You need to show us the exact command you are using. "It doesn't work" is not enough information to diagnose problems with something is wildly complex as ffmpeg
. Also, if possible, linking to the resulting media file would help too.
The resulting media, if successfully encoded, must have an audio and video bit-rate. The problem very well my be with the tools you are using to read the file.
Update!
It looks to me like you forgot the units on the -b
parameter. Try this:
ffmpeg -i 'in.wmv' -s 1280x720 -b 256k -ar 44100 -ab 64k -ac 2 'output.mp4'
Note how the -b
switch value has a k
on it.
Also, I've just got to say, the size 1280x720 is awfully large for such a low bit-rate. I would highly recommend a size either 1/2 or 1/3 of 1280x720, or increasing the video bit-rate to 512k or 768k. You are not going to get what you think you are going to get with such values.