BBC iPlayer: bigger, better, faster - as seen at AWSUKUG #11

BBC Media Services

Rachel Evans

[email protected]

bigger, better, faster

@rvedotrc

BBC iPlayer: bigger, better, faster A year ago, BBC iPlayer could have died - but it didn’t. Instead, we built a bigger, better, faster iPlayer that provides a foundation for the future. Find out how this was achieved, what part AWS plays in iPlayer’s success, and what’s next for BBC online media.” !slow timing: +0:00

mailto:[email protected]

On October 1st, 2013, iPlayer didn’t die

“On October 1st 2013, iPlayer didn’t die. But it could have. The reason iPlayer is still alive is Video Factory, and Amazon Web Services play a big part in Video Factory’s success. My name’s Rachel Evans. I’m a Principal Software Engineer in BBC Media Services. We created Video Factory.”

“For the next 45 minutes or so, I’d like to tell you the Video Factory story. How it came to exist; what it is; how we made it; and a glimpse into Video Factory’s future. And of course, what part Amazon plays in the whole story. I’ll be glad to answer your questions at the end.”

What is BBC Media Services?

Video Factory was created by BBC Media Services. Who are we? Here’s our mission statement:

“Publish all BBC AV media produced for IP platforms”

“AV” means audio and video, includes radio and TV Includes iPlayer, iPlayer Radio, News, Sport Both live and on-demand Let’s have a look at what this means in practice, for iPlayer on-demand

“Publish all BBC AV media produced for IP platforms”



Here’s iPlayer. Two programmes that we’ve published. One that we haven’t. If you see too many of these, it might mean we messed up.


✓

✓Here’s iPlayer. Two programmes that we’ve published. One that we haven’t. If you see too many of these, it might mean we messed up.

✓

✓⬅ ☹


“So this is the story of Video Factory, and this story, like many others, has a villain…” Yup, it’s ourselves, 5 years earlier.

BBC Media Services

“So this is the story of Video Factory, and this story, like many others, has a villain…” Yup, it’s ourselves, 5 years earlier.

The shiny new system

2008 - Hosted in-house; used contracted 3rd party services for storage and transcode. Limited capacity. Bad architecture. Bad engineering. Ageing badly. Didn’t scale well. This system did not have a long-term future.

The legacy system

2008 - Hosted in-house; used contracted 3rd party services for storage and transcode. Limited capacity. Bad architecture. Bad engineering. Ageing badly. Didn’t scale well. This system did not have a long-term future.

Why 1st October 2013?

In May 2012, the BBC decided not to renew that 3rd party contract. It was to be allowed to lapse, ending 30th September 2013. So this system, and therefore iPlayer, will die. “By the time the London 2012 Olympics was out of the way, we had just over 12 months to build a replacement.”

Start small !

Think big

We start planning for Video Factory. !Elasticity - peaks of demand (18 concurrent regional news). We want to use AWS, so let’s try it.

Start small !

Think big

Spring 2012: iPlayer on Sky: first venture into the cloud. This proves that we can use the cloud for storing video. Tooling was in its infancy.

Start small !

Think big

Jan/Feb 2013: iBroadcast2. Now we’re not just storing video in the cloud, we transcoding it there too. Now we’ve proved that the cloud can handle video storage and video transcode, both of which will be fundamental parts of Video Factory.

The origin of Video Factory !

!

!

!

!

!

“What does Video Factory actually do?”

Video Factory in a nutshell

Two things drive Video Factory

source video

programme data: - what programme is this; - where and when is it broadcast; - which platforms do we publication rights for

source video+

programme data


source video+

programme data

transcode, distribute, and publish

=


PrerecordedLive

Transcode

Distribute

Publish

Once we’ve got the video, the rest of the chain is the same. !“So let’s talk about live. Most iPlayer content is stuff that’s been on TV, so if we can capture and publish that, we’re set.”

Mezz-to-VOD

Mezz = Mezzanine video VOD = Video On Demand !

The world’s largest public-service video recorder

“In a secure location somewhere is part of the BBC’s TV broadcast chain.” Playout; Thomson Video Networks; RTP video over multicast UDP; includes timecodes. Capture and chunk. Mustn’t miss a single packet. Upload chunks to S3. Playout; broadcast end SNS message; find relevant chunks and join Transcode with trim; distribute; publish. Talk about inaccurate trims and “Resilient broadcast-grade system”.




What bits of AWS do we use?

For legal reasons, it’s all in the EU, hence eu-west-1. EC2 compute, VPC, ELB, Autoscaling S3, SQS, SNS, SimpleDB Cloudwatch, Cloud formation

What bits of AWS do we use?

(nothing too exciting, actually)

For legal reasons, it’s all in the EU, hence eu-west-1. EC2 compute, VPC, ELB, Autoscaling S3, SQS, SNS, SimpleDB Cloudwatch, Cloud formation

but here’s the fun part…

video is big

SD video

mpeg-ts / avc 720 x 576 9.4Mbps 25fps / mpeg audio 256Kbps

SD video1.3MB/sec/channel



= 109 GB/day/channel




x 21 channels




x 21 channels

= 2.3 TB/daympeg-ts / avc 720 x 576 9.4Mbps 25fps / mpeg audio 256Kbps

HD video

mpeg-ts / avc 1920 x 1080 ~38Mbps 25fps / mpeg audio 256Kbps

HD video4.2MB/sec/channel







x 8 channels




x 8 channels

= 2.9 TB/daympeg-ts / avc 1920 x 1080 ~38Mbps 25fps / mpeg audio 256Kbps

+ 2.9 TB/day

2.3 TB/day

5.2 TB/day

5.2 TB/dayper copy

5.2 TB/day/copy

x 2 locations

“each channel is captured in 2 physical locations” “at each location we capture 2 copies"

5.2 TB/day/copy

x 2 locations

x 2 copies

“each channel is captured in 2 physical locations” “at each location we capture 2 copies"

21TB per day

“… for a total of 21TB per day. Handling this much data wouldn’t have been possible on our previous platform, but with Amazon Web Services, Video Factory is able to handle this much data, all day, every day.”


The world’s biggest public service video recorder !

!

!

“I’d like to talk now about the practices and tooling we have in place that make this possible.”

Tooling

Continuous Integration Continuous Delivery ChaosMonkey “A tool we call stack-fetcher” Cosmos

Deployment weekly averages

(total for 10 weeks, divided by 10)

int: test: live:



int: test: live:

131



int: test: live:

13137



int: test: live:

1313734

0

2

4

6

8

10

12

Monday Tuesday Wednesday Thursday Friday Saturday Sunday

Live deployments by day of week


LIVE only. Why the spike on Monday?

0

2

4

6

8

10

12

Monday Tuesday Wednesday Thursday Friday Saturday Sunday

Full build, etc Certificate renewal

Live deployments by day of week


More balanced if you exclude cert renewal 3.5 deployment days per week vs 5 days per week No live deployments on Sunday :-)

“So, with Mezz-to-VOD in place, iPlayer is saved. We record whatever was broadcast on TV, and we publish it. So now, at the click of a button, you can enjoy world-class content, like this”

Oh. Did you spot the “big, big mistake, really huge” there? Broadcast isn’t a clean feed.

Oh. Did you spot the “big, big mistake, really huge” there? Broadcast isn’t a clean feed.

Channel logo + credit squeeze with audio overdub.

Channel logo + credit squeeze with audio overdub.

Wrong logo (should be non-animated BBC logo) Animated channel logo Subtitles marker Ident / content cross-fade

Wrong logo (should be non-animated BBC logo) Animated channel logo Subtitles marker Ident / content cross-fade

File-Based Delivery

What is FBD - e.g. EastEnders Better than M2V: higher res, cleaner than live. Delivered before broadcast Build up an archive

size of archive archive is valuable, so:

36000 files


36000 files

23000 hours


36000 files

23000 hours

540 TB


Encrypting the archive

Created queue-based system to perform encryption 14,000 files (around 210TB) to encrypt Scaled up: maxed out ec2 instances, and raised spot price

populated queue with 14,000 messages scaled up to lots of instances got to 440 instances and ran out!

c1.medium spot price in eu-west-1

scaled down to 400 instances to free some up down to 20 overnight up to 400 again in the day draining is hard

scaled down to 400 instances to free some up down to 20 overnight up to 400 again in the day draining is hard

Reducing costs

Use case: ingest once, large files Once ingested and used, files are sometimes used again, but not in a hurry “So there are two obvious solutions to this…”

1. Glacier

“Here’s one possible solution” “And here’s the other”

1. Glacier

2. Glacieror

“Here’s one possible solution” “And here’s the other”

I don’t mean this: Gla-sier Glay-sier Glay-sher (and I make no apology for freely switching between these) I mean this:

/ˈɡlæsiə/or

/ˈɡleɪsiə/or

/ˈɡleɪʃər/

I don’t mean this: Gla-sier Glay-sier Glay-sher (and I make no apology for freely switching between these) I mean this:

You have to pick one. They’re incompatible. For our case, the S3 mode was by far the more convenient. But it lacks SNS notifications. So we needed a component to manage this, to make Glacier invisible to client components.

Glacier(the S3 storage class)

orGlacier

(the service in its own right)

You have to pick one. They’re incompatible. For our case, the S3 mode was by far the more convenient. But it lacks SNS notifications. So we needed a component to manage this, to make Glacier invisible to client components.

Video Store

encapsulates the glacier and encryption logic

!The store interface

Background encryption

Fetching (fast - no decryption, no glacier)

Cache expires…

Fetching: - retrieve from glacier, with poll - slow decrypt - then it becomes a fast fetch

the list interface !scaling - three separate ASGs all updated via the same stack parameter



File-based delivery !

“Video Factory provides video-on-demand publication for iPlayer via Mezz-to-VOD and File-Based Delivery. It delivers better quality video, faster, more reliably, and on a more scalable and more maintainable system. But let’s think bigger. Where do we go next? Here’s a short video from a speech given a few months ago by our Director-General.”

I’ve removed the video from this presentation to save space.

You can watch the video (in the context of Lord Hall’s speech) here:

https://www.youtube.com/watch?feature=player_detailpage&v=95SXJYkoWbM#t=749

“Imagine the possibilities. What might iPlayer become? Where is it going? Where is Video Factory going?”

Simulcast (“Watch Live”)

Bring the handling of live IP audio and video in-house Build on the success of Video Factory VOD Mostly not in the cloud, so only a very brief overview…

Only the packager is in the cloud Explain what HLS (Apple) is Explain what HDS (Adobe) and Smooth (Microsoft) are Explain rewind window





Converging Live and

On-Demand

Here’s the latter half of the Simulcast chain.

Here’s the latter half of the Simulcast chain.

And here’s the Mezz-to-VOD chain, fed from exactly the same video feed. But we’re transcoding again, and always late. We can do better…

L2V is triggered by the same event as Mezz-to-VOD. L2V is an order of magnitude faster. However L2V only does some formats (albeit they’re important ones), and doesn’t trim accurately. So we deliberately allow L2V and M2V to run in parallel; L2V will win, M2V is better.

“At BBC Media Services we have to handle audio - that is, radio - as well as video, so we’re creating Audio Factory.” “How does Audio Factory work?”

Audio Factory


Audio Factory

like Video Factory,


Audio Factory

like Video Factory,but without the pictures




File-based delivery !

Live & Audio

“So as well as video on demand; there’s the simulcast chain providing live video; and live-to-VOD bridging the two together, so that programmes are playable as soon as possible. Audio - including BBC Radio - is handled almost identically to video, so at last we’re handling audio and video, live and ondemand, all in-house, using a consistent, proven set of technologies. ” !“For the final section today I’d like to talk briefly about the importance of data.”

Show me the data

Data is key to understanding what happened, and to making decisions.

Monitoring

SQS: CloudWatch alarms in stacks Other CloudWatch alarms (e.g. ELBs, EC2 network, EC2 cpu) iSpy and Splunk

iSpy and Splunk

Splunk is a 3rd party product for searching, monitoring, and analysing data. iSpy is the set of libraries and protocols we use to get the data from our applications, into Splunk. Via SNS and SQS. We use Splunk for: debugging; ad-hoc and on-demand reporting; monitoring; alerting.

Splunk is a 3rd party product for searching, monitoring, and analysing data. iSpy is the set of libraries and protocols we use to get the data from our applications, into Splunk. Via SNS and SQS. We use Splunk for: debugging; ad-hoc and on-demand reporting; monitoring; alerting.

Collecting interesting data

The list: all goes into Splunk.

Collecting interesting data• Deployments

• ChaosMonkey terminations

• AutoScaling activity

• CloudWatch alarm state changes

• CloudTrail

• CloudFormation stack changes


Collecting interesting data• Deployments

• ChaosMonkey terminations

• AutoScaling activity

• CloudWatch alarm state changes

• CloudTrail

• CloudFormation stack changes➜ git repository


Having the data to support decisions about cost, combined with the power and responsibility to act on those decisions, adds a whole extra dimension to software engineering.

APIs


APIs

Data


APIs

Data

Decisions about cost


“It took us just over a year to build the basic video-on-demand features of Video Factory that we had to build, to prevent iPlayer from dying. It was a completely new solution: new architecture, new code, new platform. We chose the cloud because it was more flexible, more reliable, more scalable. We chose Amazon because it was a mature cloud platform that provided the right technical and support services that we needed.”

MMXIV

“It took us just over a year to build the basic video-on-demand features of Video Factory that we had to build, to prevent iPlayer from dying. It was a completely new solution: new architecture, new code, new platform. We chose the cloud because it was more flexible, more reliable, more scalable. We chose Amazon because it was a mature cloud platform that provided the right technical and support services that we needed.”

MMXIV

“We moved to Continuous Integration and Continuous Delivery so that the benefits of higher quality and faster turnaround could be enjoyed by everyone - by our engineers, by the product stakeholders, by the licence-fee-paying audience. Building Mezz-to-VOD to avoid killing iPlayer was just the beginning. I’m very excited about seeing the future of Video Factory unfold on Amazon, and I hope you enjoy using iPlayer even more now that you’ve heard the story behind it. Thank you.”

Questions

Rachel Evans [email protected]

@rvedotrc Media Services


Questions



We’re hiring!


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Parts of AWS used by Video Factory

EC2 & VPC AutoScaling

ELB & Route53 IAM Users & Roles

S3 & EBS SQS & SNS

SimpleDB & RDS CloudWatch

CloudFormation