avformat/mpeg: increase score for short mpeg-ps by 1

Fixes Ticket 3855

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 5109ce2017c15202275b33bce58ec9d88044eeb5)

Conflicts:
	libavformat/mpeg.c
avformat/mp3dec: Improve seeking frame sync code

Fixes Ticket3884

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 1b5ccae0f2045ac86bc9e1257cec1b3fba81315f)
avformat/matroskadec: do not trust the default duration to be the real 1/timebase if its less than 5fps

Fixes Ticket3980

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit be695ee389724d713e1b8a61ef899fe1795193ce)
Move get_avc_nalsize() and find_start_code() to h264.h

This allows sharing them with the h264 parser

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 4898440f6bd19152373969159fff057b532c6374)

Conflicts:

	libavcodec/h264.c
	libavcodec/h264.h
avcodec/h264: simplify find_start_code()

this also uses avpriv_find_start_code(), though no speed change is expected as
the area searched is generally small

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 3b678da5e386c138316954e867d595f946666051)

Conflicts:

	libavcodec/h264.h
avcodec/h264_parser: rewrite the parse_nal_units() loop logic based on h264.c

Fixes Ticket4011

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 69a9a90d2ef795162074be24e3ad2182a8676af2)

Conflicts:

	libavcodec/h264_parser.c