I take to upload the highest quality of videos to youtube that I can, usually uploading videos in significantly greater bitrate than the site will eventually use, figuring that I might as well give them the best source possible so that it’s not doubling up on the compression artifacts from a low bitrate source when they transcode it. I’m typically encoding to MP4 AVC with a 20 quality quantizer setting, resulting in somewhere around 150-200MB/minute. Dramatically overkill for youtube, and watching the videos locally (before uploading) the quality is very high.
But I’ve been noticing a drop in quality of the videos I’m posting when I watch them on youtube that are typical of a lowered bitrate. Loss of fine detail, more blocky compression artifacts, etc.
As an example, I uploaded this video just now, and it’s the worst looking video in 1080p I’ve uploaded to youtube. The original looks fine, but that version is a blocky mess with very little detail.
In comparison, a similar video I uploaded a few years ago. Now it definitely shows the signs of compression, but not nearly to the same degree. And I’m not sure about this, but I think the video probably looked better years ago when I uploaded it - but I’m only going from memory.
Which means I don’t know if it’s dynamically scaling down the bitrate on the fly, or if they lower the bitrate that they transcode the files to internally over time. But I have thought to myself a few times over the last few years “did they drop the bitrate again?”
Is there anything to it? Has youtube been lowering their bitrates over the last few years?