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Opus audio 6ch track mapped wrong to stereo output

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Thanks Meter: 18
 
By SoreGums, Member on 15th August 2017, 02:53 AM
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Getting speach/dialog out the right speaker and surround sounds out of the left speaker.
Enabling mono audio sends speach to both speakers - however now sound is mono...

Works fine on computer, proper mapping, speach and sfx in both left and right speakers.

Nvidia Shield TV, mx player pro updated from play store

Code:
General
Complete name                            : video.mkv
Format                                   : Matroska
Format version                           : Version 4 / Version 2
File size                                : 611 MiB
Duration                                 : 1 h 11 min
Overall bit rate                         : 1 192 kb/s
Encoded date                             : UTC 2016-11-19 14:14:53
Writing application                      : mkvmerge v9.2.0 ('Photograph') 64bit
Writing library                          : libebml v1.3.3 + libmatroska v1.4.4

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5.1@Main
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 1 h 11 min
Bit rate                                 : 1 000 kb/s
Width                                    : 1 920 pixels
Height                                   : 1 088 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.020
Stream size                              : 513 MiB (84%)
Writing library                          : x265 2.1+20-c64393b415adf0e8:[Windows][GCC 6.2.0][64 bit] 10bit: KG7x [x265.ru]
Encoding settings                        : wpp / ctu=64 / min-cu-size=8 / max-tu-size=32 / tu-intra-depth=1 / tu-inter-depth=1 / me=1 / subme=2 / merange=57 / no-rect / no-amp / max-merge=2 / temporal-mvp / no-early-skip / rskip / rdpenalty=0 / no-tskip / no-tskip-fast / strong-intra-smoothing / no-lossless / no-cu-lossless / no-constrained-intra / no-fast-intra / open-gop / no-temporal-layers / interlace=0 / keyint=250 / min-keyint=23 / scenecut=40 / rc-lookahead=20 / lookahead-slices=6 / bframes=4 / bframe-bias=0 / b-adapt=2 / ref=3 / limit-refs=3 / no-limit-modes / weightp / no-weightb / aq-mode=1 / qg-size=32 / aq-strength=1.00 / cbqpoffs=0 / crqpoffs=0 / rd=3 / psy-rd=2.00 / rdoq-level=0 / psy-rdoq=0.00 / log2-max-poc-lsb=8 / limit-tu=0 / no-rd-refine / signhide / deblock=0:0 / sao / no-sao-non-deblock / b-pyramid / cutree / no-intra-refresh / rc=2 / pass / bitrate=1000 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ipratio=1.40 / pbratio=1.30
Default                                  : Yes
Forced                                   : No

Audio
ID                                       : 2
Format                                   : Opus
Codec ID                                 : A_OPUS
Duration                                 : 1 h 11 min
Bit rate                                 : 180 kb/s
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Rear: L R, LFE
Sampling rate                            : 48.0 kHz
Frame rate                               : 50.000 FPS (960 spf)
Compression mode                         : Lossy
Stream size                              : 92.3 MiB (15%)
Language                                 : English
Default                                  : Yes
Forced                                   : No

Text
ID                                       : 3
Format                                   : PGS
Muxing mode                              : zlib
Codec ID                                 : S_HDMV/PGS
Codec ID/Info                            : Picture based subtitle format used on BDs/HD-DVDs
Duration                                 : 1 h 9 min
Bit rate                                 : 9 500 b/s
Count of elements                        : 2080
Stream size                              : 4.75 MiB (1%)
Language                                 : English
Default                                  : No
Forced                                   : No

Menu
00:00:00.000                             : en: Chapter 1
00:06:52.871                             : en: Chapter 2
00:11:50.376                             : en: Chapter 3
00:14:51.474                             : en: Chapter 4
00:20:36.902                             : en: Chapter 5
00:28:36.715                             : en: Chapter 6
00:32:29.739                             : en: Chapter 7
00:36:59.050                             : en: Chapter 8
00:41:57.014                             : en: Chapter 9
00:45:26.057                             : en: Chapter 10
00:47:07.658                             : en: Chapter 11
00:49:37.391                             : en: Chapter 12
00:53:09.853                             : en: Chapter 13
00:56:50.532                             : en: Chapter 14
01:00:19.407                             : en: Chapter 15
01:03:43.778                             : en: Chapter 16
 
 
17th August 2017, 05:19 PM |#2  
Thirumalai.K's Avatar
Recognized Contributor
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Quote:
Originally Posted by SoreGums

Getting speach/dialog out the right speaker and surround sounds out of the left speaker.
Enabling mono audio sends speach to both speakers - however now sound is mono...

Works fine on computer, proper mapping, speach and sfx in both left and right speakers.

Nvidia Shield TV, mx player pro updated from play store


It's expected behaviour. MX Player audio output is always stereo.
We have implemented audio passthrough. But, not all codecs are supported in passthrough. And your audio receiver should also support the decoding of the particular codec.

We will forward your concern to our developer team.
16th September 2017, 02:15 PM |#3  
SoreGums's Avatar
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Quote:
Originally Posted by Thirumalai.K

It's expected behaviour. MX Player audio output is always stereo.

Not sure that addresses my issue. (6ch input audio being mapped correctly to 2ch output)

Playing Ac3 or other 6ch audio, get dialog in both speakers...

Hopefully this was a canned response and the problem was actually understood.

I fixed it by transcoding all the files via manual downmixing and producing a dual audio file with the original 6ch audio and the proper stereo 2ch downmix audio.
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16th September 2017, 03:11 PM |#4  
InvalidDNA's Avatar
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Can you share a sample clip?
I don't have any such issues.
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16th September 2017, 03:17 PM |#5  
Thirumalai.K's Avatar
Recognized Contributor
Thanks Meter: 4,012
 
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Quote:
Originally Posted by SoreGums

Not sure that addresses my issue. (6ch input audio being mapped correctly to 2ch output)

Playing Ac3 or other 6ch audio, get dialog in both speakers...

Hopefully this was a canned response and the problem was actually understood.

I fixed it by transcoding all the files via manual downmixing and producing a dual audio file with the original 6ch audio and the proper stereo 2ch downmix audio.

Our development team has tried to reproduce the issue. But, couldn't reproduce it.

It will be helpful if you can share the video with us. We will test it with our test devices.
20th September 2017, 05:26 PM |#6  
Junior Member
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HW Opus work only with 2 ch
Hi, I have the same problem with Opus sound track.
I found it work as expected when not use HW+ for audio (disable opus in HW audio decoder)
When use HW, MX Player play only R and L channel.. not play central channel.

I enable HW for OPUS to solve SW decoder problem, with specific bitrate
Yesterday, 12:40 PM |#7  
Thirumalai.K's Avatar
Recognized Contributor
Thanks Meter: 4,012
 
More
Quote:
Originally Posted by SoreGums

Getting speach/dialog out the right speaker and surround sounds out of the left speaker.
Enabling mono audio sends speach to both speakers - however now sound is mono...

Works fine on computer, proper mapping, speach and sfx in both left and right speakers.

Nvidia Shield TV, mx player pro updated from play store

Quote:
Originally Posted by baudav

Hi, I have the same problem with Opus sound track.
I found it work as expected when not use HW+ for audio (disable opus in HW audio decoder)
When use HW, MX Player play only R and L channel.. not play central channel.

I enable HW for OPUS to solve SW decoder problem, with specific bitrate

We have managed to get the same video based on @SoreGums metadata.
After looking at the video, it seems to be channel mapping issue.

The channel mapping order on the video is FL+FR+FC+LFE+BL+BR. But, according to the opus specification, it should be FL+FC+FR+BL+BR+LFE.

If you use HW decoder or HW+ Audio Decoder (If you have enabled in settings) for Opus, Then you will face the issues. Most of the device has opus decoders from Google which expects the channel order as per the Opus specification. So, It downmixes the wrong channels based on the standard order.


On FFMpeg based players, FFMpeg follows the FL+FR+FC+LFE+BL+BR layout. So, it won't be an issue.
You can enable SW audio from audio track selection panel as a workaround. In our tests, when SW audio is used there is no issue.
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