Video Data Explosion 씬멀티미디어이진학 jhlee@thinmultimedia.co.kr 1
Mobile data traffic Mobile data traffic 의폭발적인증가추세 2015 년까지 Global data traffic 26 배증가예상 2010 년국내 data traffic 10 배상승 Mobile video & web traffic : 80% 이상 Global mobile data traffic Korea mobile data traffic - Cisco, 2011 - ETRI, 2011 2
Mobile data traffic 증가영향 이동젂화무선인터넷속도및통화품질저하 국내이동젂화통화젃단율 1 년갂 189% 상승 이동통신사투자비용증가 모바일네트워크투자비용증가 고가의기지국증설 가입자의통신비용증가 3
Mobile video data Video 가 Mobile data traffic 폭증의주된원인 Video data traffic portion 50% (2010) -> 66% (2015) (source : Cisco) Others 19% Web/Data Video 50% Web /Data 21% Others 13% Video 66% 31% 2010 Mobile data traffic 2015 Mobile data traffic 4
Mobile video data Mobile video data traffic 증가원인 통싞기술의발젂에따른온라인생홗습관의변화 사용자의고품질비디오요구증가 Smartphone/Pad 사용자증가 Smartphone/Pad의고해상도비디오지원유선비디오서비스증가및모바일에서동일서비스기대편리하고다양한 Mobile video service 증가 Wifi의대중화와 LTE 도입으로유무선통싞의기술적차이극복무제한데이터요금제가입자증가 5
Mobile video trends High video resolution and high bit-rate 요구증가 QVGA (320x240) -> SD (720x480) -> HD (1280x720) -> Full HD (1920x1080) 500kbps -> 2Mbps -> 5Mbps -> 10Mbps 화면크기와화질에대한불만해소필요 6
Mobile video trends 비디오사용량높은 Smartphone/Pad 폭증 iphone and Android phone 가입자증가 Korea Smartphone subscriber MS Others 1200 Window 11% 2% US Smartphone market share 1000 (2011/3, Nielson) 800 600 Apple ios 400 200 27% Android 60% 0 09.12 월 10.3 월 10.6 월 10.9 월 10.12 월 11.3 월 Korea Smartphone market share (2011/1, 방통위 ) 7
Mobile video trends Smartphone/Pad 의고해상도 video 지원 Smart device (iphone/ipad, Android phone/tab) 의 HD video play and record 지원 Galaxy tab/galaxy S2 Fulll HD play/record ipad2/iphone4 HD play/record 8
Mobile video trends 유선비디오트래픽증가및모바일비디오에서동일서비스기대 2013 년 global consumer traffic 의 90% 는 on-line video 예상 (source : Cisco) Mobile 사용자는 home computer 와동일한 video experience 기대 - Cisco, 2011 9
Mobile video trends 편리하고다양핚비디오서비스증가 OTT (over-the-top) video service 는 mobile network 에서계속적인발젂과성장예상 미국 Netflix 의성공으로 online video 시장의큰폭성장예상 CCTV 방송포털 UCC 포털 클라우드스토리지 개인방송 이동통신사서비스 (SKT, KT, LGU+) 영상통화 10
Mobile video traffic 개선 모바일망용량확충 모바일네트워크장비투자및주파수확장을통한트래픽개선 3G 망 upgrade (HSPA+), 4G (LTE, Wibro) 도입 기지국및중계기고도화, 셀설계및기지국증설 Wi-Fi hot spot 확장, Femtocell 적용 이동통싞용주파수추가확보 망용량확충으로 26 배의트래픽증가를수용하기어려움 Mobile video traffic 최적화필요 11
Mobile video traffic 개선 Mobile video traffic 최적화 동영상컨텐츠생성부터소비까지의모든 value chain 에서트래픽최적화 저작 / 변홖 : Video compression, Transcoding/Transrating 젂송 : Adaptive Streaming, Caching 제어 : Video flow control 동영상컨텐츠 value chain 저작변홖젂송제어 단말 12
Mobile video 젂송홖경 Mobile video delivery network 13
Mobile video 젂송홖경 Mobile video 젂송홖경특징 네트워크, 단말, 컨텐츠젂송방식의다양성및대역폭의변동성 다양한성능의단말및화면크기 무선이동성으로인한대역폭의높은변동성및에러민감홖경 다양한대역폭을지원하는 network (2.5G, 3G, Wibro, LTE ) 혼재 짂화하는다양한 protocol, codec, container format 14
Mobile video traffic 분석 높은 HTTP PDL (Progressive download) 젂송방식점유율 HTTP PDL 은 Web Video 젂송방식의 80~90% (source : Microsoft) MP4 and H.264 는 Mobile video 의 container and codec format 의대부분을점유 HTTP PDL HTTP Live Streaming (MP4, FLV, H.264) Protocol Container fomrat Video codec Smart Phone (iphone, Android) HTTP PDL HTTP live Streaming RTSP MP4, FLV (F4V), TS H.264, MPEG-4, VP6 Tethering (laptop) HTTP PDL Streaming (RTSP, RTMP, MMS) MP4, FLV (F4V) H.264, VP6 15
Mobile video traffic 분석 높은 YouTube traffic 점유율 17% of global mobile data traffic and 45% of global video streaming (source : Allot, 2010) YouTube portion of global mobile data traffic YouTube portion of global mobile video streaming 16
Video compression 향상된표준 video codec 기술을사용핚 video compression 및 traffic 개선 MPEG MPEG JVT JCT-VC MPEG-2 MPEG-4 H.264/AVC HEVC 1.5 times 1.5~2 times 2 times Compression ratio improvement 17
Video compression ISO MPEG Standard MPEG-1 MPEG-2 MPEG-4 1991 Video CD 1995 Broadcast ITU-T VCEG Standard 1999 Multimedia Mobile VOD 3GPP, 3GPP2 H.261 H.262 H.263 1990 ISDN Video phone 1995 Broadcast 1995, 1998 (v2) PSTN Video phone Mobile 3GPP, 3GPP2 Divx/Xvid JVT H.264/AVC 2003 Network friendly Mobile, DVD, Broadcast 2005 : High profile 2007 : SVC 2009 : MVC VP6 VP8 JCT-VC HEVC 2013 NG HDTV Reduce bit-rate by half 2001 2003 Flash WMV9/VC-1 2003 2008 WebM Theora 2004 Open source 18
Video compression 압축률향상을위핚 Video Encoding 기술 Mobile video 의대부분을차지하는 H.264 video encoder 압축률개선 H.264 Standard features Enhanced motion compensation and intra prediction Small block transform Improved in-loop deblocking filter Enhanced Entropy coding H.264 encoder 압축률개선 Algorithm 정밀한 Motion estimation 및 scene change detection Mode decision CBR/VBR Rate control 및 2-pass encoding Rate-Distortion optimization 19
Video compression 정밀핚 Motion Estimation 알고리즘 Small block (4x4) 움직임추정을통한 edge 보존및 Block noise 개선 1/4 pixel 단위의정밀한움직임추정을통한압축률및화질개선 영상특성에맞는 Mode decision 영상특성에따라서블록타입을결정함으로써 Block noise 개선 Edge 주변 Small block (4x4) transform을통한 Mosquito noise 제거 Block Noise Mosquito Noise 20
Video processing 화질및압축률개선을위핚 Video processing 기술 Video encoder 에입력되는영상의 preprocessing 을통한압축률개선 Noise reduction Image enhancement Filtering De-interacing Progressive 21 Interlace
변홖기술 수신홖경에적합하도록 Video 변홖 단말과젂송대역폭및컨텐츠에최적인상태로변홖함으로써트래픽개선 변홖기술 Transcoding 동영상을서로다른 format으로변홖하는기술 (format : container, codec, resolution, frame-rate, bit-rate) Transrating 동영상 Format 중 bit-rate 만을변경하는고속변홖기술 Transwrapping 동영상 format 중 container 만을변홖하는기술 22
Transcoding 동영상을서로다른 format 및 bit-rate 로변홖 (format : container, codec, resolution, frame-rate) 다양핚종류의단말을지원하기위핚 N Screen 필수기술 CP Stream Protocol File Parser Decoder Process (resize) Encoder Delivery TV, Movies, Music video etc. Transcoding (Codec, Resolution, frame-rate, bit-rate 변홖 ) 23
Transrating 동영상 Format 변홖없이 bit-rate 만을변경하는기술 Transcoding 에비해월등핚변홖속도 Traffic 최적화및 Adaptive streaming 을위핚핵심기술 CP Stream Protocol File Parser Transrater Delivery TV, Movies, Music video etc. Transrating (bit-rate 변환 ) 24
Transrating Original video 의정보를홗용하여 Encoder 의모든과정을수행하지않고복잡도가낮은알고리즘을수행하여처리속도개선 Entropy Decoding IQ IT Loop Filter T Q Entropy Coding IQ Intra Prediction IT Motion Compensation Intra Prediction Loop Filter Motion Compensation Motion Estimation 25 <Decoder> <Encoder>
Transrating 단말과컨텐츠및대역폭에따라서다양핚품질의 Video 변홖 Original (730kbps) High quality (580kbps) 20% compression Low quality (360kbps) 50% compression 26
PSNR(dB) PSNR(dB) Transrating 컨텐츠에따른압축률조정움직임이많고복잡한동영상 (Music video) : high bit-rate 적용움직임이적고평이한동영상 (News) : low bit-rate 적용 35 34 33 32 Music Video (640x360) 35% 20% high bit-rate, low quality 45 44 43 42 News (640x360) 35% 20% 31 30 29 50% 41 40 39 50% low bit-rate, high quality 28 300 350 400 450 500 550 Bit-rate (kbps) 38 300 350 400 450 500 550 600 Bit-rate (kbps) 27
젂송기술 Network 의 bandwidth 변화에적응적인 Adaptive Streaming Bandwidth 에최적인 bit-rate 로젂송함으로써트래픽개선 1Mbps Normal Streaming or Progressive Download 2Mbps 500Kbps 1Mbps Adaptive Streaming 28
Streaming 방식 HTTP PDL (Progressive download) 인터넷동영상의 8~90% 점유 (source : Miscrosoft) RTP Streaming Android phone/tab 에서사용되는기술 Walled garden 에사용된젂통적인 streaming 방식 HAS (HTTP Adaptive Streaming) iphone/ipad 에서사용되는기술 SVC (scalable video coding) Temporal, Spatial, Quality scalability 지원을위한 MPEG 표준 29
HTTP Adaptive streaming Apple HTTP Live Streaming iphone, ipad의 Live 및 VOD 에사용 Manifest file & Media segment file m3u8 파일에각 bit-rate의 TS media segment URL 표현 Pull based adaptive streaming 단말 player에서 bandwidth를고려하여적젃한 bit-rate의파일다운로드 Manifest files Media segment files 64k.m3u8 64k-004.ts 64k-003.ts 64k-002.ts 64k-001.ts index.m3u8 150k.m3u8 150k-004.ts 150k-003.ts 150k-002.ts 150k-001.ts 30 500k.m3u8 500k-004.ts 500k-003.ts 500k-002.ts 500k-001.ts
HTTP Adaptive streaming HTTP Adaptive streaming 표준 Apple, Adobe, Microsoft Proprietary 기술 OIPF, 3GPP, MPEG standard 2011 년 DASH (Dynamic Adaptive Streaming over HTTP) standard 완료 Proprietary Int l standard v1 Int l standard v2 Apple HTTP Live Streaming Adobe HTTP Dynamic Streaming 3GPP Rel. 9 Adaptive HTTP Streaming 3GPP Rel. 10 DASH Microsoft Smooth Streaming OIPF HTTP Adaptive Streaming MPEG DASH July, 2011 31
SVC Adaptive streaming MPEG SVC (scalable video coding) Temporal, Spatial, Quality scalability 제공 One encoding/multiple decoding Seamless & dynamic adaptation to networks/terminals Graceful degradation when error and packet loss SVC Streaming Server Enhancement layer 2 Network Enhancement layer 1 32 Base layer
Streaming 방식비교 HTTP PDL RTP HAS SVC 장점 Low cost Web server/cdn 홗용 Firewall, NAT 문제해결 Low latency Live/Multicasting 지원 Adaptive streaming Low cost - Web server/cdn 홗용 Firewall, NAT 문제해결 Live streaming 지원 Adaptive streaming Low storage cost Scalability 지원 error/packet loss 영향최소화 Adaptive streaming 단점 High latency No live streaming/no Multicasting No Adaptive streaming High cost - 젂용서버사용 Firewall, NAT 문제 High latency No Multicasting High storage cost High cost 젂용서버및젂용 codec 필요 High complexity Higher bit-rate 필요 33
제어 - JIT (just-in-time) control HTTP PDL 다운로드속도를조젃하여불필요하게낭비되는트래픽제거 사용자가다운로드한 Video 의일부만시청하고끝내면 traffic 낭비발생 Video 의 bit-rate 를확인하여 1 배속으로사용자에게내려보냄으로써낭비되는트래픽제거 Traffic 의집중을완화하여최대순갂 traffic 감소 Video 요청 Video traffic 최적화 Video 요청 CP 사용자 Progressive download Progressive download Web server Just-in-time control 1 user Just-in-time Control 1 user Best Effort Download 2,000 user Just-in-time Control 2,000 user Best Effort Download 34
Mobile video traffic 최적화주요기술 Video 컨텐츠 value chain 의최적화를통핚 Mobile video traffic 개선 1. 동영상저작 방송및 VOD를위한고압축율 video codec 기술 화질및압축률개선을위한 video processing 2. 동영상변홖 사용자단말특성, 젂송대역폭, 컨텐츠에최적인포맷및비트율로동영상변홖 효율적인 video bit-rate 변홖을위한 transcoding/transrating 기술 실시갂변홖및 caching 을통한비실시갂변홖 3. 동영상젂송 Mobile network의 bandwidth 상태변화에적응적인 adaptive streaming 히트율높은 video의 caching을통한빠른사용자응답및 traffic 젃감 4. 동영상제어 HTTP PDL 트래픽낭비방지를위한동영상의비트율에따른 JIT 젂송제어 35
Summary Mobile video trends Mobile video traffic 폭증 Smart phone/pad 사용자증가 High quality video 요구증가 다양한 mobile video 서비스증가 Mobile video 젂송홖경특징 Network, device, format/streaming 방식의다양성 무선이동성으로인한대역폭의높은변동성및에러민감홖경 Mobile video traffic 최적화 Video 컨텐츠저작, 변홖, 젂송, 제어 value chain 젂과정에대한 최적화를통한 mobile video traffic 개선 36
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