The SCC Writer supports a start_tc parameter that offsets all output timestamps by a given timecode, e.g. 01:00:00;00, to avoid negative times when events start at t=0s (see #473/#474). However, the SCC Reader has no corresponding parameter to reverse this offset when reading such files back.
Without this, reading an SCC file produced with start_tc applied means that all timestamps are shifted forward by the offset, breaking round-trips (e.g. TTML --> SCC --> TTML ) and producing incorrect output when the reader is used downstream.
Propose to add an equivalent start_tc parameter to SccReaderConfiguration that subtracts the specified timecode from all parsed timestamps, matching the inverse of the writer's behavior.
The SCC Writer supports a
start_tcparameter that offsets all output timestamps by a given timecode, e.g. 01:00:00;00, to avoid negative times when events start at t=0s (see #473/#474). However, the SCC Reader has no corresponding parameter to reverse this offset when reading such files back.Without this, reading an SCC file produced with
start_tcapplied means that all timestamps are shifted forward by the offset, breaking round-trips (e.g. TTML --> SCC --> TTML ) and producing incorrect output when the reader is used downstream.Propose to add an equivalent
start_tcparameter toSccReaderConfigurationthat subtracts the specified timecode from all parsed timestamps, matching the inverse of the writer's behavior.