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Sound is odd


mikech
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I wrote a much bigger post but my browser ate it, so I'm just going to be short about this:
 
I gave this software a trial run. The ATV4 client seems to have some kind of audio issue, regardless of your audio settings in the OS (Digital, Stereo, Auto) that makes the sound seem mono and bass-heavy. I thought it was the volume boost setting on the server, so I set that to 1 to preserve source audio volume. Nope.

This happens with videos that have AAC audio and videos that have AC3 audio. I was looking at switching from Plex, but the audio differences are just too jarring. I have swapped back and forth between the two apps playing the same sequence of the same file and the Emby version sounds worse.
 
This doesn't seem to be the case from my limited experience with the web and Android clients, so I really think it's a tvOS "early software weirdness" issue and not something in the server. I hope you patch this out, because I really do like the iTunes-style UI with fanart over Plex's look, but until the audio tracks don't sound like a cheap subwoofer is overactive I can't justify buying into it.
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I have not experienced this nor heard of anyone else who has either.  Please post a transcode or remux log from playback.  Thanks.

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I haven't heard this either, but I don't have a great sound system attached to my Apple TV, so I'm not a good filter for this. 

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I tried playing a video today for the purposes of generating a log. There's three files made within the same minute called remux, directstream, and transcode. I don't know which one you may want/need, so I'm attaching all three.

directstream-4fa72acb-50f7-4d4f-8881-fa83c4f0b62e.txt

remux-219644ac-e8a8-4f33-8661-d11f26ba14ab.txt

transcode-766967a8-6304-4b97-b005-b894d2437c5c.txt

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Please also indicate which of the three cause the audio problem you're mentioning. For what it's worth, in the first log, the original audio from the video file is preserved as-is.

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Well, that's the thing. I don't know what's causing this. All I know I push the play button in Emby on ATV4 and the sound seems oddly processed compared to Plex on the same device, or even compared to Emby on other platforms. I streamed one video file that's generally representative of my video collection (DVR recordings converted into MKV 264 by MCEBuddy) and it created those three logs. However, it's worth adding that even video files that aren't transcoded DVR recordings, like a video you download online, is the same way.

 

Are the three logs unusual? I'm new to the app in general. I see the other two files are converting the AC3 audio to AAC audio. I don't know what I can do here but I'm willing to try whatever you suggest.

 

 

----

update: Here's my transcoding settings in playback:

Hardware acceleration: None

Transcoding thread count: Auto

Throttling: Checked

FFMpeg: Custom version (path is \%appdata%\Roaming\Emby-Server\ffmpeg\20160410\ffmpeg.exe)

Transcoding temporary path: empty

Audio boost when downmixing: 1 (reduced from 2 default to see if this was the problem)

Edited by mikech
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Are you seeing this with playback in the first log labeled directstream? I think that is valuable information to find out because as I said we are transmitting the original audio as-is, so any sound issues with that would be completely out of our control.

 

In the next two logs we are converting the audio and there we do have some ability to change parameters to possibly find a better result. what is your speaker setup?

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I don't know the how and why behind it making a directstream log. I tried watching a few seconds of another show just now and it only made a remux log. I haven't changed any settings or done anything differently since then.

 

For reference, when serving to Apple TV is it supposed to transcode the audio to AAC? My understanding is Plex plays it directly.

 

My speaker setup is a Samsung sound bar hooked up over HDMI. I've owned Apple TV since December and haven't had this issue anywhere else. The Apple TV itself is set to Auto sound settings but I've also tried Dolby Digital and Stereo and it hasn't changed anything.

Edited by mikech
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It looks like potentially there's an issue we can fix to ensure the audio will always direct play. whether that will fix your sound issue or not remains to be seen but it would be a good place to start.

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Are you sure your soundbar isn't adding some sort of processing?

 

Does it tell you what format of audio it is receiving when you play?

 

If it can accept Dolby Digital, that is what you should set your Apple TV to.  I get DD passed straight through to my receiver.

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My soundbar is basically a stereo speaker with processing effects turned off. The sound it produces is consistent among multiple devices (HTPC, Fire TV, Apple TV). Any weird presets like Music or Game or Sports are all turned off. It isn't 5.1 speakers, so I generally leave it at Auto, but flipping to Dolby or Stereo doesn't change anything in Emby.

 

I'll try to watch more videos in Emby over the weekend and see what log files it produces. I think the three logs produced by a video I ran to test before was an anomaly.

Edited by mikech
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If you're able to try the beta server I think the transocode should be corrected to preserve the original audio.

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I'll give the new server a try. I used several videos today and every one of them produced remux logs.

Input #0, [file name redacted]
  Metadata:

    CREATION_TIME   : 2016-07-30T07:53:56Z

    ENCODER         : Lavf56.1.0

  Duration: 00:38:20.36, start: 0.045000, bitrate: 5327 kb/s

    Stream #0:0: Video: h264 (Main), yuv420p(tv, bt709), 1920x1078 [SAR 1:1 DAR 960:539], 29.97 fps, 29.97 tbr, 1k tbn, 180k tbc (default)

    Stream #0:1(eng): Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s (default)

Output #0, hls, to '[redacted].m3u8':
  Metadata:
    encoder         : Lavf57.32.100
    Stream #0:0: Video: h264, yuv420p, 1920x1078 [SAR 1:1 DAR 960:539], q=2-31, 29.97 fps, 29.97 tbr, 90k tbn, 1k tbc (default)
    Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      encoder         : Lavc57.34.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (ac3 (native) -> aac (native))


Input #0, matroska,webm, from [redacted]':

  Metadata:

    encoder         : no_variable_data

    creation_time   : 1970-01-01 00:00:00

  Duration: 00:23:51.09, start: 0.000000, bitrate: 2491 kb/s

    Stream #0:0: Video: h264 (High), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)

 
Output #0, hls, to [redacted]':

  Metadata:

    encoder         : Lavf57.32.100

    Stream #0:0: Video: h264, yuvj420p, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 23.98 fps, 23.98 tbr, 90k tbn, 23.98 tbc (default)

    Stream #0:1: Audio: aac (LC), 44100 Hz, stereo, fltp, 128 kb/s (default)

    Metadata:

      encoder         : Lavc57.34.100 aac

Stream mapping:

  Stream #0:0 -> #0:0 (copy)

  Stream #0:1 -> #0:1 (aac (native) -> aac (native))

I'll find the beta server and give it a try and report back.

 

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Beta is still remuxing AC3 and ACC tracks into new ACC tracks.

 

I think some of it is just processing relating to stereo. This soundbar I've had for years, has two pieces connected together (I wasn't home when it was installed) that I think are supposed to be left and right, and when playing through Plex the sound seems to be sending more audio through both channels and creating a sound that feels much more full. Emby seems to be putting a lot of the sounds through the right speaker, creating a different... I dunno if I want to call it soundscape? Turning "Reduce Loud Sounds" on in the Apple TV can make it more prominent. I usually keep that setting left on all the time, though a couple apps such as Pandora refuse to run with it.

 

The difference between listening to the same apps between the two apps is such that I don't want to say that Emby is actually 'worse' because it's probably just 'different', but someone who has been using Plex for six months can feel like something is "missing" from the left channel. If someone went the other way, they'd maybe think Plex sounds more monaural.

Edited by mikech
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I think I've figured it out but I've gotta do some more testing first. I have gotten two new directstream logs that copied AC3 audio but I still have AAC -> AAC transcoding in another. See attachments.

 

Haven't tested it out enough yet, but my theory is this has something to do with the Reduce Loud Sounds (dynamic range) setting on the Apple TV. Turn it on so that gunshots and explosions don't wake the neighborhood and everything gets transcoded.

directstream-66b41743-98f7-4256-84c5-9a8faf7c1ef2.txt

remux-8a812844-4377-4958-9694-f154af795e61.txt

directstream-d33c3eb1-598b-4bff-8161-91749a56aca7.txt

Edited by mikech
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I believe that AAC track is converting because we do not have a known audio bitrate. It looks like ffprobe might have failed to produce that. You could try refreshing it from the web client detail screen to see if that brings in a bitrate. Aside from that, all your ac3 audio should be direct streaming now, correct?

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Ran a bunch of shows through it today. AC3 was played directly, DTS was converted (sounded fine to my ears), AAC -> AAC with no known bitrate continues. Which, for me anyway, amounts for a huge amount of files because one source is putting out a lot of videos like that.

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Hey, was just wondering if I PMed you regarding sample files if you had found any progress on videos that don't include bitrate. Server seems excellent otherwise.

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