HDR & Dolby Vision

Flow Capture supports the uploading and playback of High Dynamic Range (HDR) video, which shows a greater spectrum of both contrast and color than standard video formats. Our HDR compatibility covers the HDR10 and Dolby Vision formats.

Being a relatively new technology, HDR is still limited to viewing through specific devices and platforms. Right now, you can watch HDR in the following places:

iOS & iPad OS - HDR playback is supported in-app from the iPhone 8 and the 10.5" iPad Pro models onward. We recommend a brightness setting for Dolby Vision or HDR10 that's keyed to the project's reference monitor and can be set ahead of time in Flow Capture. Realtime Review in mobile Safari only supports Dolby Vision, which is a limitation of the browser.
- You'll also want to make sure you're using the most recent version of iOS and the Flow Capture app wherever you want to watch HDR footage.
tvOS - You'll need an Apple TV 4K running the latest version of tvOS that's connected to an HDR-compatible television (e.g. LG C9 or CX) in order to view HDR footage through the Flow Capture tvOS app.
Browser - Dolby Vision is supported in Safari. Keep in mind that you will still need to have your computer connected to an HDR-capable display (e.g. Apple XDR or Sony BVM-X300) to be able to watch them.

We're actively working to increase our support for HDR across as many platforms and devices that support it as possible, so check back here, or keep an eye on our release notes for updates!

Dolby Vision & HDR10 Upload Specifications

If you're using Flow Capture for HDR playback, our requirements for uploading these files are more rigorous than those for SDR video. The files we generate for playback will be in Rec. 2020 and HEVC 10 bit, but the colors will respect the P3 constraints within the Rec. 2020 gamut.

Nearly all types of HDR uploads require the combining of at least two assets. As a result, any successful HDR upload must contain all the necessary files and be uploaded at the same time, into the same batch.

Dolby Vision

Flow Capture is compatible with Dolby CM 2.9 and 4.0. Our requirements for successfully generating a file for playback is as follows:

An .xml and .mov (ProRes) file pair to make each DV asset
Those two files will need to have the exact same file names
All file names have to start with the prefix, “dovi_”
AAC or PCM audio
ProRes LT in the legal range is recommended to keep the video’s file size more manageable

We do accept higher quality ProRes files, though they will take longer to upload and process. We also recommend that you use a standard resolution (e.g. 4096x2160, 1920x1080, etc.) which ends in an even number, as nonstandard ones or odd numbers can result in processing failures when we're trying to encode our multiple resolutions for adaptive streaming playback.

HDR10

The follow settings will help you successfully upload for playback in this format.

Audio - AAC or PCM
Framerate - Less than or equal to 30fps
Codec - 10-bit HEVC (h265) or ProRes (min. ProRes 422) 1
Color Primaries - Rec. 2020, D65-P3, or SMTPE-431/SMPTE-432 (DCI-P3) 1
EOTF - PQ (SMPTE ST 2084) 1
GOP - A value suitable for streaming (2-6 seconds).
Color Matrix - Rec.2020 non-constant luminance 2
Mastering Metadata - SMPTE ST 2086 2
Brightness - CEA 861-3 MaxFALL and MaxCLL 2

1 Core requirements for a file to be detected for HDR processing.

2 If any of these are missing, we use the values for a Sony BVM-X300 mastering display.

If you're planning to conduct reviews on an iPad, you'll want to make sure to constrain any Rec. 2020 files to that device's limit of the P3 colorspace.

When using Transkoder to create your files, you'll want to make sure that the Zero Trim setting is set to On.

HDR10 Upload Types

There's two different ways that you can work with HDR 10 on Flow Capture, each with its advantages and disadvantages. You can decide which option is the best for your desired quality and available time.

Only HDR Files

The fastest way to get HDR assets to Flow Capture. Export a set of files using the above specifications, upload the videos to Flow Capture, and we'll generate SDR versions for those who don't have the ability to view in HDR.

The advantage to this option is speed - you only have to create and upload one set of files and we make a second SDR set for you during the processing stage.

The disadvantage of this option is the loss of control over the quality from the SDR assets that are created by Flow Capture.

Combined SDR and HDR Files

This alternative allows you to generate twin sets of files for each dynamic range that get combined into a single playable asset upon upload to Flow Capture.

The process is simple; each pair of files needs to have the same name with "_sdr" and "_hdr" at the end to distinguish them. Then our system will be able to pair them together into one for playback. For example, these two files:

Demo-Asset_sdr.mov
Demo-Asset_hdr.mov

Would combine into one called Demo Asset. Depending on the viewer's platform, they would be able to view just the SDR or both the SDR and HDR streams.

The advantage to this option is quality - you have full control over the look of both SDR and HDR files on your end so you can optimize the look of each.

The disadvantage of this option is time; because you're dealing with more twice as many files, it'll take longer to get everything up.

HDR10 Metadata Sidecars

If you're unable to add certain pieces of metadata when creating the HDR10 files, you'll be able to include that information as a sidecar with the video upload. This can be done using software like Colorfront Transkoder.

Similar to combined HDR and SDR file workflow above, you'll want to use a naming scheme like the one below to make sure we're able to combine everything successfully:

Demo-Asset_sdr.mov
Demo-Asset_hdr.mov
Demo-Asset_hdr_HDR_report.txt

For an HDR-only upload, it should look like this:

Demo-Asset_hdr.mov
Demo-Asset_hdr_HDR_report.txt

When using a sidecar file to populate metadata fields that your outputting software isn't able to include, you can key off this example to create your own:

--master-display <string> --max-cll <string>

Master Display - SMPTE ST 2086 mastering display color volume SEI info. This is specified as a string which is parsed when the stream header SEI are emitted. Formatting for the string is “G(%hu,%hu)B(%hu,%hu)R(%hu,%hu)WP(%hu,%hu)L(%u,%u)” where %hu are unsigned 16bit integers and %u are unsigned 32bit integers. The SEI includes X,Y display primaries for RGB channels and white point (WP) in units of 0.00002 and max,min luminance (L) values in units of 0.0001 candela per meter square. Applicable for HDR content.

Example for a P3D65 1000-nits monitor, where G(x=0.265, y=0.690), B(x=0.150, y=0.060), R(x=0.680, y=0.320), WP(x=0.3127, y=0.3290), L(max=1000, min=0.0001): G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)

Max-CLL: Maximum content light level (MaxCLL) and maximum frame average light level (MaxFALL) as required by the Consumer Electronics Association 861.3 specification. Specified as a string which is parsed when the stream header SEI are emitted. The string format is “%hu,%hu” where %hu are unsigned 16bit integers. The first value is the max content light level (or 0 if no maximum is indicated), the second value is the maximum picture average light level (or 0). Applicable for HDR content.

Example for MaxCLL=1000 candela per square meter, MaxFALL=400 candela per square meter: --max-cll “1000,400"

You can download a file for reference from here.

HDR Device Compatibility

You can find a breakdown of what devices are compatible with Flow Capture's HDR10 and Dolby Vision integrations in our playback article.

HDR & Security

Neither HDR format is compatible with watermarked, or visible burn-in, streaming. That said, if you're interested in adding Flow Capture to your HDR workflow, our industry-standard DRM and visible overlay watermarking are perfectly compatible with HDR.

In addition, both HDR10 and Dolby Vision support Forensic Watermarking should you wish to add this to your production(s).