Under zero-hertz mode, provided that a frame arrived to the VideoStreamEncoder, the receiver may experience up to a second between incoming frames. This results in key frame requests getting serviced with that delay, which is undesired. What's worse is also the fact that if no frame ever arrived to the VideoStreamEncoder, it will not service the keyframe requests at all until the first frame comes. This change introduces VideoSourceInterface::RequestRefreshFrame which results in a refresh frame being sent from complying sources. The method is used under zero-hertz mode from the VideoStreamEncoder when frames didn't arrive to it yet (with changes to the zero-hertz adapter). With this change, when the frame adapter has received at least one frame, it will conditionally repeat the last frame in response to the key frame request. go/rtc-0hz-present Bug: chromium:1255737 Change-Id: I6f97813b3a938747357d45e5dda54f759129b44d Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/242361 Reviewed-by: Erik Språng <sprang@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Reviewed-by: Henrik Boström <hbos@webrtc.org> Commit-Queue: Markus Handell <handellm@webrtc.org> Cr-Commit-Position: refs/heads/main@{#35562}
How to write code in the api/ directory
Mostly, just follow the regular style guide, but:
- Note that
api/code is not exempt from the “.hand.ccfiles come in pairs” rule, so if you declare something inapi/path/to/foo.h, it should be defined inapi/path/to/foo.cc. - Headers in
api/should, if possible, not#includeheaders outsideapi/. It’s not always possible to avoid this, but be aware that it adds to a small mountain of technical debt that we’re trying to shrink. .ccfiles inapi/, on the other hand, are free to#includeheaders outsideapi/.
That is, the preferred way for api/ code to access non-api/ code is to call
it from a .cc file, so that users of our API headers won’t transitively
#include non-public headers.
For headers in api/ that need to refer to non-public types, forward
declarations are often a lesser evil than including non-public header files. The
usual rules still apply, though.
.cc files in api/ should preferably be kept reasonably small. If a
substantial implementation is needed, consider putting it with our non-public
code, and just call it from the api/ .cc file.