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Porn Users Forum » A couple of technical questions about video quality and format |
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09-10-11 10:25am - 4852 days | Original Post - #1 | |
rearadmiral (0)
Active User Posts: 1,453 Registered: Jul 16, '07 Location: NB/Canada |
A couple of technical questions about video quality and format I did a bit of a search to see if this had been asked or discussed before but found nothing. What is the relationship between a video’s dimensions (A x B) and the bitrate (C kbps)? I’ve seen videos that have similar dimensions but look quite different. What should I look for? Also (and this is getting really obscure…) I use a Western Digital HD TV thingy on one of my TVs. My preferred file format is wmv simply because it is relatively common and as much as Windows Media Player can piss me off, it pisses me off less than a lot of other players. But… the WD thing will only play wmv codec 9. I’m currently downloading from Third Movies and the oldest videos on the site are in codec 9, but newer ones are in codec 8. Wouldn’t 9 be better than 8? If you have a process to encode the videos one way why would you change that unless there was an obvious improvement? Thanks! | |
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09-10-11 01:45pm - 4852 days | #2 | |
anyonebutme (0)
Active User Posts: 294 Registered: Aug 23, '09 |
Higher the resolution, the better the picture. Higher the bitrate, the better the picture. Otherwise, there really isn't a relationship between the two. You can encode a video at 640x480@20mbps, or the same at 1920x1080@3mbps. But there is a point where more bitrate produces negligible improvement in video quality. Typically 640x480 - 4mbps 1280x720 - 6mbps 1920x1080 - 12mbps Of course this only applies to porn videos. Hollywood videos go up to and sometimes over 50mbps to get the desired look. For codecs, on a computer "9" is about as good as "8", negligible differences. But your hardware player only supports a limited number of decoding options. It is what it is. | |
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09-10-11 02:33pm - 4852 days | #3 | |
rearadmiral (0)
Active User Posts: 1,453 Registered: Jul 16, '07 Location: NB/Canada |
Thanks for the info. This is helpful. | |
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09-10-11 02:57pm - 4852 days | #4 | |
otoh (0)
Active User Posts: 159 Registered: Sep 17, '10 Location: UK |
I guess you can think of it like the quality setting for jpeg images. For any given dimension of a jpeg, you can save the image at varying qualities; a lower quality introduces artefacts; blockiness around edges and smooth gradients. WP as ever has a good illustration: http://en.wikipedia.org/wiki/File:Qualit...pg_vs_saveforweb.jpg So the higher the bitrate, the smoother/sharper the video even at the same resolution. But as anyonebutme said, there's an upper useful limit - same as with images, where although it depends on the image in question, saving at anything more than 70 or 80 quality doesn't lend any appreciable difference, other than a bigger file. | |
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09-11-11 12:52am - 4852 days | #5 | |
turboshaft (0)
Active User Posts: 1,958 Registered: Apr 01, '08 |
Like anyonebutme, I can't think of any relationship really, except that they can both affect quality and file size (which can both be judged fairly objectively). Of course, you can always have a big beautiful file that, at least technically, is shot as near to perfect as possible but still bores the hell out of you. Personally I look at size way more than bitrate, and sites frequently list their videos in terms of frame size, though some list both. Problem is if it's shot in a certain format--which usually corresponds to a certain size, since porn is almost 100% digital--then you shouldn't go bigger than that. Bottom line, you really can't get bigger than the original size, but smaller is always possible (sounds like an insult from a former girlfriend... ). Anyway, they are probably all compressed to some extent or another since it's the 'net. (Uncompressed video would equal massive file sizes, so be careful what you wish for.) And generally speaking the larger dimensions and higher bitrates mean somewhat less compression than smaller dimensions and lower bitrates--when in doubt, check it out! If two videos look the same to you I would choose the one that's smaller in file size and is still easy to play. Or just go crazy and choose the biggest file size every time. I believe this is badandy400's strategy. "It's incredibly obvious, isn't it? A foreign substance is introduced into our precious bodily fluids without the knowledge of the individual. Certainly without any choice. That's the way your hardcore Commie works." - Gen. Jack D. Rippper, Dr. Stranglove | |
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09-11-11 09:59am - 4851 days | #6 | |
rearadmiral (0)
Active User Posts: 1,453 Registered: Jul 16, '07 Location: NB/Canada |
Thanks for the information guys. I have a better understanding of these numbers now. I thought there was somehow a direct relationship between resolution and bitrate, but I now see that those are two different decisions that a site needs to make. | |
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10-14-11 02:03am - 4819 days | #7 | |
Micha (0)
Active User Posts: 321 Registered: Jul 04, '10 Location: san jose ca |
I much prefer HD in video and have had few problems downloading and playing 720p vids from several paysites. What has given me problems are the 1080p vids (from Xart and now Reality Kings) These three to four gig vids won't play on my puter. (running XP on a 2Gh processor) A still image appears and then nothing. I can advance using the ff slider to other still images for the entire duration of the vid. I can sometimes get movement by coaxing, but it is of short duration and very choppy. My players are WMP, VLC, and Media Player Classic. 720p works just fine for me but that format is not available at RK. Any suggestions out there? Any suggestions for vid players? Thanks for any help on this. michael unless life also gives you water and sugar, your lemonade is gonna suck. | |
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10-14-11 06:58am - 4818 days | #8 | |
BadMrFrosty (0)
Active User Posts: 124 Registered: Mar 05, '10 Location: Prague (Czech Republic) |
The codec plays a large part as well. A MPEG 1 video encoded at 640x480 4 mbps will look worse than the same video encoded using h264 at 1 mbps. You can go even further by comparing the encoding profile, number of encoding passes, cbr vs vbr and all sorts of other jargon until your head spins but usually given the video codec, bitrate and resolution you can make a educated guess at the quality level. The problem with the world is stupidity. Not saying there should be capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself? Frank Zappa Edited on Oct 14, 2011, 07:10am | |
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10-14-11 07:07am - 4818 days | #9 | |
BadMrFrosty (0)
Active User Posts: 124 Registered: Mar 05, '10 Location: Prague (Czech Republic) |
1080P video needs a lot of horsepower to decode. A 2ghz CPU cant do it without a bit of help. You have a couple of options, first a piece of software called CoreAVC and the second is to use your graphics card hardware to help. Unfortunately, both solutions require the video to be encoded in a compliant way. From my experience, very few WMV files I download from porn sites are DXVA compliant so it may be best to download and try h264 encoded mp4 or flv files. Once you have the files and one of the helpers you need to use a supported player to make use of them. I use MPC HC which given the right graphics card or CoreAvc and a compliant video file should work with default settings. The problem with the world is stupidity. Not saying there should be capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself? Frank Zappa | |
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10-16-11 12:50pm - 4816 days | #10 | |
Micha (0)
Active User Posts: 321 Registered: Jul 04, '10 Location: san jose ca |
Thankyou BadMrFrosty for your response. It is a bit over my head but thanks to search engines and this long handled spoon I'm within sight of grasping an understanding. MPC had not been my default player but I've taken another look and I think that'll change. Thanks again michael unless life also gives you water and sugar, your lemonade is gonna suck. | |
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