Only 768 kbs shows Dolby Atmos

I have several video files and I found out today my Receiver said Dolby Atmos, others showed only PCM, I did some checking.
A series of 10 Episodes, all showed Dolby Atmos except for 2. Infuse displays them at DolbyDigitalPlus 5.1
All videos are in m4v format.

English (E-AC3, 5.1)
e01 - 768 kbs - Dolby Atmos
e02 - 256 kbs - PCM
e03 - 768 kbs - Dolby Atmos
e04 - 768 kbs - Dolby Atmos
e05 - 768 kbs - Dolby Atmos
e06 - 768 kbs - Dolby Atmos
e07 - 164 kbs - PCM (AC3, 2.0)
e08 - 768 kbs - Dolby Atmos

German (E-AC3, 5.1)
e01 - 256 kbs - PCM
e02 - 256 kbs - PCM
e03 - 256 kbs - PCM
e04 - 256 kbs - PCM
e05 - 256 kbs - PCM
e06 - 256 kbs - PCM
e07 - 640 kbs - PCM
e08 - 256 kbs - PCM

Another series in (E-AC3, 5.1)
e01 to e10 - English - 768 kbs - Dolby Atmos
e01 to e10 - German - 640 kbs - PCM

As a Note
Starting a video in Dolby Atmos, it briefly shows as TrueHd with no sound then switches over to Dolby Atmos. When you start the video you will have 3 seconds of silence while the sound kicks in. No problem while in pause mode, receiver still says Dolby Atmos, so no audio interruption, that’s good.

Questions;

  1. So can I assume anything under 768 kbs will be shown as PCM and anything above 768 kbs will show Dolby Atmos?
  2. Anyway to speed up sound switching, without a 3 second sound delays?
  3. Does the kbs size work for other format? DTS, TrueHD, Dolby Digital, DTS-X etc? So I can see what is the current audio mode on my Receiver?

Welcome to the forum!

There isn’t a bitrate threshold for the types of Atmos which are/aren’t supported. However, I suspect there may be some other differences between these audio tracks which would explain why some of them are recognized as Atmos and others are not.

If you are able to upload a few samples we’d be happy to review them here.