assumeOnlyFirstVideoSampleIsSyncFrame

Treats only the first video sample in each fragmented MP4 fragment as a possible sync frame.

Enable this only for streams that incorrectly mark dependent video samples as sync frames. The first sample of each fragment must contain a usable random-access frame. Later genuine sync frames will not be used for seeking. Applies to fragmented MP4 DASH and HLS sources, including ads. Progressive sources ignore this tweak to preserve seeking. SmoothStreaming already uses this workaround by default.

Default: false.