Backstory: Basically I've set up my RasPi to run Plex Media Server. It works really great and using basically no power while I can still directplay/stream from it while away from home. Now, the dilemma is that the RasPi does not manage to play MKV files in the plex web app. Also AC3 audio does not work in any browser except for Microsoft Edge (for unknown reasons), so the issue I'm facing is a lot of file conversion into MP4 files with AAC audio and moov atom at beginning of file.
Now, to ease things up, using Sickbeard Mp4 Automator, converting MKV to MP4 is a breeze, I plug in the external HDD I use with the RasPi to my computer, boot into Ubuntu (to read file formats and support for a lot of other amazing tools) and run the manual script. Now, as you can imagine, it goes a lot faster to simply change file containers and contain the audio/video codec if it matches the RasPi requirements.
So, what I need is to search (I assume scan would be the better word) for all files in my media folder that have an
.mkv extension and contain an audio stream with AAC audio. Being able to scan for other such properties would be great as well (like video codec, x264/h264). This is simply to be able to pick the files that I know will only require container switching so I can do them first and schedule the other batch operations for better times. It kinda sucks having to stop using my media library when I'm at home because I was stupid and started randomly converting video files.