lavf/segment: add segment_format_options option
doc/muxers/segment: reword text for examples, improve consistency
avcodec/mpegvideo: free_context_frame() cannot fail, make it return void

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo: Use "goto fail" for all error paths in ff_mpv_common_frame_size_change()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo: check that the context is initialized in ff_mpv_common_frame_size_change()

The function otherwise would initialize the context without setting context_initialized
alternatively we could set context_initialized

Fixes valgrind anomalies related to ticket 3928

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo: Set err on failure in ff_mpv_common_frame_size_change()

Found-by: ubitux
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/m4vdec: Check for non startcode 00 00 00 sequences in probe

Fixes miss detection of PCM as m4v
Fixes Ticket 3928

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
doc/filters.texi: improve the wording of the expr_int_format documentation

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