{"id":21892218,"url":"https://github.com/mikewang000000/wsjpeg","last_synced_at":"2025-07-30T01:39:38.480Z","repository":{"id":95752461,"uuid":"486889323","full_name":"MikeWang000000/wsjpeg","owner":"MikeWang000000","description":"A single-file JPEG encoder","archived":false,"fork":false,"pushed_at":"2022-04-29T08:08:12.000Z","size":19,"stargazers_count":5,"open_issues_count":1,"forks_count":1,"subscribers_count":2,"default_branch":"master","last_synced_at":"2025-04-15T15:05:51.228Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"C","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"lgpl-2.1","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/MikeWang000000.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null}},"created_at":"2022-04-29T08:08:09.000Z","updated_at":"2023-09-13T06:59:18.000Z","dependencies_parsed_at":"2023-05-21T22:00:12.978Z","dependency_job_id":null,"html_url":"https://github.com/MikeWang000000/wsjpeg","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/MikeWang000000/wsjpeg","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/MikeWang000000%2Fwsjpeg","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/MikeWang000000%2Fwsjpeg/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/MikeWang000000%2Fwsjpeg/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/MikeWang000000%2Fwsjpeg/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/MikeWang000000","download_url":"https://codeload.github.com/MikeWang000000/wsjpeg/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/MikeWang000000%2Fwsjpeg/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":267793690,"owners_count":24145080,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","status":"online","status_checked_at":"2025-07-29T02:00:12.549Z","response_time":2574,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-11-28T12:57:26.748Z","updated_at":"2025-07-30T01:39:38.468Z","avatar_url":"https://github.com/MikeWang000000.png","language":"C","funding_links":[],"categories":[],"sub_categories":[],"readme":"# wsjpeg\n![](https://img.shields.io/badge/standard-C89-brightgreen)\n![](https://img.shields.io/badge/code-1%20file-brightgreen)\n![](https://img.shields.io/badge/license-LGPL%20v2.1%2B-brightgreen)\n\n## 简介\n\n这是一个单文件的 JPEG 编码器，可以将未经压缩的 24 位 BMP 位图压缩为 JPEG 图像。  \n本编码器主要用于学习了解 JPEG 的压缩原理。同时，这也是我毕业设计项目中的一部分。\n\n\n## 编译\n\nwsjpeg 代码符合 ANSI C 标准（C89/C90），因此可被近乎所有支持 C 语言的编译器编译，包括 Microsoft Visual C++ 6.0，甚至是 1988 年的 Borland Turbo C 2.0。\n\nwsjpeg 不依赖 C 标准库外的任何第三方库。\n\n如果您需要使用双精度浮点运算，请在头部添加 `#define USE_DOUBLE` ，或者在命令行使用 `-DUSE_DOUBLE` 编译选项（如果可用）。使用双精度浮点运算可以得到更加精确的计算结果。\n\n编译命令行示例：\n```shell\ncc -O3 -DUSE_DOUBLE wsjpeg.c -o wsjpeg\n```\n\n## 命令行参数\n```\nwsjpeg INPUT.bmp OUTPUT.jpg [quality]\n```\n\n参数             | 说明\n----------------|------------------------\n`INPUT.bmp`     |   需要压缩的 BMP 文件路径\n`OUTPUT.jpg`    |   输出的 JPG 文件路径\n`quality`（可选）|  质量因数，可以是 0-100 之间的整数。数值越大，输出图片质量越高，同时将产生更大的文件。默认值为 75 。\n\n\n## 输入输出文件规格\n\n**输入文件：** 输入文件需为 24 位且未经压缩的 BMP 位图。单色位图、16 色位图、256 色等 BMP 位图不被支持。被 RLE 压缩的 BMP 位图亦不被支持，尽管这类格式十分少见。\n\n**输出文件：** 输出文件为 JPEG 编码的图片文件，顺序式编码，固定使用 ISO/IEC 10918-1 : 1993(E) 中 K.3.1 给出的推荐 Huffman 表，使用规格为 4:2:0 的色度抽样 \u003csup\u003e[[?]](https://zh.wikipedia.org/wiki/%E8%89%B2%E5%BA%A6%E6%8A%BD%E6%A0%B7#4:2:0)\u003c/sup\u003e。\n\n## 如何获得 BMP 格式的 24-bit 位图\n\n由于 BMP 文件体积较大，我们在网络上接触到的多数是已被压缩过的 JPG 图像，或者是 PNG 图像。\n\n可以使用以下几种方法将这些图片转换为未经压缩的 BMP 图片。\n\n- 使用 [画图](https://support.microsoft.com/zh-cn/windows/-%E7%94%BB%E5%9B%BE-%E5%B8%AE%E5%8A%A9-d62e155a-1775-6da4-0862-62a3e9e5a511)：  \n    [文件] - [保存为] - [保存类型: 24位位图 (*.bmp; *.dib)]\n\n- 使用 [JS Paint](https://jspaint.app/)：  \n    [File] - [Save As] - [Save As Type: 24-bit Bitmap (*.bmp; *.dib)]\n\n- 使用 [ImageMagick](https://imagemagick.org/)：  \n    ```shell\n    convert \"/path/to/image\" -type truecolor \"image.bmp\"\n    ```\n\n- 使用 [FFmpeg](https://ffmpeg.org/)：  \n    ```shell\n    ffmpeg -i \"/path/to/image\" -pix_fmt bgr24 \"image.bmp\"\n    ```\n\n## 测试\n**测试机型：** MacBook Air (M1, 2020)  \n**编译参数：** `clang -O3 -DUSE_DOUBLE wsjpeg.c -o wsjpeg`  \n**图像来源：** https://esahubble.org/images/heic1502a/\n```terminal\ntime ./wsjpeg \"Andromeda Galaxy.bmp\" \"Andromeda Galaxy.jpg\"\n        0.61 real         0.56 user         0.04 sys\n```\n**Andromeda Galaxy.bmp（输入）**  \n种类：Windows BMP 图像  \n尺寸：10000 × 3197 像素  \n大小：95,910,054 字节\n\n**Andromeda Galaxy.jpg（输出）**  \n种类：JPEG 图像  \n尺寸：10000 × 3197 像素  \n大小：14,283,501 字节\n\n\n## 已知问题或缺陷\n\n本程序可以在绝大多数现代计算机上高效运行。但是，对于一些古老机型（如运行着 MS-DOS 系统的）或者嵌入式设备（如单片机）需要注意以下两点。\n\n1. 此 JPEG 编码器依赖于浮点数运算，计算效率取决于 CPU 浮点数运算性能，在不含 FPU 的处理器上运行效率低下。\n\n2. 此 JPEG 编码器会将输入文件、输出文件的所有内容缓存至 RAM，需确保 RAM 能够同时容得下输入的 BMP 文件数据和输出的 JPG 文件数据。\n\n\n## 开源许可证\n\nGNU Lesser General Public License v2.1 or later (LGPL v2.1+)\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmikewang000000%2Fwsjpeg","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fmikewang000000%2Fwsjpeg","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmikewang000000%2Fwsjpeg/lists"}