Resolving VideoToolbox kVTInvalidSessionErr (-12903) and encoder deadlocks during iOS background transitions. Covers hardware reclamation, IDR keyframe recovery, PTS deduplication, and flush timing pitfalls.
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A comprehensive engineering journey optimizing a mobile video export pipeline from 60s+ down to under 2 seconds with zero-copy encoding. Deep dives into x264 tuning, GPU shader color space conversion, mobile PBO pitfalls, CoreVideo shared memory mapping, and VideoToolbox hardware acceleration.