Key takeaways
- Dolby TrueHD is lossless and lives on Blu-ray and UHD Blu-ray discs at up to about 18 Mbps, while Dolby Digital Plus is lossy and built for streaming at roughly 384 kbps to 1024 kbps.
- Both formats carry the same Dolby Atmos object metadata, so neither one is the reason height channels go missing.
- TrueHD needs an eARC connection with roughly 37 Mbps of audio bandwidth, while standard ARC, at about 1 Mbps, is enough for Dolby Digital Plus but not for TrueHD.
- A bitstream or passthrough setting preserves Atmos object metadata for either format, while a PCM output setting typically strips it regardless of which codec is underneath.
- For disc playback use whatever TrueHD delivers by default. For streaming and broadcast, Dolby Digital Plus is the format you are getting either way, and it is not the thing limiting most rooms.
Dolby TrueHD is a lossless codec, bit for bit identical to the studio master, used on Blu-ray discs at up to 18 Mbps. Dolby Digital Plus is a lossy codec, built to fit inside 1 to 3 Mbps, used almost everywhere Atmos is streamed. That is the entire difference in one sentence. Everything else follows from it.
Both can carry Dolby Atmos object metadata. Neither is inherently the wrong choice: they are built for different jobs, disc versus stream, and confusing the two is why people expect a streamed Atmos mix to sound like a UHD Blu-ray’s and end up disappointed by something that was never actually broken.
How many bits each one spends on the same second of sound
Dolby TrueHD is lossless, reconstructing the exact studio master with nothing discarded, similar in principle to FLAC for music. Blu-ray discs typically carry it somewhere between 6 and 18 Mbps depending on the mix, using whatever bitrate the mastering studio judged necessary, since there is no fixed target, only an upper limit set by the disc’s own bandwidth.
Bitrate alone does not fully describe the relationship. Dolby’s own encoding tools allow TrueHD’s bitrate to vary dynamically within a title, rising during a busy action sequence and falling during a quiet dialogue scene, which is part of why the codec is described as lossless rather than simply high bitrate. Digital Plus, by contrast, generally runs at a steadier rate throughout a title, since the target is a reliable stream over a network connection rather than matching a variable studio master exactly.
Dolby Digital Plus is a lossy codec built around a much lower, fairly fixed bitrate. Streaming implementations of Digital Plus with Atmos typically run somewhere between 384 kbps and 1024 kbps, occasionally higher on certain services, a small fraction of what TrueHD uses for the same length of audio. That gap is deliberate: Digital Plus exists specifically to fit inside the bandwidth a home internet connection can reliably deliver.
| Property | Dolby TrueHD | Dolby Digital Plus |
|---|---|---|
| Compression | Lossless | Lossy |
| Typical bitrate | 6 to 18 Mbps | 384 kbps to 1024 kbps |
| Where it lives | Blu-ray and UHD Blu-ray disc | Streaming, broadcast, some game consoles |
| Carries Atmos metadata | Yes | Yes |
| Minimum HDMI link needed | eARC | ARC or eARC |
Disc versus stream: where each format actually shows up
TrueHD is, in practice, a disc format. Physical media has enough fixed bandwidth that there was never a reason to compress the audio lossily, so nearly every Blu-ray and UHD Blu-ray Atmos title carries its object based mix in TrueHD.
Digital Plus is, in practice, the streaming and broadcast format. Netflix, Disney Plus, and Apple TV all deliver their Atmos titles as Dolby Digital Plus, since a lossless multi megabit stream is not a realistic proposition over a shared home internet connection, even a fast one. The difference between the two experiences is covered in more depth at why streaming Atmos is not Blu-ray Atmos.
Broadcast television sits closer to the streaming side of this divide than the disc side. Live sport and cable or satellite broadcasts that carry Atmos nearly always do so through Dolby Digital Plus, for the same bandwidth reasons streaming services use it, even though the delivery mechanism, over the air or through a set top box, is technically different from an app running on a smart TV.
The HDMI connection each one actually requires
This is where most setups actually go wrong. Standard HDMI ARC, the audio return channel most TVs have shipped with since around 2010, carries roughly 1 Mbps, which is enough for Dolby Digital and DTS, and in many implementations Dolby Digital Plus as well, since streamed Atmos fits inside that ceiling.
TrueHD does not fit through ARC. It needs eARC, which the HDMI Forum specifies with roughly 37 Mbps of audio bandwidth, enough for the full lossless bitrate plus uncompressed multichannel PCM. If your TV or soundbar only has standard ARC, a Blu-ray player’s TrueHD Atmos track will either fail to pass through or get downgraded to lossy Dolby Digital along the way, while a streaming app’s Digital Plus track works exactly as intended. See eARC vs ARC: what changes and HDMI eARC explained for the connection itself.
Cable quality is a smaller factor than people assume here. Any HDMI cable that meets the High Speed or Ultra High Speed specification carries enough bandwidth for either format. The failure point is almost always the port or the menu setting rather than the cable itself, and swapping a functioning cable for a more expensive one rarely fixes a format that is not passing through correctly.
A soundbar with only an optical input cannot carry either format’s Atmos metadata. Optical tops out at Dolby Digital 5.1, no exceptions, regardless of what the source claims to be sending.
What changes to the actual sound, not just the spec
In a controlled comparison using the same mix, TrueHD’s lossless bitrate preserves slightly more low level detail and dynamic range than Digital Plus, particularly in complex passages with many simultaneous effects. Whether that is audible in a normal living room depends heavily on the speakers doing the reproducing and the room around them.
On a modest soundbar system, the practical difference is small, often not reliably distinguishable in a blind comparison. On a full 7.1.4 speaker setup driven by something like a Denon AVR-X1800H with genuinely resolving speakers, more listeners can pick out the difference, though it is a matter of degree rather than one format sounding broken.
Blind listening comparisons carried out by audio enthusiasts and some manufacturers over the years have generally found that most listeners struggle to reliably tell TrueHD apart from a well encoded Digital Plus stream of the same content below about 768 kbps, though the gap widens as Digital Plus bitrate drops toward its lower end. This lines up with what shows up during a calibration visit: complaints about flat or thin sound trace back to speaker placement and level matching far more often than to which lossy or lossless codec happened to be playing.
Whether the height channels survive the trip
Both formats carry the same underlying Atmos object metadata, so in principle neither one loses height information relative to the other. What determines whether height data survives is the chain around the codec, not the codec itself. A bitstream or passthrough setting keeps the metadata intact, while a PCM output setting on a TV or source device decodes the format early and typically discards the object data before it reaches your receiver, a distinction covered fully at bitstream vs PCM: which to choose.
It is worth being specific about what passthrough actually means here. A receiver or soundbar set to accept a bitstream signal is not decoding anything itself until the object based audio processor inside it unpacks the incoming stream, separates the underlying bed channels from the individual audio objects, and renders them to whatever speaker layout is actually connected. A PCM signal, by comparison, arrives already flattened into fixed channels by whatever device did the decoding upstream, with no individual objects left to render.
Which format reaches you, and from where
If your setup is a Blu-ray or UHD Blu-ray player connected through eARC to an AVR or soundbar with genuinely resolving height speakers, TrueHD’s lossless bitrate is worth having, and you likely already have it without doing anything, since disc playback defaults to it.
If your setup is a smart TV app or streaming stick feeding a soundbar over ARC or eARC, Dolby Digital Plus is what you are getting regardless of preference, and that is fine. It carries the same object metadata at a fraction of the bandwidth, and on the vast majority of soundbar systems the difference from TrueHD is not the thing limiting how good your room sounds. Speaker placement and calibration, covered in Atmos speaker layouts from 5.1.2 to 7.1.4, matter considerably more.
None of this makes the format question meaningless, it means the format is rarely the actual bottleneck in a home system. Time spent on speaker distance, height channel placement, and calibration returns far more audible improvement than chasing a lossless bitstream through a chain that was never going to reveal the difference clearly in the first place.
Questions readers ask about this
Technically yes, since TrueHD is lossless and Digital Plus is not, but the practical gap is often small on a typical soundbar system. On a resolving 7.1.4 speaker setup the difference becomes more noticeable, particularly in dense action mixes with many simultaneous effects, but it is rarely the limiting factor in how a room actually sounds.
No. TrueHD needs roughly 37 Mbps of audio bandwidth, which only eARC provides. Standard ARC caps out around 1 Mbps, enough for Dolby Digital Plus but not for a lossless TrueHD track, so a Blu-ray player's TrueHD Atmos mix will either fail or drop to compressed Dolby Digital over a standard ARC connection.
No. Every major streaming service, including Netflix, Disney Plus, and Apple TV, delivers Atmos as Dolby Digital Plus, since a multi megabit lossless stream is not practical over shared home internet. TrueHD is used specifically for physical Blu-ray and UHD Blu-ray discs, where bandwidth is fixed and generous.
Check the player's audio output setting first. If it is set to PCM rather than bitstream or passthrough, the player is decoding TrueHD itself and typically stripping the Atmos object metadata before the signal reaches your receiver, leaving you with a standard multichannel bed rather than genuine height objects.
Usually not. Most TVs and soundbars sold since around 2017 support Dolby Digital Plus over a standard HDMI ARC connection, and many streaming sticks pass it through by default. The more common problem is a TV audio setting defaulting to PCM, which strips the Atmos metadata even though the hardware itself supports it.
About the author
Rahul Gupta
Rahul Gupta has spent nearly a decade quietly wiring living rooms, testing soundbars in every awkward apartment layout imaginable, and untangling the kind of HDMI handshake problems that make people give up on Atmos altogether. He writes here about what actually works when you get the boxes home—not what the spec sheet promises. If a piece of gear on this site earns a recommendation, it earned it in a real room with real furniture, not a lab.
