[FFmpeg-user] Fw: Mixing wav audio and mp4 video

[Zack Thevenot]

I am having trouble mixing a WAV audio file and an audio-less MP4 video file.  I am using this command to mix WAV with AVI and WMA files, but it does not work with MP4 files:
ffmpeg -i file1.mp4 -i file2.wav -c copy -map 0:0 -map 1:0 output.mp4 -y -report

The log file gives this error:

"Could not write header for output file #0 (incorrect codec parameters ?): Invalid data found when processing input"

I have experimented with many different codecs to fix this, but to no avail. Perhaps the input files I am using are the problem instead?  

Please let me know how I can accomplish this.