avformat/libmodplug: Reduce the probe score for small input

This ensures that theres enough data for mpeg_probe() to recognize mpeg-ps
Fixes Ticket2583

Based on code by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit c605adbf562fbf535e83ae427bb681bc45e440c8)
rmdec: Pass AVIOContext to rm_read_metadata()

Fix null pointer dereference
Fixes Ticket2588

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit bf87908cd8da31e8f8fe75c06577170928ea70a8)

Conflicts:
	libavformat/rmdec.c
mpegts: only reopen pmt_cb filter if its different from the previous.

Fixes Ticket2632

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit b009267910df10c004b5f340a090d45da29089a0)
mpeg12dec: avoid reinitialization on PS changes when possible.

Fixes Ticket2574

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 970c8df73528659925819dec31c4c8c0887f0321)

Conflicts:
	libavcodec/mpeg12dec.c