HDMI audio format: PCM or Bitstream - differences simply explained

When it comes to audio formats, HDMI often includes the terms PCM and bitstream. We explain what it is and when you should use which option.

PCM and Bitstream - these are the differences

PCM (pulse code modulation) means the "raw" signal generated by the AD converter. The signal is therefore not additionally source-coded, for example by DTS or Dolby Digital, and thus converted.
As a PCM, your signal is therefore pure and usually also of the highest quality. It takes up a lot of space, but sounds very good.
There are also formats such as Dolby Digital or DTS, in which the signal is (source) coded. In these two examples, the coding runs with quality losses.
However, there are also lossless compression methods such as DTS-HD Master Audio or Dolby TrueHD.
These formats are transmitted in so-called bitstreams. Here you can choose whether your Bluray player or your AV receiver should do the decoding work, for example. Note: If your receiver does the decoding, the corresponding logo usually appears on the display.
The advantage of this is that the audio track can be stored compressed on your Bluray, but you still get the highest quality in the end. Because the pure PCM signal can be obtained again from the DTS-HD Master Audio soundtrack.
The disadvantage of this is that your receiver must also support this decoding process. In this case, you can simply let your player decode the signal and output it as PCM and not as bitstream.
It also follows that your receiver does not necessarily have to support the new HD formats in order to display them in full quality.

In the next article we will show you what you can do if your PS3 does not play any sound via HDMI.