> For the complete documentation index, see [llms.txt](https://docs.ndi.video/all/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ndi.video/all/developing-with-ndi/advanced-sdk/using-h.264-h.265-and-aac-codecs/h.265-support.md). # H.265 Support ## Supported Formats NDI assumes that all H.265 data is as specified in Annex B of ITU-T H.265 | ISO/IEC 23008-2. The data must include the start codes. We support 4:2:0 in Main, Main Still Picture, and Main10 profiles in resolutions up to 4096x2304 pixels if it is supported by decoding hardware. We recommend that an I-Frame interval of between one and two seconds; it is however very important that you recall that the SDK will inform you when I-Frame insertions are required. The recommended bitrate of the stream is provided by `NDIlib_send_get_target_bit_rate`; for HX it is considered reasonable that you allow the user to select whether you wish a bit rate in the range of 0.1 -- 2.0x the bitrate provided by this function. The recommended rules for the H.265 frame types are the same as those for the H.264 frame types described in the above section. ## Extra Data The extra ancillary data required to configure an H.265 codec must correctly be provided. This must exist for all I-frames. The structure of this data should contain concatenated NAL units in Annex B format, along with their start codes. For H.265, they are the VPS, SPS, and PPS NAL units. ## PTS and DTS The PTS and DTS are not used directly by the NDI SDK, however they are important to ensure that frames may be decoded and displayed in correct order. While we recommend that you use 100 ns intervals for these values, any time-base is technically supported if the ordering of integers is correct. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.ndi.video/all/developing-with-ndi/advanced-sdk/using-h.264-h.265-and-aac-codecs/h.265-support.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.