avcodec/hnm4video: remove redundant log message

Signed-off-by: Paul B Mahol <onemda@gmail.com>
avcodec/libfdk-aacdec: remove redundant log messages

Signed-off-by: Paul B Mahol <onemda@gmail.com>
avfilter/af_aecho: free input frame after it is being used

Signed-off-by: Paul B Mahol <onemda@gmail.com>
avformat/image2: allow muxing gif files.

Fixes Ticket #2936.
avformat/img2enc: reindent after previous commit.
avformat/gif: fix final_delay unit in documentation.
doc/muxers: document animated GIF muxer.
avformat/img2enc: simplify split planes extension selection.
avformat/mpegvideodec: check seq headers more completely during probing

Fixes probetest failure

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