Researcher:
Bakar, Gonca

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PhD Student

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Gonca

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Bakar

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Bakar, Gonca

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2017 - 20192

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Researcher Of Publications: search.filters.isAuthorOfPublication.8a8fd1cf-463e-428d-b71e-ef8c33aba90b

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    Motion-based rate adaptation in WebRTC videoconferencing using scalable video coding
    (IEEE-Inst Electrical Electronics Engineers Inc, 2019) N/A; N/A; Department of Electrical and Electronics Engineering; Bakar, Gonca; Kırmızıoğlu, Rıza Arda; Tekalp, Ahmet Murat; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 26207
    This paper proposes methods for rate adaptation by motion-based spatial and temporal resolution selection in both mesh-connected and selective-forwarding-unit (SFU) connected WebRTC videoconferencing using scalable video coding. In the mesh-connected case, the proposed motion-adaptive spatial/temporal layer selection allows each peer to send video to different peers with different terminal types and network rates at different rates using a single encoder. In the SFU-connected case, motion-adaptive rate control is used both at peers to adapt to the network rate between the sending peer and SFU by spatio-temporal resolution adaptation and at the SFU by layer selection to adapt to the network rate between the SFU and receiving peer. Experimental results show that our proposed motion-based rate adaptation achieves better perceptual video quality with sufficiently high frame rates and lower quantization parameter for video with high motion; and high spatial resolution and lower quantization parameter for video with low motion compared to simple rate-distortion model-based layer selection that does not use motion complexity, at the same rate.
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    Motion-based adaptive streaming in WebRTC using spatio-temporal scalable VP9 video coding
    (Institute of Electrical and Electronics Engineers (IEEE), 2017) N/A; N/A; Department of Electrical and Electronics Engineering; Bakar, Gonca; Kırmızıoğlu, Rıza Arda; Tekalp, Ahmet Murat; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 26207
    WebRTC has become a popular platform for real-time communications over the best-effort Internet. It employs the Google Congestion Control algorithm to obtain an estimate of the state of the network. The default configuration employs single-layer CBR video encoding given the available network rate with rate control achieved by varying the quantization parameter and video frame rate. Recently, some open-source WebRTC platforms provided support for VP9 encoding with spatial scalable encoding option. The main contribution of this paper is to incorporate motion-based spatial resolution adaptation for adaptive streaming rate control and evaluate the use of single-layer (non-scalable) VP9 encoding vs. motion-based mixed spatio-temporal scalable VP9 encoding in point-to-point RTC between two parties in the presence of network congestion. Our results show that, during intervals of high motion activity, spatial resolution reduction with sufficiently high frame rates and reasonable quantization parameter values yield more pleasing video quality compared to the standard rate control scheme employed in open-source WebRTC implementations, which uses only quantization parameter and frame rate for rate control.