Support for multiple audio tracks in video

[parth-07]

If a video have multiple audio tracks , users should be able to switch between different audio tracks .

[manorit2001]

This was completed in 48ba41d

• 2ae9086 Initial commit referencing this issue
• cacb5f6 bug fixes
• 48ba41d introduces default stream selection flag

[manorit2001]

html5-multiple-audio-tracks
with this, maybe we can let users dynamically select the audio tracks on the go from the frontend only

We will just need to put all the audio tracks from the original video file into the converted video file with proper codec, then this can be used to select languages of audio tracks