Meeting minutes
MSE bug triage
Matt_Wolenetz: MSE has 3 milestones: v2, v2 bug fixes, and backlog
Matt_Wolenetz: something we can discuss is whether the right things were picked for v2
Matt_Wolenetz: there are 19 issues in the list
Matt_Wolenetz: behaviour of the File API changed after MSE started to get used (re: createObjectURL)
… Chrome stopped auto-revoking but Mozilla and Firefox kept doing it
… auto-revoking is helpful to avoid memory leaks
… auto-revoking behaviour is being redefined
Matt_Wolenetz: MSE in Worker is the next feature
<Matt_Wolenetz> MSE-in-workers demo
Matt_Wolenetz: feature is implemented in chromium behind a flag
cyril: what are the spec changes expected to do that?
cyril: will there be breaking changes?
Matt_Wolenetz: no, there will be no breaking changes
… it will have the media element on one side (document) and media source on the other side (worker)
cyril: would that be a new API?
Matt_Wolenetz: there will be a new API as things will be allowed in a worker context
jernoble: how would a client know worker support is available?
<Matt_Wolenetz> MediaSource.canConstructInDedicatedWorker
Matt_Wolenetz: `canConstructInDedicatedWorker` will be a new attribute exposing this
Matt_Wolenetz: any feedback would be appreciated
… this is of interest to web developers
… looking forward to Safari feedback
Matt_Wolenetz: issue #37 about standardising <couldn't catch>
<Matt_Wolenetz> MSE for Audio
Matt_Wolenetz: issue #155 is basically change type
… moved from incubation to main spec
… already has some implementations, we can move to the next
Matt_Wolenetz: issue #160 is to give apps more predictability around buffering
… some implementations have more tolerance than others
… with regards to gaps before they stall
… the same torelance should apply to all
… and if there is a gap, should the implementation play through, play silence, or stall
… this has been a big interop issue and was raised as a top request by Mozilla
Matt_Wolenetz: issue #161 is about codecs parameter content
cyril: should this be solved by MPEG?
jernoble: is this truly an MSE problem?
Matt_Wolenetz: this is correct
Matt_Wolenetz: issue #28 is about allowing source object attachment for MSE
jernoble: webkit already allows this
Matt_Wolenetz: we can skip issue #88
Matt_Wolenetz: issue #100 is to promis-ify the MSE API
Matt_Wolenetz: issue #174
… support for more input and flexibity of MSE spec
cyril: with the CMAF bytestream format that wave has delevop, do we expect to update the spec at some point?
… or will it go to the rec track?
Matt_Wolenetz: i'm not sure how that document going to the rec track would look like
cyril: having a test suite, etc.
Matt_Wolenetz: i couldn't dedicate my time for that but it would be great
cyril: if someone would contribute that, would the group welcome it?
Matt_Wolenetz: no objections to that
Matt_Wolenetz: with respect to CMAF, there is a distinct mime type
<discussion around CMAF/CTA, player and browser requirements>
Matt_Wolenetz: issue #180 specifying in the bytestream format for webm how to get colour profile, and other information for vp9
cyril: it appears to be there already
Matt_Wolenetz: may only the last part is missing
Matt_Wolenetz: issue #184 "expose actual decodecs or provide coded frame bytestream or append api"
Matt_Wolenetz: issue #55 support audio/wav for MSE
… if the previous item is done, it could be done via web codecs decoded audio chunks
Matt_Wolenetz: issue #21 this is a placeholder issue for low latency work by Chris C.
… this is related to latency hint and isn't a new api for MSE
Matt_Wolenetz: issue #35 answer the questions of what actually happened after append buffer is completed
… one solution is to have structured metadata sent with updateend event
… or instead specify a new SourceBuffer Introspection API
jernoble: this is something that Will Law has been asking for a long time
Matt_Wolenetz: issue #65 is regarding audio overlay in MSE
… the spec requires a cross fade, Chrome used to have it and was dropped as no one could hear the difference
… the issue is to no longer require UA do to it
Matt_Wolenetz: issue #137 is to require full codec specificity for `isTypeSupported()`
Matt_Wolenetz: avoids decoding support only visible very late (when decoding occurs)
Matt_Wolenetz: EME and Media Capabilities are going the same path
Matt_Wolenetz: issue #186 when using multitrack streams, interop is inexistant because the spec is too flexible
… in Chromium multitrack and sequence mode, usage is very low
Matt_Wolenetz: issue #232 "add garbage collection modes to SourceBuffer"
Matt_Wolenetz: and that is it for v2 issues
… please go to the backlog and see if there is anything you want to see in v2
markw: i've one question regarding audio splicing
… there is this one issue regarding append window
… it would be great to be able to use the append window when there is a crossfade
… it is at the beginning of the sample at the moment
Matt_Wolenetz: I would recommend that you check the link ("gapless audio with mse")
… if you could also leave a comment on the crossfade issue to say that you want to keep the behaviour
cyril: following the M&E IG at TPAC, what's the support of ttml or webvtt in mp4 (inband text track) with mse
… here the request would be to populate the text track
Matt_Wolenetz: before i answer, i want to hear what Jer has to say
jernoble: we don't implement this
… and Apple platforms have inband text track via HLS
… so it may be why we never heard this as a feature request
<Matt_Wolenetz> IIRC, Jer suggested adding a Streaming VTT bytestream format to MSE
<Matt_Wolenetz> If this is desirable, please file an MSE spec bug (https://