FFmpeg

Merge pull request #1 from sandvige/copilot/add-raw-video-ts-demuxer

Fix bit_rate calculation and optimize default duration computation

Address final code review: replace recursion with loop, improve PTS validation, add VFR bitrate comment

Address code review feedback: fix bit_rate calculation, error handling, and add CONFIG guard

Fix duration calculation in rawvideo_ts demuxer using packet buffering