VPAAMP-667: Live-edge ABR ramp-up bypass for buffer-deadlock recovery#1706
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VPAAMP-667: Live-edge ABR ramp-up bypass for buffer-deadlock recovery#1706pstroffolino wants to merge 1 commit into
pstroffolino wants to merge 1 commit into
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Add an else-if branch in GetDesiredProfileOnSteadyState() that allows ABR ramp-up when the player is at the live point and the buffer is in the deadlock band (above mABRMinBuffer but at or below mABRMaxBuffer). Previously, after curl timeouts dropped the profile to index 0, the buffer would stabilise at ~6-9s during standard-latency live. The live edge means downloads arrive at approximately the same rate they are consumed, so the buffer could never grow above the 10s mABRMaxBuffer gate required for ramp-up. For LLDASH the same structural deadlock exists because the steady-state ramp-up path is skipped by the !lowLatencyMode guard. The new branch uses the same patience counter (mABRHighBufferCounter / mMaxBufferCountCheck) and the same CheckRampupFromSteadyState 30% headroom rule as the existing high-buffer path. VOD playback is unaffected (mIsAtLivePoint == false). Both LLDASH and standard-latency live benefit. Unit tests: 7 new test cases covering the bypass firing in the deadlock band, LLDASH deadlock band, patience counter, counter reset on ramp-down, and negative cases (not at live point, buffer below min, buffer above max). Test infrastructure: FakeABR.cpp getRampedUpProfileIndex and CheckRampupFromSteadyState now delegate to g_mockABRManager when available. MockABRManager.h gains a CheckRampupFromSteadyState mock.
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Add an else-if branch in GetDesiredProfileOnSteadyState() that allows ABR ramp-up when the player is at the live point and the buffer is in the deadlock band (above mABRMinBuffer but at or below mABRMaxBuffer).
Previously, after curl timeouts dropped the profile to index 0, the buffer would stabilise at ~6-9s during standard-latency live. The live edge means downloads arrive at approximately the same rate they are consumed, so the buffer could never grow above the 10s mABRMaxBuffer gate required for ramp-up. For LLDASH the same structural deadlock exists because the steady-state ramp-up path is skipped by the !lowLatencyMode guard.
The new branch uses the same patience counter (mABRHighBufferCounter / mMaxBufferCountCheck) and the same CheckRampupFromSteadyState 30% headroom rule as the existing high-buffer path. VOD playback is unaffected (mIsAtLivePoint == false). Both LLDASH and standard-latency live benefit.
Unit tests: 7 new test cases covering the bypass firing in the deadlock band, LLDASH deadlock band, patience counter, counter reset on ramp-down, and negative cases (not at live point, buffer below min, buffer above max).
Test infrastructure: FakeABR.cpp getRampedUpProfileIndex and CheckRampupFromSteadyState now delegate to g_mockABRManager when available. MockABRManager.h gains a CheckRampupFromSteadyState mock.