How do I enable FFMPEG logging and where can I find the FFMPEG log file?

I found the below stuff in ffmpeg Docs. Hope this helps! :)

Reference: http://ffmpeg.org/ffmpeg.html#toc-Generic-options

‘-report’ Dump full command line and console output to a file named program-YYYYMMDD-HHMMSS.log in the current directory. This file can be useful for bug reports. It also implies -loglevel verbose.

Note: setting the environment variable FFREPORT to any value has the same effect.

FFmpeg does not write to a specific log file, but rather sends its output to standard error. To capture that, you need to either

• capture and parse it as it is generated
• redirect standard error to a file and read that afterward the process is finished

Example for std error redirection:

ffmpeg -i myinput.avi {a-bunch-of-important-params} out.flv 2> /path/to/out.txt

Once the process is done, you can inspect out.txt.

It's a bit trickier to do the first option, but it is possible. (I've done it myself. So have others. Have a look around SO and the net for details.)