Audio settings often come with unfamiliar choices. One of the most common questions asked by home theater users and casual viewers alike is: Should I choose Bitstream or PCM? This guide explains the differences without technical fluff, helping you decide what works best for your system.
Bitstream and PCM: Defined Without Confusion
Bitstream is a method where your media device sends encoded audio data directly to your receiver. The receiver then decodes the signal into sound.
PCM (Pulse-Code Modulation) means your device decodes the audio before sending it. The receiver simply plays what it’s given.
Why This Choice Exists
Most streaming devices, Blu-ray players, and gaming consoles give you both options. The choice impacts how audio is processed, which device handles decoding, and what features you can use.
Key Differences That Actually Matter
1. Decoding Location
- Bitstream: Audio is decoded by the AV receiver or soundbar.
- PCM: Audio is decoded by the source device (console, player, etc.).
2. Surround Sound Support
- Bitstream supports advanced surround formats like Dolby Digital (AC3), Dolby TrueHD, DTS, and DTS-HD Master Audio.
- PCM supports surround audio, but not always the full range of encoded formats.
3. Display Behavior
- Bitstream: You may see format names (like Dolby Digital) light up on your receiver.
- PCM: The display usually just shows “PCM,” even if it’s sending 5.1 channels.
4. Secondary Audio and Features
- Some Blu-ray menus and commentary tracks may not play correctly in Bitstream mode due to how they mix secondary audio.
- PCM handles these better since decoding is done before output.
Who Should Use Bitstream?
You should use Bitstream if:
- You have a modern AV receiver that supports Dolby or DTS decoding.
- You want the best surround effects with minimal signal loss.
- You prefer your receiver to handle all audio processing.
- You like seeing format indicators (e.g., “Dolby TrueHD”) light up on your receiver.
Who Should Use PCM?
You should use PCM if:
- Your receiver is basic or doesn’t support advanced audio formats.
- You rely on secondary audio features or Blu-ray extras.
- You want to ensure compatibility across older devices or TVs.
- You’re using HDMI ARC, and Bitstream is causing audio sync issues.
Use Case Examples That Clarify the Choice
Scenario 1: Blu-ray Movie Night with 5.1 Setup
- If your receiver supports Dolby TrueHD, go with Bitstream to take advantage of lossless surround.
Scenario 2: Streaming via Game Console to Older Soundbar
- Use PCM. The console will decode the audio and send a ready-to-play signal.
Scenario 3: Media Server Using Plex
- Plex often transcodes or remuxes depending on the file and device. Check if your setup supports Bitstream passthrough. If not, PCM will avoid playback errors.
Does Audio Quality Change?
Audio quality doesn’t suffer just because you pick one or the other. PCM is lossless by nature. Bitstream can be either compressed (AC3, DTS) or lossless (Dolby TrueHD, DTS-HD MA). The quality depends more on the audio source and supported hardware than the transfer method.
What About HDMI ARC and eARC?
- ARC (Audio Return Channel) supports only compressed Bitstream formats like Dolby Digital and DTS.
- eARC (Enhanced ARC) supports full uncompressed multichannel PCM and high-bitrate Bitstream formats like Dolby Atmos in TrueHD.
If your TV and receiver both support eARC, use Bitstream for maximum fidelity. If not, PCM may avoid downmixing or sync issues.
How File Format Impacts This Choice
Not all audio files are equal. Some downloaded or extracted audio tracks, such as AC3, require Bitstream for proper playback on legacy receivers. If your file isn’t in a compatible format, converting may be necessary.
For that, an AC3 converter helps reformat unsupported audio files to AC3 for home theater compatibility.
Quick Checklist: Bitstream vs PCM
| Preference | Go With |
|---|---|
| High-end receiver decoding | Bitstream |
| Older soundbars or TVs | PCM |
| Full Blu-ray menus and extras | PCM |
| Minimal receiver processing | PCM |
| You want to see format logos on display | Bitstream |
| Using Dolby Atmos TrueHD | Bitstream (eARC required) |
Final Thoughts
Choose based on what your equipment can handle—not on what sounds trendier. If both settings sound the same to your ears, go with what works reliably across your content. The goal is uninterrupted, rich audio, not toggling menus hoping for magic.