how to add text watermark and convert video to 3gp with FFMPEG?

how to add text watermark and convert a video flv开发者_开发知识库 to 3gp with FFMPEG?

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Below is the code to convert flv to 3gp:

ffmpeg -i input.flv -s 176x144 -vcodec h263 -r 15 -b 200 -ab 12.8 -acodec amr_nb -ar 8000 output.3gp