What is PCM? (And the difference to raw audio) ๐Ÿ“บ

Did you find PCM as an option in your audio settings? And you don't know what it is or what difference it does?

Let me explain what is PCM in your audio settings...

What is PCM?

PCM is the digital representation of sound. PCM stands for 'Pulse-Code Modulation'.

The sound is actually a wave (analog audio signals) but PCM transforms it into digital signals.

It does that by taking samples of an audio signal at regular intervals and converting them into a series of digital values.

About the audio quality

So, is PCM good?

Well yes, PCM is generally better for many reasons. One of which is the "higher sampling rate" that other older techniques don't have. So it is suited for high-speed systems such as video and telephony applications.

PCM audio recordings are considered raw digital audio samples.

This means that the signal is pure and usually in the highest quality. The reason is that the signal does not suffer additional compression (Like DTS or Dolby Digital).


  • PCM allows the recording of any sound into a smaller space.
  • It can provide high-quality sound that can be easily edited and manipulated. It is common to divided the sound in several channels.
  • It is currently the most commonly used audio format in the world.


  • Large file sizes (When compared to compressed formats).
  • Potential for quantization errors.

What option should I use?

It's common to have a few options. Usually "Auto" or PCM.

PCM can handle a few channels (Left and Right), which "raw" audio cannot. So receivers may convert your raw audio to PCM before outputting it to you.

In theory you are a safe to use PCM if the external device has already processed the sound (and you will just output it in your TV speakers).

Unfortunately I've seen no difference in my TV setup by switching between these two options. However, a few users have seen a great improvement in sound quality when making this change. So I encourage you to test it by yourself.

Before moving on to the general comparison section, let me give a few tips.

Testing tips

As a word of advice, be sure to turn off and on your device before assessing the new audio output.

Test one setting at a time. If you make several changes at once you will never know what made it right (or wrong).

Ideally you should use an audio that you know by heart how it should be played. Check for noises and interference in all audio options before making your decision.

PCM or "raw audio output", which one is better?

The main difference between PCM and raw audio output is that PCM is a digital representation of an analog audio signal, while raw audio output is the pure (unprocessed) audio signal.

"Raw audio output" is limited to a wired connection but that's not the biggest limitation.

The big problem of the "raw audio output" is that it does not support multiple channels. So no surround sound.

Examples with PCM technology

These are real world Tvs that use PCM audio:


Frequently asked questions

"Audio out" or "Audio in"

"Audio in" is the place it will receive the audio signal from an external source and "Audio out"ย is where the device will export the audio.

So if you want to pass your the audio from your TV to a sound bar, you will connect the audio cable from the soundbar in the "audio out" slot of your TV.

Similarly, if you want your TV to output the sound from an external device (like a blu-ray player), you will connect that device in the "Audio in" slot.

PCM, Dolby Digital or DTS

PCM is uncompressed audio. Dolby and DTS use compressed audio.

So, PCM has higher audio quality than the rest.

The advantage of compressed audio is that it occupies less space.

PCM or "PassThrough"

The "passthrough technology" may be better than PCM regarding sound quality and ease of use.

One of the biggest challenges with Pass-Through audio tech is that you may experience some syncing problems, which you can resolve using PCM.

What is Bitstream

PCM is the pure digital version of the audio signal and bitstream is normally associated with the compressed form.

There are different kind of algorithms used so they each have a different name format. Popular audio bitstream formats are:

  • MP3
  • AAC

They use compression techniques to reduce the file size of the audio data. Most of the time this is achieved by removing sounds that we (Humans) cannot hear.

What is "digital audio output"

A "digital audio output" is a slot that allows an audio signal to be transmitted in digital form to another device.

If you want to output the audio of this device in another, this is the slot you are looking for.

This can be useful for transmitting audio signals over a network, or for sending audio signals to a digital audio recorder


S/PDIF is a cable interface and PCM is the technology.


HDMI is the cable (And connection) while PCM is the technology.