base_capturer_pipewire: Send frames via callback

Earlier, we were relying on CRD to periodically do frame captures.
This is however not needed since Wayland captures are event based
and once the compositor has send the event/frame to us, we can just
handover the frame to a registered callback. This ensures that we
have a single frame clock that (i.e. one present in the compositor).

Without this change, there is a chance that CRD capture clock is run
out of sync with the compositor's clock and cause unnecessary frame
delays.

See the following ideal scenario, for example, where '+' indicates
when a frame is sent by the compositor and when CRD tries to capture
it. This assumes that the same clock cycle for both CRD and the
compositor, each cycle length is enclosed within | .... |).

Compositor Frame Ready | +... | | +... |
     CRD Frame Capture | .+.. | | .+.. |

In this case, when both the clocks are in sync, CRD is able to
capture frame right after it is generated by the compositor. But if
they are completely out of sync, then CRD can always see a stale
frame (delayed by one cycle and it can cause users to feel stutter).

Compositor Frame Ready | .+.. | | .+.. |
     CRD Frame Capture | +... | | +... |

This stutter can become worse if the compositor is delayed in
generating the frames for some reason (e.g. load on the system).

Bug: chromium:1291247
Change-Id: I7c10c724fbbd87dc523d474e7ece8e8aa146fd7b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/291080
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Salman Malik <salmanmalik@chromium.org>
Cr-Commit-Position: refs/heads/main@{#39218}
7 files changed
tree: 3e20c6ca093681064d2d20bc4245f6c4984244a4
  1. api/
  2. audio/
  3. build_overrides/
  4. call/
  5. common_audio/
  6. common_video/
  7. data/
  8. docs/
  9. examples/
  10. experiments/
  11. g3doc/
  12. infra/
  13. logging/
  14. media/
  15. modules/
  16. net/
  17. p2p/
  18. pc/
  19. resources/
  20. rtc_base/
  21. rtc_tools/
  22. sdk/
  23. stats/
  24. system_wrappers/
  25. test/
  26. tools_webrtc/
  27. video/
  28. .clang-format
  29. .git-blame-ignore-revs
  30. .gitignore
  31. .gn
  32. .mailmap
  33. .style.yapf
  34. .vpython
  35. .vpython3
  36. AUTHORS
  37. BUILD.gn
  38. CODE_OF_CONDUCT.md
  39. codereview.settings
  40. DEPS
  41. DIR_METADATA
  42. ENG_REVIEW_OWNERS
  43. g3doc.lua
  44. LICENSE
  45. license_template.txt
  46. native-api.md
  47. OWNERS
  48. OWNERS_INFRA
  49. PATENTS
  50. PRESUBMIT.py
  51. presubmit_test.py
  52. presubmit_test_mocks.py
  53. pylintrc
  54. README.chromium
  55. README.md
  56. WATCHLISTS
  57. webrtc.gni
  58. webrtc_lib_link_test.cc
  59. whitespace.txt
README.md

WebRTC is a free, open software project that provides browsers and mobile applications with Real-Time Communications (RTC) capabilities via simple APIs. The WebRTC components have been optimized to best serve this purpose.

Our mission: To enable rich, high-quality RTC applications to be developed for the browser, mobile platforms, and IoT devices, and allow them all to communicate via a common set of protocols.

The WebRTC initiative is a project supported by Google, Mozilla and Opera, amongst others.

Development

See here for instructions on how to get started developing with the native code.

Authoritative list of directories that contain the native API header files.

More info