Video quality degrading?

mustangdmg

I've noticed for the last few months the video bitrates downloaded from Amazon have been getting smaller and smaller. I have subscriptions on Amazon; HBO, Paramount, Peacock, AMC and Paramount. I downloads HEVCs. For an ideal bitrate of an hour episode is between 3,000 to 5,000 kbps. a 2 hours movie is between 5,000 to 7,000 kbps. In the last few years, I downloaded a lot of stuff in those ranges. But Lately I've been seeing an episode downloaded on average 2,000 to 2,500 kbps. Movies are a hit or miss. Some is good, some is awfully low.

From what I've read and researched, a HEVC codec reduces the size of an AVC by 33% to 50% and still maintains better and higher video quality of an AVC. I downloaded a movie in HEVC and AVC, Interview with the Vampire. HEVC, 3120 kbps (2.67 gb). AVC, 10,115 kbps (8.66 gb). Based on the AVC file I downloaded, a HEVC file would've been between 6,777 kbps by 33% to 5,053 kbps by 50%. Instead it's 69.1% I downloaded a latest episode of The Last Frontier. AVC - 7243 kbps (2.92 gb). HEVC - 2152 kbps (896 mbs). At 33%, 4,853 kbps. 50%, 3,622 kbps. But it's at 70.3% reduction.

So I don't know what's happening with the quality. Is it Amazon on their end? Or it's a StreamFab issue? Hopefully, developers can take a look.

0xFeedBeef

reduction in bitrates is not necessarily a degradation of quality. I recently compared some stuff I downloaded this year vs 2023, and while the bitrates for this year were lower, GOPs in this year's downloads were significantly longer in terms of both N and M.

mustangdmg

At the risk of sounding like an idiot, what are GOP, N and M?

AnttDvdFab

Numbers don't really matter as long as when you watch it you can't see more issues than you did before. These companies spend thousands of hours reencoding their content using more advanced algorithms that are fine tuned for each show. It is expected that bit rate will go down when they do this as it saves them tons of cash in storage and streaming costs.

AnttDvdFab

At the risk of sounding like an idiot, what are GOP, N and M?
mustangdmg

https://aws.amazon.com/blogs/media/part-1-back-to-basics-gops-explained/

AllNight

Double check the video format on the download pop up window; make sure that you check both the CBR and CVBR options, especially for H.264. Usually, one of them will have a download option that is WAY higher in bitrate than the other.

Sebastian001

To put it briefly: Streamfab downloads the bitrates that Amazon uploads. If any bitrates are reduced, that's Amazon's fault.

theresay

Amazon changes video codec all the time, usually to the most advanced technology available. As mentioned before, to save storage and streaming cost. It doesn't mean a degrading in video quality. Developers are always looking for ways to better compress digital contents without sacrificing quality.

Stan001

To put it briefly: Streamfab downloads the bitrates that Amazon uploads. If any bitrates are reduced, that's Amazon's fault.

I have to agree to this statement.
As most know, streamfab does direct downloading, so for example, it's 2,000 bit rate when downloaded, it's that on the Amazon site, and streamfab can't fix it.
Also, some sites offer more than one choice under both 720 and 1080.

Double check the video format on the download pop up window; make sure that you check both the CBR and CVBR options, especially for H.264. Usually, one of them will have a download option that is WAY higher in bitrate than the other.

This is also a very interesting thing, and I barely pay attention to it. A few times, I looked up CBR vs CVBR, and most seem to think overall CVBR is better, so I just leave it, but I may try going back and forth myself now to see. I also noticed some don't even offer CBR, so then no choice.

0xFeedBeef

Incidentally, been doing more comparisons (need to free up spinny-disk space) and some of the downloads this year exceed 2023 downloads bitrate-wise. So it’s not a one-way move, Amazon are patently re-encoding.