Twitch MSE Replay — content → ad handoff in a single SourceBuffer

Replays the captured content SourceBuffer, then — without tearing down the <video> / MediaSource (i.e. without the Twitch JS cascade) — appends the ad-2 segments using sb.changeType(). Tests the intrinsic MSE content→ad handoff behavior. Compare Safari vs Chrome: does playback stall? does waiting fire? does playback resume when ad data lands?

content codec: ad codec:

idle

Default behavior: content appends in full (~8 min real-time duration if played), then the ad is appended in the same SourceBuffer after changeType(). Use "Append ad NOW" to fast-forward and trigger the handoff immediately for quicker iteration (skips remaining content appends).