- From: <bugzilla@jessica.w3.org>
- Date: Thu, 17 Oct 2013 16:22:02 +0000
- To: public-html-media@w3.org
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23549 Bug ID: 23549 Summary: Clarify definition of decode timestamp Product: HTML WG Version: unspecified Hardware: PC OS: All Status: NEW Severity: normal Priority: P2 Component: Media Source Extensions Assignee: adrianba@microsoft.com Reporter: watsonm@netflix.com QA Contact: public-html-bugzilla@w3.org CC: mike@w3.org, public-html-media@w3.org Decode timestamp is an odd concept, since the time at which a frame is decoded is implementation dependent and not visible externally. It is really only decode order that needs to be externally specified. However, decode timestamp is used throughout the specification as a proxy for decode order. Also, the decode timestamp is not actually the time at which the frame needs to be decoded, since in practice this would be too late (rendering of this frame and decoding of dependent frames takes time). Replace: "Coded Frame A unit of media data that has a presentation timestamp and decode timestamp. The presentation timestamp indicates when the frame must be rendered. The decode timestamp indicates when the frame needs to be decoded. If frames can be decoded out of order, then the decode timestamp are present in the byte stream. The user agent must run the end of stream algorithm with the error parameter set to "decode" if this is not the case. If frames cannot be decoded out of order and a decode timestamp is not present in the byte stream, then the decode timestamp is equal to the presentation timestamp." with "Coded Frame A unit of media data that has a presentation timestamp and decode timestamp. The presentation timestamp indicates when the frame must be rendered. _Decode Timestamp_ The decode timestamp indicates _the latest time at which_ the frame needs to be decoded _assuming instantaneous decoding and rendering of this and any dependent frames (this is equal to the presentation timestamp of the earliest frame in presentation order that is dependent on this frame). If frames can be decoded out of _presentation_ order, then the decode timestamps must be present in _or derivable from_ the byte stream. The user agent must run the end of stream algorithm with the error parameter set to "decode" if this is not the case. If frames cannot be decoded out of _presentation_ order and a decode timestamp is not present in the byte stream, then the decode timestamp is equal to the presentation timestamp." (emphasis added to changes) -- You are receiving this mail because: You are on the CC list for the bug.
Received on Thursday, 17 October 2013 16:22:04 UTC