An AVFormatContext leaks on errors that happen before it is attached
to its permanent place (an InputFile). Fix this by attaching
it earlier.
Given that it is not documented that avformat_close_input() is usable
with an AVFormatContext that has only been allocated with
avformat_alloc_context() and not opened with avformat_open_input(),
one error path before avformat_open_input() had to be treated
specially: It uses avformat_free_context().
Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Andreas Rheinhardt