为所有视频提供完美的缩略图
We recently introduced AVIF support to images all over the Vimeo platform. Today, on the same theme, I’d like to introduce three improvements to video thumbnails that were deployed over the last few weeks.
我们最近在Vimeo平台的所有图片中引入了AVIF支持。今天，在同一主题下，我想介绍过去几周对视频缩略图的三项改进。
Better thumbnail generation for HDR video
更好地生成HDR视频的缩略图
High Dynamic Range (HDR) images and videos boast an increased range of luminosity, which allows for the reproduction of brighter and more realistic images on compatible displays. When these images are displayed on a regular Standard Dynamic Range (SDR) screen, they need to be converted into SDR representations as well through a process known as tonemapping. There is no one right way to perform tonemapping of HDR videos. To obtain good, consistent results for the majority of Vimeo uploads, we implement our own method that is applied at transcode time.
高动态范围（HDR）图像和视频拥有更大的亮度范围，可以在兼容的显示器上再现更明亮、更真实的图像。当这些图像在普通的标准动态范围（SDR）屏幕上显示时，它们也需要通过一个被称为色调映射的过程转换成SDR表示。对HDR视频进行色调映射并没有一个正确的方法。为了让大多数Vimeo上传的视频获得良好、一致的结果，我们实施了自己的方法，在转码时应用。
In the past, our video and image transcoding systems were totally independent, which caused some inconsistencies in our processing and increased the complexity of our thumbnail generation system, as we had to work around the limitations of our image pipeline. These inconsistencies included color space conversion and tonemapping.
过去，我们的视频和图像转码系统是完全独立的，这在我们的处理过程中造成了一些不一致，并增加了我们缩略图生成系统的复杂性，因为我们必须绕过图像管道的限制。这些不一致的地方包括色彩空间转换和色调映射。
Deployment diagram of our image and video systems, previous version. Unnecessarily duplicated functions highlighted in red.
我们的图像和视频系统的部署图，以前的版本。不必要的重复功能用红色标出。
Because our thumbnails all use a standard dynamic range, we used to generate the thumbnails of HDR uploads after transcoding, using the tonemapped SDR videos. While this resulted in images that matched the SDR versions of the videos, it also caused the thumbnail generation to be delayed, which is bad both for user experience and for internal complexity.
因为我们的缩略图都使用标准的动态范围，我们曾经在转码后使用色调映射的SDR视频，生成HDR上传的缩略图。虽然...