lavf: Set the stream time base hint properly for chained muxers

This avoids warnings about using the codec time base as time
base hint.

Signed-off-by: Martin Storsjö <martin@martin.st>
Merge commit '28816050e47b6dba430a52e429d21a864cffda8e'

* commit '28816050e47b6dba430a52e429d21a864cffda8e':
  lavf: Set the stream time base hint properly for chained muxers

Conflicts:
	libavformat/segment.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avformat/mxfdec: read reel_name and source timecode from physical source package

Reviewed-by: Tomas Härdin <tomas.hardin@codemill.se>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/avpacket: simplify freeing pkt->data

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/avpacket: use av_freep(), do not leave stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/proresenc_kostya: use av_freep(), do not leave stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/escape124: use av_freep(), do not leave stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/hls: use av_freep(), do not leave stale pointers in memory

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