r/netflix – Netflix is reducing 4K quality (bitrate) intermittently during streaming

I have observed a streaming quality issue while watching season 5 of “The Crown.” I am unable to watch a full episode without repeated, extreme fluctuations in the streaming video bitrate, all while the video resolution remains at 4K and does not change.

I have performed a custom, 300-second measurement of my internet speed on fast.com, which shows 190 Mbps sustained download speeds. No apparent throttling by my ISP in this benchmark.

Exhibit 1: Fast.com speed result (IP address removed).

However, after Netflix titles start streaming at 17,720 kbps (at 4K resolution) for several minutes, the streaming bitrate is reduced to as low as 1,126 kbps, while maintaining 4K resolution. The result is a softer image with macroblocking and banding and is particularly noticeable in darker scenes or ones with lots of motion. It does not appear that Netflix is fluctuating the bitrate depending on the scene, because I have seen the lowest bitrate appear during intensive scenes, which is extremely disruptive.

The bitrate continues to fluctuate between the highest, medium, and lowest values throughout a stream, resulting in a distracting watching experience.

Exhibit 2: Netflix is playing the highest bitrate video while buffering the lowest bitrate, with statistics overlay

Exhibit 3: Still from 4K video at highest bitrate

Exhibit 4: Still from 4K video at lowest bitrate

After performing all possible troubleshooting steps, Netflix blames my ISP and refuses to escalate. My ISP says my connection is good and that the issue must be caused by Netflix.

The device I am using is a Windows 10 laptop and either the Netflix app (from Microsoft Store) or Microsoft Edge browser. My device and display support Netflix 4K. The example images above were captured with my phone’s camera and are of sufficient quality to show the difference between the high- and low-bitrate 4K streams.

Similar thread:

https://www.reddit.com/r/netflix/comments/koxoan/is_netflix_lowering_the_bitrate_drastically_when/