HTTP/2 has been explored widely for video streaming, but still suffers from Head-of-Line blocking and three-way hand-shake delay due to TCP. Meanwhile, QUIC running on top of UDP can tackle these issues. In addition, although many adaptive bitrate (ABR) algorithms have been proposed for scalable and non-scalable video streaming, the literature lacks an algorithm designed for both types of video streaming approaches. In this paper, we investigate the impact of quick and HTTP/2 on the performance of adaptive bitrate (ABR) algorithms in terms of different metrics. Moreover, we propose an efficient approach for utilizing scalable video coding formats for adaptive video streaming that combines a traditional video streaming approach (based on non-scalable video coding formats) and a retransmission technique. The experimental results show that QUIC benefits significantly from our proposed method in the context of packet loss and retransmission. Compared to HTTP/2, it improves the average video quality and also provides a smoother adaptation behavior. Finally, we demonstrate that our proposed method originally designed for non-scalable video codecs also works efficiently for scalable videos such as Scalable High EfficiencyVideo Coding (SHVC).

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Scalable High Efficiency Video
Coding based HTTP Adaptive
Streaming over QUIC
August 14th, 2020
ACM SIGCOMM EPIQ Workshop
Minh Nguyen, Hadi Amirpour, Christian Timmerer, Hermann Hellwagner

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● Motivation
● Contributions
● Proposed method
● Evaluation and discussion
○ HTTP/3 over QUIC vs HTTP/2 over TCP
○ Proposed method vs state-of-the-art methods
● Conclusion and Future work
Agenda
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● Protocols
○ HTTP/2 suffers from Head-of-line (HOL) blocking.
○ QUIC running on top of UDP can tackle this issue.
● Video streaming
○ Adaptive bitrate (ABR) algorithms are mainly designed
for either non-scalable or scalable video coding
formats.
○ Lack of an approach that works well for both non-
scalable and scalable video coding formats.
Motivation
QUIC
Stream 1
Stream 2
Stream 3
Non-scalable video Scalable video
Quality
FHD
HD
SD
Quality
FHD
HD
SD
SegmentSegment
Enhancement
layer 1 (EL1)
Base layer (BL)
Enhancement
layer 2 (EL2)
Server Client
3
HTTP/2
Stream 1
Stream 2
Stream 3
HOL blocking
Server Client

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● A systematic comparison of QUIC and HTTP/2 regarding the multiplexing feature.
● A non-scalable video streaming ABR algorithm in combination with an additional
download technique is proposed to not only improve the video quality but also to provide
a smooth adaptation behavior.
Contributions
QUIC HTTP/2
><
Non-scalable
ABR
Additional download
technique
Video quality
Smooth adaptation
Scalable video streaming
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Proposed method
● State-of-the-art ABR algorithms
○ Non-scalable based method: Aggressive ABR (AGG)
○ Scalable based method: Backfilling
● Proposed method for Scalable Video Streaming
○ Modified AGG + HTTP/2-Based Retransmission technique (H2BR)
○ Modified AGG
■ Choosing the number of layers for each segment based on the
network condition,
■ Downloading sequentially from low to high layers of each segment.
○ H2BR [PV’20]
■ Filling quality gaps in the buffer,
■ Downloading concurrently next layers and the additional layer with
priority and multiplexing features,
■ Terminating layers with termination feature.
Scalable based Backfilling
Modified non-scalable based
AGG
Modified non-scalable based
AGG + H2BR
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Proposed method
How does H2BR work?
○ Detecting gaps in the buffer.
○ If there is a gap, additional layer will be 1-level higher
(i.e., the segment has BL, the additional layer is EL 1).
○ Additional layer will be downloaded if the throughput
can sustain the next layer and additional layer so that:
■ Retransmission buffer > 0, and
■ Estimated buffer > BufferSize/4.
○ Assigning priority weights for additional layer and next
layer so that for these layers enough throughput is
allocated.
○ Sending 2 requests.
○ Terminating the additional layer if:
■ Retransmission buffer < 100 ms, or
■ Current buffer < BufferSize/4.
Modified non-scalable based AGG +
H2BR
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Evaluation and discussion
Server
Client
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ABR
algorithm
H2BR
DummyNet Tool
4G NetworkLSQUIC for QUIC
Nghttp2 for HTTP/2
LSQUIC for QUIC
Nghttp2 for HTTP/2
Video
EL 3
EL 2
EL 1
BL
Testbed
* BL: Base layer
* EL: Enhancement layer
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Evaluation and discussion
Modified AGG
(M-AGG)
Backfilling
(BF)
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Modified AGG + H2BR
(H2BR)
Compared methods
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Evaluation and discussion
Impact of packet loss rate on the performance of adaptation approaches
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Average quality level # downward switches
HTTP/3 over QUIC vs HTTP/2 over TCP
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Evaluation and discussion
# additional layers successfully downloaded by H2BR
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HTTP/3 over QUIC vs HTTP/2 over TCP
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Evaluation and discussion
Average quality level # downward switches
Impact of buffer size on the performance of adaptation approaches
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Proposed method vs state-of-the-art methods
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Evaluation and discussion
Buffer starvation when buffer size is 5s
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Proposed method vs state-of-the-art methods
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Conclusion and Future work
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● Conclusion
○ QUIC can well support concurrent streams to provide a better
performance in case of packet loss.
○ Proposed method makes non-trivial improvement in scalable
video streaming.
○ H2BR might be a burden that can lead to buffer starvation
when the buffer size is small.
● Future work
○ Investigating parameter selections for H2BR.
○ Considering different network traces and video contents.
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14. Thank you
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