Video files can contain more than just video, they usually have some kind of audio too, and sometimes subtitles or other data as well. Video processing is not an easy task, but one thing is certainly easier about it than about audio: there’s almost always just one video stream to worry about, but there can be multiple audio streams. Good, old stereo means having two audio streams, and nowadays we’ve gone much further than just two. We often have a small platoon of speakers around our couch, and each one of them might get its own audio stream.
A single container format (like MP4, MKV or AVI) can contain multiple audio streams. When transcoded, these streams can be left as they are, but sometimes you may need to map them to different speakers, merge or duplicate, even add muted streams. All these things have always been possible in Panda through raw FFmpeg commands, but recently we’ve decided to make it bit simpler.
Now you can decide if Panda should merge audio streams, with a single checkbox. The default behavior is to leave the streams mapping untouched. However, if you want to merge – Panda will intelligently pack them as audio channels into a single stream – 2 input streams will be packed as one stereo stream, 6 streams as one 5.1 surround streams, and so on.
Let us know if you have any questions.