PCM vs Bitstream Audio, Sound Quality, Compatibility, and Settings

PCM and Bitstream are device output-setting choices whose actual result depends on the codec, channel count, connection path, and receiving-device support. For an encoded soundtrack, PCM normally means source decoding to LPCM and Bitstream normally means downstream decoding of a supported encoded format, but neither setting automatically provides better sound quality. This article explains how decoding, format compatibility, and playback verification affect audio delivery.

Catalog

PCM and Bitstream Decoding in the Audio System

For an encoded soundtrack, these settings normally determine whether decoding occurs at the source or downstream. Figure 1 shows the typical behavior through a compatible HDMI connection.

Pulse code modulation, or PCM, represents audio using numerical samples. Linear PCM, or LPCM, uses uniformly spaced quantization levels and carries the samples without perceptual compression. Consumer audio menus often use PCM as shorthand for LPCM output.

With PCM output selected, the source normally decodes the encoded soundtrack and sends LPCM. With Bitstream selected, the source normally sends the supported encoded format for downstream decoding. Philips documents this distinction for PCM/LPCM and Bitstream output. [1]

Here, Bitstream refers to the output-menu choice. It is not a separate method of sampling sound, and the label alone does not identify the codec, bitrate, or channel count. The receiving equipment must support the actual encoded format.

PCM output also does not mean that the entire playback system bypasses processing. In a conventional AV receiver, decoded samples may undergo volume adjustment, speaker processing, and digital-to-analog conversion before amplification. Passive speakers receive an amplified electrical signal, not the HDMI PCM stream shown between devices.

Compatibility remains relevant after source decoding. The receiver must accept the transmitted PCM configuration. For example, Denon documents both two-channel and multichannel LPCM support on the AVR-S970H’s HDMI input. That capability belongs to the specified input and model, not automatically to every digital audio device. [2]

PCM vs Bitstream Sound Quality

PCM is not inherently better sounding than Bitstream. A useful comparison starts with the same soundtrack and asks whether either playback path changes its samples, channels, or processing.

Compression alone does not establish a quality loss. Dolby TrueHD is a lossless coding format, meaning its decoder can recover the encoded PCM samples without the information loss associated with lossy compression. [3] Sending that soundtrack as Bitstream therefore does not automatically reduce fidelity compared with decoding it in the player.

For a lossless channel-based soundtrack, source decoding and receiver decoding can deliver the same losslessly reconstructed program audio before any optional metadata-controlled or device processing. Equivalent playback still depends on matching channel handling and downstream processing, with no unwanted conversion.

A lossy soundtrack presents a different boundary. Converting it to PCM does not restore information removed during its earlier encoding. The output is uncompressed PCM, but its content still reflects the quality of the decoded source. An uncompressed output label is therefore not proof that the original recording reached the listener without loss.

Changes in channel handling can be more relevant than the decoding location. A PCM output downmixed to stereo is not equivalent to the original multichannel presentation. Comparing those two outputs would compare different channel configurations, not simply PCM against Bitstream.

Processing settings can also make comparisons misleading. Dolby documents features such as dialogue normalization, dynamic range control, and downmixing within TrueHD playback. [3] A difference in loudness or dynamics should prompt a check of those settings before it is attributed to the output format.

A meaningful listening comparison should use the same track, passage, channel configuration, and approximately matched playback level. If the receiver changes sound modes when the input format changes, that difference should be recorded as part of the comparison. A louder or more spatial presentation does not, by itself, demonstrate more accurate decoding.

PCM and Bitstream Support Over HDMI, ARC, eARC, and Optical

Audio Connection Compatibility

Connection	LPCM Channel Support	Supported Encoded Formats	Limits and Compatibility Checks
Direct HDMI to an audio system	Two-channel and multichannel LPCM on compatible equipment	Supported Dolby Digital, Dolby Digital Plus, DTS, Dolby TrueHD, DTS-HD and immersive formats	Check source output and the receiving HDMI input. A direct source-to-receiver path does not use TV ARC or passthrough.
HDMI ARC from a TV	Generally two-channel LPCM	Dolby Digital. Dolby Digital Plus, including Atmos, and DTS where supported	No multichannel LPCM, TrueHD or DTS-HD Master Audio. Check source, TV passthrough and output settings, and receiver support.
HDMI eARC from a TV	Two-channel and multichannel LPCM, including 5.1 and 7.1 on compatible devices	Supported high-bitrate formats, including TrueHD, DTS-HD Master Audio and immersive formats	Both endpoints must support eARC. Check source format, TV passthrough and output settings, and receiving-device support. eARC alone does not guarantee every format.
Consumer optical S/PDIF	Two-channel LPCM	Supported legacy surround formats such as Dolby Digital or DTS	No multichannel LPCM, Dolby Digital Plus, TrueHD or DTS-HD Master Audio. Check source output, any TV passthrough, and receiver decoding.

How HDMI Capability Negotiation Affects PCM and Bitstream

HDMI capability information, such as Extended Display Identification Data, or EDID, can affect the format actually transmitted. Philips documents cases in which a source decodes an unsupported encoded format and sends LPCM in response to the connected device’s reported capabilities. This fallback depends on the device and its settings, so selecting Bitstream does not guarantee encoded output. Section 7 explains how to verify the received format and channel count. [1]

Documented Compatibility Example: Sony HT-S2000

Sony’s HT-S2000 format matrix lists DTS:X for its eARC input but not its ARC or optical inputs. The example shows why compatibility must be checked for the specific model and input. These receiving-format specifications do not describe the soundbar’s physical speaker count. [5]

Surround Sound and Dolby Atmos With PCM and Bitstream

Surround playback depends on more than whether the receiver displays PCM or Dolby. Channel-based audio and object-based immersive audio carry different information.

Multichannel LPCM can preserve a decoded channel-based surround mix over a compatible connection. Receiving PCM therefore does not imply that only the left and right channels remain. The channel configuration must be checked separately.

Dolby Atmos includes information that a compatible renderer uses to adapt the presentation to the speaker arrangement. Dolby documents three home entertainment transports with different audio forms. [6]

Dolby Atmos Transport Comparison

Transport Type	PCM/Bitstream Form	Lossless/Lossy Status	Required Compatible Path
Dolby Digital Plus with Atmos	Encoded bitstream with Atmos metadata	Lossy encoded audio	Compatible HDMI or eARC path. ARC can carry it where source, TV passthrough and receiving device support it.
Dolby TrueHD with Atmos	Encoded bitstream with Atmos metadata	Lossless encoded audio	Compatible HDMI or eARC path preserving TrueHD and Atmos metadata to an Atmos-capable receiver.
Dolby MAT 2.0	PCM audio carrying Atmos metadata	Lossless PCM transport	MAT-capable source and receiving device over compatible HDMI or eARC, with MAT passthrough if a TV is in the path.

MAT’s lossless PCM transport does not reverse information loss from an earlier lossy source encoding. [6]

Ordinary channel-based LPCM and Dolby MAT output should consequently not be treated as identical. A player that outputs only a conventional channel mix does not provide the same object metadata as a supported Atmos transport. Conversely, a system using PCM within Dolby MAT can still deliver Atmos.

For an encoded Atmos soundtrack, the playback path must preserve its supported transport and metadata through to a compatible renderer. The presence of an Atmos option at one device does not establish support throughout the system.

A further distinction is the difference between receiving an immersive soundtrack and applying an upmixer. An upmixer can distribute channel-based content across additional speakers. That does not prove that the source contained Atmos objects or other immersive metadata. Dolby describes its surround upmixer separately from Atmos decoding and rendering. [6]

The useful target is therefore a verified combination of source format, transport, and receiving mode. Speaker activity alone is insufficient evidence that the intended soundtrack reached the system unchanged.

Choosing PCM or Bitstream for TVs, Soundbars, and AV Receivers

The starting setting should follow the connection route and the receiving device’s capabilities. Figure 2 separates a direct audio-system connection from a route that passes through the television.

PCM or Bitstream by Setup

Setup	Typical Starting Point	Required Support	Expected Result
Stereo audio system accepting PCM	PCM	Compatible two-channel PCM input	Decoded stereo playback
Player and receiver both supporting the same channel-based codec	PCM or Bitstream	Equivalent channel handling and a compatible connection	Decoding at either device without an automatic fidelity advantage
Player supports the codec, receiver accepts multichannel PCM but lacks that decoder	PCM	Source decoding and multichannel PCM input	Playback without relying on the receiver’s missing codec decoder
Optical connection used for compatible encoded surround	Bitstream	Matching source format and receiver decoding	Encoded surround within optical connection limits
Encoded Atmos soundtrack sent to a compatible audio system	Supported Bitstream or passthrough mode	End-to-end support for that Atmos transport	Receiver decoding and rendering
Source using Dolby MAT for Atmos	Its supported Atmos output mode	Compatible MAT path and receiver	PCM audio with Atmos metadata

These are conditional starting points derived from the format and connection requirements in Sections 1–4. They are not universal presets.

Television terminology needs particular care. Samsung distinguishes PCM, Auto, and Pass-through in its support guidance. Its description of PCM output as left and right channels concerns the television setting being discussed, not the capabilities of PCM as a format. Menu availability and behavior must be checked for the television model. [7]

PCM and Encoded Audio Settings on PS5 and PS4

Console setup should distinguish the hardware model, connection, and playback application. A setting suitable for one game or video path should not be assumed to control every application.

PS5 Output and Application Settings

PS5 audio controls are under Settings > Sound > Audio Output. HDMI Device Type identifies the connected equipment, while the AV amplifier options set the channel count and speaker positions. Audio Format (Priority) controls output for games and video applications, while the disc player can use separate audio settings. [8]

PS5 supports Dolby Atmos for compatible HDMI equipment. To enable it, open Settings > Sound > Audio Output > Audio Format (Priority) and select Dolby Atmos. The complete connection path must support the selected output. [13]

For a connected PS5, television, and audio system, begin at a low playback volume.

1. Open Settings, Sound, Audio Output.

2. Confirm the selected output device and HDMI device type.

3. Set the applicable channel configuration to match the audio system.

4. Select the supported format for the intended playback path.

5. Check the disc player’s separate audio settings when testing disc playback.

6. Confirm the result at the receiving device.

Available settings depend on the configuration. A change made for games should therefore be verified again with the actual video or disc application being used. [8]

PS4 Output Settings and Connection Limits

On PS4, Sony identifies Settings, Sound and Screen, Audio Output Settings, Audio Format, Priority, as the format-setting path. Linear PCM is the documented default. Optical output configuration is separate, and the CUH-2000 series has no optical digital output terminal. [9]

For a PS4 with the required connection available, use the following sequence.

1. Identify whether audio leaves the console through HDMI or optical.

2. Open Audio Output Settings.

3. Select the applicable primary output port where required.

4. Choose a format supported by the connected system.

5. Play identified content and inspect the receiver’s input information.

The same PCM-versus-Bitstream logic applies, but hardware differences affect the available route. Instructions for an optical-equipped PS4 must not be applied to a model without that connector.

Checking the Audio Format Received by the Sound System

The receiving device provides the most useful evidence of what passed through the connection. A source menu shows the requested output, while an input-information screen shows what reached the audio system.

For example, Denon’s AVR-S970H Information page lists Sound Mode, Input Signal, Format, and Sample Rate separately. Format identifies input-channel information, while Sound Mode identifies the active playback mode. [10]

The check requires the existing source, display, audio system, remote controls, and content with an identified soundtrack. No measurement instrument is required for a basic format check. Keep playback volume low while changing settings, and follow equipment instructions before altering physical connections.

1. Record the device models, connection route, selected soundtrack, and current output settings.

2. Play a passage from the identified soundtrack.

3. Open the receiver or soundbar’s input-information display.

4. Record the received format and channel count, where available.

5. Change only the relevant output setting.

6. Replay the same passage and compare the information.

7. Restore the working setting if sound disappears or the result no longer matches the intended configuration.

When testing source decoding of a multichannel soundtrack, multichannel PCM is the expected indication if the path supports those channels. A stereo indication requires investigation before concluding that the receiver received the complete surround mix.

Some products expose fewer details than the Denon example. If the display shows only PCM, that label alone may not establish the channel count. Use the product’s documented information screen or companion application if it provides more detail.

This procedure confirms format delivery, not perceptual transparency or exact digital sample identity. Sound from every speaker also does not prove that every speaker received an independent source channel. The listening mode must be considered alongside the input information.

PCM and Bitstream Troubleshooting

Troubleshooting should start with the observed symptom and one controlled change. Replacing several settings at once makes it harder to identify which part of the signal path caused the problem.

Audio Output Troubleshooting [11, 12]

Symptom	Possible Cause	Action	Verification
No sound after selecting Bitstream	Unsupported encoded format	Try compatible PCM output and confirm codec support	Playback returns and the input format is identified
Surround content arrives as stereo	Downmixing or connection restriction	Check channel settings and the television’s output mode	Intended input channels appear
Atmos is missing	Track, transport, or passthrough mismatch	Confirm the selected track and supported Atmos route	Receiver identifies the intended immersive format
Disc playback differs from games	Separate application settings	Inspect the disc player’s audio configuration	Retest the same disc track
Optical output remains silent	Wrong input, disabled output, cable issue, or format mismatch	Check the selected input and optical settings	A known compatible signal plays
Dialogue and picture are misaligned	Processing or connection-dependent delay	Test the model’s sync controls or a supported direct connection	The same passage shows improved alignment

After changing a setting, verify the received format and channel count because restoring sound or reducing delay does not necessarily preserve the intended surround or immersive audio.

Conclusion

The appropriate setting preserves the intended audio presentation through the complete signal path. Successful playback alone does not confirm that the intended channels or immersive metadata have been retained. Checking the receiving device’s input format and channel information establishes whether the selected output meets the system’s playback requirements.

Technical References:

[1] Philips. “What is the difference between audio formats?” Philips, 2017. Article No. XC000011974.

[2] Denon. “About HDMI.” AVR-S970H Owner’s Manual. Denon, 2022.

[3] Dolby Laboratories. “Dolby TrueHD lossless audio.” Dolby Laboratories, n.d.

[4] HDMI Licensing Administrator, Inc. “HDMI® Enhanced Audio Return Channel (eARC).” HDMI Licensing Administrator, Inc., n.d.

[5] Sony Corporation. “Supported Audio Formats.” HT-S2000 Help Guide. Sony Corporation, 2022. Document No. 5-045-382-11(4).

[6] Dolby Laboratories. “Dolby Atmos for Compact Entertainment Systems: Immersive Surround Sound from a Stereo Form Factor.” Dolby Laboratories, 2016.

[7] Samsung. “Change the audio format on your Samsung TV.” Samsung, n.d. Article No. ANS10005199.

[8] Sony Interactive Entertainment. “How to change audio settings on PS5 consoles.” Sony Interactive Entertainment, n.d.

[9] Sony Interactive Entertainment. “How to change the audio output on PS4 consoles.” Sony Interactive Entertainment, n.d.

[10] Denon. “Information.” AVR-S970H Owner’s Manual. Denon, 2022.

[11] Sony. “My TV doesn't output sound through the DIGITAL AUDIO (OPTICAL) OUT port.” Sony, 2026. Article ID 00027070.

[12] Sony. “Audio from the soundbar or home theater and is out of sync with the TV picture.” Sony, 2026. Article ID 00198181.

[13] Nishino, Hideaki. “PS5 update rolls out globally with new accessibility, audio, and social feature enhancements.” Sony Interactive Entertainment, 2023.

Frequently Asked Questions [FAQ]

1. Why Do Blu-ray Menu Sounds or Picture-in-Picture Commentaries Disappear With Bitstream Output?

Interactive sounds and secondary commentary may depend on the player’s secondary-audio mixing setting. Sony’s guidance for applicable players identifies BD Audio Mix as the control for combining these sounds with the main presentation. Confirm the setting in the player’s operating manual, since enabling mixing can change how the soundtrack is output.

2. Can Activating a Receiver’s Second Zone Change the Main Room’s Audio?

Yes, certain receivers impose additional restrictions when multiple zones share one source. For example, the Denon AVC-X4700H manual describes configurations in which using two-channel PCM for ZONE2 also changes the main zone to two-channel PCM. Confirm the applicable zone configuration and shared-source restrictions in the receiver’s manual before changing the source output.

3. Does Windows Exclusive Mode Automatically Mean Bitstream Output?

No. WASAPI exclusive mode describes how an application accesses the audio endpoint, not whether the transmitted audio is PCM or an encoded soundtrack. It bypasses the shared Windows audio engine, but the application must still select a format supported by the device and driver.

4. Can an HDMI Audio Extractor Pass Bitstream While Requiring PCM for Its Analog Output?

Yes, HDMI passthrough and analog extraction can have different capabilities. Some devices pass encoded multichannel audio through HDMI while accepting only two-channel PCM for conversion to analog audio. Confirm the analog extraction format and decoder support in the applicable manufacturer datasheet, rather than relying on the HDMI passthrough specification.

5. Can a Compatible Super Audio CD Player Output PCM Instead of DSD?

Yes, some compatible players provide a separate DSD output setting. Sony documents players that output PCM through HDMI when DSD Output Mode is disabled during Super Audio CD playback. Confirm this behavior in the specific player’s manual, since a general PCM or Bitstream setting does not establish its DSD handling.