-->
获得免费通行证加入我们的流媒体连接- 11月13日至16日; Register Now!

回顾:ViCueSoft CodecWar

Article Featured Image

CodecWar is an analysis service created by ViCueSoft, the developer of codec analy-sis工具VQ分析仪,VQ DVK,和VQ Probe. 该网站有两个主要功能. First, 它提供了一个免费的图书馆 codec comparisons relating to all relevant compression standards, 专有和开源. Using this func例如,您可以快速比较VVC与最新版本的 AV2, with outputs including both RD-Curve and BD-Rate comparisons. 这个功能使该网站对任何需要保持当前编解码器比较的人都很有用.

其次,该站点允许您配置编码器,对单个或多个测试文件进行编码, 并为输出生成rd曲线. In both use cases, you can use test files provided on the 网站或上传您自己的,并使用网站上的编解码器进行编码或上传您自己的. However, if you upload your own clips or codecs for the comparison function, you’ll be charged for the associated processing time.

这个网站还在建设中. As currently configured, the ideal users are researchers who 正在寻找一种方便的方法来比较使用相关数据集的编解码器和编解码器开发人员正在寻找一种结构化的方法来对其他编解码器进行基准测试. In contrast, it’s not a particularly convenient way for streaming producers to run experiments to 优化它们的编码参数,尽管它可能会发展成这样.

Compare Video Codecs

此功能对最终用户是免费的,允许他们选择和修改的不同观点 the data that ViCueSoft has already crunched. 这是一种很有用的方法,可以用来理解不同的编解码器是如何比较的 剪辑及比较方法. All of this data is free; you just need to configure the data you want to see and download the report.

To start, as seen in Figure 1, you can choose 从模板或您自己的选择. At a high level, each comparison comes down to one or more codecs compared using one or more test clips.

comparing codecs

Figure 1. 在比较编解码器时,您可以选择模板或自己的比较点.

Codec support is growing; for example, when I started my review, the only VP9 codec available was the SVT-VP9 codec, which historically has been a poor performer. By the last day, ViCueSoft had added libvpx. HEVC选项是MPEG参考编码器,这是伟大的 researchers but irrelevant for producers, and SVT-HEVC,另一个差劲的表现. Here, x265 is the obvious choice for the HEVC codec (and I’m sure ViCueSoft will add it soon). While you can upload any codec you would like, this means additional encoding charges and inconvenience.

In contrast, 该服务为AV1提供了更好的选择, 包括SVT-AV1和libaom, and VVC, 包括MPEG参考编码器和Fraunhofer的开源实现. Similarly, H.264 included both the MPEG reference encoder and x264, the logical choice. 这个服务很好地满足了我的好奇心, 这是怎么最新的版本 AV2 compared to VVC.

You can see this in Figure 2. I’ve already selected the VVC reference encoder as the reference codec, 我将其与AVM/进行比较Research 4 codec using the random access (RA)配置.

comparing vvc to av2

Figure 2. Comparing VVC with the latest version of AV2

Note the “How it works” button on the top left of Figure 2. 在本例中,它显示一个YouTube 视频,但在其他屏幕上,它会显示更详细的说明. ViCueSoft做得很好 在整个UI中散布这些帮助屏幕以协助您的操作.

Next, you choose the clips to compare, as shown in Figure 3. 你可以按任意一个排序 the parameters at the top; you can see the resolution op下拉列表中的选项. The site includes an excellent mix of 测试剪辑,包括所有 genres and some familiar clips like Crowd­Run, WITCHER3, and Tango, which you can view and download at codecwar.com/gallery.

选择要比较的片段

Figure 3. 选择要比较的片段

请注意,并非所有测试剪辑都可用于所有编码比较, meaning each codec in the available configurations. For example, 在ViCueSoft添加libvpx之后, I attempted to compare it to x264 using both VBR configurations. 中只有一个测试片段可用 free comparison, a 480x270@60 fps clip that held little interest.

To be clear, the most common comparisons will have multiple options; the VVC versus AV2 comparison I ran had more than 40 comparison clips. While the number of 剪辑将增加随着时间的推移,更边缘你的编解码器/配置定量比较,夹子越少 will likely be available for the free comparison.

Figure 4 shows the top section of the results. Overall, AV2 proved 26.2% more efficient than the reference VVC codec as com采用AOM分段三次埃尔米特插值多项式方法 (PCHIP)与Polyfit相比. If 你根本不知道是哪一个Polation方法选择,你是 in good company; fortunately, ViCueSoft有一篇博客文章 that seems to indi证明PCHIP更准确.

Vicuesoft编解码效率

Figure 4. 根据ViCueSoft的计算, AV2 is about 26% more efficient than the VVC reference codec, which is impressive.

Of course, 如果不了解用于每个编码器的命令字符串,则没有质量比较是完整的. 您可以访问所有转码的这些 通过CodecWar界面的Profiles页面中的Configurations选项卡. This tab also contains the configuration files you might need for performing your own custom transcodes 在我要描述的第二个函数中.

At the bottom of 图4中,您看到了这个功能 to toggle between BD-Rates (for Bjontegaard Delta-Rates) and RD-Curves (for Rate Dis­tortion-Curves). 你可能知道,一个速率-distortion graph plots the quality levels of the codecs at different bitrates, while BD-Rate quantifies the difference into a single number.

例如,在左边 Figure 5, 你可以看到rd曲线比较ing VVC and AV2 at different bitrates for the 使用VMAF剪辑子午线 metric. AV2 is the bluish line atop the curve, with the gray VVC on the bottom. 你可能已经猜到了, 上面的夹子质量较好.

rd曲线表示代码

Figure 5. 以下是来自VMAF CodecWar报告的RD-Curve演示.

右侧显示的BD-Rate计算将这些差异量化为单个数字ber, in this case, 34.85%. 对于这个分析,VVC is the so-called anchor codec to which we’re comparing AV2. 由于数字是绿色的, it means that, on average, AV2 delivers the 与VVC的34级质量相同.85% lower bit­rate. If the number were red, it would mean that AV2 was less efficient.

再一次,指的是底部 Figure 4, the BD-Rate report shows the BD-Rate value for all clips; you can download a sample BD-Rate report for VMAF. The RD-Curve report includes the data shown in Figure 5 for all test clips; you can download VMAF的样本RD-Curve报告. 注意,您可以查看和保存 任何一个报告 指标显示在底部 Figure 4.

每次你选择一个报告,你可以点击“阅读更多关于这个研究”显示在顶部 在图4中查看数据 Figure 6. 这提供了一个概述,链接到 the GitLab location where you can download the codec, and details about the metric and interpolation method.

codecwar report

Figure 6. Details about the report shown in Figure 4

配置视频编码器

第二个CodecWar用例是定制编码配置文件, encode a file, 并生成任意的rd曲线 the metrics shown in Figure 4. 这个选项更有用,但也更复杂,有点脱节. 此外,你必须付费才能玩.

你通过这个过程 a five-step wizard, first choosing your codec. In this operation, you can only select a single codec. As shown in Figure 7我选择了使用x264的AVC codec. 同样,您可以选择任何编解码器 可在系统中或上传任何 请联系ViCueSoft.

自定义编码管道x264

Figure 7. Creating my custom encoding pipeline for x264

在步骤2中,您可以选择一个预设,可以是标准配置 你的服务或者你的self. Or you can create your own custom configuration. I chose a custom 要达到的配置 Figure 8.

配置自定义编码

Figure 8. 配置自定义编码

你从左上角开始选择创建一个模板,模板就会自动生成参数,然后显示在中间的可编辑编码器文本字段中. 您可以通过编辑文本来更改文本字段中的任何参数. However, if 修改命令 string, you’re in charge of making sure 命令字符串有效. If it’s incorrect, you’ll fail the validation phase discussed next.

Similarly, for those codecs operated via a configuration file, you are able to upload a custom configuration file. As mentioned, to see what comprises a configuration file, 您可以从客户配置文件屏幕中的配置选项中下载由ViCueSoft创建的一个. 不幸的是,“它是如何工作的” video file doesn’t address what a configuration file is and where to access one; it just states that you can upload one, 哪个复杂的手术适合我.

一旦您完成更改或添加 不同的配置文件,您单击右下角的验证按钮. 编码器尝试转码一个短文件以验证新的配置. If 如果成功,您可以继续. If there’s an error, 在继续之前,必须调试它并使新的配置工作.

没有编码GUI,并且给定 breadth of 编解码器可用,真的不能 be. 所以,你负责 ensuring the configuration options are correct. This shouldn’t be 对于了解参考编码器的研究人员或正在评估自己编解码器的编解码器开发人员来说,这是一个问题, 但它可能是为那些寻求运行一些编码实验的普通用户. 对我来说,一个复杂的问题是x264编解码器使用了x264编码器, 而不是FFmpeg中的x264编码器, 所以典型的FFmpeg命令不起作用. That wasn’t a huge deal, but it slowed me down. If technically feasible, 开发人员应该考虑对像x264这样的编解码器使用类似ffmpeg的命令, x265 (if and when added), and VP9 instead of or in addition to the native encoder commands.

Returning to the interface tour, in the bottom middle of 图8中,您可以看到QP值ues used for the multiple encodes, which you can also edit. If 你喜欢,你也可以选择 the encoding points via bitrates, although you’ll have to choose or create a preset that encodes using VBR.

然后,按右下角的Validate来验证更改是否有效. In the upper left of the Validation screen, 您可以看到与您编写的编码作业相关的费用. 这些代表CodecCash,成本为0.9 Euros each. 你可以在 codecwar.com/pricing.

The middle screen 表明我们通过了所有的 验证测试和 are free to proceed. Once 您已经验证了配置(Figure 9), it’s saved 使用默认配置,并且每次部署该编解码器时它都会作为选项显示.

传递新配置

Figure 9. The new configuration has passed; we can proceed.

接下来,选择要用所选配置编码的剪辑. Pricing is based on the codec, resolution, and frame rate. In Figure 10, you can see that based on the formula applied by the site, CrowdRun (1080p@50 fps) counts as 39 streams, for a total price of eight codec cash units.

choosing the streams

Figure 10. Choosing the streams, setting the price, and starting the encode

Encoding time depends on the clip, codec, and configuration. Most of the preset configura设置为最大值 quality, which obviously  extends the encoding time. 开始编码后,有一个状态屏幕可以查看 确定你的进步. Once complete, you can access the results in the Workspaces tab. As shown in Figure 11 (on page 52), once you access the job, you can view three categories of results.

The Configuration tab details test parameters like command strings, 详细日志显示播放编码次数和 other performance data. Metrics选项卡包含 the RD-Curves for the clips that you encoded, with all of 同样的指标显示在中间 Figure 11.

rd-curves codewar

Figure 11. Here are the RD-Curves for the selected clips that I encoded.

您可以以JSON格式导出所有结果以供将来处理,但不能运行comparisons of 生成的结果文件. So, if you ran CrowdRun with x264 with a single B-frame and then 16个b帧,你无法装载 在这个界面中比较两者.

Concluding Thoughts

At a high level, the ideal customer for the sec的编码相关功能 CodecWar is a compressionist who doesn’t have the programming skills (or time) to automate their test管理和报告活动. 这当然包括我.

挑战在于每个压缩师都有自己独特的分析和报告 schema. 我主要依赖于RD-Curve和BD-Rate数据,但也依赖于可视化 the 的持续时间内的度量分数 the file to spot 质量下降,以及像文件和标准数据中最低质量帧这样的数据评估…的可能性 transient quality 问题和质量可变性. I’d love the ability to upload some files, choose some parameters, 然后下载结果, but only if 它提供了我所依赖的数据来做出我认为明智的决定. Building an application that can support many of these idiosyncratic schemas will be tough, but ViCueSoft is off 令人印象深刻的开始.

Streaming Covers
Free
合资格订户
Subscribe Now Current Issue Past Issues
Related Articles

Review: Ant Media Server (Enterprise Edition)

本文将重点介绍Ant Media Server和流媒体服务器支持的许多特性. 观众还将学习如何在亚马逊网络服务上配置WebRTC流媒体服务器,以及如何启动和运行直播流和视频点播流.