Fixes #893.
Configurable with --transport_stream_offset_ms. This is needed to compensate for possible negative timestamps in inputs, which could happen on ISO-BMFF with EditLists. Issue #112. Change-Id: I0fce8766c9df2911b9bb859c1e54052a8ed2abfb
Issue: #342. Change-Id: Iaa890450615573da84b8934b2ba3ee3602d6fb74