Since the launch of the iPhone in 2007 (and Android phones shortly thereafter), mobile has become an ever-increasing part of the computing landscape. Users find themselves reaching for their phones or tablets on the go. They don't stop there, though. They also use them during times that they might have wanted to use a notebook or a desktop computer in the past.
At home, my wife only uses an iPad, since the majority of her computing is checking email, surfing the web, watching online videos, and reading ebooks. None of these tasks need much processing power. This is true of many users.
Steve Jobs, the late CEO of Apple, called traditional computers “trucks,” since they're capable of doing more that most people use them for. Like a truck, there will aways be people who don't strictly speaking “need” a traditional computer, but who prefer to “drive” one.
For many though, mobile devices are becoming more and more popular as ways to get online because they help people consume content anytime and anywhere. You might not be able to easily watch a video on a laptop while in line at the Post Office or while vacuuming the carpet, but with a tablet or smartphone, you can.
This is where your church's live stream comes in. Just as some people will prefer to watch on a television, others will want (or perhaps only be able to) watch on mobile devices.
Streaming HD content, though, could be a problem for some mobile viewers.
It's not that mobile devices can't display HD content, most can. The problem is that users paying for data on a cellular plan might not want to watch an hour-long 1,920x1,080 stream when a 640x360 stream will save them quite a bit of money.
Also, with LTE quickly becoming the standard, it's easy to forget that there are still a fair number of 2G and 3G devices out there. Locations with bad connection speeds will cause problems as well.
That's what makes streaming to mobile such a challenge. At one end of the spectrum, one user might have a slow, limited connection on an older smart phone. At the other end, another might have an LTE or WiFi connection and a high resolution screen.
If your church is streaming pristine 1080p video, some viewers might be very happy, but others will feel like it's overkill.
You could combat this by streaming at multiple resolutions and bit rates. You'd be tailoring each stream to a different potential audience segment, or rather each potential situation.
In their developer library, Apple recommends eight streams starting at 416x234 at 12 frames a second with a total bit rate of 264 for poor cellular data speeds. For WiFi, Apple's top recommendation is a 1,920x1,080 stream at 29.97 frames per second with a total bit rate of 8,628. The remaining six streams incrementally fill the gaps.
The basic strategy they advocate is to have many streams so that the viewer can watch the best possible video. By having this many streams, the device can choose a slightly better stream. Contrast that to having two streams, one at a low bit rate and at a high bit rate. While a viewer with a great device and internet connection could choose between the two based on preference, another viewer with an if-fy connection couldn't. What's worse is that a viewer with a moderately good connection that was less than the top end would still be forced to go with the low-bit-rate connection.
Your online player software would need to check whether the viewer was using cellular or not and determine the maximum resolution the device could support.
This isn't an easy process to complete if you're not familiar with it.
Many live-streaming hosts handle a lot of the heavy lifting for all these things, though. My live-streaming host, for example, allows me to enable adaptive-bit-rate streaming.
Then, it's up to me and my encoding software to send my host up to three streams that they will use to deliver the live stream to mobile devices.
This doesn't come without a cost in CPU and bandwidth usage. It is for this very reason that I haven't yet implemented it personally, although it is a better method than sending a single moderate-bit-rate stream, which is what I'm doing now.
Some day internet infrastructure and device resolutions will hit a point where our ability to stream content to anyone at any time isn't limited by these same factors. Some devices have pixel density greater than the eye can resolve. LTE connection speeds sometimes surpass those of wired internet. For those people, that day has arrived.
Until, this becomes the universal condition, we'll continue to struggle.
