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Labmeeting - 20150831 - Overhead and Performance of Low Latency Live Streaming using MPEG-DASH

Labmeeting - 20150831 - Overhead and Performance of Low Latency Live Streaming using MPEG-DASH

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Bouzakaria, N.; Concolato, C.; Le Feuvre, J.
The 5th International Conference on Information, Intelligence, Systems and Applications, IISA 2014

Bouzakaria, N.; Concolato, C.; Le Feuvre, J.
The 5th International Conference on Information, Intelligence, Systems and Applications, IISA 2014

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Labmeeting - 20150831 - Overhead and Performance of Low Latency Live Streaming using MPEG-DASH

  1. 1. NTUST - Mobilizing Information Technology Lab Overhead and Performance of Low Latency Live Streaming using MPEG-DASH Bouzakaria, N.; Concolato, C.; Le Feuvre, J. The 5th International Conference on Information, Intelligence, Systems and Applications, IISA 2014, Advisor:Jenq-Shiou Leu Student:Bing-Syuan Wang Date:2015/8/31 National Taiwan University of Science and Technology
  2. 2. NTUST - Mobilizing Information Technology Lab Outline • Introduction • Related Works • Live Dash Streaming Latency • Experimentations and Results • Conclusion 2
  3. 3. NTUST - Mobilizing Information Technology Lab Introduction • HTTP Streaming technologies have been introduced recently to deliver multimedia streams. • An important standard in the field of HTTP streaming is the MPEG Dynamic Adaptive Streaming over HTTP (DASH) standard. • HTTP/TCP vs RTP/UDP 3
  4. 4. NTUST - Mobilizing Information Technology Lab Introduction • DASH is not initially adapted for low latency. • Using “chunked-transfer encoding” over HTTP 1.1. • Using low latency video coding tools. -H.264/MPEG-4 AVC standard. 4
  5. 5. NTUST - Mobilizing Information Technology Lab Related Works • An HTTP streaming chain with typical segment duration of 1s would introduce a delay in the order of 3s compared to RTP. • With chunked-transfer encoding and with a proper download strategy, the latency depends on the duration of the HTTP chunks. • The average bitrate loss of GDR(Gradual Decoding Refresh) compared to periodic IDR(Instantaneous Decoding Refresh) was between 11 and 17% 5
  6. 6. NTUST - Mobilizing Information Technology Lab Related Works • Using the ISO Base Media File Format (lSOBMFF) in HTTP streaming systems, including DASH. • The goal of this paper: HTTP streaming using DASH with the combined usage of HTTP "chunked- transfer" encoding, GDR encoding and the ISO Base Media File Format. 6
  7. 7. NTUST - Mobilizing Information Technology Lab Live DASH Streaming Latency • Basic DASH Latency -Client, MPD(Media Presentation Description), MPD@availabilityStartTime • Low Latency DASH -Segments are further divided in smaller parts and these parts delivered using HTTP chunks -availabilityStartTimeOffset (ASTO) 7
  8. 8. NTUST - Mobilizing Information Technology Lab Live DASH Streaming Latency • Segment duration (ds) • Fragment duration (dc) • λ represents a margin introduced in the computation of ASTO to cope with UTC mismatch between the client and the server ASTO = AST − (AST − ds + dc + λ)=ds − dc − λ 8
  9. 9. NTUST - Mobilizing Information Technology Lab Experimentations • 1) Content generation: -encoding, GDR, ISOBMFF, MPD • 2) Content distribution: -”chunked-transfer” encoding • 3) DASH client: -processing incomplete segments 9
  10. 10. NTUST - Mobilizing Information Technology Lab Results 10
  11. 11. NTUST - Mobilizing Information Technology Lab Results 11
  12. 12. NTUST - Mobilizing Information Technology Lab Conclusion • HTTP Streaming is the new approach for streaming video over the Internet, for live and on demand cases. • This paper described an implementation of a streaming system comprising a DASH live encoder generator, a DASH-aware web server and a DASH client. • This paper validated the approach for very low latency streaming in local networks, with latency as low as 240 ms. 12

Notas del editor

  • 雖然基於數據包的流媒體解決方案,例如使用RTP,可以實現延遲,在幀的順序,沒有今天用於這種非常低的延遲流HTTP流傳輸解決方案,例如DASH。
  • video conferencing or live streaming with voting.
    通常,HTTP應答消息中發送的數據是整個發送的,Content-Length消息頭欄位表示數據的長度。數據的長度很重要,因為客戶端需要知道哪裡是應答消息的結束,以及後續應答消息的開始。然而,使用分塊傳輸編碼,數據分解成一系列數據塊,並以一個或多個塊發送,這樣伺服器可以發送數據而不需要預先知道發送內容的總大小。通常數據塊的大小是一致的,但也不總是這種情況。
  • 一些研究論文已發表有關現場或低延遲過串流HTTP。
    segmentation process 2. fully produced 3. the download time of the segment
    does not describe what happens for shorter chunks.
    本文然而,不考慮它的HTTP流媒體使用,不評估開銷高清晰度的序列。
  • report that the approach is inefficient for bitrates lower than IMbps.
  • 被延遲:the segmentation delay; the asynchronous fetch of media segments; the time to download the segments; and the buffering at the client side.
  • 被延遲:the segmentation delay; the asynchronous fetch of media segments; the time to download the segments; and the buffering at the client side.
  • encoding the video in realtime, in particular using the GDR scheme; segmenting and formatting the video segments according to the ISOBMFF; and generating the DASH Media Presentation Description (MPD).
    範圍為1片段攜帶一個視頻幀到1片段攜帶整個段。
    當一個新的片段被發布,該服務器發送該片段作為一個chunk。採用這種方法,該段的下載可以開始該段是完全準備好和發布前。

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