[FFmpeg-user] multiple outputs

[Nisar Ahmed]

I am using ffmpeg to produce a. mp4 audio/video and b. mp3 audio only
files. I am using libmp3lame as audio codec but it seems that Windows Media
Player 12 isn't playing audio but Quicktime and VLC does. I was thinking of
changing audio codec to AAC but don't know how is it going to impact the
mp3 encoding.

Does specifying file format means that ffmpeg will pick the appropriate
encoding itself or do we have to specify explicitly for each output,
currently I am only specifying it once.

Following is the illustration of my ffmpeg command.

ffmpeg -i input -vcodec x264 -acodec libmp3lame output1.mp4 output2.mp3

I am thinking of changing it to

ffmpeg -i input -vcodec x264 -acodec aac output1.mp4 output.mp3