创造一个成功的编解码器的配方，以满足所有的口味
Last month, I hosted a Bitmovin event 被称为“编解码器之战”，它比较了H.264, VP9, HEVC, AV1和VVC，以确定每个编解码器的部署机会. 为这次活动做准备让我思考了说服视频发行商采用新编解码器的因素, which I present herein.
H.264是最后一个编解码器全垒打，也可能是最后一个. 它在广播领域取得了成功，因为它是一个标准, was commercially reasonable, 并且提供了比MPEG-2更好的编码效率. H.264占据了流媒体的主导地位，因为它的性能优于VP6，而且在商业上是合理的，而且Adobe和苹果也部署了H.264 decode, providing near playback ubiquity. The fact that H.264 was a standard eliminated the fear, uncertainty, 以及困扰非基于标准的编解码器并鼓励播放无处不在的怀疑(FUD)因素. 它还确保了硬件实现所需的低成本硅的供应. Twelve years later, H.264 is still the predominant video codec.
In contrast, VP8 performed similarly to H.264, and so had few takers, other than YouTube. VP9提供了更好的编码效率, 但从未在广播领域站稳脚跟，有一定的FUD因素, although this has diminished over time. Adoption has largely been limited to high-volume, YouTube等公司部署的长尾用例, Facebook, and Netflix.
HEVC offers better encoding efficiency than H.264 .但受到普遍认为不合理的商业条款的阻碍. Nonetheless, because HEVC is a standard, 在硬件市场，专利使用费可以转移给消费者, like mobile devices, over-the-top (OTT) devices, smart TVs, and set-top boxes. As a standard, HEVC已被纳入大多数高动态范围(HDR)技术, locking out VP9 and VC1, at least for now. As a result, HEVC已被公司广泛部署到客厅, particularly 4K and HDR videos. HEVC也广泛应用于安全等市场, contribution, and on-camera encoding, 它们几乎总是由基于标准的技术主导.
In streaming, however, HEVC的吸引力很小，仍然无法在浏览器上运行，而在桌面pc上，HEVC的市场份额接近90% (Chrome), Firefox, Internet Explorer, and Opera). 在苹果为iOS/Mac/ Apple TV设备添加HEVC播放功能18个多月后, 似乎只有少数公司利用了这个机会来提高QoE或降低带宽成本.
What have we learned? First, encoding efficiency and encode/decode performance are table stakes; if the technology doesn’t outperform existing technologies, it’s got no chance. Second, 当一种新的编解码器能够为一组新的设备和客户提供访问时，生产商将急切地部署它. Third, other than companies like Netflix, Facebook, or YouTube, 大多数流媒体生产商不会采用新的编解码器来节省带宽或提高QoE. Fourth, 许多因素会影响编解码器的市场接受度, 包括不合理的商业条款和与知识产权相关的FUD.
What does this mean for AV1? At this point, 尽管编码时间在减少，解码需求似乎也不大, compression efficiency is still in doubt. Certainly, 开放媒体联盟的公司将确保计算机硬件的供应, mobile, and broadcast applications, 以及浏览器支持和令人印象深刻的早期内容采用者列表. 这一点，再加上流媒体和广播市场不断变化的重要性，可能会推动AV1走得比VP9所希望的更远. However, 一些潜在的内容采用者担心潜在的ip相关问题, and at this point, 目前尚不清楚AV1是否会创造HEVC或其继任者没有涉足的新市场, VVC. 另一个可能的结果是AV1主要由联盟内的公司使用, like VP9 is today.
What about VVC, the standards-based successor to HEVC, 一些早期的测试显示，它的压缩效率明显高于AV1? Because it will be a standard, VVC将主导广播市场和二级市场，比如安全市场, on-camera encoding, and contribution. However, absent some dramatic change in royalty policy, it won’t succeed in traditional streaming markets, as is the case with HEVC today.
What does this mean for you? 没有像汤姆·克兰西那样的事件摧毁了世界上的电脑安装基础, set-top boxes, smart TVs, 以及移动和OTT设备(电磁脉冲), perhaps?), no single codec will ever replace H.264; we’re in a multi-codec world. And, as you already know, 编解码器可用于部署这一事实并不意味着您应该部署它. You’ll likely find codecs that enable entry into new markets very alluring; those that allow you to serve an existing market more efficiently, not so much.
[本文发表于2018年11月/ 12月号。 Streaming Media Magazine as "The Recipe for Codec Success."]
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