frame_tracker.cpp.hpp

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#include "fl/video/frame_tracker.h"
#include "fl/stl/int.h"
#include "fl/math/math.h"
#include "fl/stl/noexcept.h"
 
namespace fl {
namespace video {
 
FrameTracker::FrameTracker(float fps) FL_NO_EXCEPT {
    // Convert fps to microseconds per frame interval
    mMicrosSecondsPerInterval = static_cast<fl::u32>(1000000.0f / fps + .5f);
}
 
void FrameTracker::get_interval_frames(fl::u32 now, fl::u32 *frameNumber,
                                       fl::u32 *nextFrameNumber,
                                       u8 *amountOfNextFrame) const FL_NO_EXCEPT {
    // Account for any pause time
    fl::u32 effectiveTime = now;
 
    // Convert milliseconds to microseconds for precise calculation
    fl::u64 microseconds = static_cast<fl::u64>(effectiveTime) * 1000ULL;
 
    // Calculate frame number with proper rounding
    *frameNumber = microseconds / mMicrosSecondsPerInterval;
    *nextFrameNumber = *frameNumber + 1;
 
    // Calculate interpolation amount if requested
    if (amountOfNextFrame != nullptr) {
        fl::u64 frame1_start =
            static_cast<fl::u64>(*frameNumber) * mMicrosSecondsPerInterval;
        fl::u64 frame2_start =
            static_cast<fl::u64>(*nextFrameNumber) * mMicrosSecondsPerInterval;
        fl::u32 rel_time = microseconds - frame1_start;
        fl::u32 frame_duration = frame2_start - frame1_start;
        u8 progress = map_range<fl::u32, u8>(rel_time, 0, frame_duration, 0, 255);
        *amountOfNextFrame = progress;
    }
}
 
fl::u32 FrameTracker::get_exact_timestamp_ms(fl::u32 frameNumber) const FL_NO_EXCEPT {
    fl::u64 microseconds =
        static_cast<fl::u64>(frameNumber) * mMicrosSecondsPerInterval;
    return static_cast<fl::u32>(microseconds / 1000) + mStartTime;
}
 
} // namespace video
} // namespace fl