VersionControl:PRs/maybelle-config/297 - Revision history

DrivingThatTrain: cryptograss/maybelle-config#297, as GitHub has it

2026-11-09T17:39:09Z

cryptograss/maybelle-config#297, as GitHub has it

← Older revision		Revision as of 17:39, 9 November 2026
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	\|url=https://github.com/cryptograss/maybelle-config/pull/297		\|url=https://github.com/cryptograss/maybelle-config/pull/297
	\|author=magent-cryptograss		\|author=magent-cryptograss
	\|state=~~open~~		\|state=merged
	\|base=production		\|base=production
	\|branch=magent/strip-empty-sdtp		\|branch=magent/strip-empty-sdtp
	\|opened=2026-11-09 11:51:10		\|opened=2026-11-09 11:51:10
	\|pushed=2026-11-09 11:50:56		\|pushed=2026-11-09 11:50:56
	\|merged=		\|merged=2026-11-09 17:39:05
	\|closed=		\|closed=
	\|worked_on_by=magent, skyler (testing on an iphone 17), with justin		\|worked_on_by=magent, skyler (testing on an iphone 17), with justin

DrivingThatTrain: cryptograss/maybelle-config#297, as GitHub has it

2026-11-09T17:06:17Z

cryptograss/maybelle-config#297, as GitHub has it

← Older revision		Revision as of 17:06, 9 November 2026
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	\|deploy=		\|deploy=
	}}		}}
			<pre class="pr-body">## Why

			Skyler's iPhone 17 shows nothing (no picture, no sound) when Safari's own player plays a release's stream. Over five rounds of test streams ([test page](https://magent-cryptograss.github.io/av1-iphone-test/)), tapped on the phone:

			- AV1 plays, as a plain file and as a stream, with Opus or AAC sound, in full colour range too.
			- The IPFS gateway isn't it: the release's stream copied byte for byte to GitHub also fails.
			- The release's exact stream, with only the 12-byte empty `sdtp` box removed from the video init segment, plays (test 18).

			ffmpeg 7.1 (Lavf 61.7, from `python:3.12-slim`'s Debian) writes that empty `sdtp` into every video init segment. ffmpeg 8 doesn't. The audio-only rendition has none, and it is the one that always played.

			## What

			- `_drop_empty_sdtp(init_segment)` in `transcode.py`: walks moov → trak → mdia → minf → stbl, removes any `sdtp` that is exactly a 12-byte empty full box, and shrinks every parent's size to match. It leaves alone an `sdtp` with entries, and any file with a 64-bit or malformed box.
			- Run on each `stream_/init.mp4` right after ffmpeg succeeds, before the poster, probe and pin.

			## Checked

			- Applied to the real release's `stream_360p/init_2.mp4` (`QmbYnW…`), the output is byte-identical to test 18's init segment, which Skyler's iPhone played.
			- 5 new tests (`tests/test_drop_empty_sdtp.py`); the full delivery-kid suite passes, 144 tests.
			- Not checked: a full encode on the delivery-kid image (ffmpeg 7.1) end to end.

			## Not in this PR: existing releases

			26 of the 44 HLS Releases on PickiPedia carry the empty `sdtp` (all encoded by Lavf 61.7.103); the other 18 have none. Fixing them means rewriting their init segments, which gives each a new CID, so a new Release page superseding the old via `subsequent_to`, as `scripts/reladder.py` already describes. That's a call for a person.

			Redeploy delivery-kid.
			Worked on by: magent and Skyler (testing on an iPhone 17), with Justin, in #uploads-and-embeds</pre>

DrivingThatTrain: cryptograss/maybelle-config#297, as GitHub has it

2026-11-09T11:51:15Z

cryptograss/maybelle-config#297, as GitHub has it

New page

{{PR
|repo=maybelle-config
|number=297
|title=delivery-kid: drop the empty sdtp box that stops iPhones playing releases
|url=https://github.com/cryptograss/maybelle-config/pull/297
|author=magent-cryptograss
|state=open
|base=production
|branch=magent/strip-empty-sdtp
|opened=2026-11-09 11:51:10
|pushed=2026-11-09 11:50:56
|merged=
|closed=
|worked_on_by=magent, skyler (testing on an iphone 17), with justin
|moods=uploads-and-embeds
|deploy=
}}