🎬 音视频工具Video & Audio
MP4 转 MP3（视频提取音频）MP4 to MP3 Converter
从 MP4、MOV、WebM、MKV 等视频中提取声音并保存为 MP3：可选 128–320 kbps 码率、立体声或单声道，可截取开始和结束时间，还能写入标题和歌手标签；解码和编码都在浏览器本地完成。Extract the soundtrack from MP4, MOV, WebM, MKV and other videos and save it as MP3 — 128–320 kbps, stereo or mono, optional start/end trim and title/artist tags. Decoding and encoding both run locally in your browser.
MOV 转 MP4（无损转换）MOV to MP4 Converter
把 iPhone、相机或 QuickTime 的 MOV 视频转成 MP4：H.264/HEVC + AAC 的文件直接无损转封装，几秒完成且画质不变，可选“快速启动”让网页和手机边下边播；ProRes 等不兼容编码会提示并可改为重新编码。Convert MOV videos from iPhones, cameras or QuickTime to MP4. H.264/HEVC + AAC files are remuxed losslessly in seconds with identical quality, with optional fast start for streaming on the web and phones; incompatible codecs such as ProRes are flagged, with a re-encode option.
视频转 GIF 动图Video to GIF Converter
把 MP4、MOV、WebM 视频片段做成 GIF 动图：在预览中定位开始时间，设置时长（最长 30 秒）、帧率、宽度和播放速度，可选全局调色板减少闪烁、是否循环；逐帧精确截取，在浏览器本地生成。Turn a clip of an MP4, MOV or WebM video into an animated GIF — pick the start in the preview, then set length (up to 30 s), frame rate, width and speed, with an optional global palette to reduce flicker and loop on/off. Frames are captured precisely and the GIF is built locally.
视频压缩（减小视频文件大小）Video Compressor
在浏览器里压缩 MP4、MOV、WebM 视频：可按目标文件大小（例如压到 25 MB 以内发邮件或聊天）或按画质档位压缩，降低分辨率到 1080p/720p/480p，调整音频码率或去掉声音，还能只截取一段，处理前预估大小。Compress MP4, MOV or WebM videos in your browser — aim for a target file size (e.g. under 25 MB for email or chat) or a quality level, downscale to 1080p/720p/480p, lower the audio bitrate or drop the sound, and optionally keep just one segment, with a size estimate before you start.
视频裁剪（画面裁切）Video Cropper
裁掉视频画面的黑边、水印区域或多余部分：在预览上拖动和缩放裁剪框，或直接输入像素坐标，一键套用 1:1、9:16（抖音/Reels）、16:9、4:5 等比例，同时可截取开始和结束时间，保留声音，本地导出。Crop black bars, a corner or unwanted areas out of a video frame — drag and resize the crop box on the preview or type pixel values, snap to 1:1, 9:16 (TikTok/Reels), 16:9, 4:5 and more, trim start and end, keep the audio, and export locally.
在线录屏（屏幕录制）Online Screen Recorder
直接在浏览器里录制整个屏幕、某个窗口或浏览器标签页，可同时录入系统/标签页声音和麦克风解说，支持暂停继续、画质和帧率选择，录完立即预览并下载 MP4/WebM；无需安装软件、没有水印、不上传。Record your whole screen, a single window or a browser tab right in the browser, with tab/system audio and microphone narration mixed in, pause/resume, and quality and frame-rate options; preview and download MP4/WebM as soon as you stop. No install, no watermark, no upload.
摄像头测试（在线检测）Webcam Test
在线检测电脑或手机摄像头和麦克风是否正常：一键打开实时画面，显示实际分辨率、实测帧率、设备支持的最大分辨率和宽高比，可切换多个摄像头、测试 4K、查看麦克风音量电平、镜像显示并拍照保存。Check that your webcam and microphone work: open a live preview in one click and see the actual resolution, measured frame rate, the maximum resolution the device reports and the aspect ratio. Switch between cameras, test 4K, watch the microphone level meter, mirror the view and save a snapshot.