Dolby Vision, HDR10+ and Atmos in IPTV on Apple TV: what you need to know

By the Supernova developer · · 6 min read

Your TV supports Dolby Vision, your receiver shows the Atmos logo with streaming apps, yet your IPTV player shows “HDR10” or plays plain 5.1. This is one of the most common questions about IPTV on Apple TV. The answer depends on three things: the format of the file, what the Apple TV can output, and what the player does in between.

We build Supernova, and we spent a lot of time on exactly this problem for its Apple TV engine. Here is what we learned, in plain words.

As always, a reminder: Supernova is a player and doesn’t provide any content. Everything below applies to the M3U playlist or Xtream account you add yourself.

The HDR formats in two minutes

  • HDR10 is the common base. The video is in 10-bit with a wider range of brightness, and a single set of “static” metadata describes the whole film. Every HDR TV supports it.
  • HDR10+ adds dynamic metadata, adjusted scene by scene, so the TV can adapt the picture more precisely. Among Apple TV models, only the Apple TV 4K from 2022 outputs HDR10+, and your TV must support it too.
  • HLG is the HDR format of broadcast TV. It needs no metadata and stays watchable on non-HDR TVs.
  • Dolby Vision also uses dynamic metadata, stored as small packets called RPU in the video. It comes in several profiles, and that’s where it gets complicated.

Dolby Vision profiles: why it matters

  • Profile 5 is used by streaming services. It has no HDR10 base: played on a TV without Dolby Vision, the picture looks purple and green.
  • Profile 8.1 is the most common single-layer format: a regular HDR10 picture plus Dolby Vision metadata. A TV without Dolby Vision simply shows the HDR10 part. Profile 8.4 does the same on top of HLG.
  • Profile 7 comes from UHD Blu-ray discs. It has two layers: an HDR10 base and an enhancement layer, called MEL (minimal) or FEL (full). Remuxes of UHD Blu-ray files often keep this format.

The Apple TV 4K plays profiles 5 and 8 natively. Profile 7 isn’t supported as is, which is why so many players fall back to the HDR10 base layer for Blu-ray remuxes: the picture is still HDR, but the Dolby Vision metadata is thrown away.

What Supernova does

On Apple TV, Supernova plays files with NovaEngine, its own engine built on FFmpeg and Apple’s hardware decoders:

  • Profiles 5, 8.1 and 8.4 are sent to the Apple TV as real Dolby Vision when your Apple TV and your TV support it. The TV switches to Dolby Vision mode.
  • Profile 7 is converted to profile 8.1 on the fly while you watch, the same way the reference tool dovi_tool does: the HDR10 base is kept, each RPU is rewritten, and the TV switches to Dolby Vision. With a MEL file, nothing is lost. With a FEL file, the information of the enhancement layer is lost, as on every other Apple TV player, but the Dolby Vision metadata stays.
  • No Dolby Vision on your TV? Supernova plays the HDR10 base layer (or the HLG base for profile 8.4) instead. For profile 5, which has no such base, it lets Apple’s player convert the picture so that colours stay correct.

The player shows a badge with the format actually played (for example “Dolby Vision”, “HDR10+” or “DV → HDR10”), along with the resolution, the codec and the frame rate. No guessing.

Sound: Atmos, TrueHD and DTS

  • Dolby Digital Plus (E-AC-3) is the format used by streaming services, and it can carry Dolby Atmos. For Atmos to reach your receiver or soundbar, the player must pass the track through without decoding it. Supernova does exactly that, for Dolby Digital and Dolby Digital Plus, so the Atmos objects are kept.
  • Dolby TrueHD and DTS come from Blu-ray discs. The Apple TV can’t send them as is to a receiver. Supernova decodes them and outputs multichannel sound up to 7.1. You get all the channels, but the Atmos objects carried inside a TrueHD track are not kept.

Tip: in Settings › Video and Audio › Audio Format, leave Change Format off unless you have a specific reason. The Apple TV then picks the best format your system supports.

The Apple TV settings to check

  1. Settings › Video and Audio › Format: choose 4K SDR or 4K HDR. With 4K SDR and the two options below, the menus stay in SDR and the TV only switches mode for HDR content: a popular combination.
  2. Match Content › Match Dynamic Range: on. The TV switches to Dolby Vision, HDR10 or HLG depending on the film. Supernova respects this setting.
  3. Match Content › Match Frame Rate: on. A film shot at 24 frames per second plays at 24, without the small regular judder you’d get at 60.
  4. Your TV: the HDMI input must be in enhanced mode (often called “HDMI Ultra HD Deep Colour” or “Input signal plus”), otherwise it won’t accept HDR.

Bitrate and network

A 4K remux of a UHD Blu-ray can reach 60 Mb/s or more. To absorb the small hiccups of the network, NovaEngine reads ahead and keeps around 64 MB in memory, about 9 seconds at 60 Mb/s. Even so, for this kind of file, a wired Ethernet connection is the safest choice. And remember that the quality you get can never be better than what your source sends.

Other formats worth knowing

  • HEVC (H.265) is the usual codec for 4K and HDR. It’s decoded by the Apple TV chip.
  • AV1 is more efficient, but most Apple TV models have no hardware decoder for it. Supernova uses the chip when it can, otherwise decodes it in software and warns you if your Apple TV can’t keep up (likely in 4K on older models).
  • MKV is a container, not a codec: whether a MKV plays well depends on what’s inside. NovaEngine opens MKV, MP4 and TS directly.

On iPhone, iPad and Mac

NovaEngine is only on Apple TV. On iPhone, iPad and Mac, Supernova uses Apple’s player and VLC. HDR content displays on HDR screens, but the full chain described above (native Dolby Vision on the TV, Atmos passthrough to a receiver) is an Apple TV thing.

FAQ

Why does my player show HDR10 for a Dolby Vision file?

Usually because it’s a profile 7 file (a UHD Blu-ray remux) and the player only keeps the HDR10 base layer, or because the TV or the Apple TV settings don’t allow Dolby Vision. Check Match Dynamic Range and your TV’s HDMI mode first.

Is Dolby Vision always better than HDR10?

On a good TV, the dynamic metadata helps, especially in dark or very bright scenes. But a well-mastered HDR10 picture is already excellent: the difference is less dramatic than going from SDR to HDR.

Does Supernova make my streams look better?

No player can add quality that isn’t in the source. What Supernova does is make sure nothing is lost on the way: the right format sent to the TV, Atmos kept, all audio channels played.

Want to try it? Our step-by-step guide for Apple TV shows how to add your playlist, and our comparison of Apple TV players puts Supernova next to the alternatives.

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