Netflix's streaming movie service is finding itself on more and more devices, and recently the company's blog featured a detailed account of exactly how movies are encoded. While many companies hide behind misleading resolution figures like "720p video," video geeks know that bit rate is a much better indicator of how good a video will look. Netflix gets pretty in-depth with the specifications of the new encodes:
"The VC1 encoders are more efficient than the WMV3 encoders, so we are currently encoding VC1AP at slightly lower birates: 375, 500, 1000, and 1500kbps, all square pixel. At some point we are likely to add a couple more resolutions of non-square pixel encodes capturing the original pixel-aspect-ratio of the source."
And the new high-definition encodes:
"We experimented with first-generation WMV3 encodes at 4000kbps and 5500kbps, but settled on second-generation HD encodes with VC1AP at 2600kbps and 3800kbps, which extends their accessibility down to lower home broadband connections. As with SD, encodes of film material are at 24fps, and encodes of shot-to-video material are at 30fps (or 25fps for PAL), rather than the 60fps that would come from a Blu-ray disc - we judged the 60fps content as too expensive of bandwidth for now. In general, these encodes are definitively better than SD, but won't challenge well-executed Blu-ray encodes - that would require a bitrate out of reach for most domestic broadband today. We believe Moore's law will drive home broadband higher and higher enabling full 1080p60 encodes in a few years."
It's definitely worth checking out the full blog, as even more details are revealed, including why only stereo audio is included and how video quality is adjusted to match your connection speed. We haven't done a full evaluation of Netflix's new HD video streams yet, but we're hoping they're close to Vudu's HDX content, which does a very good job of approaching Blu-ray levels even with current bandwidth limitations.