dropouts in ac3 stream amazon fire

[fuzzthekingoftrees 10]

If I play a video with an ac3 audio track the app uses Direct/I for playback. I get dropouts in the audio. The dropouts seem to be at random intervals at an average rate of 3-4 per minute. Each dropout lasts no more than a quarter of a second. When the dropout occurs I get silence and the 5.1 light on my amp goes off. The video is unaffected and continues playing smoothly.

 

This seems to affect all videos with an ac3 audio track if the file is played using the internal video player.

 

The Fire TV is connected to the amp via HDMI. I can play the same videos to the same amp from Emby Theatre or Kodi or Emby for Media Center or chromecast and they work fine. I don't have any other apps on my Fire TV that pass ac3 to the amp so I cannot check to see if this is an Emby only problem.

[ebr 14930]

Any interruption in a bitstreamed audio stream usually sends the receiver into a mute state which it then takes it a bit of time to recover from.  You will notice this when pausing any item with bitstreamed audio as the audio usually doesn't start right back up when you unpause.

 

Based on that, I'm guessing that maybe the Fire is getting bogged down in some way causing it to drop "frames" of audio.  I have not seen this behavior in my setup at all but I use mainly a Shield.

 

If you can send a log from the app during which this happens, maybe I can spot something.

[fuzzthekingoftrees 10]

OK. I sent you a log

I'm logged in as fuzz. I was playing Son of Saul. I just played 30 seconds or so from the start of the movie. The audio dropped out twice during that time.

[ebr 14930]

Thanks.  I see a bunch of the following in your log.  That may or may not be related though because I see more of this than just a couple times.

W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting
W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting
W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting
W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting
W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting
W/AudioTrack(  393): releaseBuffer() track 0xabcf7ed8 disabled due to previous underrun, restarting

The Fire TV app right now is on a fairly old version of Exo because, at the time I was doing all the player work last, Amazon had not ported the new Exoplayer yet.  They have now so the next major update to the app will also update Exo and perhaps clear this up.

[mediatalent 0]

I have a Sony Bravia 55XD8599 LED HDR 4K Ultra HD Android TV and I'm experiencing the same random dropouts as the OP describes in the Emby for Android TV app when playing any file that has an AC3 codec ... but AAC and DTS work fine.

[fuzzthekingoftrees 10]

Did the recent release of the Fire TV app get the update to Exoplayer?

I still get the dropouts for mkvs with ac3 audio.

It doesn't seem to happen if the original file had DTS audio which is now being transcoded to ac3 by the server.

[ebr 14930]

Did the recent release of the Fire TV app get the update to Exoplayer?

I still get the dropouts for mkvs with ac3 audio.

It doesn't seem to happen if the original file had DTS audio which is now being transcoded to ac3 by the server.

 

Yes, it did.  I'm afraid I haven't seen this issue so I don't know what it is.

[Luke 37113]

In the direct stream situations, what is the audio bitrate? Maybe it is a little too high?

[fuzzthekingoftrees 10]

In the direct stream situations, what is the audio bitrate? Maybe it is a little too high?

I'll look into this to see if it is the bitrate causing the problem I'm guessing these files have 640K ac3 streams.

When you say the bitrate is a little too high what is it too high for? My amplifier can definitely handle the 640K ac3 as the same files play fine through emby theatre into the same amplifier. Network is no problem, the fire TV is connected to the server over ethernet.

Are you thinking that the internal fire TV player cannot pass ac3 at this bitrate?

 

I'm beginning to think the fire TV is not the answer to my TV streaming needs.

[Luke 37113]

Are you thinking that the internal fire TV player cannot pass ac3 at this bitrate?

 

Yes I'm wondering about this.

[fuzzthekingoftrees 10]

I did some testing. It does seem to be related to bitrate.

I made a sample file up with the same audio track transcoded into several bitrates and using both ffmpeg and eac3to (aften) encoders.

I get the dropouts with 640K or 576K ac3 but not with 512K or lower.

The dropouts seem less frequent with the 576K stream (every 40-60 seconds vs every 20-30) but this is just a feeling as the dropouts are quite random so it would take a much larger sample to determine accurately.

It doesn't matter which encoder created the ac3 tracks same thing happens with 640K audio from Blu-ray as with the ffmpeg or aften output.

What I don't know, because I don't have another amp, is whether this is an issue with the fire TV in general or just the fire TV with my amp.

As I said before same amp works fine with the same files from emby theatre.

[ebr 14930]

Is it a 1st or 2nd gen Fire?

[fuzzthekingoftrees 10]

it's a 2nd gen, the 4K one with no optical port

There was an OS update today I haven't tested it again since. I think the update was mostly to add Alexa features.

[arrbee99 1561]

Interesting. Was getting what sounds remarkably similar while watching a compressed bluray rip of The Goonies last week....

 

 

This was with a Win 10 PC sending the stream (direct stream / play can't remember which) via ethernet to 2nd gen FTV, then to the TV via HDMI - no amp or surround anything, just the TV speakers.

 

Can't really remember how long its been going on, think its fairly recent but pretty vague about that. Something to do with vlc vs. exoplayer if thats what its called ?

[arrbee99 1561]

Played X-Men using DCA / DTS (whatever that is) at 1536kbps and the audio was fine. it was Direct Streaming. Changed it to AC3 at 448kbps and audio also fine. It was Direct Playing.

 

Played Tintin using DCA / DTS and the audio was fine. It was Direct Streaming. Changed it to AC3 at 640kbps and audio was doing its dropping out thing. It was Direct Playing.

 

Direct Streaming is where it remuxes the sound ?

[ebr 14930]

Interesting.  Amazon does not publish a bitrate in their support specs for AC3 - only sample rate and bit depth.  I guess there is a limit though so we may have to start transcoding these things.

[Kramerika 16]

We are getting this from the TV speakers on our Fire TV while watching recordings of live TV.  It has not happened on our Shield TV for the same recordings.  I switched from the internal player to VLC when it became annoying, and the problem did disappear although I need to do more testing as it was for a very short remaining portion of a recording.  The recorded programs are using AC3 5.1.

[fuzzthekingoftrees 10]

I switched from the internal player to VLC when it became annoying, and the problem did disappear

Do you mean the internal VLC player as in Direct/V

The problem for me is that when I do this the 5.1 gets downmixed to stereo.

[Kramerika 16]

Yes, from Direct/I to Direct/V.  I don't know about down mixing because I am using the stereo TV speakers.  I have our surround sound system on the TV with our Shield TV, and we do not experience this issue there.  If it was down mixing from 5.1 to stereo, that would annoy me as well, so it obviously should be resolved somehow to allow for 5.1 sound without the random hiccups in sound.  We have been using Emby and this Fire TV to watch recorded TV via Emby for a long time, and this only started recently.

Edited April 24, 2017 by Kramerika

[enigy715 5]

Hi all! New emby user here - love Emby! I'm having this same problem as OP on 2nd gen Fire TV. I uploaded the logs, has there been a resolution identified other than downmixing to stereo or using VLC?

[ebr 14930]

Hi. This appears to be an issue introduced by the recent update to Fire OS.  We are trying to figure out the best way to work around it.

[ebr 14930]

If one of you are in the Fire TV beta program, please test this out when you get 1.4.3.  Thanks.

[enigy715 5]

Ok,will do, but are you referring to Fire TV OS beta or Emby app beta?

[enigy715 5]

Ok,will do, but are you referring to Fire TV OS beta or Emby app beta?

 

Nevermind, I see that you were referring to Emby beta.  I sent a request to join the Amazon Fire TV beta.  Soon as I can get that installed I will test it out and report back the results to that thread.  Thank you!

[aptalca 70]

Just my 2 cents. I do get the random audio drop outs with the fire tv and ac3. But they are not exclusive to emby. I also get them with plex (direct play) and occasionally netflix.

 

My tv is only stereo so I set emby to downmix to stereo and I no longer have any issues.

 

With Netflix, though, there wasn't anything I could do. If I turn off dolby in fire tv settings, I lose 4k

 

I think this is an issue with the fire tv