1

Topic: AAC 7.1 playback issues

Hello,

I have tested the mkv outputs of Hybrid in both Smplayer and VLC player.
Everything is working flawlessly except the AAC streams with 8 channels and only those which were encoded from DTS-HD 7.1 streams.

All the other AAC streams are working as excellent: 7.1 AAC streams encoded from TrueHD stream, all the 5.1 AAC streams encoded from both 5.1 DTS-HD and TrueHD streams.

I have checked these non-working (7.1 AAC streams encoded from DTS-HD) streams in media info and media info reports them without any issue (they were reported with exactly the same infos provided as the working streams) I have checked the streams in Mkvtoolnix as well, but found nothing wrong around them.

It is strange for me that an AAC 7.1 stream encoded from TrueHD is working flawlessly, while an other AAC 7.1 stream encoded from DTS-HD isn't, however after encoding in Hybrid I
checked both AAC streams in Quicktime and they were playing back without any issue. Smplayer said: "aid: no" and the stream is muted.

I got stuck with AAC encoded 7.1 DTS-HD streams. Please help.

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Re: AAC 7.1 playback issues

Okay, so the 7.1 stream encoded from a DTS-HD stream:

  • works fine in Quicktime

  • doesn't work in SMPlayer

and an 7.1 stream encoded from a TrueHD source works fine in both players?

a. Have you tried another player like MPC-HC or VLC?
b. Did you use the same aac encoder for both streams? What settings did you use?

My guess atm. is that the streams use different sampling rates and may be bit depth and that SMPlayer might not support all sampling rates and bit depth settings for aac content.
7.1 DTS-HD content might be 24 bit with 96kHz,....

Cu Selur

3 (edited by mparade 2017-05-28 13:53:21)

Re: AAC 7.1 playback issues

Selur wrote:

Okay, so the 7.1 stream encoded from a DTS-HD stream:

  • works fine in Quicktime

  • doesn't work in SMPlayer

and an 7.1 stream encoded from a TrueHD source works fine in both players?

a. Have you tried another player like MPC-HC or VLC?
b. Did you use the same aac encoder for both streams? What settings did you use?

My guess atm. is that the streams use different sampling rates and may be bit depth and that SMPlayer might not support all sampling rates and bit depth settings for aac content.
7.1 DTS-HD content might be 24 bit with 96kHz,....

Cu Selur

Hello,

A 7.1 stream encoded from TrueHD source works fine in SMplayer and Quicktime but not in VLC player.
Until now, I have tried only VLC, SMplayer, and QuickTime.
I am using in Hybrid every time the same qaac AAC encoding and filter settings: "keep input sample rate", keeping all the channels without any filter used (no DRC, normalize, gain etc.), and using a quality factor of 127.

Thanks for the help.

4

Re: AAC 7.1 playback issues

The keep sample rate might be what is causing your problems.
->
a. check whether the sampling rates of the TrueHD and DTS-HD source you use differ
b. try whether enforcing a 48kHz sampling rate helps with the problem
c. check the bit depth of the source (16bit vs. 24bit)

Cu Selur

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Re: AAC 7.1 playback issues

Selur wrote:

The keep sample rate might be what is causing your problems.
->
a. check whether the sampling rates of the TrueHD and DTS-HD source you use differ
b. try whether enforcing a 48kHz sampling rate helps with the problem
c. check the bit depth of the source (16bit vs. 24bit)

Cu Selur

According to tsMuxer and BDInfo all my sources are 48kHz and 24 bit (both the 5.1 and 7.1 DTS-HD and 7.1 TrueHD. I do not know how reliable these tsMuxer and BDInfo reported infos can be...).
I have checked the files in MPC-HC, but unfortunately the result wasn't positive.

My last chance is to reencode them to 48kHz and see if they will become playable.

6 (edited by mparade 2017-05-28 19:41:53)

Re: AAC 7.1 playback issues

mparade wrote:
Selur wrote:

The keep sample rate might be what is causing your problems.
->
a. check whether the sampling rates of the TrueHD and DTS-HD source you use differ
b. try whether enforcing a 48kHz sampling rate helps with the problem
c. check the bit depth of the source (16bit vs. 24bit)

Cu Selur

According to tsMuxer and BDInfo all my sources are 48kHz and 24 bit (both the 5.1 and 7.1 DTS-HD and 7.1 TrueHD. I do not know how reliable these tsMuxer and BDInfo reported infos can be...).
I have checked the files in MPC-HC, but unfortunately the result wasn't positive.

My last chance is to reencode them to 48kHz and see if they will become playable.

No success. Even if reencoding the stream using 48Khz. The same has happened in all three players: audio track is muted. Quicktime can play back the output of Hybrid correctly.

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Re: AAC 7.1 playback issues

Okay, all three players use libav as backend, so this might be a libav issue.

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Re: AAC 7.1 playback issues

Selur wrote:

Okay, all three players use libav as backend, so this might be a libav issue.

I have tried the latest stable Kodi as well. In Kodi I cannot even switch to 7.1 AAC streams (so not muted as in other players but even cannot be swittched to). Kodi immediately switch back to the non 7.1 AAC stream.
As I wrote above, except these AAC 7.1 streams everything is played back correctly in Kodi as well as in all other above mentioned players.

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Re: AAC 7.1 playback issues

Kobi also uses libav wink
As a side note: personally I use flac for 7.1 streams since a. it's lossless and b. smaller than TrueHD or DTS-HD.
Does Kodi support 7.1 flac?

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Re: AAC 7.1 playback issues

Selur wrote:

Kobi also uses libav wink
As a side note: personally I use flac for 7.1 streams since a. it's lossless and b. smaller than TrueHD or DTS-HD.
Does Kodi support 7.1 flac?

I think, it does. I will test if there is no any chance for an AAC 7.1 to work in Kodi.

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Re: AAC 7.1 playback issues

Selur wrote:

Kobi also uses libav wink
As a side note: personally I use flac for 7.1 streams since a. it's lossless and b. smaller than TrueHD or DTS-HD.
Does Kodi support 7.1 flac?

Regarding the flac encoding settings I guess you would recommend q=8, and to set bps to the bit depth of the source audio, right?

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Re: AAC 7.1 playback issues

Since flac is lossless q basically just sets the compression/size and the speed. Lower value -> lower compression -> higher speed&size.
Yes, bps would be typically set to the bit depths of the source unless you need another depths, for example in case you playback equipment only supports up to a specific bit depth. smile

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Re: AAC 7.1 playback issues

Selur wrote:

Since flac is lossless q basically just sets the compression/size and the speed. Lower value -> lower compression -> higher speed&size.
Yes, bps would be typically set to the bit depths of the source unless you need another depths, for example in case you playback equipment only supports up to a specific bit depth. smile

Hybrid encoded my 24bit TrueHD source as 16bit according to mediainfo however (I checked because the size seemed to be very small) I set bps to 24bit.

14

Re: AAC 7.1 playback issues

Sounds like a bug.
What does the audio encoding call look like?

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Re: AAC 7.1 playback issues

Selur wrote:

Sounds like a bug.
What does the audio encoding call look like?

level 4: starting Helper:
"C:\PROGRA~1\Hybrid\ffmpeg.exe" -y -threads 12 -i "C:\Users\BOGRDI~1\AppData\Local\Temp\iId_5_aid_4352_lang_eng_18_47_48_6110_01.ac3" -ac 8 -ar 48000 -acodec pcm_s16le -f wav -

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Re: AAC 7.1 playback issues

Selur wrote:

Sounds like a bug.
What does the audio encoding call look like?

Complete debug output as an attachement.

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Re: AAC 7.1 playback issues

will look into it smile

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Re: AAC 7.1 playback issues

If you analyse your source with mediaInfo, does it report 24bit?

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Re: AAC 7.1 playback issues

Selur wrote:

If you analyse your source with mediaInfo, does it report 24bit?

mediainfo reports this:

Audio #1
ID                                       : 4352 (0x1100)
Menu ID                                  : 1 (0x1)
Format                                   : TrueHD / AC-3
Format settings, Endianness              : Big
Muxing mode                              : Stream extension
Codec ID                                 : 131
Duration                                 : 1 h 24 min
Bit rate mode                            : Variable / Constant
Bit rate                                 : 640 kb/s
Maximum bit rate                         : 9 675 kb/s
Channel(s)                               : 8 channels / 6 channels
Channel positions                        : Front: L C R, Side: L R, Back: L R, LFE / Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 spf)
Bit depth                                : 16 bits
Stream size                              : 387 MiB (2%)
Service kind                             : Complete Main


Bdinfo reports this:

AUDIO:

Codec                           Language        Bitrate         Description     
-----                           --------        -------         -----------     
Dolby TrueHD Audio              English         0 kbps          7.1 / 48 kHz / 24-bit (AC3 Embedded: 5.1 / 48 kHz / 640 kbps)
Dolby Digital Audio             English         320 kbps        2.0 / 48 kHz / 320 kbps / Dolby Surround
Dolby Digital Audio             Polish          640 kbps        5.1 / 48 kHz / 640 kbps
Dolby Digital Audio             Czech           640 kbps        5.1 / 48 kHz / 640 kbps
Dolby Digital Audio             Hungarian       640 kbps        5.1 / 48 kHz / 640 kbps
Dolby Digital Audio             Slovak          640 kbps        5.1 / 48 kHz / 640 kbps
Dolby Digital Audio             Arabic          640 kbps        5.1 / 48 kHz / 640 kbps
Dolby Digital Audio             English         320 kbps        2.0 / 48 kHz / 320 kbps

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Re: AAC 7.1 playback issues

Since Hybrid doesn't use bdinfo it doesn't really matter what bdinfo reports.

Cu Selur

21 (edited by mparade 2017-05-30 19:33:43)

Re: AAC 7.1 playback issues

Selur wrote:

Since Hybrid doesn't use bdinfo it doesn't really matter what bdinfo reports.

Cu Selur

I think only the core is 16bit. The thd stream should be 24 bit (but maybe not).

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Re: AAC 7.1 playback issues

Selur wrote:

Since Hybrid doesn't use bdinfo it doesn't really matter what bdinfo reports.

Cu Selur

I have found this regarding TrueHD bit depth analysing:

The one issue with TrueHD is that information about the actual bitdepth is not contained anywhere in the TrueHD track. In result  24 bit value is used by default.Since  the bit-depth is simply not known before the processing, eac3to has no other choice than to fully decode the full track and check the bit-depth of every single audio sample (of which there are usually 48000 for every second of the runtime). If all 24-bit audio samples have trailing 8 bits zeroed out, eac3to will state that it’s a 16-bit track and trim zeros out without quality loss. eac3to output will look like the following in such case:
[a04] The original audio track has a constant bit depth of 16 bits.
[a04] Superfluous zero bytes detected, will be stripped in 2nd pass.
[a04] Reducing depth from 24 to 16 bits...
The size difference of 24-bit and 16-bit FLAC files converted with MakeMKV (via FFmpeg) and eac3to accordingly, was insignificant and equals to few megabytes only. Which means that latest versions of FLAC compressing fake zeroed out bits perfectly.

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Re: AAC 7.1 playback issues

a made a few adjustments to use ffmpeg additional to MediaInfo in case MediaInfo doesn't provide a bit depth.

Cu Selur

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Re: AAC 7.1 playback issues

Selur wrote:

a made a few adjustments to use ffmpeg additional to MediaInfo in case MediaInfo doesn't provide a bit depth.

Cu Selur

Hallo,

Hybrid is extracting using tsMuxer instead of ffmpeg however I set "prefer ffmpeg for extraction from transport streams "and make a very huge thd + ac3 file. I just would need the thd part that is why I would like to use ffmpeg instead.

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Re: AAC 7.1 playback issues

Would need a debug output level 9 of the job creation to see why Hybrid chooses tsMuxeR over ffmpeg. smile