WEB-DL Quality Question
Hello - I need some help understanding something. I'm looking at two WEB-DL files from reputable groups that are identical in nearly all ways (see details below), except one file is noticeably larger than the other (2.8GB vs 3.47GB, for example). I thought WEB-DL's should be the same size if they're from the same source (AMZN in this instance), so I'm a little confused as to why there's such a disparity in size when all else appears equal.
Any idea's what could explain the difference in file size here? I'm assuming the FLUX file is older based on when it was first uploaded vs the NTb one. Could this have something to do with it?
Bonus question: Which file would you choose in this situation?
(1) 1080p.AMZN.WEB-DL.DDP2.0.H.264-NTb
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FileSize......: 2.80 GiB
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Duration......: 42 min 35 s
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Video.........: High@L4 | 1920x1080 @ 9 197 kb/s
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Audio.........: English Dolby Digital Plus | 2 CH @ 224 kb/s
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Subtitle......: English / English.
(2) 1080p.AMZN.WEB-DL.DDP.2.0.H.264-FLUX
- FileSize......: 3.47 GiB
- Duration......: 42 min 12 s
- Video.........: High@L4 | 1920x1080 @ 11.3 Mb/s
- Audio.........: English Dolby Digital Plus | 2 CH @ 224 kb/s
- Subtitle......: English.
Edit: Thanks for all the replies! For anyone who stumbles upon this later on with a similar question, there's some really great replies in the comments below worth checking out. In my case, the file size difference was due to the difference in bitrate, where the bitrate differential is likely due to either (A) the region where the AMZN WEB-DL occurred (with different regions having different bitrates), or (B) the release group modifying the bitrate to fit a specific need (like limiting the file size). Knowing both release groups here tend to prioritize quality, I'm guessing the region is likely the main driver in the difference in bitrate size.
The date of the upload doesn't matter. What matters is the bitrate given.
9 197 kb/s vs. 11.3 Mb/s means that the FLUX release is packing >20% more image data into the file, so the picture will look crisper, contains more visual information, and is less compressed in general.
Depending on your display you might not actually notice the difference, but on a good, large HD panel you will be able to spot differences here and there, particularly when it comes to fast change of scenes, swift light/dark changes, and rapid movements.
That makes sense and helps to conceptualize the impact of the bitrate difference. I guess I was under the impression that bitrate would be set at the source and not by the release group, but seems I may have been wrong in that assumption. Thanks for the info!
The source defines the bitrate at which it is streaming, which sets the theoretical maximum. The release group then decides if and how much they want to compress the file.
Theoretical maximum because the release group could go above spec, but that wouldn't add any benefits.
Hi, the difference in size you are seeing is because of the different video bitrates. The Ntb one has a slightly lower bitrate, so for videos that are about the same duration, this translates to a lighter file.
Whether or not you could perceive the difference amounts to your sensibility and experience with this kind of things as well as to your monitor.
Gotcha. Any idea why the bitrate would be different on a WEB-DL from the same source? I figured bitrate would remain the same if the file is being downloaded and DRM stripped, with all else (source, resolution, etc...) remaining equal.
Streaming providers are known to have different bitrates in different regions.
Oh, good call. I didn't even consider that!
Bitrate, every group use different encode.
Ohh, I didn't realize the release groups would set the bitrate. I figured that was set at the source. But that makes sense. Thanks for helping to clear this up! I was at a loss trying to connect the dots on the size differential here.
Different groups specialize in different target audiences. Some seek the highest quality, others want not to exceed a certain number of gigabytes, etc.
Flux is considered a good quality group so I would go for that one: https://trash-guides.info/Sonarr/Sonarr-Release-Profile-RegEx/
Edit: just realized that ntb is also in that exact list. In that case go for the highest bitrate for better quality. Thus the flux one.
Thanks for the reply and the link! I agree, based on everything I'm learning in this thread, seems like the FLUX version is the way to go for the added bitrate.
My guess is the source file is the same sorce file, but some groups process the file to cut down the file size.
If there's some re-encoding, would the file still be considerd "WEB-DL" at this point?
Wouldn't the raw unaltered stream be a webrip rather than a web dl?
"Rip" implies re-enconding. Web-DL is the exact video stream as it is transmited, without any further re-encondings by the release group. Unless I'm wrong...?
Process, meaning like encode? Or can it be processed in other ways that doesn't alter the quality?
I noticed that the smaller file is longer, interestingly enough. So there does appear to be some level of trimming I'm assuming, but I wouldn't have expected the longer file to be the smaller one.