bitstream vs pcm
(Last Updated On: August 27, 2020)

When it comes to setting up an audio system, people often confuse PCM with bitstream. Others don’t even know which option to choose or why it’s the best for them.

And though most people have different hearing capabilities, it’s important to know which option is better for your audio purposes.

This article serves as a guide to help you understand the difference between bitstream and PCM. It will also give you helpful insight to allow you to know which format is better for your streaming or digital purposes.

 

What is PCM?

PCM is an acronym for Pulse Code Modulation, a method of converting analog signals into digital form with no compression.

A PCM stream regularly samples the amplitude of an analog signal at uniform intervals. It then uses numeric (binary) coding to quantize the signal.

That means that a PCM file is basically a series of zeros and ones interpreted from analog sound waves.

pcm pulse code modulation

PCM is common in telephone systems, CD formats, Keyboard pianos, computer audios, digital videos and CD formats.

It helps to record a movie soundtrack or musical data without occupying much space. To help you understand this, compare the size of a vinyl record to a CD.

PCM Audio in Home Theater

DVDs, CDs, and Blu-ray disc players use linear plus code modulation (LPCM). This type of PCM file has a variety of digital audio applications.

More importantly, you can transfer it from the disc to your home theater system in two ways:

  • Through HDMI connection

While PCM is a digital interpretation of analog signals, you can listen to the audio data by using the signal in its digital form. To do that, you will need to send the signal to your home theater through a digital coaxial, digital optical or HDMI connection.

For the home theater system to allow you to enjoy the audio, the receiver converts the signal back in analog form.  That’s because the human ear can only interpret analog audio signals. For this reason, the digital audio data has to be converted before sending it to the speakers and amplifier.

  • Through analog audio connections

For an analog connection, the Blu-ray Disc, DVD or CD player can internally convert the PCM signal in analog form. That will allow you to transfer the re-created analog signal to a stereo receiver or a home theater system through a standard analog audio cable.

In this scenario, the stereo receiver doesn’t perform an additional conversion for you to hear the audio. This type connection is available in most CD players, though some of them can also transfer digital signals through HDMI connection.

What is Bitstream?

Bitstream (also known as Binary sequence) is a sequence of information bits represented by 0’s and 1’s. This digital information series is suitable for networking, PC, and audio applications.

In audio application, bitstream converts audio data into digital information bits and transfers it to a receiver.

This method of transferring data is common in home theater systems that create specific surround sound formats like Dolby Digital, DTS:X, Atmos, TrueHD, DTS HD-Master Audio and others.

 

Bitstream Use In Home Theaters

In home theater systems, bitstream basically involves transferring encoded sound signals from a source device to a compatible receiver or AV processor/ power amplifier.

These audio signals are usually available in various surround sound formats.

The receiver detects the encoded surround sound formats and proceeds to decode the information according to the instructions embedded in the bitstream signal.  It further adds additional post-processing and converts the signal in analog form. That allows the system to amplify the sound and send it to the speakers for you to hear it.

A bitstream process starts with the sound mixer and content creator. The content creator must decide the surround sound format to use for recording a live transmission. The sound mixer/ engineer then proceeds to encode the audio in bits corresponding to the chosen format.

After the process is complete, the digital bits are placed on a satellite or cable service, embedded on a live transmission or saved on a disc (Blu-ray, UHD Blu-ray, and DVD). When it comes to playing the audio, the required bitstream is sent from the source device to the home theater receiver using a physical connection.

That includes HDMI, digital coaxial and digital optical cable. It can also be sent wirelessly to your home network through an antenna.

The receiver then decodes the digital bits according to the assigned channels and sends the signal to the amplifiers. That allows the listener to hear the audio from the loudspeakers.

 

The Difference Between PCM and Bitstream

pcm vs bitstream


Similarities Between PCM and Bitstream

While PCM and bitstream are very different, these two settings are very similar when applied in audio production. Here are several similarities that are worth noting before you can decide which option is best for you:

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

The Bottom Line

So that’s it, the difference between bitstream and pcm. To reiterate, while audio signals are produced in different ways in both cases, there is no audible difference between Bitstream and PCM files.

However, bitstream files are encoded to give you a surround sound experience when using a compatible media player. On the other hand, most audio players only support the PCM format while transmitting sound. That means you should check your device’s compatibility when choosing between the two. We hope we sufficiently answered your question what is the difference between pcm and bitstream.