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Dolby True HD problems with Creed 2 and The Nun

Posted: Thu Mar 28, 2019 9:13 am
by mike_mgoblue
Several months ago, I watched The Nun on Blu-ray. The Dolby True HD audio did not have any audio problems while watching the Blu-ray. I ripped the Blu-ray using MakeMKV. Then, while watching the MKV version on my TV with the HDMI Out from the laptop computer, there were several spots where the Dolby True HD version of the audio would always "cut out" in the exact same spots. I was not happy about this, but I didn't think it was that big of a deal because the Dolby True HD version of the audio was not the only format - there was also a 5.1 DTS Master Audio format. Thankfully, the DTS Master Audio format did not have any problems. ... I thought this may have been just a "one-time" fluke.

But, I recently watched Creed 2 on Blu-ray with Dolby True HD audio and there were no problems with the audio. I then ripped Creed 2 using MakeMKV. I then tried to watch Creed 2 on my TV using the HDMI Out from my laptop computer. The 7.1 Dolby True HD audio format immediately started hearing "dropouts" in audio. This was another movie where there was a 5.1 DTS Master Audio format. Thankfully, the DTS Master Audio format did not have this problem. But, it is very frustrating and apparently not a fluke that the Dolby True HD version of Creed 2 has this audio problem on Dolby True HD.

I tried listening to Creed 2 on my laptop and I did not notice these audio dropouts in Creed 2 while watching on the screen of the laptop and using the two speakers built into the laptop. Obviously it is different when you are sending out a 7.1 signal via HDMI and simply listening to that same 7.1 source in a 2-channel environment, but I just thought I would mention that.

Thank you for your time and help.

Re: Dolby True HD problems with Creed 2 and The Nun

Posted: Thu Mar 28, 2019 9:54 am
by Grauhaar
Most of the TVs accepts only Dolby Digital 2.0 (max DD 5.1) or PCM 2.0, but not the enhanced formats like normal DTS or DTS HD Master or Dolby Dgital True HD. These formats are only playable meaningful with some AV Receivers with a lot of speakers connected. I would say, it makes zero sense to use the enhanced formats (not supported in any case) with TV speakers or Soundbars conected with ARC to the TV or PC speakers, because the speakers are to bad to transport the addional information to the ears. And don't forget, the enhanced formats uses much more space. I have seen DTS HD Master tracks with 4-6 GB in size (15-20% of the Blu-ray).

The playing software/hardware is informed via HDMI protokoll what the TV supports (video resolutions, refesh rates and also the audio formats), so the original audio stream is downmixed to DD 2.0 (max 5.1) or PCM 2.0. If there is a bug in the downmixer of DD True HD to DD 2.0 or DD 5.1, you can hear it. To support an DD True HD track in the downmixer, special support is needed, because the implementation of the DD HD formats is completely different. If the downmixer is not aware of this, it assumes that this is an normal DD 5.1 track and produces wrong audio data.
Maybe some TVs understand DTS 2.0 or 5.1 but not DTS HD formats. But in case of DTS HD this is simple, any DTS HD track has the DTS core (2.0, 5.1 or whatever) and the DTS HD part is defined as an extention. If the DTS decoder supports only DTS 5.1, it sees only the DTS core part and not the DTS HD part, it is simply ignored.

Re: Dolby True HD problems with Creed 2 and The Nun

Posted: Fri Mar 29, 2019 2:29 am
by mike_mgoblue
Hi Grauhaar,

Thank you for taking the time to write back and help. ... I should clarify a couple things.

1. When I mentioned that I was only using "two speakers" I was referring to when the 7.1 Dolby True HD was being watched directly on my laptop on the laptop screen. The only two speakers on the laptop are the Left Speaker and Right Speaker built into the laptop. This did not produce any "dropouts" in audio with the 7.1 Dolby True HD signal, even when watching on this 2.0 source.

2. When I mentioned I was using the HDMI Out on my laptop, the HDMI is actually going to my Onkyo A/V Receiver. The A/V Receiver has all the most recent firmware updates and is fully compatible with Dolby TrueHD. Most other movies work fine. For some reason the movies Creed 2 and The Nun have "dropouts" with the Dolby True HD signal, though. I do have a 5.1 speaker system setup. The audio actually never reaches my TV, just the A/V Receiver.

UDPATE: I was previously under the presumption that the problem must be with the Dolby True HD signal found in the MakeMKV file, because the audio "dropouts" always happened in the exact same spots when watching the movies Creed 2 and The Nun using the HDMI Out going to the A/V Receiver. However, I now believe the problem may be caused by the MPC-BE Player. ... I say this because today I downloaded the VLC Media Player. I don't like VLC because the video is "choppy" when I use it. However, in order to test the Audio, I downloaded VLC and confirmed the Dolby True HD 7.1 soundtrack in Creed 2 does NOT experience these "audio dropouts" at all. These "audio dropouts" only occur when using Dolby True HD in the MPC-BE Media Player. ... This is very unfortunate, because VLC doesn't play the video as well as MPC-BE does. My only solution is to just watch the video on MPC-BE while listening in the DTS Master Audio format that does not experience "audio dropouts" on MPC-BE.