tsdemux: Better handle PCR<=>PTS conversion (big difference, latency, ...)

Submitted by Marc-André Lureau @elmarco

Link to original bug (#608148)

Description

Created attachment 152305
a segment

Yacast provides apple http live streaming streams, but the segments are not playable with ffdec_h264 (using 0.10.8.2)

ffmpeg can play it fine :)

(original "live" playlist http://stream7.nrj.yacast.net/iphone/nrj/nrjtp/nrj_tvparis_300.m3u8)

segment attached

Attachment 152305, "a segment":
seq_nrj_tvparis_300-113780.ts