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Bitstream vs. PCM: Which is Better?

Bitstream vs PCM

Bitstream vs. PCM: Which is Better?

Bitstream and PCM are two popular forms of audio transmission from a source to a receiver. To ensure your audio needs are met and to guarantee your money doesn’t go to waste, we will shed some light on these two audio compression and reproduction methods.

These two methods help in the transmission of audio from transmitters and media players to the speakers and receivers in your home theater system. Although Bitstream and PCM are comparable technologies, they differ in how data is compressed and encoded.

In this guide, we will discuss some key differences between Bitstream and PCM to help you in making an informed decision. Let’s get started!

Bitstream vs. PCM: Side-by-Side Comparison

BitstreamPCM
What is it?Audio translation system that converts the analog output audio signal into digital bits and sends the information to a receiverUncompressed digital representation of an analog signal that involves quantizing the signal to a sequence of binary values and sampling the signal periodically at a set rate
TransmissionCompatible with players and receivers that support only digital sound transmissionCompatible with players and receivers with analog and digital sound transmission support capability
Optical / CoaxialDigital optical or coaxial output support can go up to 5.1Limited output for digital optical or coaxial support
CompatibilityCompatible with modern players that fully support surround sound formatsCompatible with most available players, including CD, DVD, and Blu-ray players
Audio OutputTo deliver high-quality audio output through the speakers and receivers, transmission needs to be more flexibleTo reduce the quality degradation with better output, transmission requires more bandwidth
Secondary AudioOptions might be limited, but the secondary audio quality is guaranteedBetter support provision for high-resolution secondary audio channels
File FormatFile formats can vary from DTS, Dolby Digital, etcUsually stored in AIFF or WAV file formats

Bitstream vs. PCM: Overview

Bitstream, also referred to as binary sequence, is an audio translation system that converts the analog output audio signal into digital bits from the source and transfers the information to a receiver. Once it breaks the audio signal into small parts, it relays it into the format that you choose. Several surround sound formats, such as Dolby Atmos, Dolby Digital, DTS X, TrueHD, and DTS Master Audio use Bitstream.

On the other hand, PCM converts audio signals into a series of digital values corresponding to the amplitude of the analog waveform. Used in different audio applications like Blu-ray, PCM is commonly known as linear pulse code modulation or LPCM. Since the PCM signal is uncompressed, it requires more bandwidth space.

Bitstream vs. PCM: What’s the Difference?

While both PCM and Bitstream provide high-quality audio, there are some subtle differences between the two. Let’s break them down below.

Compatibility

Bitstream is compatible with most modern players, which support surround sound formats compared to PCM, which is compatible with CD, DVD, and Blu-ray players. PCM is also more flexible and hence can support most media players compared to Bitstream, which generally works with modern devices that feature high resolution surround sound format support.

Decoding

While PCM players decode audio files before moving the data to the receiver, Bitstream players send compressed audio files to a receiver before decoding the information. Unlike PCM, which is limited by the quality of the audio player, Bitstream focuses on things like DTS Dolby Digital to improve the quality.

Audio File

PCM media players allow the conversion of audio between digital and analog formats. On the other hand, Bitstream uses encoded audio files and specific surround sound formats for digital transmission.

Bitstream also uses audio compression leading to better audio codecs for outputs like Atmos, Dolby Atmos, DTS HD Master Audio, Dolby TrueHD, and DTS.

Connection

PCM requires a physical connection between the AVR and the player. This means it transforms a continuous value analog and continuous time into discrete time and then moves a digital signal with a discrete value in the channel. On the contrary, Bitstream can work through wireless or wired connection to transmit audio streams via different mediums provided it’s from a compatible media player.

Loudspeakers producing audio
PCM can only work via physical connections whereas Bitstream can work completely wirelessly.

©oobqoo/Shutterstock.com

Audio Output

PCM uses a much higher bandwidth for a better output. Bitstream transmission, on the other hand, offers much more flexibility for speakers and receivers to provide a higher-quality audio output.

Secondary Audio

PCM performs much better as it supports high-resolution secondary audio channels. Bitstream has good secondary audio support with options that are not as versatile as with PCM. 

Transmission

PCM can work with receivers and players that support both digital and analog audio transmission, unlike Bitstream which only works with receivers and players that support digital sound transfer. This means the bits in Bitstream are generally transmitted at regular intervals with no start or stop signals.

Optical / Coaxial

The PCM format supports a limited amount of digital coaxial output options, compared to Bitstream, which is more versatile and supports both digital coaxial and optical output of up to 5.1 systems. 

Soundbar

Since most soundbars support surround sound, you can easily set them to Bitstream. With Bitstream, the source device will send compressed surround audio to the soundbar to give you the best sound. But, if the soundbar doesn’t work with surround sound, then you need to set it to PCM.

Bitstream vs. PCM: Similarities

Although Bitstream and PCM are quite different, they have several similarities when applied in audio production.

  • You can play both Bitstream and PCM files in most Blu-ray and DVDs disc players.
  • They both offer a great sound quality.
  • Both signals need to be converted into analog form to be heard through the speakers.

Pros and Cons of Bitstream

ProsCons
Increases the chances of improved sound qualityRequires a high-quality receiver in order to achieve improved performance
Provides support for 5.1 channels of optical and coaxial outputSupplementary audio is poor quality compared to its primary audio functions
In charge of decoding the audioEmbeds more workload on the high-quality receiver which can easily break the device
Offers more flexibility in playing Hi-Res audio
Bitstream offers a faster sound transmission 

Pros and Cons of PCM

ProsCons
Helps unlock high-quality secondary audioThe decoding and encoding can be complex
Compatible with most CD, DVD, and Blu-ray playersWhen the modulating signal changes between samplings, there can be an overload
Allows decoding in any type of player devicePCM audio quality transmission only relies on the media player used
Transmits high-res audio files with the wired system
Offers a smoother communication connection with very little sound latency

Bitstream vs. PCM: 10 Must-Know Facts

  • Bitstream outperforms PCM in the ability to use coaxial outputs and in terms of audio efficiency.
  • Both PCM and Bitstream produce high-resolution audio which makes it hard to know the differences.
  • Although they have different outputs, both Bitstream and PCM function excellently with DVD and Blu-Ray players.
  • A PCM soundtrack consists of the left channel and the right channel.
  • Supported frequencies and application compatibility of both PCM and Bitstream are more important concerns than sound and propagation.
  • Due to its low-frequency subcarrier modulation implementation, PCM audio reduces the pulse width error of the transmitted signal.
  • Both Bitstream and PCM have the capability to deliver high-quality audio to a level you can’t easily differentiate.
  • Bitstream Uses DTS technology to maximize audio settings.
  • When using PCM, the AV receiver has less control over the audio signal as all the processing is done by the source device. With Bitstream, the AV receiver has more control over the audio signal as it is responsible for decoding the signal. 
  • Both PCM and Bitstream must convert the audio files to analog, to achieve the output you require from your speakers.

When to Use PCM

Although both PCM and Bitstream work to improve the audio quality, there are concrete reasons to use the PCM configuration. For instance, if you are looking for a direct and fast connection that reduces output latency, your best option is PCM configuration. You can even use PCM for high-quality secondary audio. 

You can also pick PCM if your sound system supports only the audio file from the player. Additionally, you can choose the configuration if you are looking to stop the receiver from converting audio files. While PCM works with every type of player, it may fail to provide a smooth transmission when you have a sophisticated sound system.

When to Use Bitstream

You can use Bitstream if your receiver has better processing power or when your sound system relies on the receiver for processing the files. You can also pick Bitstream if you are looking to enjoy 5.1 surround sound or maximum flexibility while playing high-resolution audio.

But, while using Bitstream for secondary audio, the output can be limited. If you don’t have a high-end receiver, the processing capability will be reduced, hence there will be no improvement in the sound quality. You, therefore, need to invest in a high-end receiver so as to see a noticeable difference.

Bitstream vs. PCM: Which One is Better for You?

It’s not easy to pick a clear overall winner. Since there are instances where one performs better than the other, choosing the right one depends on the kind of audio quality you’re looking for and the setup you have. You will need to consider different factors before choosing between these two to get the best possible audio quality.

Most of the time, Bitstream outperforms PCM in audio efficiency and the ability to use coaxial outputs among other things. Furthermore, the Bitstream files are encoded to offer a surround sound experience.

If you are trying to watch TV and you don’t have any devices attached, PCM is a clear choice. But if you’re working with a home theater system with speakers or a soundbar connected, Bitstream is the best choice.

Frequently Asked Questions

Should I use PCM or Bitstream?

If you have a soundbar with 2.1ch that does not support Atmos, then you may go for the PCM option. If the device supports Dolby Atmos, then Bitstream should be selected.

What is LPCM?

Linear pulse code modulation, or LPCM, refers to an audio transmission configuration featuring uncompressed audio files. Also called PCM Plus, it has linearly uniform quantization levels. Except for the quantization precision and sample rate, the system and process for LPCM and PCM are the same. LPCM uses raw audio, AU Audio, AC3, WAV, AIFF, RF64, and MPEG audio and only works with an HDMI connection via coaxial or optical.

Is PCM audio high quality?

Since PCM audio is uncompressed and lossless, no audio data is lost, so it results in a higher-quality audio file. It’s also compatible with most devices thus making it an ideal choice for applications where compatibility is required.

What’s the best format for PCM?

AIFF, WAV, and AIFF are arguably the most common uncompressed audio file formats for PCM. While they use similar data, they store the data in slightly different ways.

Is PCM the same as Dolby Digital?

PCM is uncompressed raw audio. Dolby Digital is compressed audio (somewhat like an MP3), which is essentially the PCM version, and compressed in a lossy manner. So, in general, PCM will sound better, since the Dolby Digital version is made from it.
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