x265 を Homebrew, apk, apt, MacPorts, Nix, pacman, scoop でインストール

プロジェクトリンク

• ホームページ
• 上流ドキュメント
• パッケージマネージャページ

コマンドとエイリアス

• x265

プロジェクトの歴史

MulticoreWare launched x265 in 2013 to build a high-efficiency, high-performance HEVC encoder. The official documentation says x265 was backed by video technology providers including Telestream and Doremi Labs, with additional unnamed companies and open-source contributors.

x265's ancestry is explicit: the project leverages many video-encoding features and optimizations from x264. Historically that made x265 less a greenfield command-line tool and more a transfer of hard-won encoder engineering practices into the newer HEVC standard, whose block structure, prediction tools, and UHD goals demanded much more computation.

採用の歴史

Adoption followed the rise of HEVC in distribution workflows that needed better compression than H.264, especially for UHD and bitrate-sensitive delivery. x265 was integrated into FFmpeg through `libx265`, giving it the same practical route into scripts, transcoders, and GUI frontends that helped x264 become ubiquitous.

The project has continued active release engineering. The Read the Docs release notes show x265 3.5 in 2021, 3.6 in 2024, 4.0 in 2024, 4.1 in 2024, and 4.2 on 2026-04-19, with ongoing work on rate control, scene-cut handling, Dolby Vision-related signaling, ARM and RISC-V SIMD, film grain signaling, and multiview/alpha/screen-content features.

使われ方

Users invoke `x265` directly for HEVC elementary streams or use it through applications such as FFmpeg. As with x264, common workflows revolve around presets, CRF or bitrate control, pixel format and bit-depth choices, and tuning for speed versus compression efficiency.

x265 is especially relevant in package collections because HEVC encoding is compute-heavy and licensing-sensitive. A packaged `x265` gives users a repeatable CLI and library target for archival transcodes, streaming ladders, UHD delivery, and codec experiments, while the GPL/commercial licensing model shapes how downstream binaries are distributed.

パッケージ好きにとっての重要性

x265 matters to package people because it is the open software implementation most associated with practical HEVC encoding. It is not merely a reference encoder: it is meant to be fast enough for real workflows and optimized across CPU families.

Its release history also tracks where software video encoding pressure moved after H.264: HDR, UHD, ABR ladder generation, ARM servers and desktops, RISC-V optimizations, and interoperability features such as Dolby Vision metadata and film-grain signaling.

タイムライン

• 2013: MulticoreWare launches the x265 HEVC encoder project.
• 2014-02: x265 is integrated into FFmpeg/Libav-era multimedia tooling, making it widely reachable from transcoding workflows.
• 2020-05-29: x265 3.4 is released with ABR ladder and ARM64 work among its notes.
• 2021-03-16: x265 3.5 is released.
• 2024-09-13: x265 4.0 is released with alpha channel, screen-content coding, and MV-HEVC features.
• 2026-04-19: x265 4.2 is released with threaded motion-estimation experiments, updated HEVC level support, and ARM/RISC-V optimization work.

Related projects

• x264 is the AVC encoder whose ideas and optimizations x265 explicitly builds on.
• FFmpeg integrates x265 through `libx265` for HEVC encoding.
• SVT-HEVC is another HEVC encoder family documented near x265's own HEVC ecosystem.
• VVenC and Kvazaar are related open HEVC/VVC-era encoder projects often compared in codec tooling discussions.

ソース

• https://en.wikipedia.org/wiki/X265
• https://multicorewareinc.com/what-we-do/audio-video-solutions/x265-hevc-encoder/
• https://www.ffmpeg.org/general.html
• https://x265.readthedocs.io/en/master/cli.html
• https://x265.readthedocs.io/en/master/introduction.html
• https://x265.readthedocs.io/en/master/releasenotes.html