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What's the big deal about DTS on IOS?


horstepipe
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Hello

I was just looking again into the IOS app and it feels really nice. Libmpv does a very good job about the video, but for most of my movies I don't have audio because of the lack of DTS capability. So I cannot/do not want to transcode (not even the audio) serverside, but there shouldn't be the need of it anyway. Playing the same files within VLC on IOS works fine (video AND audio). So why is Emby not able to do the same? I'd really like to understand what reasons prevent you from a simple "downmix to stereo on the device" or whatever option. I can't imagine it's about licencing, as VLC is a free product. So what's the point?

Generally spoken, if the client is able to handle stuff, the server shouldn't be burdened with that unnecessary task imo.

Best regards and stay healthy!

Edited by horstepipe
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libmpv supports it but to use it on iOS would require special licensing, so that's essentially the hold up there.

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Thanks,

so vlc e.g. doesn't have to pay for this special licensing as it is non commercial software against to yours? Or how do they do it? ūüôā

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Or is the key difference that your product is proprietary? I'm just curious about those backgrounds. Guess an additional in-app purchase "codec pack" isn't an option?

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  • 2 months later...

@cayars

you seem to be a more communicative team member ūüôā

would you please mind to spend some more words on this (if possible)? So basically:
- why is Emby the only player which is not capable of playing dts tracks on IOS and TVOS?

- can we expect a change in a medium term?

 

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On 11/06/2020 at 12:35, horstepipe said:

Generally spoken, if the client is able to handle stuff, the server shouldn't be burdened with that unnecessary task imo.

I won't comment on the core of this issue, but would just say that the transcoding of audio is trivial in comparison with handling video.  It is not in any way a "burden" to the server.  In any case, servers don't care about "a burden" that doesn't actually overload them.

Paul

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10 hours ago, horstepipe said:

@cayars

you seem to be a more communicative team member ūüôā

would you please mind to spend some more words on this (if possible)? So basically:
- why is Emby the only player which is not capable of playing dts tracks on IOS and TVOS?

- can we expect a change in a medium term?

 

I don't do any iOS development or anything Apple at all, so I really have no idea except for what's been said. I'll take a "mile high shot" but hope someone correct me if I get this wrong.

From a quick read it seems like iOS doesn't provide DTS support out of the box for apps to use so they need to provide it themselves.  That means they need to license the codecs in any commercial use situation which can get very pricey!

Since the very large amount of time iOS devices are going to play back via built in speaker or headphones you're going to be in a stereo like environment at best and wouldn't really be able to take advantage of what DTS offers for spacial separation.  As Paul mentioned Emby can pretty easily convert the audio on the fly to a different format the device supports "out of the box" so it just makes sense to do this.  This avoids extra codec cost considerations, keep the apps low cost and just shifts the "burder" over to the server which can handle this easily.  So it's WIN, WIN this way.

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28 minutes ago, cayars said:

I don't do any iOS development or anything Apple at all, so I really have no idea except for what's been said. I'll take a "mile high shot" but hope someone correct me if I get this wrong.

From a quick read it seems like iOS doesn't provide DTS support out of the box for apps to use so they need to provide it themselves.  That means they need to license the codecs in any commercial use situation which can get very pricey!

Since the very large amount of time iOS devices are going to play back via built in speaker or headphones you're going to be in a stereo like environment at best and wouldn't really be able to take advantage of what DTS offers for spacial separation.  As Paul mentioned Emby can pretty easily convert the audio on the fly to a different format the device supports "out of the box" so it just makes sense to do this.  This avoids extra codec cost considerations, keep the apps low cost and just shifts the "burder" over to the server which can handle this easily.  So it's WIN, WIN this way.

Sometimes a DTS to AC3 conversion requires a full transcoding, for example I have a lot of VC1 + DTS files. My iPhone can directly play VC1 files, but converting DTS to AAC also converts the video because you can't deliver VC1 using HLS. In these cases a conversion on the client side is advantageous. But that costs money.

In short, if a DTS conversion is required and the video format is not compatible with HLS, a full transcoding will be required.

Edited by vdatanet
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Yes that's very true.  You can also manually add a default 2 channel audio track to these types of files which solves the transcoding problem you mention.

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2 minutes ago, cayars said:

Yes that's very true.  You can also manually add a default 2 channel audio track to these types of files which solves the transcoding problem you mention.

That's also very true, but most users do not have the knowledge to do so.

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There are also problems delivering HEVC + AC3 using HLS. Emby uses MPEGTS and it should be used fMP4, I don't know if that's the reason, but there are a lot of reports of people complaining about green artifacts. In that case, client DTS decoding should be useful. That requires DTS licencing and users should pay for that. Maybe a Premiere feature could be added like "Client DTS decoding".  But I don't know if it is technically and economically viable.

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fMP4 would be nice to have especially on anything Apple. Right now I'd think AVC + AC3 using HLS would be the least problematic but I'm not up on "apple knowledge" like many of you so I'm learning as I go from you guys. :)

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Green artifacts while remuxing HEVC + DTS to HEVC + AC3 are not an specific Apple issue, there a lot of issues in theses forums:

 

Keep in mind that HLS is a protocol developed by Apple.

Edited by vdatanet
changed are for are not specific
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I get your points but that's not what was trying to get at (is that grammar correct lol?).

So I'll try in an exaggerated way:

How can a small company like MrMC, which is being run just as a side job, afford these capabilities/licensing whatever, but Emby can't? For sure there's a quite simple answer on that all parties are fully aware off so I don't get why you try to keep it that secret from your interested users.

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libdca is a free DTS Coherent Acoustics decoder developed by VideoLAN, it's used by ffmpeg and vlc media player. Maybe MrMC people have been able to compile MPV adding support for that library.

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Probably best to ask them how they handle the legal licensing issue unless using passthrough to allow another device that's license to handle the codecs.  I've not followed that project at all so I know less then or equal to anyone else here. :)

PERSONAL OPINION ONLY: can't state that enough but I'm not personally worried about DTS much in my setup these days.  DTS is kind of like DVD at this point and has been trumped by Dolby, sort of like how Bluray trumped DVD discs.  Yes a super simplification but that's just me talking about my own personal media collection and my own personal setup.  I don't see a big future for DTS while Dolby Atmos is taking over. (In my personal world anyway).

Are you seeing the same thing or thinking the same?

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5 minutes ago, cayars said:

Probably best to ask them how they handle the legal licensing issue unless using passthrough to allow another device that's license to handle the codecs.  I've not followed that project at all so I know less then or equal to anyone else here. :)

PERSONAL OPINION ONLY: can't state that enough but I'm not personally worried about DTS much in my setup these days.  DTS is kind of like DVD at this point and has been trumped by Dolby, sort of like how Bluray trumped DVD discs.  Yes a super simplification but that's just me talking about my own personal media collection and my own personal setup.  I don't see a big future for DTS while Dolby Atmos is taking over. (In my personal world anyway).

Are you seeing the same thing or thinking the same?

This summer I've purchased about 20 blu-rays and most of them are like this. So DTS is still alive. I use MakeMKV don't want to convert anything.

1619751180_Anotacin2020-08-21105248.thumb.jpg.3e0d99c0957fe56494e6bf29016bc2ad.jpg

Edited by vdatanet
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51 minutes ago, cayars said:

...unless using passthrough to allow another device that's license to handle the codecs.

TVOS doesn't allow passthrough at all anymore for any app so that's definitely not the reason.

 

Quote

Are you seeing the same thing or thinking the same?

nope, I'm with vdatanet. Current and upcoming (german) bluray releases mostly have a dts track.
Thanks for participating guys!

Edited by horstepipe
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11 minutes ago, horstepipe said:

nope, I'm with vdatanet. Current and upcoming (german) bluray releases mostly have a dts track.

Can you not easily add another audio track if needed to your media?

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6 minutes ago, cayars said:

Can you not easily add another audio track if needed to your media?

Sure, but I spend pretty much $ in hifi equipment so I don't aim to get lower bit rates or any other downsides. Besides that, I can simply stay with MrMC or Kodi (sideloaded). I'd prefer the official Emby client because the UI is amazing, but this is a show stopper for me personaly.

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  • 8 months later...
On 8/20/2020 at 1:08 AM, horstepipe said:

@cayars

you seem to be a more communicative team member ūüôā

would you please mind to spend some more words on this (if possible)? So basically:
- why is Emby the only player which is not capable of playing dts tracks on IOS and TVOS?

- can we expect a change in a medium term?

 

Regarding macOS: 

 

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  • 1 month later...
On 5/10/2021 at 5:51 AM, Luke said:

Regarding macOS: 

 

 

So.. the macos Emby app, how similar is it to the tvos/ios one? Does it also use mpv? In other words, is this some little progress getting dts support on tvos?

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