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10th January 2016, 20:40 | #22 | Link | ||
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11th January 2016, 13:50 | #23 | Link | |
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And maybe tamp down on the sarcasm, or whatever it is, and answer questions and correct mistakes directly instead of throwing out non sequiturs. |
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17th February 2016, 14:10 | #24 | Link |
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Widescreen NTSC DVDs are not quite 16:9 (1.77778:1). The standard NTSC DVD has a resolution of 720x480. It also has a signalled Pixel Aspect Ratio of 40:33. This tells the decoder to stretch the image out horizontally. This makes the actual Aspect Ratio 1.81818:1 (720/480 = 1.5, 1.5 x (40/33) = 1.818...).
480 x 1.81818 = 872, so 480p DVDRips should really 872x480. However, 872 is not mod16. Ideally clips should be mod16, however with newer decoders it seems far less important (I have yet to find any player that struggled with anything other than mod2). If you want to be safe, go with 864x480 (1.8:1) and crop to reduce error. It is worth bearing in mind that some mastering facilities may have made the mistake of assuming a DVD to be 16:9 also. When I can I have a look through the DVD for squares or circles to check what the actual aspect ratio is (logos in the credits are always a good indicator). If you do find the DVD has been mastered at 16:9 then I would go with 852x480 (again, not mod16, so go with 848x480 if you want to be safe). It is also worth bearing in mind that when muxing to MKV (with MKVToolNix GUI) you can manually set the playback Aspect Ratio (see screenshot). While I don't use this to encode at Aspect Ratios far off (not all devices read this header correctly) it is useful to get things exact. For example, if you encode at 848x480 and wish to have it (when possible) be resized to 1920x1080 on your display it is worth setting the flag (although an error of 0.63% is really not much of an issue). Also, for reference PAL DVDs are also not exactly 16:9 (1024x576). They use an aspect ratio of 16:11, so 576p content should be really be resized to 1048x576 (or 1040/1056 if you wish to keep it mod16). Hope this helps explain things, Ben Last edited by bcn_246; 12th September 2023 at 00:20. Reason: cleanup |
24th February 2016, 11:49 | #25 | Link | |
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There have been quite a few threads here about this problem. |
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25th February 2016, 15:38 | #27 | Link |
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Nope - Comodore Amiga is:
at first non ITU video source at second capable to do MOD16 in horizontal and any MOD1 in vertical at third it can use (ICS/OCS) 2 pixel clocks and (ECS/AGA) 3 different pixel clocks at fourth is Amiga is not capable to decode H.265 with reasonable speed even with most fastest accelerator board (for today such as Apollo which is something around 150MHz MC68060 i.e. somewhere around 200MHz 486DX). And to not be completely OT: H.265 is not optimized for SD resolution (compression efficiency will be significantly bellow promised 50%). |
25th February 2016, 20:17 | #28 | Link |
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I don't know if that is true. Implementation maturity might not be there to be able to deliver x264 quality at half the bit rate in x264's sweet spot, but we're not THAT far off with 1.9 now. 50% is probably achievable with some content (low noise).
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26th February 2016, 20:17 | #29 | Link | |
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Even if H.265 will deliver few % gain then IMHO is not worth all fuzz behind it. But yes, i never saw objective test with focus on how H.265 scaling with source resolution - based on experience with previous codecs i don't expect different behavior. |
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26th February 2016, 22:59 | #30 | Link | |
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The advantage of HEVC goes up with high resolutions; it's >50% at 3840x2160. But it's not JUST high resolutions. |
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29th February 2016, 19:41 | #31 | Link |
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Can you elaborate on what makes HEVC more interesting the higher the resolution goes ?
Are we talking about transparency, metrics, perceptual quality ?
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29th February 2016, 22:39 | #32 | Link | |
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Lots of other HEVC features provide efficiency improvements irrespective of frame size. So there's a base efficiency improvement, and an additional frame size differential improvement. |
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1st March 2016, 12:20 | #33 | Link |
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Oh I see... Thanks for your answer
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6th March 2016, 22:01 | #34 | Link | |
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My own practical test shown that BBC rules don't work for modern TVs. Adobe adopted these rules some time ago and now their HD to SD scaling has black bars on side which I'm not that sure is correct for modern TVs (as they use square pixels and seams to have no compensation for "old standard"- Sony broadcast monitors have special setting for it). Last edited by kolak; 6th March 2016 at 22:03. |
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8th March 2016, 00:26 | #35 | Link | |
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Optimally encode to 704x576 from 16:9 with full raster and no black bars and standard PAL sample aspect ratio, and circles should be circles. |
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