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Clamp simulcast layers#1084

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hiroshihorie wants to merge 7 commits into
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hiroshi/clamp-simulcast-layers
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Clamp simulcast layers#1084
hiroshihorie wants to merge 7 commits into
mainfrom
hiroshi/clamp-simulcast-layers

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@hiroshihorie hiroshihorie commented May 15, 2026 •
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Summary

  • Port Swift SDK simulcast lower-layer clamping behavior to Flutter.
  • Clamp lower-layer max framerate so it does not exceed the configured top layer.
  • Clamp lower-layer bitrate only when the layer does not actually downscale resolution.
  • Use the larger output dimension when computing simulcast scale-down values.
  • Add coverage for clamp behavior, ladder length, unchanged presets, priority preservation, and computed encodings.

Testing

  • git diff --check main...HEAD
  • flutter test test/utils_test.dart
  • flutter analyze --no-pub lib/src/utils.dart test/utils_test.dart

@hiroshihorie
fix simulcast lower layer clamps
d53eeff
@hiroshihorie
refactor simulcast preset computation
1fd294b
@hiroshihorie
test: cover full-clamp, ladder length, happy path, priorities
1646229 
Ports the four SimulcastPresetsTests cases that were missing from the
initial port: same-resolution full clamp, parameterized ladder length
over the < 480 / [480, 960) / >= 960 cutoffs, no-overshoot pass-through,
and priority forwarding through the clamp.
@hiroshihorie
guard empty preset list in computeSimulcastPresets
f36c403 
Mirrors the Swift guard let lowPreset = presets.first else { return
[baseParameters] } fallback. Unreachable from current call sites since
both default ladders return >= 1 entry, but keeps the function safe
against future callers passing an empty requestedPresets with a default
that could collapse to empty.
@hiroshihorie
align encodingsFromPresets scaleDownBy with clamp helper
b95f066 
Use max/max (preset's larger dimension vs output's larger dimension) to
match the Swift Dimensions.encodings(from:) helper and the new
_clampSimulcastPreset's scaleDownBy calculation. Equivalent for
matching-aspect presets, only differs when a caller mixes a
non-matching-aspect preset with the output dimensions.
@hiroshihorie
Merge branch 'main' into hiroshi/clamp-simulcast-layers
de04492
@hiroshihorie hiroshihorie changed the title Hiroshi/clamp simulcast layers Clamp simulcast layers May 18, 2026
@hiroshihorie hiroshihorie marked this pull request as ready for review May 19, 2026 10:49
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@cloudwebrtc cloudwebrtc cloudwebrtc approved these changes

@xianshijing-lk xianshijing-lk Awaiting requested review from xianshijing-lk xianshijing-lk is a code owner

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@hiroshihorie @cloudwebrtc