PCM and bitstream are two ways a player can send digital audio to a television, soundbar or AV receiver. The best setting depends less on sound quality than on which device you want to decode the audio and which formats your connection supports.
Key takeaways
- Choose PCM when the source device should decode the audio.
- Choose bitstream when a compatible receiver or soundbar should handle decoding.
- HDMI, eARC and optical connections support different channel and format combinations.
Related guides: Mono vs. Stereo: Differences in Recording and Playback What Is a Stereo Microphone? Uses and Techniques
Quick answer: Choose PCM when you want the source device—such as a TV, console or Blu-ray player—to decode the soundtrack. Choose bitstream when you want a compatible soundbar or AV receiver to decode Dolby or DTS formats. When both devices decode the same format correctly, neither setting is inherently higher quality.
| Setting | Where decoding happens | Often best for |
|---|---|---|
| PCM | Source player or TV | Simple compatibility, system sounds, mixed secondary audio, stereo output |
| Bitstream | Soundbar or AV receiver | Dolby/DTS decoding, receiver format indicators, direct home-theater playback |
What is PCM?
Pulse-code modulation (PCM) represents sampled digital audio. When a menu says “PCM,” it usually means the source device will decode a compressed soundtrack first and send the resulting audio channels onward as PCM.
PCM can be stereo or multichannel. It is not automatically limited to two channels; the number of channels depends on the source, device settings and connection bandwidth. HDMI can carry multichannel PCM, while optical connections commonly limit uncompressed PCM to stereo.
What is bitstream audio?
Bitstream—sometimes labeled “Auto,” “RAW,” “Passthrough” or “Bitstream out”—sends an encoded soundtrack to the next device for decoding. That stream may contain Dolby Digital, Dolby TrueHD, DTS, DTS-HD Master Audio or another supported format.
Your soundbar or receiver must support the format it receives. If it does, its display may show the Dolby or DTS format name while it decodes the signal.
Does PCM or bitstream sound better?
If the same soundtrack is decoded correctly, PCM and bitstream should contain the same underlying audio information. Moving the decoding step from the player to the receiver does not automatically improve detail, bass or surround separation.
Audible differences usually come from something else: different speaker layouts, volume matching, dynamic-range settings, downmixing, room correction, format support or connection limits. For example, a player might decode a soundtrack to stereo PCM because its output is configured for two channels, while bitstream allows the receiver to decode the original surround format. That is a configuration difference, not proof that bitstream itself sounds better.
HDMI, eARC and optical connection limits
HDMI and eARC
HDMI offers enough bandwidth for multichannel PCM and a wide range of compressed formats. HDMI eARC is designed to return higher-bandwidth audio from a television to a compatible soundbar or receiver, including formats that ordinary optical audio cannot carry.
The HDMI Licensing Administrator’s eARC overview lists uncompressed 5.1 and 7.1 audio alongside high-bitrate formats such as Dolby TrueHD and DTS-HD Master Audio. Support still has to exist at both ends of the connection.
HDMI ARC
Standard ARC has less bandwidth than eARC. The formats available through it depend on both devices and the television’s passthrough support. A TV may accept a format from an external player but convert or downmix it before returning audio over ARC.
Optical and coaxial S/PDIF
Optical and coaxial S/PDIF normally support stereo PCM and selected compressed surround formats such as Dolby Digital or DTS. They generally do not carry lossless high-bandwidth surround formats or multichannel uncompressed PCM.
This leads to a common practical choice: use stereo PCM over optical for a two-channel system, or use bitstream when you need a supported compressed 5.1 format.
When should you use PCM?
- Your receiver or soundbar does not support the source format, but the player can decode it.
- You use a stereo television, amplifier or pair of powered speakers.
- You need the source device to mix menu sounds, accessibility audio, voice chat or secondary Blu-ray audio into the main signal.
- You hear silence, dropouts or incorrect channel mapping when bitstream is enabled.
- You want a straightforward output that does not depend on the receiver recognizing a particular codec.
When should you use bitstream?
- Your AV receiver or soundbar supports the soundtrack’s Dolby or DTS format.
- You want the receiver to handle decoding and show the incoming format on its display.
- Your optical connection needs a compatible compressed surround format instead of stereo PCM.
- You want a disc player to pass the primary soundtrack directly without mixing secondary audio.
- Your television and audio system both support passthrough for the format you are using.
Recommended starting points by device
| Device or setup | Starting setting | What to check |
|---|---|---|
| TV speakers | PCM or Auto | Choose the option that produces clear stereo sound without delay |
| TV + stereo soundbar | PCM | Confirm lip sync and that the TV is not adding unwanted processing |
| TV + surround soundbar/receiver | Passthrough or Bitstream | Confirm the exact Dolby/DTS format is supported across the full signal path |
| Game console + receiver | Multichannel PCM or console-recommended output | Verify speaker layout, chat audio, latency and game-specific format support |
| Blu-ray player + receiver | Bitstream | Disable secondary-audio mixing if you want the receiver to decode the primary soundtrack |
| Optical stereo system | PCM | Set the source to two-channel output |
These are starting points rather than universal rules. Device menus use inconsistent labels, and one television may pass formats that another converts. Check the manuals for the TV, source and audio device when a format does not appear as expected.
Blu-ray secondary audio can change the answer
Some Blu-ray discs include menu sounds, commentaries or picture-in-picture audio. A player may need to decode the main soundtrack, mix in that secondary audio, and output PCM. If you disable secondary-audio mixing, the player can usually pass the primary encoded soundtrack for the receiver to decode.
If a receiver stops showing a lossless format after secondary audio is enabled, that does not necessarily mean anything is broken—the player may simply be performing the required mix.
PCM or bitstream for gaming?
Multichannel PCM is often a sensible starting point when a console connects directly to a compatible receiver or television over HDMI. The console can render the game audio and send the channels without an additional codec step. Bitstream can be appropriate when a sound system requires a specific supported home-theater format.
Prioritize correct channel mapping and low latency. If one setting creates lip-sync delay or causes the console to output only stereo, try the other and recheck the speaker configuration.
What about streaming apps?
Streaming-device and TV apps commonly use Dolby Digital Plus or decode to PCM, depending on the hardware and settings. Atmos availability may depend on the app, subscription, program, device, connection and receiver. Selecting “bitstream” cannot add a format that the content or equipment does not provide.
For a compatible Dolby Atmos soundbar, Dolby’s setup guidance recommends HDMI, ARC or eARC and bitstream output when the soundbar should receive and decode the Atmos signal. That is a device-specific reason to choose bitstream, not a rule that bitstream is always superior.
Common PCM and bitstream myths
- “PCM is always uncompressed stereo.” PCM can contain multiple uncompressed channels when the connection supports them.
- “Bitstream always sounds better.” Correctly decoding the same soundtrack in a different device should not create extra quality.
- “PCM cannot work wirelessly.” PCM and bitstream describe audio representation and processing, not a universal wired-versus-wireless rule. Wireless systems can use different transports and codecs internally.
- “The receiver must show Dolby for surround to work.” A receiver may show “PCM” while receiving correctly decoded multichannel audio.
- “Changing the setting upgrades the source.” Output settings cannot create channels or fidelity that are absent from the original soundtrack.
Troubleshooting incorrect or missing audio
- Confirm the source device’s speaker layout and output format.
- Check that every device in the chain supports the selected format—not only the receiver.
- If the source passes through a TV, confirm the TV’s digital-audio output and passthrough settings.
- Try PCM to determine whether the source can decode the soundtrack successfully.
- Try bitstream or passthrough to determine whether the receiver can decode it directly.
- Match volume before comparing. Different output modes can play at different levels, and louder often seems better.
- Check lip sync, dialogue clarity and channel placement with familiar material.
For more background on channel layouts, read our guide to mono and stereo audio. If you are building a computer-based setup, our audio-interface guide explains how playback hardware fits into the signal chain.
Information reviewed: July 2026. Device menus and supported formats change with models and firmware, so use the manuals for the exact TV, console, player and receiver as the final authority.
Final recommendation
Use PCM when the source device is the better or more compatible decoder. Use bitstream when a compatible soundbar or receiver should decode the original Dolby or DTS stream. If both options produce the correct channel layout without delay, keep the one that is easier to operate—there is no universal sound-quality winner.
