Trouble converting AVI file to MP4 with Handbrake

What HandBrake version are you using with what presets and on what Mac OS X version?
In order to find out, what may be wrong with your videos, you can use one of the following three applications to analyse a sample .avi video file.

• VideoSpec (free)
• MediaInfo (free)
• Media Inspector (2.99 USD € in the Mac App Store (MAS))

When done, you can use the "Report" (VideoSpec) and "Export" (Media Inspector) button to export a report,
attachable to your next post via the button.
In MediaInfo you have to go to the Menu Bar, select View > Text and copy the text via CMD+A > CMD+C and paste it via CMD+V into your next post.​

 

Or MPEGStreamclip.