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PCM vs. Bitstream: Which Is Better?

If you’re connecting a media device like a Blu-ray player to your home theater setup, you’ll have two standard audio options available, PCM (pulse-code modulation) or bitstream.

Unless you’re a hardcore audiophile, it might be difficult to know which option will help you optimize your sound system’s performance.

Although both PCM and bitstream are capable of producing the same audio quality, there’s a big difference in how they decode your audio files.

This article will give you an in-depth comparison between PCM vs. bitstream. You’ll learn the pros and cons of each and have a clear understanding of which option works best for you.


PCM Overview

PCM creates a digital representation of analog signals. This technology was first developed in 1939 and is still commonplace today. One of the benefits of PCM is that no compression occurs during conversion. Large files transfer onto a smaller virtual or physical space. Moving music recordings from vinyl records to CDs provides a visual representation of this process.

When you use PCM for home theater audio, your Blu-ray player will decode the analog file before sending it to your receiver. You won’t need a receiver with a powerful processor, because its only job will be delivering the files to your speakers for output.

The signal runs to your home theater through HDMI, coaxial, or digital optical connections. These connections allow the receiver to convert the signal into its original analog form because the human ear can only detect analog sounds.

If you’re running an analog connection, your device (Blu-ray, DVD, or CD player) will perform an internal conversion of the PCM signal. A standard analog audio cable will be sufficient for you to transfer the audio to a stereo receiver in this case. 


Bitstream Overview

Bitstream is a sequence of digital data consisting of 0’s and 1’s. In the case of home theater, bitstream takes your audio data, converts it into a digital format, and sends it to your receiver.

The audio samples sent from your source device should be available in a variety of surround sound formats. Once your receiver detects the embedded information from the bitstream signal, it converts it into an analog format. Bandwidth shouldn’t be a concern because the files remain compressed in your player. 

Content creators and sound engineers handle the bitstream design process. They determine which surround sound format to select based on the type of audio recording. The audio

becomes encoded in the form of digital bits before formatting. The last step consists of transferring the bits onto a disc (DVD, Blu-ray, etc). It’s also possible to embed them onto a cable or satellite service, streaming source, or live TV broadcast.

Bitstream limits you to digital sound transmission. You have more flexibility if you want to run a wireless connection via an antenna or home network. Just like PCM, you can also go with HDMI, coaxial, or digital optical wired connections.


PCM vs. Bitstream: Similarities

If you’re running a standard HDMI audio input, it’s not likely that you will hear a difference between the two options. Neither option requires a secondary audio output or high-resolution codec. Both configurations can work well with the majority of DVD and Blu-ray devices. 

What’s more, many contemporary players may give you the option to switch between PCM and bitstream with no interference. In both cases, audio files will need to be converted into an analog format before you can hear them.

The majority of AV receivers facilitate both styles of transmission as well. Try testing out each configuration to see which works best with your speaker system.


PCM vs. Bitstream: Feature Comparison

While this isn’t an exhaustive list, here are some considerations to focus on when contrasting features and functionality when comparing PCM vs. bitstream.

Compatibility

PCM works with most run-of-the-mill DVD, CD, and Blu-ray players. Bitstream is compatible with premium devices that support surround sound formats, such as Dolby Atmos and DTS:X. 

Connection

You’ll need a physical connection from the AV receiver to your source device with PCM to transmit the larger audio files. Bitstream gives you the freedom to use either wired or wireless connections, provided that you have a compatible device.

Audio Files

With PCM, the player handles the conversion process. Analog signals convert into a digital format before being sent to the receiver. Bitstream encodes digital files according to specific formatting requirements. 

Audio Output

PCM requires more bandwidth usage to prevent audio quality from dropping. Bitstream’s audio transmission gives you greater flexibility for receivers and speakers to deliver superior sound.

The situation reverses when it comes to secondary audio channels. PCM can handle hi-res secondary audio, while bitstream will downgrade it due to bandwidth incompatibility issues. 

Secondary Audio

PCM is well-equipped for providing high-resolution secondary audio channels. It does have the drawback of having a two-channel system. You are limited to left and right speaker audio.

Bitstream has fewer options for transmitting secondary audio. You may have to switch to a lower resolution if you still want to listen to it.

Transmission

PCM supports both analog and digital formats. With bitstream, you’re limited to media players that support digital sound transmission.


PCM vs. Bitstream: Differences

The core differences between both configurations can be device-specific. The most deciding factor for most people will boil down to the file quality produced by your receiver.

PCM uses an unprocessed signal generated by the AD converter. Codecs such as Dolby Digital or DTS won’t alter the quality.

Bitstream uses coded audio files. Concerns come up because encoding can result in a loss of quality. To circumvent this problem, lossless compression methods, such as Dolby TrueHD and DTS-HD Master Audio, have been developed. 

You’ll have the option to decide which device you want to handle decoding with bitstream. It’s worth figuring out if your Blu-ray player or AV receiver has better technical specifications to handle this process. If you’re unsure which of your devices handles decoding, just check the display panel.

PCM has a wider array of devices with which it can perform well. Bitstream limits you to devices configured for hi-res surround sound.


Understanding PCM

Let’s explore what happens when you set your output audio to PCM. Your Blu-ray device will take all audio files and decode them. It will then send the uncompressed files to your home receiver. Your receiver won’t have to perform any additional decoding before sending your audio to your amplifiers and speakers.

If you want to make sure you’re running a PCM connection, check your display panel. It will read either “PCM” or “LPCM” (linear pulse-code modulation.) If you’re a fan of secondary audio tracks, such as film commentaries, PCM will be your best bet. Your player will be able to decode multiple audio tracks without your bandwidth suffering. 

You’ll run into difficulties with PCM if you’re opting for a coaxial or digital optical connection. PCM is limited to two-channel signals. You’ll only have sound coming out of your left and right speakers in these scenarios. Coaxial and digital optical cables lack the bandwidth capacity to transfer uncompressed, full surround audio.


Why Should You Choose PCM?

PCM is the ideal audio setup for you if you meet several criteria:

  • You hate latency and want to ensure a faster, more direct connection.
  • You’re a fan of additional audio tracks like commentaries and want them to sound good.
  • Your receiver doesn’t have enough processing power to decode audio files.
  • Your sound system’s configuration works better with decoding files in the player.

PCM has the added benefit of being compatible with almost any device. Bear in mind that your audio quality will be somewhat contingent on your player with PCM. Unless you have a state-of-the-art system, you shouldn’t have to worry about a significant loss in audio quality.


Understanding Bitstream

Bitstream converts audio data into a digital form before sending it to the receiver. Unlike PCM, decoding does not happen in your primary device, such as a gaming console. The audio files go to your receiver before decompression.

An exception to this rule might come into effect if you have a cable or satellite box receiving bitstream. Decoded information comes to your television before distribution. 

Bitstream is the more commonplace with home theater setups that create surround sound formats. To confirm you have bitstream selected, you can once again check your front panel display. It will read Dolby, Dolby TrueHD, DTS, etc., based on the type of decoded bitstream signal.

If you select a secondary audio setting with bitstream, you will experience a reduction in audio quality. Bitstream connections work via HDMI, coaxial, and digital optical cable. You can also go with a wireless connection if that suits your preference. 


Why Should You Choose Bitstream?

Take advantage of a bitstream configuration if these criteria apply if you:

  • Want to have the experience with surround sound.
  • Have a receiver capable of higher-quality audio processing.
  • Want to utilize 5.1 channel supports over a digital optical or coaxial connection.
  • Have a sound system that requires your receiver to decode the audio files.
  • Want the freedom to utilize the wireless speakers for your home theater.

Bitstream eliminates the analog to digital conversion process you have to worry about with PCM. The result? Better sound quality. You can up the ante by adding more speakers to your home entertainment system. You’ll feel like you’re right in the middle of a herd of dinosaurs while watching that Jurassic Park movie!

Remember that bitstream works best if your audio system has considerable processing power. The difference will be negligible if you’re working with more average equipment. 


PCM vs BitStream: Which is Better?

Taking which type of connection you want to implement into consideration can also influence your decision. Coaxial and optical digital cables will give you maximum flexibility to use either PCM or Bitstream. 

A bitstream connection can send a Dolby Digital or DTS 5.1 to your receiver. You are limited to a two-channel signal with PCM. The reason for this limitation stems from how much bandwidth capacity coaxial and optical digital cables possess. Unlike HDMI, they aren’t able to transfer uncompressed, surround sound audio signals.

In the same vein, HDMI is necessary if you’re transferring Dolby Digital Plus, Dolby TrueHD, or DTS-HD Master Audio.


Defining Secondary Audio

Given that secondary audio is one of the main differentiators between PCM and Bitstream, let’s explore what it means in greater depth. Secondary audio program (SAP), also called secondary audio programming, is an auxiliary audio channel that allows encoded dual audio and supplementary audio tracks in a multimedia file. 

These tracks can range from music tracks, video tracks, cartoons, and opening/closing credits. It is designed for analog television and is part of the multichannel television sound (MTS) standard that various broadcasting companies adhere to today.

Hardware Considerations

Real-world examples can help elucidate whether PCM or Bitstream will be the best option for your home theater setup. Let’s assume you’re the proud owner of a PlayStation 5 and you’ve connected it to your AV receiver with an HDMI cable.

If you set your PS5 to bitstream, it sends an unprocessed audio signal straight to your AV receiver. Your receiver will handle decoding as long as it supports your sound codec set on your PS5.

If you set your PS5 to PCM, the PS5 will be responsible for decoding the audio signal. The performance of the respective devices meditates the quality. AV receivers tend to take the cake here as a general rule of thumb. PCM would be the superior option if you’re lacking an AV receiver and you’re running the sound through your TV box.

Personal Considerations

Use all of the information you’ve learned about the differences between PCM vs. bitstream to your advantage. The best setup will be contingent upon your equipment and desired outcomes.

If secondary audio options are a must-have, PCM should be your go-to choice. Bitstream can provide you with a more robust audio experience if you have the requisite hardware.