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Question about Dts on Xbox One


samwise78

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You can set the in app bitrate setting, although dropping it that low will cause additional transcoding.

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samwise78

You can set the in app bitrate setting, although dropping it that low will cause additional transcoding.

 

Checked in the Emby Theater App on Xbox and was set to Auto.

Setting it manually to 1080p - 60Mbps makes no difference..

Is this a limitation of the NAS when audio remux DTS>AC3 is needed in a high bitrate movie?

Don't notice the same issue when playing back a (different) lower bitrate video with DTS audio and remux is needed although the upload from the NAS is just as slow (between 1-2MB/s)

 

Thanks

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samwise78

Shouldn't it just work on auto though?
I didn't think that the DTS>AC3 remux would affect the transfer speed that significantly..?
If it's expected behaviour then I'll have to remux the audio myself and direct play Blu-Ray rips.
Thanks

 

<Edit>

 

Lowering the bitrate in the app kicks off a full transcode (unwanted) as opposed to a direct stream (wanted)

Edited by samwise78
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samwise78

Bumping this - hoping for traction..

 

Posted on the QNAP forums too in the Emby thread over there:

 

"The exact same files play fine in Plex so this has to be something on the Emby side of things.

The DTS audio movie file in Plex direct streams, so video is untouched and audio is remuxed to aac on the fly. Happens almost instantly and playback is flawless.
Average send speed from NAS to Xbox is 9MB/s
The DTS audio movie file in Emby direct streams too, video is untouched and audio is remuxed to ac3 on the fly. Happens almost instantly but playback is unwatchable - audio and video breakup within 10 seconds.
Average send speed from NAS to Xbox is 2MB/s

I've even tried using the git builds at https://www.johnvansickle.com/ffmpeg/ as advised by Luke on the Emby Community forums which - when I was on 3.1.2 made a big difference with another movie file (lower video bitrate with DTS audio) but no dice with my straight rip of the Force Awakens Blu-Ray."

 

Thanks

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You can't go around saying the exact same file plays fine in other software, when they are not playing it the same way. We are trying to offer a little better experience by encoding the audio to a better format but it may require additional troubleshooting. At this point I think we should just encode to aac.

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samwise78

You can't go around saying the exact same file plays fine in other software, when they are not playing it the same way. We are trying to offer a little better experience by encoding the audio to a better format but it may require additional troubleshooting. At this point I think we should just encode to aac.

 

I'd like to understand why Emby seems to struggle so much with the higher bitrate video when remuxing audio though..

 

If the NAS was choking on the remux I'd expect to see memory & CPU significantly higher than standard idle values..

The NAS is barely breaking a sweat when it attempts to remux DTS>AC3, but the upload speed from QNAP > Xbox never goes above 3MB/s so becomes a stuttery mess.

Emby direct playing the AC3 version is completely fine..

 

The memory & CPU usage on the NAS when Plex is remuxing DTS>AAC isn't much higher than idle but upload speed is basically tripled?

 

Happy to help troubleshoot - and provide whatever outputs are needed..

 

Thanks

Sam

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samwise78

It doesn't. I think these are just limitations of the UWP video player.

??

Surely the player is just playing back the temporary version file that is created by the direct stream/audio remux process?

Which would be the same video and an AC3 soundtrack?

How come it doesn't struggle playing back the same video where I already converted and remuxed DTS>AC3?

Or how come it doesn't struggle playing back a different movie (lower video bitrate - still remuxing DTS>AC3)?

 

There must be something causing the low throughput for files like this that isn't affecting files that can be direct played.

The remux occurs on the server and not the client right?

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In other words I think that is just how fast the video player is consuming data and not any kind of server side transmission problem. The more primitive formats we use (eg AAC), the simpler things are for the player and at this point that's the direction I'll probably go in if that's what we have to do to make it just work.

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samwise78

Doesn't the player just request the file and server delivers 'a' file?

I really think the fact the bitrate of the movie is a factor here as it highlights that direct streaming/remuxing audio seems to lead to a scenario where only 3MB/s will be sent from the server or received at the Xbox client.

 

I'd be really interested to see if aac cures this apparent limitation or not..

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No, it's not that simple as decoding is obviously a factor. The player does not have an unlimited memory buffer therefore if decoding is happening at a slower rate on the device it will also have to download data at a slower rate.

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samwise78

No, it's not that simple as decoding is obviously a factor. The player does not have an unlimited memory buffer therefore if decoding is happening at a slower rate on the device it will also have to download data at a slower rate.

I may be over-simplifying here but - if the player is playing (decoding) the file: a MKV containing 1080p H264 & AC3 streams (either before or after remux) why does it download at a faster rate for files it can direct play?

Or to paraphrase why does it download data at a slower rate for a direct stream file if all the remuxing is happening on the server..?

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the player is decoding and downloading data all at the same time. The speed of the downloading is going to be limited not only by network but also by the rate of decoding, because it only has a small amount of buffer available to store data that hasn't been decoded yet.

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samwise78

the player is decoding and downloading data all at the same time. The speed of the downloading is going to be limited not only by network but also by the rate of decoding, because it only has a small amount of buffer available to store data that hasn't been decoded yet.

But surely the buffer size is the same on the player (Xbox) regardless of whether the file is direct playing or direct streaming?

Or does the ET app on the Xbox have to do more decoding for direct streaming than direct playing?

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Probably the same but what I'm trying to tell you is that the rate of decoding is not the same because different formats are being used. We are using the built-in video player from the device just like the other apps are, and it is going to have different behavior depending on what formats are being used and what output methods are being used.

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samwise78

Probably the same but what I'm trying to tell you is that the rate of decoding is not the same because different formats are being used. We are using the built-in video player from the device just like the other apps are, and it is going to have different behavior depending on what formats are being used and what output methods are being used.

Sorry to sound like a stuck record - I must be missing something elementary here, as I thought the formats were the same?

 

File 1 - Force Awakens.mkv - containing 1080p H264 & AC3 (created by me)

File 2 - Force Awakens.mkv - containing 1080p H264 & AC3 (created by Emby server during direct streaming call)

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Ok I thought we were comparing to the other app that is using aac. In this case, yes they are still very different because the completed file is static and the player can seek that using primitive operations. Once ffmpeg comes into play it's no longer static, and the video player is going to treat it like a forward moving live stream. That makes them different enough that any comparison is apples to oranges because the video player is going to have different behaviors that are applied for the two streams. 

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samwise78

OK, thanks.

Must have a smaller buffer for "live" streams then as a file with a lower video bitrate (still DTS audio) direct streamed just fine despite the 3MB/s "ceiling".

I'd be interested in helping test any DTS>AAC direct stream functionality if you go down that route but for now will have to incorporate the DTS>AC3 remux into my ripping routine..

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samwise78

Been thinking about this some more based on the direct streaming of the file itself and the mention of the inbuilt player on the Xbox maybe having certain (unknown) buffer/data/bandwidth constraints when decoding/playing.

 

Presumably the Plex app for Xbox also uses the same inbuilt player?

 

If we're talking about bandwidth or buffer sizes on the player then Plex server manages to send (and the player receives and "decodes") between 6 and 8MB/s when direct streaming the same video file i.e. video untouched and DTS>AAC remux/transcode.

 

Really keen to know if changing from DTS>AC3 to DTS>AAC in Emby fixes this apparent invisible 3MB/s limit when direct streaming and how simple a change it is to make..

Would it be a selectable option or choice (When direct streaming choose DTS>AC3 or DTS>AAC) or would it need to be changed permanently..?

 

Thanks

 

<edit>

 

VLC player for the Xbox can Direct Play the movie with DTS audio via SMB, steady 4MB/s from the NAS

Any plans to incorporate other players?

Edited by samwise78
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