Today, if you go on the internet, you will see it’s all about video. YouTube, streaming news and sports highlights as well as premium live streaming of sport events are common place. Streaming film and entertainments services such as Netflix, Amazon Prime and Apple TV have challenged the traditional over-the-air TV broadcasters. IP Video for security and surveillance is all-pervasive in many countries and almost everyone is reliant on today’s video conferencing applications (Zoom, Webex and Go2Meeting etc).
Now short form videos are ubiquitous in social media applications such as Facebook, TikTok etc. Network Emulators play a key role when it comes to verifying the user experience and ensuring that buffering videos don’t ruin the engagement. So, what do application developers, software developers and equipment manufacturers need to consider in a Network Emulator when verifying video applications?
Three things to consider in a Network Emulator:
- Buffer SizeVideo applications such as video conferencing uses software with adaptive bit rate algorithms (ABR) to adjust the bit rate. The application requires that the Network Emulator must be able to buffer at least 10 seconds of video. This enables the video conferencing software to adjust the transmission video bit rate in time. As a result, a Network Emulator’s buffer size for bandwidth throttling needs to be in the region of 20 Mbytes.
Streaming Video Packet Drop Estimation Tools
Video streaming systems and video quality estimation tools use the Markov method to estimate lost video packets. The Markov method is described in G.1050 Appendix II and is also referred to there as the Gilbert-Elliott model. Network Emulators require Markov 2-state Packet Drop in applications where the video streaming developer needs to add random packet drops in a controlled fashion using the same algorithm that the video streaming software uses to estimate the number of lost packets. This enables independent testing of video streaming software enabling precise correlation with the streaming software’s video quality estimation tools.
Video Support (MPEG H.264/H.265)
H.264 (Advanced Video Coding) is by far the most commonly used format for the recording, compression and distribution of video content, and is used by the majority of video industry developers. High Efficiency Video Coding (HEVC), also known as H.265 is H.264’s successor. In comparison to H.264, H.265 offers from 25% to 50% better data compression at the same level of video quality, or substantially improved video quality at the same bit rate. It also supports higher resolutions including 8K UHD. H.265 is now being used by many video developers, and is the second most widely used video coding format after H.264. As such, Network Emulators now need to support MPEG filtering and corruption of dynamic payloads to H.264 and increasingly to H.265.
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