Studying Chris Milk
Chris Milk, like most of us lesser mortals, is using the h.264 MP4 codec. However, the key is in the profile and level he uses. We encountered these settings often in our encoding tools, but usually didn’t pay a whole lot of attention to them. Now we know better..
The Baseline profile is primarily used for decoders with limited computing power, like mobile applications. Google also recommends the Baseline profile for h.264 video playback on Android. This makes it the go to profile for mobile VR, like Google Cardboard and Gear VR.
The level describes the max resolution and bitrate acceptable. Each device supports videos up to a certain h.264 level. For example, iPhones only support videos up to level 3.1 (1920×1080@30 is the absolute max for iPhone 5.. so pretty appalling for VR video playback), while most Android phones will play level 4.2 videos just fine.
The resolution of 3840×2160 is the official Ultra HD (UHD) standard for 4k videos, also referred to as 2160p. This resolution has a 16:9 aspect ratio, not the 1:1 aspect ratio you usually start with when shooting stereoscopic VR content. This means that the video resolution is compressed in the vertical direction. So in other words, these videos have more pixel density on the horizontal axis than on the vertical axis, and so everything in the scene looks short and fat.
Read more at www.purplepillvr.com