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  "markdown": "> **Repository:** [jvet/HM](https://vcgit.hhi.fraunhofer.de/jvet/HM). HEVC HM reference software. Latest release: [HM-18.0](https://vcgit.hhi.fraunhofer.de/jvet/HM/-/releases/HM-18.0), Apr 20, 2023. Last commit: Jul 27, 2026. License: BSD-3-Clause.\n\nHM (HEVC Test Model) is the reference encoder and decoder for [H.265 / HEVC](/codecs/video/hevc/). It exists for conformance testing and HEVC coding-tool research.\n\nAs an encoder it is a curiosity. HM has no threading and is slower than [x265](/tools/software-encoders/x265/)'s slowest presets, it places keyframes on a fixed `IntraPeriod` rather than detecting scene changes, and it takes only raw YUV. Use x265 for real work. The VVC and AVC counterparts are [VTM](/tools/software-encoders/vtm/) and [JM](/tools/software-encoders/jm/).\n\n## Build\n\nThe latest release is `HM-18.0` (April 2023).\n\n```sh\ngit clone --branch HM-18.0 https://vcgit.hhi.fraunhofer.de/jvet/HM.git\ncd HM\ncmake -S . -B build -DCMAKE_BUILD_TYPE=Release\ncmake --build build --parallel\n```\n\nCurrent GCC (16) stops on new warnings because the project builds with `-Werror`; add `-DCMAKE_CXX_FLAGS=-w` to the first `cmake` command to get past them.\n\nThis produces `TAppEncoderStatic` and `TAppDecoderStatic` in `bin/`. The manual is in `doc/software-manual.pdf`.\n\n## Encode a raw file\n\nHM needs raw planar YUV plus the size, frame rate and frame count. Settings come from a config file in `cfg/` (`encoder_randomaccess_main10.cfg`, `encoder_lowdelay_main10.cfg`, `encoder_intra_main10.cfg` and so on):\n\n```sh\n./bin/TAppEncoderStatic -c cfg/encoder_randomaccess_main10.cfg -i input.yuv -b stream.265 -o recon.yuv \\\n  -wdt 1280 -hgt 720 -fr 24 -f 48 --InputBitDepth=10 -q 32\n./bin/TAppDecoderStatic -b stream.265 -o decoded.yuv\n```\n\n`-q` is a fixed QP, not a CRF equivalent. The decoder output should match `recon.yuv` bit for bit. The result is a bare HEVC elementary stream; mux it with [MP4Box](/tools/utilities/mp4box/) or [FFmpeg](/tools/utilities/ffmpeg/).\n"
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