Compare the bit rate for video, photos, and audio.
Video has the highest bit rate, photos are moderate, and audio has the lowest.
What are the characteristics of streaming stored video?
Uses buffering, can prefetch data, and tolerates moderate delay but not loss.
What are the characteristics of streaming live audio and video?
Low-latency delivery, limited buffering, real-time constraints.
What are the characteristics of conversational voice and video over IP?
Highly delay-sensitive, requires low jitter and low loss for interactive communication.
How does the encoding of analog audio work (in simple terms)?
Sample the waveform, quantize values, and encode them digitally.
What are the three major categories of VoIP encoding schemes?
- Narrowband
- Broadband
- Multimode
What are the functions that signaling protocols are responsible for?
- User location
- Session establishment
- Session negotiation
- Call participation management
What are three QoS VoIP metrics?
- End-to-end Delay
- jitter
- packet loss.
What kind of delays are included in ‘end-to-end delay’?
- audio encoding
- convert to packets
- normal network delays (queuing, etc)
- Playback delay
- Decoding delay
How does ‘delay jitter’ occur?
Variable queueing and network congestion cause packets to arrive at uneven intervals.
What are the mitigation techniques for delay jitter?
Buffering, playout smoothing, and adaptive jitter buffers.
Compare the three major methods for dealing with packet loss in VoIP protocols.
- FEC adds redundancy
- interleaving spreads losses
- error concealment estimates missing audio.
How does FEC deal with packet loss in VoIP? What are the tradeoffs?
Adds redundant packets to recover lost data; trades bandwidth for robustness.
How does interleaving deal with packet loss? What are the tradeoffs?
Reorders audio segments so losses affect small parts; increases delay and unsuitable for real-time voice.
How does the error concealment technique deal with packet loss in VoIP?
Uses previous audio or prediction to mask missing packets.
What developments led to the popularity of consuming media content online?
Broadband growth, better compression, powerful devices, and CDNs.
Provide a high-level overview of adaptive video streaming.
Client selects video chunk bitrates dynamically based on network conditions.
Which protocol is preferred for video content delivery - UDP or TCP? Why?
TCP
- delay/loss sensitivity
- Failure to encode from loss
What was the original vision for the protocol for video delivery, and why was HTTP chosen?
Original vision was for a server stateful protocol, but HTTP won shifting the burden to the client
Summarize how progressive download works.
Client downloads video linearly over HTTP and begins playback before completion.
How to handle network and user device diversity?
Provide multiple bitrate/quality versions of content.
How does bitrate adaptation work in DASH?
- Each video divided it chunks
- Bitrate function input → outputs chunk to be downloaded
- Client adapts based on estimation of network conditions
What are the goals of bitrate adaptation?
- low or zero re-buffering
- high video quality
- low quality variations
- low startup latency
What signals can serve as input to bitrate adaptation algorithms?
Throughput estimates, buffer occupancy, and download times.
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Module 1: Quiz10
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Module 1: Practice Quiz5
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Module 2: Quiz21
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Module 2: Practice Quiz4
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Module 3: Quiz21
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Module 3: Practice Quiz14
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Module 4: Quiz23
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Module 4: Practice Quiz21
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Module 5: Quiz13
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Module 5: Practice Quiz27
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Module 6: Quiz10
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Module 7: Practice Quiz18
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Module 7: Quiz13
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Module 8: Practice Quiz33
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Module 8: Quiz21
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Module 9: Practice Quiz24
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Module 9: Quiz16
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Module 10: Practice Quiz13
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Module 10: Quiz14
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Module 11: Practice Quiz25
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Module 11: Quiz15
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Module 12: Quiz12
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Module 7: AI11
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Module 8: AI18
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Module 9: AI23
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Module 10: AI23
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Module 11: AI28
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Module 12: AI24
