FFmpeg output file format with no extension

Question

I'm developing a system which needs to store videos in the form:

/path/to/video/<md5 of the file>

So I do not have an output extension. I'm using ffmpeg to convert those videos, but it seems that it uses output file extension to determine the output format, so here's my problem.

Due to the fact I don't have an output extension in file names, is there a way to specify the output format directly in the command line without create temporary files or dirty solutions like this ?

Solution

Use the -f parameter to tell ffmpeg which output-format to use. E.g

ffmpeg -i input.mpg ... -f mp4 output.mp4