Fix pgc compilation with --disable-optimizations.

-O1 disables dead code elimination on pgc, use -O instead.
Merge remote-tracking branch 'cehoyos/master'

* cehoyos/master:
  Fix pgc compilation with --disable-optimizations.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Fix libswscale compilation with --disable-optimizations on x86-32.

Fixes ticket #2477.
cmdutils: make the "-help filter=" output less confusing

Example:
Filter overlay
  Overlay a video source on top of the input.
    Inputs:
       #0: main (video)
       #1: overlay (video)
    Outputs:
       #0: default (video)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavf/gif: simplify streams type checking.
lavf/gif: remove unused fields.
lavf/gif: trim unnecessarily long netscape ext code.

Extension description comments are now placed along the avio calls, the
always defined macro removed, and the always true loop_count check as
well (loop option is bound to 0-65535).
lavf/gif: merge gif_write_{packet,video}.

Avoid a pointless split.
lavf/gif: support only GIF codec.
lavc/gif: avoid encoding 0x0 images.

It seems browsers don't like it very much.
evrcdec: use memmove() instead of memcpy() when regions can overlap.

This occurs also with valid files.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavu: add av_clipd_c

Signed-off-by: Paul B Mahol <onemda@gmail.com>
examples/filtering_audio: fix frame leak.

The frame is not used after being added to the filter
graph, there is no need to keep the reference.
colorbalance filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>
colorchannelmixer filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>
svq3: use memmove to avoid overlap in memcpy.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/mpegvideo_motion: Check P field references

If a reference is unavailable use a field from the current
picture
Fixes null pointer dereference

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'cigaes/master'

* cigaes/master:
  examples/filtering_audio: fix frame leak.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
lavfi/vf_aspect: improve compatibility of parsing.

Try to accept both the old "num:den" and the new "num/den"
syntax. Fix "aspect=2" being ignored due to a missing den.

Also remove a duplicated #include.
ffmpeg: make -aspect work with -vcodec copy.