Debugging your video and making it better
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Transcript of Debugging your video and making it better
Overview• Understand what your video is doing• Tools to inspect and measure• Approaches to fixing/improving issues
Areas to Explore
• Metadata• Encoding Quality• Player Errors and QoS• CDN Performance & Multi-CDN switching
Metadata
• ffprobe (ffmpeg)• mediainfo• Bento4 (Prog/Fragment MP4s)• mediastreamvalidator (HLS)• DASH-IF Dash Validator
• http://dashif.org/conformance.html
Encoding Quality
• Quality differences between renditions and encodings.
• Source/Reference vs. Distorted• YUV/RAW frames• Scaling for smaller frame sizes
Encoding Quality Tools
• ”rawvideo” format for RAW frames• Filters for PSNR & SSIM
• ffmpeg -i source.mp4 -i 1080-Output4.mp4 -lavfi "psnr=psnr.log" -f null –
• [Parsed_psnr_0 @ 0x7fb20a60afa0] PSNR y:37.646030 u:43.235161 v:43.402693 average:38.821154 min:16.338695 max:48.619757
Encoding Quality Graphs
Encoding Quality Tools
• Netflix VMAF• https://github.com/Netflix/vmaf• http://techblog.netflix.com/2016/06/toward-practical-perceptual-video.html
• Perceptual Video Quality Assessment
Player Errors and QoS
• Tracking from Player integration• Vendors
• Mux• Nice People at Work, Youbora• Conviva• Streamlyzer
Player Errors
• Fatal Errors• HTML5/MSE errors not always descriptive• Browser/Version issues• CDN issues/failures
Startup Time
Re-buffering
Upscaling/Downscaling
CDN/Delivery Performance
• Global Audience• CDN Issues
• Capacity/Throughput• Outages
• ISP/Routing/Peering Issues• End User Issues
United States
Cedexis Radar, Throughput, Last 30 Days
Australia
Cedexis Radar, Throughput, Last 30 Days
Multi-CDN Switching
• Always use the “best” CDN for each user• Real User Measurement• Flexible Routing Priorities• Leverage in CDN contracts• Cache Hit Ratio
