Do I need to keep the AC3 track if I am keeping a DTS, DTS-HD MA, TrueHD?

[MarioVideo]

Hello,

I am trying to reduce my movie library size and have always kept all English AC3, DTS, DTS-HD MA, TrueHD and Atmos tracks, but I think I can save space by just keeping the best quality track as I believe they will play in receivers that don't have DTS, DTS-HD MA, TrueHD and Atmos capability. I read somewhere that they have the AC3 inof built in or they will play in receivers without DTS. Is this the case? Can I safely save space by omitting the AC3 tracks?

[pandy]

Did you ever compared for example AC3 and DTS or DTS-HD MA and TrueHD? If there is no significant difference in terms of content then i would keep smaller version of audio (so AC3 over DTS) .

[johns0]

That pertains to authored dvd/blu-ray where ac3 are kept to keep disc playable in most settings,if for just mkv/mp4 playback then just use the best audio your receiver can play

[jagabo]

just use the best audio your receiver can play

And hope you next one supports it too. And the next one. And the next one...

[johns0]

Op can always make an ac3 from the audio he keeps if ever needed.

[MarioVideo]

Thank for the responses! They are very much appreciated! johns0 makes a good point of being able to create another audio from the lossless source, which you cannot do the other way around. I can tell the difference being an ex-audio engineer. Not only is the quality better but there are less artifacts.

[Ennio]

If preserving 3D audio is important to you, I don't think audioformats like Dolby Atmos and DTS:X can be recoded while keeping trajectory data and target audio packets. At least not with freeware.
When encoding with a "lossy" codec, you may want to consider using EAC3. In my experience it sounds better than AC3 at equal bitrate. And which for EAC3 isn't limited to 640 kbps.