Did you buy a new TV set? Well, hello and welcome! It’s time to choose between the PCM and Bitstream audio options.
Your TV set receives audio signals from consoles, players (DVD/Blu-ray/CD), and other source devices. The TV—in turn—outputs processed audio through its speakers.
Media players and TVs have different audio and video output options, depending on the connector. On the HDMI connector, PCM and Bitstream are the two audio output settings.
You can set your TV to either PCM or Bitstream — it barely affects your audio output quality. However, you need PCM to enjoy secondary audio and Bitstream for other digital connectors outside HDMI.
This article explains PCM and Bitstream in detail. It is a guide for comparing and understanding both audio options.
Let’s get started!
What Is PCM?
Pulse Code Modulation (PCM) is an audio transmission technology that has been around for over a hundred years. It is responsible for collecting analog signals, such as audio recordings and reproduction, decoding the data, and converting it to digital audio waves.
Audio applications like Blu-ray use PCM technology, the primary option in your TV and other sound systems.
When you use the PCM setting, your media player decodes all the audio by itself. It sends the decoded audio signals to the AVR (or TV — depending on how you set up your home theater).
The AVR does not perform any additional audio processing. It simply passes the audio on to the TV or external speakers.
PCM supports the transmission of secondary audio features like audio commentaries, supplementary audio tracks, and on-screen button sounds.
What Is Bitstream?
Technically, Bitstream is a binary sequence of sound data that your media device uses to convert audio signals into digital bits.
Bitstream technology transfers encoded audio signals over the HDMI connector from the source player to the AVR or soundbar.
If you select Bitstream as your audio output setting, the source player will not decode the audio signals. It will send the encoded signals to your AVR.
In turn, the AVR will process the incoming audio data before sending audio to the TV or external speakers.
Regardless of these differences, the sound output from Bitstream is barely different from PCM. Bitstream is also known to support more audio frequencies.
Comparison: PCM Vs. Bitstream
Now that you know the difference between PCM and Bitstream, you’re probably wondering which one is best. The audio quality from PCM or Bitstream sounds the same to the average listener.
Some people argue that there aren’t any significant differences between the two audio options. However, there are certain factors you must consider before choosing either as your TV audio setting.
This section will compare both technologies based on compatibility and other factors.
Let’s get to it!
PCM and Bitstream audio output settings are compatible with multiple devices. However, PCM is the primary audio transmission setting in most devices.
PCM is the older of the two technologies, and older media devices support it. It has also evolved with the times and is compatible with newer devices.
In comparison, Bitstream is the new exchange student — cool and trending but can’t speak the language fluently.
Bitstream is new and was designed to serve new media devices in the market. It is not compatible with old media players.
Bitstream transmits audio signals on a single bit stream, which keeps bandwidth usage at a minimum. This low bandwidth capacity limits its transmission abilities to digital sounds only.
The low bandwidth allows Bitstream to transmit signals via wireless connections. However, Bitstream won’t work with analog devices like old CD players and retro movie systems.
In comparison, PCM has a higher transmission bandwidth which can support both analog and digital sounds. It remains the industry standard for audio transmission.
Here, PCM falls short of modern expectations.
Audio signals transmitted over PCM are decoded, uncompressed, and have high bandwidth. While HDMI can transmit large audio data, other digital connectors cannot.
PCM is not the best option if you use an optical or coaxial digital connector. They don’t have the capacity for high-bandwidth transmissions. Hence the resulting audio will lose some quality.
On the other hand, Bitstream does well with optical and coaxial connectors, supporting surround sound audio formats like Dolby TrueHD and DTS-HD.
4. Secondary Audio
Secondary audio describes any audio track that plays alongside the original audio in a movie or video. It includes descriptive voiceovers, commentaries, and multi-language audio translations.
Secondary audio transmission demands a high bandwidth capacity. Over HDMI, PCM can simultaneously decode and transmit primary and secondary audio with no loss of quality.
In comparison, Bitstream has a lower bandwidth capacity, so it struggles with secondary audio features.
To accommodate the secondary audio over Bitstream, the source player has to reduce the audio resolution of surround sound formats (i.e., DTS-HD to DTS) before sending audio to the AVR.
The AVR will receive the lower resolution signals and decode them accordingly.
Should My TV Be Set To PCM Or Bitstream?
If we merely evaluate the audio output quality of each format, there is no obvious winner. The best option for your TV depends on how you set up your home theater and the connectors you use.
Setting your TV to PCM means it will not process audio signals. It will only output audio that the source player already decodes.
PCM is the best option if you’re transmitting from older media players. It’s also the audio setting of choice if you want to output primary and secondary audio.
If you choose the Bitstream audio option, your TV will receive encoded audio signals from the source. The TV has to decode and compress the signals internally before outputting audio.
We recommend this setting only if you use an AVR or soundbar between your player and TV. The AVR or soundbar will receive and process the audio signals before sending audio to the TV.
Letting your TV speakers take on the job of processing audio signals is not advisable. It often results in reduced audio quality or low output volume.
Set your TV to Bitstream if you have a soundbar system and you want to enjoy high-resolution and surround sound audio formats. It is also best for transmitting audio via Bluetooth, coaxial, or optical cables.
PCM and Bitstream are technologies that manage audio signals in your TV. They are so similar in quality that most users do not detect any difference in their audio output.
However, PCM and Bitstream are quite distinct — in terms of features and performance. Use the Bitstream audio option if your home theater setup includes an AVR or surround speakers. If you’re only using your TVs built-in speakers, use PCM.
While PCM is the industry standard for audio output, Bitstream, combined with newer digital devices, brings a few new tricks to the table. Enjoy!
Gabriella ‘Diogo is a content writer with a vested interest in tech hardware and equipment. She shares her knowledge and processes in an easy-to-grasp, lighthearted style. When she’s not testing or researching device performance, you’ll find her writing short stories or rewatching episodes of her favorite sitcoms.