Converting 10-bit HDR video to 8-bit SDR

A clip captured on a recent iPhone or mirrorless camera may contain 10-bit HDR video, yet look dim, washed out or strangely flat when sent to an older television, office monitor or shared family screen. The source is not necessarily faulty. The display simply may not understand the HDR signal, or an app may decode it differently. Turning that signal into an 8-bit SDR version creates a file designed for those ordinary screens.

That SDR version should be graded, not merely forced through a bit-depth setting. The colour volume, highlight roll-off and metadata all need attention, while the original HDR file remains untouched. Australian teams often describe the brief in plain terms: it needs to “just play everywhere”. A practical conversion gives clients, broadcasters, agencies and social platforms a dependable file without asking every viewer to change their television.

Why HDR needs a deliberate conversion

Ten bits per colour channel provides 1,024 tonal steps, compared with 256 in an 8-bit file. That extra precision helps original footage preserve gradients in skies, skin and low light. Reducing it without proper processing can cause banding, especially after compression. The issue becomes more visible on a standard television viewed in a bright room than it does on a calibrated HDR reference monitor.

HDR also carries a wider brightness range and colour gamut than SDR. Depending on the camera, the signal may use PQ, HLG or Dolby Vision, often with SMPTE ST 2084 or BT.2020 identifiers. A standard screen cannot reproduce those values. If the brightness and gamut are simply clipped, highlights turn white, shadows lose detail and saturated colours can appear unnatural.

This mix is common in Australian homes. A household in Sydney, Melbourne or Brisbane may have a recent HDR television beside an older panel, a laptop and several phones with different playback support. Foxtel, ABC iview, YouTube and Netflix can also present the same upload differently across devices and apps. Many Australian post houses therefore prepare a Rec.709 SDR master alongside an HDR version for clients.

Choosing the right SDR target

Decide the delivery target before changing settings. SDR describes the tonal and colour system, not one compulsory resolution. A 4K SDR master can look sharp on a compatible 4K television, while a 1080p file may be safer for email, social uploads and older screens. Keep the source frame size unless a client specifies otherwise; resampling and tone mapping are separate decisions.

For a conventional television master, use BT.709/Rec.709 primaries, a D65 white point, the Rec.709 transfer characteristic and an 8-bit pipeline that exports as YUV 4:2:0 8-bit. The viewing environment is commonly treated as gamma 2.4. Set the colour tags consistently so players do not guess that the footage is BT.2020, PQ or HLG.

An H.264 MP4 remains the safest delivery choice for broad compatibility. H.265 in MP4 can reduce size while retaining good quality, but some older Australian TVs, browsers and editing applications handle it poorly. Match the original frame rate when possible: Australian broadcast material often uses 25 or 50 fps, while phone clips may arrive at 30 or 60 fps. Mixed-frame-rate timelines need care before export.

Tone mapping versus simple bit-depth reduction

Tone mapping is the central operation. It compresses the HDR scene into the brightness range available on an SDR display and maps colours from the wider HDR gamut toward Rec.709. A good result rolls bright windows, lamps and light sources off gradually instead of cutting them to white. It also protects shadow detail without lifting every dark area into a grey haze.

The source transfer function affects the method. PQ is an absolute luminance system, commonly described with nits, and may carry static or per-frame HDR metadata. HLG is relative and designed to work with compatible displays, so conversion needs a different tone curve. Dolby Vision profiles may add dynamic metadata. Remove HDR flags only after the tone-mapped image has been rendered; stripping metadata earlier cannot recover clipped colour or luminance.

Global tone mapping is often enough for straightforward shots, but local highlight mapping can preserve more apparent detail in faces against bright backgrounds. Start with a neutral preset, then adjust exposure, highlight roll-off, midtone contrast and saturation on a reasonably calibrated screen. Scopes or waveform tools help reveal clipping, although a normal consumer television remains the final reference. For most creators, subtle changes preserve the camera’s intended look better than an aggressive “HDR look” in SDR.

Preparing media in a reliable workflow

Work from a copy or proxy, retain the camera originals and finish editorial decisions before lossy delivery encoding. Decode the full HDR sequence to ordinary frames, then apply the tone map and colour conversion as one consistent pass. Check that every shot uses the expected input colour space and transfer function. A mistaken tag on one clip can shift its colour even when the rest of the sequence is correct.

After grading, a desktop utility can handle the final transcode without another round-trip through a non-linear editor. The Pavtube HD Video Converter can run on Windows or Mac to turn a finished master into an 8-bit delivery file with the required dimensions, codec and bitrate. Keep the professional tone-mapping stage separate: a general file converter cannot be relied upon to interpret every HDR format or dynamic metadata profile.

Choose quality settings based on the destination rather than saving the largest possible file. For a 1080p H.264 master, roughly 15–25 Mbps is a practical starting point for clean detail; demanding 4K footage may benefit from about 40–70 Mbps, especially with grain or fast motion. Test unusual textures before batch processing. Large masters also matter to regional Australian studios, where uploading to a national client or cloud service can take longer than the render itself.

Grading and exporting in common software

Adobe Premiere Pro can perform the conversion through its colour-management workflow or the HDR-to-SDR tone-mapping controls available in current versions. Assign the HDR input correctly, choose an SDR Rec.709 output, select a suitable tone-map method and then fine-tune the result. The exact menu names vary by version, but the essential order remains: identify the source, map tone and gamut, inspect, then export.

DaVinci Resolve offers detailed control on its Color page and is a strong choice when a team already manages multiple deliverables. iMovie may import some camera files and produce a playable result, but its controls are not a substitute for a dedicated HDR-to-SDR grade, and compatibility depends on the source and macOS version. For a final delivery encode from an approved master, an HD Video Converter can provide a focused route to common MP4 and H.264 settings.

During export, explicitly select 8-bit, Rec.709 colour tags and standard-range or full-range video to match the receiving workflow. Do not copy HDR10, PQ or HLG metadata into the SDR file. Keep the audio track independent of the video conversion; AAC at 192–320 kbps suits many online uses, while broadcast clients may require their own specification. Name the SDR and HDR versions clearly so neither can be uploaded by mistake.

Checking the final playback experience

Quality control matters as much as the export. Play the result on the actual screen types the audience will use: the family television, a laptop, an iPhone, an Android handset and a client monitor. Include a 4K television if that is the final display. Bright daylight can make a weak contrast choice obvious, particularly in Brisbane, Perth or Darwin, where a living room can be much brighter than a grading suite.

For online delivery operations, monitor the path beyond the edit suite as well. The approach in Grafana delivery monitoring illustrates how dashboards can reveal service delays, failed jobs and bottlenecks in a video pipeline. A creator may not run that kind of infrastructure, but the principle applies: confirm that the uploaded SDR file, its thumbnail and the playback stream are all being served correctly.

A final SDR master should look natural on a standard screen without appearing dull on an HDR one. Preserve the HDR original for future work, deliver the 8-bit Rec.709 file for general viewing, and record the export settings beside each project. That combination gives Australian audiences a stable playback experience across television apps, meeting rooms, phones and older hardware without sacrificing the richer source for later use.