demux_lavf: set duration to -1 if unknown

`demux->duration` is set to -1 on initialization, and some checks rely
on it being -1 when unknown. Before this commit, we set
`demux->duration` to 0 when unknown. This is incorrect and breaks rtsp
logic for disabling seeking outside of cached regions.

To fix these issues, initialize `total_duration` and `av_duration` at
-1. They're only changed if a real duration is detected, so in cases
where the duration is unknown, demux->duration is set to -1 correctly.

Fixes: e6afc53e7c ("demux_lavf: get total duration from track durations")

0 files changed, 0 insertions, 0 deletions