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Commit 85b3f01b authored by Ady Abraham's avatar Ady Abraham
Browse files

SurfaceFlinger: better fit content to refresh rate 

Enhance the current algorithm for content based refresh rate selection
to choose a refresh rate that aligns better to the content. If no refresh
rate fits to the content we choose the lower one.

Fixes: 129874336
Test: Swappy render at 90fps, 45fps, 30fps
Test: Youtube video playback on 24fps, 25fps, 30fps, and 60fps
Change-Id: Ia6b1f2a1d78e257e0de99ba12c14ca3721b4ad26
parent 8f1ee7fd

services/surfaceflinger/Scheduler/Scheduler.cpp

+19 −8
Original line number Diff line number Diff line
@@ -405,23 +405,34 @@ Scheduler::RefreshRateType Scheduler::calculateRefreshRateType() { 
    }



    // Content detection is on, find the appropriate refresh rate

    // Start with the smallest refresh rate which is greater than the content

    // Start with the smallest refresh rate which is within a margin of the content

    RefreshRateType currRefreshRateType = RefreshRateType::PERFORMANCE;

    constexpr float MARGIN = 0.05f;

    auto iter = mRefreshRateConfigs.getRefreshRates().cbegin();

    RefreshRateType currRefreshRateType = iter->first;

    while (iter != mRefreshRateConfigs.getRefreshRates().cend()) {

        if (iter->second->fps >= mContentRefreshRate) {

        if (iter->second->fps >= mContentRefreshRate * (1 - MARGIN)) {

            currRefreshRateType = iter->first;

            break;

        }

        ++iter;

    }



    if (iter == mRefreshRateConfigs.getRefreshRates().cend()) {

        return RefreshRateType::PERFORMANCE;

    }

    // Some content aligns better on higher refresh rate. For example for 45fps we should choose

    // 90Hz config. However we should still prefer a lower refresh rate if the content doesn't

    // align well with both

    float ratio = mRefreshRateConfigs.getRefreshRate(currRefreshRateType)->fps /

            float(mContentRefreshRate);

    if (std::abs(std::round(ratio) - ratio) > MARGIN) {

        while (iter != mRefreshRateConfigs.getRefreshRates().cend()) {

            ratio = iter->second->fps / float(mContentRefreshRate);



    // TODO(b/129874336): This logic is sub-optimal for content refresh rate that aligns better

    // with a higher refresh rate. For example for 45fps we should choose 90Hz config.

            if (std::abs(std::round(ratio) - ratio) <= MARGIN) {

                currRefreshRateType = iter->first;

                break;

            }

            ++iter;

        }

    }



    return currRefreshRateType;

}