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

bigger, better, faster
Rachel Evans
BBC Media Services
rachel.evans@bbc.co.uk
@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

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

“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

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.

✓
✓
⬅ ☹
Here’s iPlayer.

“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
programme data:

source video
+
programme data
=
transcode, distribute,
and publish
programme data:

Live Prerecorded
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

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

SD video
1.3MB/sec/channel

SD video
1.3MB/sec/channel
= 109 GB/day/channel

SD video
1.3MB/sec/channel
x 21 channels

SD video
1.3MB/sec/channel
x 21 channels
= 2.3 TB/day

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

HD video
4.2MB/sec/channel

HD video
4.2MB/sec/channel
x 8 channels

HD video
4.2MB/sec/channel
x 8 channels
= 2.9 TB/day

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:

Deployment
weekly averages
int:
131
test:
live:

Deployment
weekly averages
int:
131
test:
37
live:

Deployment
weekly averages
int:
131
test:
37
live:
34

12
10
8
6
4
2
0
Live deployments
by day of week
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
LIVE only.
Why the spike on Monday?

12
10
8
6
4
2
0
Live deployments
by day of week
Full build, etc Certificate renewal
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
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.

Channel logo + credit squeeze with audio overdub.

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
size of archive

36000 files
23000 hours
size of archive

36000 files
23000 hours
540 TB
size of archive

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

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
or
2. Glacier
“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)
or
Glacier
(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

Fetching (fast - no decryption, no glacier)

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.

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.

• Deployments
• ChaosMonkey terminations
• AutoScaling activity
• CloudWatch alarm state changes
• CloudTrail
• CloudFormation stack changes

• 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
@rvedotrc
Media Services

Questions
Rachel Evans
@rvedotrc
Media Services
We’re hiring!

Parts of AWS used by Video Factory
EC2 & VPC
AutoScaling
ELB & Route53
IAM Users & Roles
S3 & EBS
SQS & SNS
SimpleDB & RDS
CloudWatch
CloudFormation

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

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