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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
| Bitstream | PCM | |
|---|---|---|
| What is it? | Audio translation system that converts the analog output audio signal into digital bits and sends the information to a receiver | Uncompressed 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 |
| Transmission | Compatible with players and receivers that support only digital sound transmission | Compatible with players and receivers with analog and digital sound transmission support capability |
| Optical / Coaxial | Digital optical or coaxial output support can go up to 5.1 | Limited output for digital optical or coaxial support |
| Compatibility | Compatible with modern players that fully support surround sound formats | Compatible with most available players, including CD, DVD, and Blu-ray players |
| Audio Output | To deliver high-quality audio output through the speakers and receivers, transmission needs to be more flexible | To reduce the quality degradation with better output, transmission requires more bandwidth |
| Secondary Audio | Options might be limited, but the secondary audio quality is guaranteed | Better 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.
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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
| Pros | Cons |
|---|---|
| Increases the chances of improved sound quality | Requires a high-quality receiver in order to achieve improved performance |
| Provides support for 5.1 channels of optical and coaxial output | Supplementary audio is poor quality compared to its primary audio functions |
| In charge of decoding the audio | Embeds 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
| Pros | Cons |
|---|---|
| Helps unlock high-quality secondary audio | The decoding and encoding can be complex |
| Compatible with most CD, DVD, and Blu-ray players | When the modulating signal changes between samplings, there can be an overload |
| Allows decoding in any type of player device | PCM 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.
