded 1080p successfully end to end.
Two token types, not one
The player uses a two-stage token chain:
| Token | Where | TTL | Purpose |
|---|---|---|---|
hdnts= |
query string, acl=/* unencoded |
~25 seconds | fetch the master playlist |
hdntl= |
URL path, acl=%2f* encoded |
~24 hours | media playlists + segments |
The master response rewrites each variant URL with a 24h hdntl token. So the
hdntl token is the durable one worth handing to a downloader. Chasing a
hdnts URL by hand is pointless -- it dies before you can paste it.
Confirmed by experiment
- Concurrency is not limited. Two independent ffmpeg downloads ran at full bitrate while Firefox played the same match. Three concurrent readers of one token, no complaint from the edge. Akamai token auth is a stateless HMAC check; it has no viewer counter.
- No CDN cookies exist. All 13 relevant cookies are on
bristolrovers.co.uk; nothing is scoped toakamaized.net. The token in the URL is the whole auth. - Stream is 1920x1080 H.264 + AAC ~5.2 Mbit/s -> roughly 4.7 GB per match.
- Output is MPEG-TS even though yt-dlp names it
.mp4. That is what--hls-use-mpegtsbuys: a killed process still leaves a playable file. - Player is Bitmovin, embedded on the club site.
0_xm5vrrw6is a Kaltura entry id and identifies the match -- the catcher dedupes on it.
Gotcha: which URL form a Python client can fetch
Earlier notes here blamed a TLS handshake difference. That was wrong. The 403 splits by token form, not by client:
| URL form | Python | ffmpeg |
|---|---|---|
index.m3u8?hdnts=... (master, query token) |
200 | 200 |
hdntl=.../index_N.m3u8 (media, path token) |
403 | 200 |
Consequences:
- Mint a master URL and hand that to the downloader.
record_live.pydoes this: it calls the entry API for a fresh master immediately before recording. - Force
--downloader ffmpeg. yt-dlp's native HLS downloader fetches variant playlists with Python and dies on the path-token URLs. This is required, not a preference. probe.pyis diagnostic scaffolding and inherits the path-token 403 -- do not use it to conclude a token is dead.
Firefox, not Chrome
yt-dlp reads cookies from a running Firefox. Chrome/Edge lock their cookie DB while running (yt-dlp issue 7271), and an unattended job cannot close the browser to read them.
The stream never ends
After full time the feed switches to a static league slate and keeps serving
indefinitely at full CBR bitrate (~4.7 Mbit/s to encode a still image). There
is no #EXT-X-ENDLIST, so ffmpeg never finishes, and there is no stall to
detect either -- from the downloader's point of view it is a healthy live
stream forever.
Keep the duration cap. catcher.py and record_live.py pass
ffmpeg_o:-t $DURATION_MIN*60. Without it, a feed that behaves like the video
one above fills the disk with a logo.
Note the sample size. This is one video observation, and it is contradicted
by one audio observation: on 2026-09-02 an audio stream ended cleanly by
itself (rc=0 at 165 min, against a 180 min cap that never fired). So "the
stream never ends" is a property of that video feed, not an established rule.
Treat the cap as a safety net rather than as the only stop condition.
Observed: video, 116 min recorded for a 23:00 kickoff, still running at 01:04 and stopped manually. Audio, 165 min, self-terminated. Budget ~3.5-4 GB per copy per match at 40 MB/min.
Status
Unattended recording works. A scheduled task started record_live.py at 03:15
for an 03:45 kickoff, found the stream in 16 seconds, and recorded 165 min of
audio to a playable MPEG-TS with nobody awake.
Sample sizes are one. One video capture, one audio capture. Where the two disagree (stream termination, whether an entry id persists between matches), neither is established -- do not build on either without more matches.
Verified
- Token chain end to end in plain Python: session cookie -> JWT -> entry API -> master playlist. No browser, no fingerprint forging.
- Recording via ffmpeg, video (1080p) and audio (~122 kbps AAC).
- Scheduled unattended run, including that Task Scheduler launches it correctly.
- Concurrency: several readers of one token, alongside a playing browser.
Not verified
- Login. Everything above rides an
SSESScookie lifted from a desktop Firefox profile. Obtaining a session from credentials has never been run./user/loginis a standard Drupal form (name,pass,form_build_id,form_id,captcha_token) with no reCAPTCHA script and no 2FA mention, butcaptcha_tokenis an unknown and testing it risks a lockout that would take out the working session too.
Decision: do not automate login
The cookie lasts ~87 days and matches are weekly, so automating login saves about four manual actions a year -- while being the riskiest step and the only one needing a stored password. Refresh the cookie by logging in manually on the desktop each quarter and provisioning it to the recording host instead. That makes cookie provisioning the open problem, not the captcha.
Use Firefox as the session holder. Two independent reasons: its cookie DB stays readable while running (Chrome/Edge lock theirs), and it holds the login durably where Chrome has been observed dropping it within a day.