# Technical Requirements The following technical requirements are specific to each NDI format, but if a device can support more than one format, it will be certified and tested under both types separately. In addition to the following technical requirements, [Interoperability Requirements](https://docs.ndi.video/all/developing-with-ndi/ndi-certified/certification-guidelines/interoperability-requirements) must be followed. {% hint style="info" %} You can find other examples of bandwidth requirements [on this page](https://docs.ndi.video/all/getting-started/white-paper/bandwidth). {% endhint %} *** ## **NDI High Bandwidth** The specific criteria for NDI High Bandwidth certification are: * [**Interoperability requirements**](https://docs.ndi.video/all/developing-with-ndi/ndi-certified/certification-guidelines/interoperability-requirements) * **I Frame only** for Keyframe * Less than **100ms** latency * **SpeedHQ** codec {% hint style="success" %} The transmission of NDI is agnostic to any specific aspect ratio. You can expect it to work regardless of your resolution {% endhint %} | Resolution Supported | Frame/Fields | | -------------------- | -------------- | | 2160p | 60, 50, 30, 25 | | 1080p | 60, 50, 30, 25 | | 1080i | 60, 50 | | 720p | 60, 50, 30, 25 | | 576i | 50 | | 480p | 30, 25 | | 480i | 60, 50 | | Codec | Supported Bit Depth | Chroma Subsampling | Color Space | | ------ | ------------------- | --------------------- | ----------- | | SHQ0-7 | 8bit, 10bit | 4:2:0, 4:2:2, 4:2:2:4 | YUV | *** ## **NDI HX2** This certification is for products that support NDI HX2 but cannot pass the technical certification requirements of NDI HX3. Critically, they still pass the Interoperability requirements. These devices may have slower latency or keyframe or a larger GOP. The key criteria are: * [**Interoperability requirements**](https://docs.ndi.video/all/developing-with-ndi/ndi-certified/certification-guidelines/interoperability-requirements) * **150ms** glass-to-glass latency * Keyframe response time under **80ms** * Current SDK or previous SDK (6.0 currently, 5.6 previous as of this writing) * **H.264** or **H.265** encoding | Resolution Supported | Frame/Fields | | -------------------- | -------------- | | 2160p | 60, 50, 30, 25 | | 1080p | 60, 50, 30, 25 | | 720p | 60, 50, 30, 25 | | 480p | 30, 25 | | Codec | Supported Bit Depth | Supported Chroma Subsampling | Color Space | | ---------- | ------------------- | ---------------------------- | ----------- | | H.264 | 8bit, 10bit | 4:2:0, 4:2:0:4 | YUV | | H.265 HEVC | 8bit, 10bit | 4:2:0, 4:2:0:4 | YUV | *** ## **NDI HX3** This certification is for products supporting NDI HX3 that fit one of the following criteria: * [**Interoperability requirements** ](https://docs.ndi.video/all/developing-with-ndi/ndi-certified/certification-guidelines/interoperability-requirements) **Encoder** * **H.264** or **H.265** encoding * **GOP** setting set to **20** * Video compression set to **low latency** **Latency** * **100ms** Glass-to-glass Latency * Keyframe response time under **80ms** **Compression** * Quality: no visible compression artifacts * Compression: **constant bitrate** (CBR) | Resolution Supported | Frame/Fields | | -------------------- | -------------- | | 2160p | 60, 50, 30, 25 | | 1080p | 60, 50, 30, 25 | | 720p | 60, 50, 30, 25 | | 480p | 30, 25 | | Codec | Supported Bit Depth | Supported Chroma Subsampling | Color Space | | ---------- | ------------------- | ---------------------------- | ----------- | | H.264 | 8bit, 10bit | 4:2:0, 4:2:0:4 | YUV | | H.265 HEVC | 8bit, 10bit | 4:2:0, 4:2:0:4 | YUV | *** {% hint style="warning" %} **NDI HX1** is a legacy format that will be discontinued over time. As such we are not certifying devices that support this format. Contact our [technical support team](mailto:support@ndi.video) if you have any questions. {% endhint %} *** ## NDI 6 Optional Features #### **HDR** With [NDI 6](https://ndi.video/tech/ndi6/), HDR is now officially supported as a sender and receiver for **NDI HX (HX2 and HX3 only)** and **NDI High Bandwidth**. To qualify under either, the following must be met: * HDR optional toggle - not every receiver is HDR compatible, and NDI strives for forward and backward compatibility. HDR must be allowed to turn off at the end user's request * BT\_2020 or BT\_2100 primaries (as defined in the SDK for [**HDR**](https://docs.ndi.video/docs/advanced-sdk/hdr)) * 10 and 12-bit video #### NDI Bridge With NDI 6, NDI Bridge functionalities can now be embedded into a device or application to connect across networks, even across the public Internet, easily. As this is a connection method rather than a quality metric, certification will depend on the ability to implement the following: * NDI Bridge optional toggle - Bridge must be enabled or disabled at the end user's request * Fields to enter IP, port, username, and password * Connection success or failure messaging {% hint style="warning" %} We conduct testing on common industry standards, but certification only covers widely used resolutions and aspect ratios. Other resolutions and aspect ratios may work but are not officially certified at this time. {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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