riff: retry reading metadata without padding if it fails with

Fixes Ticket1821

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit d0c27e88d2bb495d61bd32f41769f767a0c2a802)
riff: ignore ff_read_riff_info() failure.

Some files simply contain invalid info tags.
Fixes unrelated bug posted into Ticket1821

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 09456d0df13404f004ab3a341d9ac21b7e5e6d6d)
avidec: try to support oddly muxed MMES stream

Fixes ticket1804

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit be89693ddc5a8cdeaf3edf48fb584d6adca54de0)
lavc/ass_split: check for NULL pointer in ff_ass_split_override_codes().

This is consistent with the other ff_ass_split_* functions.

It also fixes a crash when trying to split a dialog with text=NULL
(which seems to happen when the text of the dialog is empty); basically,
this commit fixes crashes when trying to encode an empty text subtitle
dialog (see subrip and mov_text encoders).

Fixes Ticket2048.
(cherry picked from commit c83002a4f8042ccfa0688a9a18e8fa0369c1fda8)
tiffdec: Use the correct height field.

Fixes Ticket913

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 4784a135b2b0fe4d1b4c6256bd37265fc45aed3d)

Conflicts:
	libavcodec/tiff.c