mpeg2gif

#!/bin/sh
# Convert mp4 video to animation GIF.
# Requirement: ffmpeg

if [ -z "$1" ]; then
  (
  echo "Usage: $(basename $0) video-file.mp4 [extra-options]

Convert mp4 video to animation GIF.
i.e: if ~/Downloads/video-file.mp4 was passed, ~/Downloads/video-file.gif was generated.

To change/add ffmpeg options, just append any options you want after the video filename.
"
  ) >&2
  exit
fi
input="$1"
shift
opts="$@"

if [ -z "$( echo "$opts" | grep -- '-r ')" ];then
   opts="$opts -r 10"
fi
if [ -z "$( echo "$opts" | grep -- 'scale= ')" ];then
   opts="$opts -vf scale=320:-1"
fi

output=$(echo "$input" | sed 's/\.[^\.]*$//').gif

#echo ffmpeg -i "$input" $opts "$output"
ffmpeg -i "$input" $opts "$output"

ソースコードを https://github.com/ecoopnet/smartphone-development-tools に移植しました。
今後の更新は上記リポジトリを参照してください。