Nowadays there are so many setting options on players, receivers and home cinema systems that you can no longer see the forest for the trees. However, some settings are very important. If you have a Blu-ray player then you have probably seen the options Bitstream and PCM. But, what are these options for and what’s the difference between Bitstream and PCM audio?
Difference between Bitstream and PCM audio?
If you have connected your Blu-ray player to a receiver or home cinema set via HDMI, there are two options for the transmission of audio; Bitstream and (L) PCM. In terms of audio quality, there is in principle little difference if you connect the player via HDMI, but there is a difference in the way the audio is forwarded.
Blu-ray audio – PCM
If you set the player to PCM audio playback, the player itself ensures that the (HD) audio formats on the Blu-ray disc (for example DTS-HD and Dolby TrueHD ) are decoded. The audio is then sent uncompressed to your home cinema set or receiver. This set or receiver then no longer has to decode signals itself, so that the audio can be sent directly to the (amplifier and) speakers. You will see the PCM logo burning on the display of your set or receiver. This option is mainly used when the receiver does not support decoding of (HD) audio formats. The player then picks it up so that the receiver only has to play the audio.
Blu-ray audio – Bistream
When you select the Bistream option, the player ignores the decoder options for audio and the signal is sent unencrypted to the receiver or home cinema set. The set or receiver then uses its own decoders to convert the signal into a usable signal for the amplifier and speakers. You will then see the log of the relevant audio format appear on the display of your receiver or set (Dolby, DTS, etc.). This option can always be used if your receiver or set supports decoding the audio formats you want to play back. It is always possible to switch between PCM and Bitstream.