New Video Technologies Emerging with Rollout of 2K and 4K Ultra HD Videos
Huawei mLAB has made the following key findings by tracking and performing in-depth analysis on leading OTT video websites:
1. About 90% of video content on the Internet is encoded in H.264 format. However, a more advanced video encoding format, H.265, is becoming popular with special H.265 video zones being provided by Sohu, Letv, and Xunlei Kankan. With the same image definition, H.265 reduces the required bandwidth by almost one half than H.264. With the same bit rate, H.265 increases the image definition by about 50% over H.264.
Sohu has officially rolled out the first H.265 HD video zone in the industry, providing more than 200 films of HD (500 kbit/s), ultra HD (1 Mbit/s), and original definition (2 Mbit/s). Such H.265 HD videos can only be watched on a PC-installed Sohu client according to HPD. With the same bit rate, H.265 increases the image definition significantly over H.264. The maturation of the H.265 encoding technology will continue to boost the development of 4K videos.
2. DASH and DASH-like transmission methods begin to emerge.
(1) YouTube is the first video service provider to adopt the standard DASH transmission method on the Android-based client and PC-installed Chrome web browser.
(2) Video websites in China follow DASH. Video clips are requested according to the HTTP1.1 URL plus byte range. The size of each video clip requested according to DASH is smaller than that requested according to HPD.
3. As the network bandwidth increases, more HD videos are provided at OTT video websites, with videos of 720p and higher resolutions accounting for 51% at YouTube and Sohu, and for 85.5% at Tencent.
4. OTT service providers have started to plan their 4K video strategy with the maturation of 4K video technologies:
(1) An increasing number of 4K videos are provided on the PC-installed YouTube client, whereas the mobile YouTube client supports videos of 1080p, 2K, 360-degree, and such a high frame rate (HFR) as 60 frame per second (FPS).
(2) China's first self-produced 4K TV series have been released on the PC-installed Sohu client, with an H.265 video zone going live. The mobile Sohu client, however, supports videos of the original definition and blue-ray disc (BD) (1080p).
(3) The PC-installed iQIYI client supports 4K videos, which increase gradually by quantity. The mobile iQIYI client supports 1080p videos.
5. More types of videos are released along with diversified new video technologies.
(1) YouTube has released the first 8K video source in the industry.
In June 2015, YouTube released an 8K film named Ghost Towns, which is the first in the industry. The film stars a deserted mine pit, and is shot by moving the camera almost at the same speed as the objects.
The film is shot using 6K camera equipment, and then is enhanced to 8K through later-stage processing.
To watch the film, optimal computer hardware is required in addition to a high screen definition and a fast network access speed.
(2) YouTube has released 60 FPS videos.
Following its efforts to roll out 60 FPS videos on the YouTube player (PC-installed Chrome web browser) in June 2014, Google continued to integrate HFR videos into the Android- and iOS-based mobile YouTube clients in July 2015.
In typical cases, 25 or 30 FPS ensures uninterrupted but not smooth video playing. 60 FPS guarantees smoother video playing, especially when the videos feature intense motions, and therefore provides better user experience when compared to 30 FPS. The PC-installed Chrome web browser for YouTube supports videos of up to 4K at 60 FPS. To watch these videos, users must use UEs with a high bandwidth and high-performance encoding hardware. The bit rate of 60 FPS videos is almost twice that of 25 FPS videos.
(3)YouTube has released 360- and multi-degree videos.
YouTube launches a new 360-degree video technology. These videos are shot using six cameras, and then processed using full-view video software in typical cases.
The following figure shows the process of 360-degree video production.
When users watch 360-degree videos on their PCs using the Chrome web browser, they only need to press , or hold the left mouse button and drag the screen, to change the view of angle. When users watch 360-degree videos on their mobile phones, the videos automatically change the viewing angle with user movements coordinated by gyroscopic sensors or manual sliding). The Chrome web browser, Android-based client, and iOS-based client all support 360-degree videos.
YouTube 360-degree videos are produced by combining the images obtained using six cameras. The original images contain more information about the viewing angles than common images. The typical aspect ratio of 360-degree videos is 2:1, which is different from the 16:9 aspect ratio of common videos. The images displayed on a web browser for 360-degree videos are stretched and partial, providing lower definition than common images.
(2) Multi-view videos
Multi-view videos are shot using multiple cameras from various viewing angles. Such videos are transmitted according to DASH. The four images of each video clip are sent to the local buffer simultaneously to achieve seamless switchover. The transmission duration of multi-view videos is n times longer than that of common videos (n indicates the number of views).
The following figure shows the process of multi-view video production.
In February, 2015, YouTube released the first multi-view video source, which allows users to switch between different viewing angles easily. As shown in the following figure, users can watch the performance of Madilyn Bailey from any of the four viewing angles by clicking the corresponding camera icon. Multi-view videos can be watched only on PCs by using the Chrome web browser.