How can I convert a wav file to an flv, resampling to a rate of 11kHz, and encoded with speex?
Is it possible?
Yes, you can do it using ffmpeg. Speex is in the list of ffmpeg's supported audio codecs. You will need to compile ffmpeg with --enable-libspeex added to the configure flags, or you can try finding a precompiled version that has libspeex support added.
Ffmpeg builds are available at zeranoe.com, and this is their latest build for windows (it has speex support).
Your command line should be something like this:
ffmpeg -i myinputfile.wav -acodec libspeex -ar 11025 myoutputfile.flv