affiliation 1) eindhoven university of technology department of mathematics and computer science

Affiliation 1) Eindhoven University of Technology Department of Mathematics and Computer Science HG 6.57, P.O. Box 513, NL-5600 MB, Eindhoven, The Netherlands 2) Philips Research NatLab Prof. Holstlaan 4, 5656AA Eindhoven, The Netherlands IFD – a technique for improving the quality of wireless video streaming Author: S. Kozlov 1 . Co-authors: Peter v.d. Stok 1,2 , Johan Lukkien 1 Bandwidth variations Sender’s buffer 2. MPEG over wireless link • Link: 802.11b • UDP effective throughput • Discretisation time: 40ms • Microwave oven on: between 5 and 13 seconds 5. Conclusions • Simple (only the sender should be changed) • Cost effective (small buffers needed) • Works with any terminals supporting RTP reception and equipped with a general MPEG decoder • Very reactive against fast network fluctuations • Very small buffer (2 frames) -> low latency (80ms) • Tolerating bandwidth degradation of up to 50% of the video bit-rate 1. Introduction A crucial point in using wireless networks for multimedia tasks is the effective use of highly fluctuating network resources. Using the sender buffer as instant indicator of the varying network state, we implement a simple yet effective technique to greatly improve the quality of video streaming over wireless link. 3. IFD (I Frame Delay) scheduler Frame inter- dependencies: losing a P frames (red cross) causes the dependent frames to be decoded incorrectly (grey crosses) Packets get lost here Quality degradation C W S incoming frame waiting (buffered) frame sent frame WHILE (TRUE) DO WHILE (C is empty) DO Nothing IF (W is empty) THEN Store C in W ELSE IF (C is of type I) THEN Overwrite W with C ELSE IF (C is of type B) Discard C ELSE IF (W is of type I or P) Discard C ELSE Overwrite W with C 4. Testing and validation I 0 B 1 B 2 P 3 B 4 B 5 P 6 B 7 B 8 (I 9 ) • Stream: 1min, 25fps, 3 various bit-rates • Link: 802.11b • Microwave oven on: between 20s and 40s Video bit-rate: 4Mbps. Losing B frames mostly when the oven is on Video bit-rate: 5Mbps. No I or P frames get lost Video bit-rate: 8Mbps. Also I and P frames get lost when the oven is on Cumulative weight of B frames is more than 50% Video: 4Mbps, bandwidth: 2.5Mbps Video: 4Mbps, bandwidth: 1.6Mbps Losing an I or P frame: size,kB fram e 40 20 B fram es Iframes P fram es Socket buffer Physical and link layers (802.11) Layers above link layer Bandwidth variations may cause the buﬀer to overﬂow Buffer occupancy:

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I. B. B. P. B. B. P. B. B. (. I. ). 0. 1. 2. 3. 4. 5. 6. 7. 8. 9. IFD – a technique for improving the quality of wireless video streaming Author: S. Kozlov 1 . Co-authors: Peter v.d. Stok 1,2 , Johan Lukkien 1. 1. Introduction - PowerPoint PPT Presentation

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Affiliation1) Eindhoven University of Technology

Department of Mathematics and Computer Science

HG 6.57, P.O. Box 513, NL-5600 MB, Eindhoven, The Netherlands2) Philips Research NatLab

Prof. Holstlaan 4, 5656AA Eindhoven, The Netherlands

IFD – a technique for improving the quality of wireless video streaming

Author: S. Kozlov 1. Co-authors: Peter v.d. Stok 1,2, Johan Lukkien 1

Bandwidth variations

Sender’s buffer

2. MPEG over wireless link

• Link: 802.11b• UDP effective throughput• Discretisation time: 40ms• Microwave oven on: between 5 and 13 seconds

5. Conclusions• Simple (only the sender should be changed)• Cost effective (small buffers needed)• Works with any terminals supporting RTP reception and equipped

with a general MPEG decoder• Very reactive against fast network fluctuations • Very small buffer (2 frames) -> low latency (80ms)• Tolerating bandwidth degradation of up to 50% of the video bit-rate

1. Introduction A crucial point in using wireless networks for multimedia tasks is the effective use of highly fluctuating network resources. Using the sender buffer as instant indicator of the varying network state, we implement a simple yet effective technique to greatly improve the quality of video streaming over wireless link.

3. IFD (I Frame Delay) scheduler

Frame inter-dependencies: losing a P frames (red cross) causes the dependent frames to be decoded incorrectly (grey crosses)

Packets get lost here

Quality degradation

C W S

incoming frame

waiting (buffered) frame

sent frame

WHILE (TRUE) DOWHILE (C is empty) DO NothingIF (W is empty) THEN Store C in WELSE

IF (C is of type I) THEN Overwrite W with CELSE IF (C is of type B) Discard CELSE IF (W is of type I or P) Discard CELSE Overwrite W with C

4. Testing and validation

I0B1B2P3B4B5P6B7B8(I9)