I’m preparing for my per-title presentation at Streaming Media East next Tuesday (presentation description below) and found some anomalous results for lower-resolution files produced by YouTube. I’m including YouTube in the analysis because I’ve always respected their work and for perspective vis a vis other per-title technologies that I’ll analyze (including Elemental MediaConvert QVBR, Capella Systems SABL, Epic Labs Lightflow, QEncode, and hopefully Bitmovin).
To test all technologies, I uploaded the same set of 21 test clips and then downloaded the encoding ladder produced by each technology, YouTube included. Then I analyzed the clips in the Hybrik Cloud platform, producing a range of metrics like VMAF, SSIM, and PSNR. When reviewing the YouTube scores, I was surprised by the poor quality of lower-resolution clips as measured by Hybrik so I wanted to confirm them with the Moscow State University tool on my local workstation. In this video, I do that and show that the low scores measured in the YouTube clips correspond with noticeably poorer frame quality than the baseline clips encoded using 200% constrained VBR.
Not sure why this would be; if anyone has a clue, please let me know. In all previous analysis, YouTube quality has always been top notch and these results are very surprising.
If you’re in Manhattan next week, stop by and say hello at Streaming Media East.
Here’s the video best watched in full screen.
Here are the details of the per-title presentation.
T103. A Survey Of Per-Title Encoding Technologies
Tuesday, May 7: 1:45 p.m. – 2:30 p.m.
Per-title encoding techniques customize the encoding ladder to match the encoding complexity of the source, saving bandwidth on easy-to-compress videos and ensuring the quality of more complex footage. Codec specialist Jan Ozer compares the efficiency, implementation issues, and costs of multiple commercially available and open-source alternatives for live and VOD per-title encoding. Learn what per-title encoding is, how the various options work, and which is the best option for you.
Speaker:Jan Ozer, Principal, Streaming Learning Center and Contributing Editor, Streaming Media