As promised here's a follow-up to the trial of HD HTTP adaptive streaming we ran during Wimbledon.
The trial produced a lot of useful feedback and data for us. So much, in fact, that it's taken us longer than expected to digest it all and make plans for our next trial; more about that later.
The HD adaptive bitrate trail on three screens.
Our objectives for the trial covered two broad areas: we wanted to see how the HTTP Adaptive bit rate player performed in real-world conditions and we also wanted to gain a better understanding of how our infrastructure - the systems behind the scenes that supply video to the player - would handle the traffic generated by ABR streaming.
Many of you took the time to give us feedback about how the player was working. As we expected there were a few issues: some of you were not getting full quality HD; occasionally a fragment of old video would show up in the stream; sometimes the bit rate switching was not as stable as we would have liked. We read each of the 212 comments and categorised the problems into eight distinct areas so we could start work on fixing them:
- iPlayer user interface
- Variations in video quality
- Delays / buffering
- Old video fragments
- Latency relative to live event
- Switching performance
- Jerky playback
In general though the adaptive bit rate streaming seems to have been a success. Here's what A Poskitt wrote in a comment on the blog post:
Andy, I am at the end of the line here in Wales with max. speed 0.5MB. However your streaming is like I have never seen it before, continuous and clear as a bell even on the maximum 4 that I receive. I have seen real TV on my computer for the first time!
The feedback you gave us has already been put to good use; it's told us things we couldn't have found out in the lab. We literally couldn't have done it without you.
It's also given the programmers who are working on this a great incentive to make it work even better; I think a remark I overheard sums that up: "Isn't it amazing that people are taking so much time to write detailed, accurate feedback - makes it all seem worthwhile". It does indeed. Thank you all for taking the time to share your thoughts and comments with us.
So, what next? One of the things that disappointed quite a few people was that we were only able to run the trial during office hours. That was disappointing for us too - we want to know more about how well HTTP adaptive bit rate streaming works on domestic broadband connections. When the trial is run during office hours, unsurprisingly, most of the traffic comes from office networks. So this weekend we're going to run a trial for the Hungarian Grand Prix. We'll cover the qualifying session from 12:10 to 14:20 on Saturday and the race from 12:05 to 15:25 on Sunday. See you there.
Andy Armstrong is the Technical Architect for Programmes and On Demand