How to play this video file ?

[wakkavn]

I bought an android box recently, the seller copied some video files in the HDD. I tried to play these file in Windows but no successful, they're only playable by a specific program in the box. I uploaded an example to MEGA, please help me figure out what I'm missing ? Codec, software or these files are encrypted ?
The original extension of the file is .txt. I've changed it to .mkv, but no thumbnail show up.
https://mega.nz/#!cYNVUCwI!jmGgg6w0Ksa7MaBWtTgKpsciTVma6sqr9OlWvOiLlgo

[Baldrick]

Try open it with mediainfo see what it says under video and audio codecs.

[wakkavn]

MediaInfo shows this.
When playing in that specific program, the video's about 5 minutes length. But here it shows an hour.

[poisondeathray]

According to mediainfo, there is no video. It's audio only @ 141MiB - that is 100% of the filesize. Can you confirm the physical size is the same on disk ?

The math is approximately correct 320kbps at 1h1min is about 141MiB . The filesize would be larger if there was video

But you can try VLC, or MPCHC, or potplayer . They have included codecs and should be able to play anything if the file isn't corrupt/damaged

[aedipuss]

doesn't appear to be a valid video file or audio .ac3 file either. your first clue should have been when you received a file that ended with .txt, the other person didn't do something right.

[Budman1]

If you change the extension to ac3 potplayer plays music but of course there is no video in this file.

[wakkavn]

The .txt extension is to hide these files from other media player in the box. The original extension must be something like mkv or mp4... I found a key file in the app's folder. It contains:

"& )! !% ((!##%"s!")%#%(

Is this some kind of encyption file ?
@Budman1: Did the music play fluently on your device ?

[Budman1]

@wakkavn, It sounded like it was slightly garbled, especially the voice of the singer. Player showed the bit rates, etc. of the audio is suspicious. If there is a key that would probably explain why and it is most likely encrypted:

[wakkavn]

I made an backup ".apk" file from the android app. Do you think someone with good knowledge of android can find out method of encryption ?

[Budman1]

Nope:
1. Apps keep their METHOD of encryption a closely guarded secret.
2. You are not supposed to do that anyway.

It's like this method: The start is simple but can be encrypted several ways to mean the same thing and by changing the key each time, many many variations can be created: