ugoira
Ugoira is a custom animation format used by Pixiv. A Ugoira is a Zip file of images, played back using a custom Javascript player.
To download a Ugoira, use the "Save as video (right click and save)" link beneath the image. This is a WebM conversion that can be played on regular video players, but is not lossless in quality.
To upload a Ugoira, paste the Pixiv URL into the source field on the upload page, or upload using the bookmarklet. Uploading a Ugoira file from your computer will not work.
Technically, a Ugoira consists of Zip file containing each frame in JPEG or PNG format, and a separate JSON file containing the delay between each frame. Since each frame has a separate delay, it's possible for a Ugoira to have a variable frame rate. A custom Javascript player is used to play animations back. Since the JSON file containing the frame delays is separate from the Zip file containing the images, saving raw Ugoiras and playing them outside of a browser is difficult.
Ugoira is a custom format exclusive to Pixiv. Animations from other sites cannot be Ugoira.
Ugoira is often considered inferior to animations found on other sites due to Pixiv's limitations on uploading GIFs or MP4 videos. As a result, artists may convert their animations to GIFs before uploading, introducing dithering and/or color banding, and Pixiv's recompression process can introduce additional JPEG artifacts, affecting the overall quality of Ugoira animations.
另请参见
This tag implicates animated (learn more).
要下载ugoira，请使用图像下面的链接“保存为视频（右键单击并保存）”。这是可以在常规视频播放器上进行的WebM转换，但质量并非无损。
要上传Ugoira，请将Pixiv URL粘贴到上传页面上的源字段中，或使用书签上载。从您的计算机上传Ugoira文件将无法工作。
从技术上讲，Ugoira由包含JPEG或PNG格式的每个帧的ZIP文件以及一个包含每个帧之间延迟的单独的JSON文件。由于每个帧都有一个单独的延迟，因此Ugoira可能具有可变的帧速率。自定义JavaScript播放器用于播放动画。由于包含帧延迟的JSON文件与包含图像的ZIP文件分开，因此很难在浏览器外保存原始的Ugoiras并在浏览器之外播放它们。
Ugoira是Pixiv独有的自定义格式。来自其他站点的动画不能是Ugoira。
由于Pixiv上载GIF或MP4视频的局限性，Ugoira通常被认为不如其他站点上的动画。结果，艺术家可以在上传之前将其动画转换为GIF，引入抖动和/或颜色调节，而Pixiv的重新压缩过程可以引入其他JPEG文物，从而影响Ugoira动画的整体质量。