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How to achieve one second above the fold (ATF)?

Last Updated: Jul 04, 2018

What is one second ATF?

One Second ATF aims at minimizing the time spent from the time the playback start to the time the first frame appears so as to shorten the time the audience wait as much as possible.

This capability relies mainly on the optimization of cloud services and the combination of the video player. Using Alibaba Cloud’s function of one second ATF, the fastest speed to open the first frame is about 200ms. If the Internet downlink speed is high enough, the first frame can be opened instantly.

How to achieve one second ATF?

  • APP

    One second ATF can be achieved by using RTMP SDK + FLV playback protocol. The FLV protocol is selected because the structure of FLV is more stable than that of the RTMP.

  • PC browsers

    PC browsers’ video playback kernel usually adopts FLASH plug-in (Chrome supports MSE currently, but it doesn’t have obvious advantage over FLASH). The playback strategy of FLASH players is a relatively rigid forced buffering mode. No more room for the optimization of ATF speed, which is generally difficult to achieve within one second. This can be seen by the performance of many major video and live platforms.

  • Phone browsers

    Safari support the HLS(m3u8) well, and even utilizes the iPhone hard solution chip to help video playback. So if DNS is cached, the ATF speed is fairly OK. But that is limited to the iOS platform. For the performance of Android system, that only relies on the video player of the browser (system browser, QQ browser and UC browser).

Consequence of One Second ATF

The realization of one second ATF relies on the smart buffering of videos on the cloud. Buffering cannot avoid delay. For a good video player, while obtaining scaling one second ATF capability, delay control is required. Otherwise, one second ATF causes delay simultaneously, which causes more loss than gain in live scenarios which has high requirements on interaction such as shows.