Solution for “Unsupported audio signal. Check your device output.” error with Amazon Instant Video on Roku.
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On a Roku 2 XS player some Amazon Instant Video movies (and most trailers) produce the error “Unsupported audio signal. Check your device output.” when played on some Sony Bravia televisions through the HDMI connection. There is a simple solution that worked for me although you have to give up Surround sound. Use the Roku remote to do this:
1. From the main menu choose settings.
2. Choose Audio mode.
3. If “Surround sound” is selected, choose instead “Stereo”.
4. Exit all menus.
That’s what fixed it for me.
What is happening?
Sony documents here that many of its devices, including its LCD, Plasma, and CRT TVs, support only PCM audio input. PCM stands for Pulse Code Modulation, and if I understand correctly is the “raw” or completely uncompressed signal. Typically for the best audio, you use PCM and not something smaller and compressed such as .mp3 because compression tends to lead to a loss of fidelity. Amazon Instant Video is a streaming media service, and so it would make sense that Amazon might want to reduce the amount of bandwidth being used by its customers by using a compressed audio for Surround Sound instead of the uncompressed PCM. And so therefore this compressed, non-PCM signal is not supported by many Sony devices. Switching the Roku to Stereo instead of Surround Sound indicates that Amazon is probably still using PCM for the Stereo signal. Amazon can do this because Stereo probably requires less bandwidth than Surround Sound so they have the option to use the full PCM instead of compressing the signal.