2009编码器枪战

哇! 又一年过去了. And so it’s time for another round of encoding tool updates. 在这篇综述中, 我要比较一下输出的质量, 速度, and codec-related feature set of the most prominent crop of sub-$1,并以报告卡的形式提供结果. For the most part, the best in each category rated an A, the worst a C, and the rest B’s. 尽管这将因编码工具和类别而异, a C grade should be a concern if you’re currently using or plan to use the encoding tool. Where a feature is significantly limited in a particular encoder, I've noted it in the tables with asterisks and explained the issue in the text.

短暂的, 用于质量测试, I produced SD (640x480 at 30 fps at 468Kbps video/32Kbps audio) and HD (1280x720 at 29.97 fps, 800Kbps视频/128Kbps音频)文件.264, VP6, and VC-1 codecs; I compared output quality with other encoding tools using the same operating system. 我制作了所有的比较质量测试, predeinterlaced files to isolate the encoding quality rather than the scaling and deinterlacing quality of the respective tools. 测试缩放和去隔行质量, I used a 1-minute DV file containing multiple scenes with sharp edges, 对角线, and other jaggy magnets; I then compared the output of the respective tools.

测试性能, I timed the encoding of a single 1-minute file and then timed how long it took to encode five 1-minute files, 部署所有可用的技术来加快编码时间, such as running multiple instances of On2 Flix Pro and Sorenson Squeeze on both the Mac and Windows platforms for the five-file encoding trials. 对于Windows，我用的是2.8-GHz Dual-Processor, Quad-Core HP xw6600 workstation running XP with 3MB of RAM. 对于Mac的编码，我在3上进行了测试.2-GHz Dual-Processor, Quad-Core Mac Pro running Leopard with 8MB of RAM.

就支持的特性而言，这因编解码器而异. 对H.264, 我研究了诸如访问基线之类的特性, main, 还有高调; support for context-adaptive binary arithmetic coding (CABAC) entropy encoding; and the breadth of B-frame configuration options. For VP6, I looked at access to two-pass encoding and also the VP6-S and VP6-E options. ,但它还是, I looked at access to the tweaking parameters enabled in WMV SDK 11 and support for Silverlight output.

Adobe Media Encoder CS4
CS4是Adobe媒体编码器(AME)的一个伟大版本。, as the program gained both batch capabilities and stand-alone operation, meaning that you can run the program separately from Premiere Pro (or other CS4 apps) and insert files or Premiere Pro sequences for encoding. 更令人印象深刻的是, you can send sequences from Premiere Pro to AME and continue editing in Premiere Pro, a dream feature that easily justifies the suite upgrade price for most serious Premiere Pro editors.

然而，也有一些限制. 例如, the new watch folder functionality doesn’t trigger automatically when a file gets dropped into the folder; you have to start the encoding process manually, a limitation that hopefully will be addressed in a future release. The other negative is that you can’t open multiple instances of AME to boost the 速度 of multiple file encodes, 你可以用许多其他程序来做什么, 包括微软表达式编码器2, On2 Flix Pro, and Sorenson Squeeze—the latter two on both Mac and Windows. Nor does Adobe offer a tool like Apple’s Qmaster to make encoding on multiple core computers like our 8-core HP xw6600 more efficient. 由于AME在Windows Media和H.264 output, this primarily impacts VP6 encoding times, as I detail below.

在输出质量方面, it was a different story for the Mac and Windows versions, Windows提供了更好的H.264 quality and the ability to produce WMV files, which AME can’t do on the Mac. 在两个平台上，H.264的可配置性受到限制. 您可以选择基线, main, 还有高调, but you can’t choose CABAC entropy encoding or control B-frame sequencing. Not surprisingly, though, you can output in the new F4V format for Flash.

不过，在Windows系统中，H.264 quality was quite good—very close to that produced by Sorenson Squeeze, which produced the best quality among the reviewed programs. Mac H.264 quality was spotty, though—poor in our SD trials and very good in HD. 在我们的性能测试中，AME是一个令人尖叫的问题, with the fastest five-file encoding times on both the Mac and Windows. 总的来说，如果你是一个随意的H.264 producer, AME is fine in Windows, but you may wish to look elsewhere for the Mac.

The big story with VP6 is that AME gained two-pass encoding capabilities, 是什么将输出质量提升到了顶级水平, 接入VP6-S, the "simple" version of the codec that’s ideal for HD video or video produced for low-power devices. As mentioned before, the big negative for AME and Flash is encoding time. 在我们的8核HP工作站上, 例如, Squeeze produced five 1-minute test files in 10:28 (min:sec), 而AME CS4 33:30完成了同样的任务. The difference was even more stark on our 8-core Apple loaner: On2 Flix Pro took 6:22; AME took 47:20. If you’re trying to encode Flash files in a hurry, AME is not for you on either platform. 如果你不赶时间，这是一个不错的选择.

在Windows平台上, Windows Media quality is good and encoding times are quite good; AME should prove adequate for any producers not looking for the ability to tweak their Windows Media files or create a Silverlight player.