ganler
commented
4 years ago Problem: Video gets stuck and rebuffering...
- Bitrate: Higher => Better Quality => Huger File Size
- Frame rate: Higer => Better Fluency => Huger File Size
Old approach: Dynamic Streaming over HTTP(DASH)
When Video Rate > Capacity, the video gets stuck and gets into a rebuffering period.
Adaptive Bitrate (ABR) Algorithm
Choose available periods adaptively depending on the network and playback buffer condition.
Challenge
The future is unknown...
Past throughput observation cannot predict the coming network condition...
User side:
- users don't want higher/extra bitrate => cuz it will deplete the playback buffer and finally result in videos' getting stuck.
So ABR has to wait for a while to adapt this noisy cloud of future possibilities.
So we need to plan for the future for a better user experience.
Pensieve
Input: Observation@{Bandwidth, Current BitRate, Buffer} Output: Next bitrate.
Contrib:
- First network control system using modern DRL.
- Delivers 12~25% QoE, with 10~30% less buffering than the previous ABR algorithm.
- Tailors ABR decisions for different network conditions in a data-driven approach.
Previous fixed ABR algorithms
All these are based on fixed heuristics based on designers' insights.
=> Simplified inaccurate model leads to suboptimal performance.
MPC: conservative throughput prediction
Pensieve
Future Questions
- Does Pensieve generalize?
Others
When doing the evaluation, we can compare the algorithms with the offline optimal result.
Does xxx generalize?
https://openreview.net/pdf?id=SJlCkwN8iV
RL for video streaming(QoE).