The decoder location changes
Infomir describes optical Bitstream as compressed sound passed to downstream equipment, while PCM is decoded output. The receiving device’s capabilities therefore matter when choosing the mode.
A mode called Bitstream is not automatically better for an older receiver. If it cannot decode the supplied format, the route may not produce usable sound. Check the exact receiver manual and source format.
Compare the intended optical route
Confirm that the cable reaches the chosen audio system and that the receiver uses the correct input. Keep HDMI picture and optical sound as separate parts of the setup. A visible picture does not establish optical audio routing.
Use one known item and change only the documented output mode for the comparison. Keep listening levels moderate and do not simultaneously change receiver processing.
Keep format evidence attached to the item
A successful simple soundtrack does not prove every multichannel format works. Record the source and selected mode when reporting a difference.
The cited settings concern supported Linux/WebKit MAG embedded portals. This article explains their decoding roles without claiming a hands-on codec test or a universal menu on every MAG model.
Questions answered
Does Bitstream mean the MAG decodes the compressed audio?
Infomir describes it as passing compressed sound to the downstream decoder.
Does a working optical stereo test prove all formats?
No. Check each relevant source format and receiver capability.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.