Implement SourceBuffer.writeHead attribute #4559
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This change implements a partial interface for SourceBuffer, adding the writeHead attribute. This attribute returns the highest buffer presentation timestamp written to the SbPlayer. The writeHead attribute is guarded by a Runtime Enabled Feature SourceBufferWriteHead. This feature is enabled by default for Cobalt builds and disabled for all other builds. Link to the original PR with most of the functional changes: youtube#121 b/326652276
osagie98
requested review from
sideb0ard,
jasonzhangxx,
xiaomings,
andrewsavage1 and
borongc
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Just realized that since the new interface is only included in Cobalt Starboard media builds, we may not need to guard it by a RuntimeEnabledFeature. I can remove that if needed |
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Ideally we'd add a web test for this in https://github.com/youtube/cobalt/tree/main/third_party/blink/web_tests/external/wpt/media-source/
third_party/blink/renderer/modules/mediasource/source_buffer_write_head.idl
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third_party/blink/web_tests/external/wpt/media-source/SourceBuffer-writeHead.html
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third_party/blink/web_tests/external/wpt/media-source/SourceBuffer-writeHead.html
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| #if BUILDFLAG(USE_STARBOARD_MEDIA) | ||
| for (auto&& buffer : buffers) { | ||
| if (!buffer->end_of_stream()) { | ||
| write_head_ = std::max(write_head_, buffer->timestamp()); |
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Did we consider extending media/filters/chunk_demuxer_unittest.cc for the new behaviour?
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There's an existing bug to address this b/380001431, it's unblocked now so I'll be able to add tests for this and other ChunkDemuxer changes
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| [ | ||
| ImplementedAs=SourceBufferWriteHead | ||
| ] partial interface SourceBuffer { |
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Since this is an interface extension, could we put it in a blink/renderer/modules/cobalt or some such? That way it'd make it easier down the line to identify all Cobalt Web Platform extensions.
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Sure, is that the practice we'll have going forward? I approached it how it would look if it were merged to Chrome.
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I'm less sure about the right way to approach this change, because my understanding is that it's more likely to be upstreamed (and I think relatively soon?), so we actually wouldn't want it to be separate from the other changes. But maybe we want to always separate it out until it's actually accepted upstream as it may also change once it goes in upstream. I'll think about it and add it to go/cobalt-web-api-design
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Decided this should be in a cobalt-owned location in the discussion at https://docs.google.com/document/d/1RhlGcSINBxBkPeA45JAtkQHt9lrnkl7b1rYbQ2PFLCI/edit?resourcekey=0-OpkmEwqsdvkmlwC22Npjpw&tab=t.0#bookmark=id.pkppexmi8025
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I can move this as soon as we have a defined location for these interface changes to go
This change implements a partial interface for SourceBuffer, adding the writeHead attribute. This attribute returns the highest buffer presentation timestamp written to the Renderer. The writeHead attribute is only included in Cobalt Starboard media builds.
Link to the original PR with most of the functional changes: #121
b/326652276