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HDMI Audio Return Channel Conundrum

Scott Wilkinson  |  Mar 2, 2012

I have a Panasonic TC-P50GT30 plasma TV and Pioneer VSX-1121 A/V receiver, both of which support HDMI version 1.4 with Audio Return Channel (ARC). The AVR's HDMI output is connected to the TV's HDMI input 1, which is the only input with ARC capability. I also have a PS3 connected to one of the TV's other HDMI inputs. When I play a Blu-ray disc on the PS3 and listen to the audio through my AVR, all I see on the AVR display is Stereo. However if I connect the PS3 to the AVR directly, I see Dolby Digital (or whatever the audio format is) on the AVR display. Does the Panasonic plasma not pass the advanced Blu-ray audio formats, such as Dolby Digital Plus, Dolby TrueHD, and DTS-HD, to my AVR via HDMI ARC?

Dan

First of all, your connection scheme seems pretty whacky to me. Why would you connect the PS3 to the TV rather than the AVR to begin with?

For those who might not be familiar with Audio Return Channel, this feature of HDMI 1.4 allows compatible devices to send audio from an HDMI input to a compatible HDMI output—in other words, in the opposite direction of the normal signal flow. It's used mainly with an ARC-compatible TV and AVR connected in the normal manner—that is, the AVR's HDMI output is connected to the TV's ARC HDMI input. (As with the GT30, not all HDMI inputs on a given TV are ARC-compatible.) When you watch the TV's internal tuner or online streaming apps, the audio is sent back to the AVR along the same cable that usually carries audio and video from the AVR to the TV. This eliminates the need for a separate TosLink or coax digital-audio cable from the TV to the AVR when the audio is generated by the TV itself, as shown in the diagrams above.

ARC can convey Dolby Digital, DTS, and PCM, but none of the advanced codecs, such as Dolby Digital Plus, Dolby TrueHD, or DTS-HD. After all, none of these codecs are used with over-the-air, cable, or streaming content.

I'm kinda surprised that your connection scheme works at all—ARC is not intended to take audio coming into one HDMI input and send it out from another input. I would definitely connect the PS3 to one of the HDMI inputs on your AVR instead of the TV, which will simplify the system and let you hear all the advanced codecs in their full glory. If you use the TV's internal tuner or online apps, keep the AVR's HDMI output to the TV's ARC HDMI input, and you'll hear the audio from the TV without having to connect a separate audio cable from the TV back to the AVR.

If you have an A/V question, please send it to askhometheater@gmail.com.

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