On Tue, Mar 09, 2010 at 06:01:01PM -0200, Sebasti?n Lacuesta wrote: > if I use -af lavcresample=8000 instead of -srate 8000, then I have the > following error: > [libopencore_amrnb @ 0x18ee010]Only 8000Hz sample rate supported You could try them both, but that alone seems to indicate that mencoder is broken when resampling is involved.