PCM vs Bitstream for Soundbars: Which Audio Format?

What PCM means on a soundbar listing

PCM stands for pulse-code modulation. It is an uncompressed digital audio format that carries sound as a stream of digital samples. When your TV sends audio as PCM to a soundbar, the soundbar receives the digital signal and turns it into sound without any extra decoding step. PCM can carry stereo audio or multichannel audio, but it requires enough bandwidth on the connection to deliver all channels.

On a soundbar listing, PCM support means the bar can accept this uncompressed signal from a TV or source device. Many TVs output PCM as the default for apps and over-the-air broadcasts. If the listing does not name a specific audio format such as Dolby Atmos or DTS, the soundbar may still accept PCM from an HDMI ARC or optical connection.

What bitstream means on a soundbar listing

Bitstream refers to a compressed, encoded audio format such as Dolby Digital, DTS, or Dolby Atmos. The source device (a Blu-ray player, streaming box, or TV app) sends the encoded data to the soundbar, and the soundbar must have a built-in decoder to turn it into sound. Unlike PCM, bitstream keeps the original encoded format intact, so the soundbar controls the decoding.

A soundbar listing that names a format like Dolby Atmos or DTS:X is telling you that the bar includes a decoder for that bitstream format. A listing that only states a channel count like 2.0 or 5.1 does not tell you which bitstream formats are supported. You would need to read the maker's page to see which compressed formats the soundbar can decode.

The internal links best Dolby Atmos soundbars and best soundbars with rear speakers point to models that state these decoding features.

How HDMI and optical connections carry each format

The connection between your TV and soundbar matters because each connection has different limits. HDMI ARC can carry both PCM and compressed bitstream formats. HDMI eARC, as the HDMI 2.1 specification notes, supports the most advanced audio formats and the highest audio quality. This makes eARC the connection to prefer when you want to send a bitstream like Dolby Atmos to a soundbar.

Optical (Toslink) connections can carry PCM and compressed bitstreams, but they cannot carry the same bandwidth as HDMI eARC. Optical typically handles two channels of PCM or a compressed bitstream like Dolby Digital. For uncompressed multichannel PCM, HDMI provides a stronger path.

Check the ports on your TV before buying. If your TV only has optical, look for a soundbar that accepts the compressed bitstream formats your TV can output. If your TV has eARC, a best HDMI ARC soundbar with eARC support gives you the most flexibility.

Reading a listing title for audio format

Soundbar listing titles usually name the channel layout and the formats a bar supports. A title with "2.0" tells you the bar has two channels and no subwoofer. A title with "Dolby Atmos" tells you the bar includes a decoder for that bitstream format. A title with "5.1" tells you there are five main channels and one subwoofer channel, but it does not always state which bitstream formats are decoded.

The absence of a format name can simply mean the seller did not state it. The learn article on soundbar channels explains how to read a channel count. Reading a maker's product page next to a listing tells you which formats a specific model decodes.

When a title names two formats such as "Dolby Atmos" and "DTS:X," the bar includes decoders for both bitstream types. If the title names only one, check the maker's page to see if the other is supported. Comparing two soundbars on stated details means comparing these named formats, not guessing at unlisted ones.

Which format suits your connection

If you watch mostly broadcast TV, apps, and stereo music from your phone, PCM is a simple and reliable choice. Your TV sends an uncompressed signal that any soundbar can accept over HDMI ARC or optical.

If you watch movies from a Blu-ray player or a streaming service that supports Dolby Atmos, bitstream lets the soundbar decode the full encoded format. You would send the bitstream from the source to the TV, then from the TV to the soundbar over eARC. For this, you need a soundbar that states Dolby Atmos or DTS support.

The best 2.0 soundbars and the best soundbar guides cover simple sets where PCM is a common input. For a home theater layout with a separate subwoofer or rear speakers, the best soundbar with separate subwoofer guide lists models that pair HDMI inputs with decoding features.

What to pick for your situation

Questions

Which is better for a soundbar, PCM or bitstream?

Neither is universally better. PCM is uncompressed and simple, while bitstream preserves an encoded format such as Dolby Atmos for the soundbar to decode. Choose based on the source content and the connection between your TV and soundbar.

Can an optical cable carry PCM or bitstream?

Optical can carry both PCM and compressed bitstream formats. It typically carries two channels of PCM or a compressed bitstream like Dolby Digital. For uncompressed multichannel PCM or high-bandwidth formats like Dolby Atmos, HDMI eARC is the stronger connection.

Does HDMI ARC support bitstream audio?

HDMI ARC supports compressed bitstream formats such as Dolby Digital. HDMI eARC, as the HDMI 2.1 specification states, supports the most advanced audio formats and the highest audio quality. For advanced bitstreams like Dolby Atmos, eARC is the preferred connection.

How do I know what a soundbar can decode?

Read the listing title for named formats such as Dolby Atmos or DTS:X. If the title only states a channel count like 2.0 or 5.1, visit the maker's product page to see which compressed formats are decoded.

Should I set my TV to PCM or bitstream?

Set your TV to match what the soundbar supports. If the soundbar accepts the bitstream formats your TV can output, choose bitstream. If you are not sure, PCM is a common default that works over HDMI ARC and optical for stereo TV sound.