This is mostly automated global search and replace

The deprecated aconvert filter is disabled, if it still has users
it should be updated

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

Inside send_silence(), delta_ts was used inconsistently:
sometimes as the new value, sometimes as the old value.

Consistently use it as the new value, and add an argument
to know the last segment duration.

Reviewed-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

This is following 568c70e7.

Based on patch by Anton Khirnov
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Also remove it in once case when it is not needed.

Signed-off-by: Paul B Mahol <onemda@gmail.com>

The invalid test did not cause any actual problem since
the first branch is only possible with bogus filters.

Fix coverity issue CID 733850.

This allows the iteration callbacks to discover the internal class and
options, and show them when required.

concat_in.pts starts at 0 for each segment, so the duration
of the silence was too long, except at the first stitch.