Electron v11, r2-streamer-js HTTP server + prototype no-HTTP streamer (Session.protocol.registerStreamProtocol)

[danielweck]

WIP :)

[danielweck]

Everything works ... except Session.protocol.registerStreamProtocol() which fails for streaming video/audio media, ironically :(

See:
electron/electron#21018 (comment)
#990 (comment)

[danielweck]

The Electron bug will be fixed in v11 (we are currently at v9):
electron/electron#22955 (comment)

[danielweck]

Electron 11 registerSchemesAsPrivileged() and registerStreamProtocol():
https://unpkg.com/browse/electron@11.0.1/electron.d.ts#L6207

Protocols that use streams (http and stream protocols) should set `stream:
true`. The `<video>` and `<audio>` HTML elements expect protocols to buffer
their responses by default. The `stream` flag configures those elements to
correctly expect streaming responses.

...but not in Electron 10:
https://unpkg.com/browse/electron@10.1.5/electron.d.ts#L12931

[danielweck]

r2-navigator-js Electron 11: https://github.com/readium/r2-navigator-js/pull/58/files

[danielweck]

I confirm that registerStreamProtocol() "works" in Electron 11.0.1, including with stream: true in registerSchemesAsPrivileged(). However, audio seeking (and presumably, video, although I haven't had time to test this yet) fails. I am seeing the following event sequence emitted by the HTML audio element, but no requests are made to registerStreamProtocol() when seeking with a mouse click towards the end of the audio resource (i.e. where buffers haven't been fetched yet ... or for that matter, even if they have been fetched already):

1. seeking
2. waiting
3. seeked
4. canplay
5. playing
6. canplaythrough

[danielweck]

When we activate the debug mode to visualize audio buffers, and here's what we see:

Seeking working (regular HTTP 1.1 byte-range partial requests):

Seeking not working (registerStreamProtocol):

[danielweck]

The good news is that it looks like I am not alone in experiencing this new class of bugs in registerStreamProtocol():

electron/electron#21018 (comment)

...as reported by the same developer who implemented the initial fix:

electron/electron#22955

...so let's watch this space. But for now, we need to continue using an HTTP server (at least for audio/video resource, but in that case we might as well stick with the r2-streamer-js HTTP server for now, and wait until Electron is fixed to make a complete move to registerStreamProtocol()).

[danielweck]

In reference to the comment above: #1258 (comment)
...it looks like somewhere between Electron v11 and v13 the video/audio streaming buffering bug was fixed, so we are now able to migrate 👍