Merge remote-tracking branch 'qatar/master'

* qatar/master:
  movenc: Write chan atom for all audio tracks in mov mode movies.
  mpegtsenc: use avio_open_dyn_buf(), zero pointers after freeing
  doc/avconv: add some details about the transcoding process.
  avidec: make scale and rate unsigned.
  avconv: check output stream recording time before each frame returned from filters
  avconv: split selecting input file out of transcode().
  avconv: split checking for active outputs out of transcode().
  avfiltergraph: make some functions static.

Conflicts:
	ffmpeg.c
	libavfilter/avfiltergraph.c
	libavfilter/internal.h
	libavformat/mpegtsenc.c
	tests/ref/fate/acodec-alac
	tests/ref/fate/acodec-pcm-s16be
	tests/ref/fate/acodec-pcm-s24be
	tests/ref/fate/acodec-pcm-s32be
	tests/ref/fate/acodec-pcm-s8
	tests/ref/lavf/mov

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