What Happens If You Send a Dolby Atmos Signal to a 7.1 Receiver

By / 2 months ago / Technology / 1 Comment

Estimated reading time: 4 minute(s)

dolby surround receiver amplifier home cinema atmos

Apparently it is possible. I learned this because my new TV supports Atmos signals. Even though my receiver only supports 7.1 I was able to select Atmos as spatial sound in Windows. I was surprised that the Atmos signal worked on the 7.1 receiver, but the answer to why is pretty simple.

Atmos is delivered not as a codec, but as an extension to True HD that gets folded into the bitstream to maintain backwards compatibility with older gear. When a compatible decoder is detected, the Atmos extension will be processed. When a non-compatible decoder is detected, the extension data gets ignored and you hear just the regular 5.1 or 7.1 Dolby True HD soundtrack.

And it’s a good thing they did it this way, otherwise Atmos blurays might have needed to include two versions of the soundtrack, waste of space. This method ensure compatibility.

Dolby Digital Plus, a codec used by video streaming services such as Netflix and Vudu, also supports Atmos. The same process at work with True HD applies here: the Atmos extension gets folded into the DD+ bitstream, and is either decoded or ignored depending on your receiver’s capabilities. A key difference between the DD+ and True HD codecs, however, is that DD+ uses lossy compression.

Johny

Johny (John-Erik) Krahbichler is the CEO and main author of Gadgetzz, since 2009. While Mr. Krahbichler's expertise is in consumer electronics, his true passion is science´, and educating the world about the universe we inhabit. Check out the non-profit Scientific Literacy Matters Currently Johny is using his experience from covering trade shows such as the CES, to work with trade show exhibition marketing.

One Comment

  • Lord Omen21. May, 2020

    So all that extra data is just gone. Fucken Dolby

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