mm-4094, amd video compression engine: the route towards low-latency cloud gaming solutions, by...

AMD VIDEO CODING ENGINE THE ROUTE TOWARDS LOW-LATENCY CLOUD

GAMING SOLUTIONS

| AMD VCE FOR LOW-LATENCY CLOUD GAMING | NOVEMBER 19, 2013 2

AGENDA

Introduction

Low Latency Encoding

AMD Video Coding Engine

Conclusions

Introduction


A LITTLE BIT OF HISTORY!

2008/9

2011/12

Perf/W

Year

CPU

CPU-based

Video Coding

CPU GPU

CPU HW

IP

GPU-

accelerated

Video Coding

HW-

accelerated

Video Coding


CPU VS. GPU VS. FIXED-FUNCTION-HW VIDEO COMPRESSION

Pros

‒ No extra dollars

‒ Higher achievable qualities at target bitrates (less architectural limitations)

‒ High Flexibility & Short Lead Time

‒ Can be optimized by advanced IS (e.g. MMX)

Cons

‒ Limited Operations per WATT

‒ Monopolized CPU

Examples

‒ Handbrake/x264

CPU Pros

‒ No extra dollars

‒ Part of CPU available for other tasks

‒ SW-based – Still Flexible & relatively Short Lead Time

Cons

‒ Limited Operations per WATT

‒ Major design and code changes to leverage parallelism

‒ Massive parallelism impacts quality/bitrate

Examples

‒ GPU-accelerated MainConcept Enc.

‒ GPU-accelerated x264

CPU+GPU Pros

‒ Fast!

‒ Power Efficient!

‒ Most of CPU available for other tasks

Cons

‒ Additional Area Cost

‒ Least Flexible (hard coded)

‒ Long lead time

Examples

‒ Applications in the market that support:

‒ AMD VCE

‒ Intel Quick Sync

‒ NVIDIA NVEnc

Fixed-Function HW

AMD Video Coding Engine


AMD VIDEO CODING ENGINE (VCE)

VCE is AMD’s dedicated fixed-function video coding engine for improved video encoding performance


VCE TARGET PLATFORMS

AMD APUs

AMD Discrete GPUs

Server Yes Yes

Desktop Yes Yes

All-in-one Yes Yes

Premium Notebook Yes Yes

Value Notebook Yes Possible

Tablet Yes N/A


VCE MAIN USE CASES

(**) Courtesy of CiiNow, Inc.

(*) Courtesy of Cyberlink, Inc. VCE


Up to 3x 1080p@~30fps per instance

Low-power budget

Multi-streaming support

Configurable speed/quality tradeoff

Flexible/programmable to meet various use-cases

VCE CAPABILITIES


DESIGN ASPECTS OF VCE

Bitra

te


VCE CREW – OUR EVERYDAY STORY!

“I don’t believe in perfection. I don’t think there is

such a thing. But the energy of wanting things to be

great is a perfectionist energy!”

Reese Witherspoon Hollywood Actress & Academy Award Winner

“Have no fear of perfection – you’ll never reach it!”

Salvador Dalí Spanish Painter/Artist

Low Latency Encoding


Latency is the elapsed time between the user’s input and his/her perception of the corresponding game reaction

LATENCY IS KEY! WHAT IS LATENCY?

Game client

Game server

Game Engine

Code Picture Buffer

Decoder

Decoded Picture Buffer

Display

User

Encoder

Buffer

Graphics Commands Rendered Frame Compressed Stream

Network Packets NAL Units Decoded Frame

Encoder

Ren

der

ing

Network

< 100–150 ms −


Game server

Encoding latency is the elapsed time between a frame is rendered on the server and it is decoded on the client

LATENCY IS KEY! WHAT IS ENCODING LATENCY?

Game client

Game Engine

Code Picture Buffer

Decoder

Decoded Picture Buffer

Display

User

Encoder

Buffer Encoder

Network

Rendered Frame Compressed Stream

Network Packets NAL Units Decoded Frame

Ren

der

ing


VCE Quality Presets

ENCODE SPEED VS. QUALITY HOW FAST CAN VCE ENCODE?

1080p 720p 480p

Speed 95 fps

215 fps

535

Balanced

80 fps

180 fps

470

Quality 40 fps 90 fps 250


0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

Inst

anta

ne

ou

s b

itra

te (

mb

its/

s)

Frame number

CQP

Avg. Bitrate (6Mbit/s)

Constant Quantization Parameter (CQP)

BUFFERING DELAY VS. QUALITY WHY BUFFERING?

Tranmission over a Constant Bitrate (CBR) channel of 6 Mbit/s ?

Buffering

Transmission delay

(latency!)

APU13-RubyDemo_703f_1280x720_IDR60_CQP26.h264


Constant Bit Rate (CBR) Rate Control

‒ Control transmission delays (i.e., # bits per picture) by adjusting QPs

‒ Leaky bucket model

‒ Defined by the triplet

‒ Avoid encoder buffer underflow and overflow (i.e., transmission bitrate = encoding bitrate)

BUFFERING DELAYS VS. QUALITY WHAT IS CBR?

Encoder buffer fullness

time

B

…

b0

S0

b1

S1 S2

b2

S0+De

Encoder can predict the decoder

buffer fullness

Buffering latency is smaller than B/R

Output Rate (R)

Initial

Fullness (F)

Buffer

Size (B)

Input Rate

Decoder buffer fullness

time

B

F

b1

T1

b2

T2 … T0

b0

T0-Dd


Variable Bit Rate (VBR) Rate Control

‒ Channel can stop transmission without loosing synchronization (e.g., packet based networks)

‒ Leaky bucket model

‒ Defined by the triplet

‒ Avoid only encoder buffer overflow (i.e., transmission bitrate may be higher than the encoding bitrate)

LATENCY VS. QUALITY WHAT IS VBR?

Allows shorter buffering delay

AMD Media SDK exposes two VBR modes: Peak-Constrained VBR, and Latency-Constrained VBR


0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

Inst

anta

ne

ou

s b

itra

te (

mb

its/

s)

Frame number

VBR High Buffering Latency

CQP


High buffering delay

‒ Peak-Constrained VBR

‒ Target Bitrate = 6 Mbps

‒ Peak Bitrate = 6 Mbps

‒ VBVBufferSize = 6 Mbits (i.e., buffering latency of 1000 ms)

‒ IDRPeriod = 60

LATENCY VS. QUALITY HOW BUFFERING LATENCY IMPACTS QUALITY?

Reduce overshoots with

limited quality impact

APU13-RubyDemo_703f_1280x720_IDR60_PC_VBR.h264


0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

Inst

anta

ne

ou

s b

itra

te (

mb

its/

s)

Frame number

VBR Low Buffering Latency

VBR High Buffering Latency

CQP


Low buffering delay

‒ Latency-Constrained VBR



‒ VBVBufferSize = 0.1Mbits (i.e., buffering latency of 16 ms)

‒ IDRPeriod = 60


Minimum buffering delays

APU13-RubyDemo_703f_1280x720_IDR60_LC_VBR.h264


Low buffering delay


Poor IDR frames quality

Replace IDR frames with partially intra-encoded frames

Frame 300 (IDR)


Intra-refresh principle

ERROR RESILIENCY VS. QUALITY WHAT IS INTRA-REFRESH?

IDR P P P


Intra-refresh principle

‒ Spread out Intra Units throughout successive pictures

‒ Constraint inter/intra-prediction to preserve error resiliency (i.e., Dirty/Clean Maps)

ERROR RESILIENCY VS. QUALITY WHAT IS INTRA-REFRESH?

Restriction on Search Region


I D D D C I D D C C I D C C C I



Intra-refresh with low buffering delay

‒ VBR Rate Control




‒ IDRPeriod = 60

HOW INTRA-REFRESH IMPACTS QUALITY?

ERROR RESILIENCY VS. QUALITY

APU13-RubyDemo_703f_1280x720_IR_IDR60_LC_VBR.h264





Frame 300 (IDR)





Improved IDR frames quality

Frame 300 (Intra-Refreshed)


VCE vs. Software Encoder

‒ VBR Rate Control




‒ IDRPeriod = 60

‒ Intra-refresh

HOW GOOD IS VCE?

COMPARATIVE EVALUATION

Software Encoder

X264_APU13-RubyDemo_703f_1280x720_ultrafast_ir.h264


VCE vs. Software Encoder

HOW GOOD IS VCE?

COMPARATIVE EVALUATION

VCE Software Encoder

Conclusions


CONCLUSIONS

Fixed-Function HW acceleration is the prevalent technology for video compression

AMD MediaSDK and RapidFire allow application developers to configure VCE parameters

‒ Latency/Error Resiliency/Quality

‒ Number of encoded streams/Power/NW-efficiency

VCE offers an out-of-the-box solution for ultra-low latency cloud gaming

‒ Special rate control settings

‒ Intra-refresh support

Deployed in the solutions of various cloud-gaming partners

Thank You!


DISCLAIMER & ATTRIBUTION

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The information contained herein is subject to change and may be rendered inaccurate for many reasons, including but not limited to product and roadmap changes, component and motherboard version changes, new model and/or product releases, product differences between differing manufacturers, software changes, BIOS flashes, firmware upgrades, or the like. AMD assumes no obligation to update or otherwise correct or revise this information. However, AMD reserves the right to revise this information and to make changes from time to time to the content hereof without obligation of AMD to notify any person of such revisions or changes.

AMD MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE CONTENTS HEREOF AND ASSUMES NO RESPONSIBILITY FOR ANY INACCURACIES, ERRORS OR OMISSIONS THAT MAY APPEAR IN THIS INFORMATION.

AMD SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. IN NO EVENT WILL AMD BE LIABLE TO ANY PERSON FOR ANY DIRECT, INDIRECT, SPECIAL OR OTHER CONSEQUENTIAL DAMAGES ARISING FROM THE USE OF ANY INFORMATION CONTAINED HEREIN, EVEN IF AMD IS EXPRESSLY ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

ATTRIBUTION

© 2013 Advanced Micro Devices, Inc. All rights reserved. AMD, the AMD Arrow logo and combinations thereof are trademarks of Advanced Micro Devices, Inc. in the United States and/or other jurisdictions. Other names are for informational purposes only and may be trademarks of their respective owners.

mm-4094, amd video compression engine: the route towards low-latency cloud gaming solutions, by...

Technology

conclusions2 amd vce

latencyconstrained vbr

vce crew

vce capabilities

various usecases10 amd

amd video coding engine

vce main use cases

transmission bitrate