estimate_timings_from_pts: Warn about A/V streams for which no duration could be set

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
estimate_timings_from_pts: Also consider packet duration

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
estimate_timings_from_pts: simplify filesize end check

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
estimate_timings_from_pts: Try to get the duration for all streams

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
estimate_timings_from_pts: Execute max 1 iteration extra to find more than 1 duration

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>