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26th September 2005, 11:33 | #1 | Link |
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Correct Aspect-Ratio in x264?
I used XVID all the time to encode PAL DVB-streams - now I want to test x264.
Most streams I encode are in 720x576. In XVID I selected the 4:3-PAL setting for the Aspect-Ratio, so the video will be stretched correctly during playback. In x264 I have the option "Sample AR". I would like to know what settings I need to type in for correct 4:3-PAL and 16:9-PAL in x264. |
26th September 2005, 11:53 | #4 | Link |
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Or......
PAL 4:3 DAR = 16:15 PAL 16:9 DAR = 64:45 NTSC 4:3 DAR = 8:9 NTSC 16:9 DAR = 32:27 EDIT: In February 2006 I conceived a tool called ARS Calculator to help people work out Aspect Ratio Signalling (ARS) ratios (ie: PAR, SAR, DAR) for use with encoders such x264 and XviD Cheers
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Last edited by SeeMoreDigital; 2nd October 2006 at 16:10. |
26th September 2005, 12:51 | #6 | Link |
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Personally speaking I prefer to use the (4:3 or) 16:9 DAR calculations because they will always output an (4:3 or) 16:9 shaped image, regardless of the sources pixel size/ratio.
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29th September 2005, 21:48 | #9 | Link | ||
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Quote:
Good Example a 52.000µs capture: DAR = 1,3333 * 576 / 702 = almost 1,094:1 = PAR 128:117 Here a 702x576 is truely DAR 4:3 @ PAR 1,094 Bad example, a fullscreen 720x576 DVD as source: DAR = 1,3333 * 576/720 = 1,06664 = the common error of generic par happens here 720 * (128/117) / 576 = DAR 1,3675:1 equals not 4:3 (1,3333) DAR = 1,3675 * 576 / 720 = PAR 1,094:1 = ok Quote:
480x576 px sources do have 53,3333us (same as 720x576). 768x576 do have 52,0000us 53,3333/52,0000 = 1,02564 <--- our diff. factor! So do resize 480 x 576 to 768*(1,02564) x 576 = 788x576 or do crop 480 x 576 to 480/1,02564 x 576 = 468x576 and resize to 768x576 If you do respect these your eyes when watching mpeg4s via HTPC will kiss you. Last edited by Inc; 29th September 2005 at 21:54. |
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29th September 2005, 15:17 | #12 | Link |
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Added more info on SAR in the daily builds FAQs.
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MPEG-4 ASP Custom Matrices: EQM V1(old), EQM AutoGK Sharpmatrix (aka EQM V2), EQM V3HR (updated 01/10/2004), EQM V3LR, EQM V3ULR (updated 04/02/2005), EQM V3UHR (updated 17/12/2004) and EQM V3EHR (updated 05/10/2004) Info about my ASP matrices. MPEG-4 AVC Custom Matrices: EQM AVC-HR Info about my AVC matrices My x264 builds. Mooo!!! |
29th September 2005, 17:21 | #14 | Link | |
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Quote:
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29th September 2005, 18:46 | #15 | Link |
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Just in-case anybody needs to know, here are the FFdshow "overlay settings" I use in-conjunction with MediaPlayer Classic: -
Encodes with AR signalling in AVI, MP4, MKV and OGM work perfectly.... Cheers
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29th September 2005, 21:13 | #16 | Link |
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ok thanks a lot
zplayer vmr and ffdshow overlay mixer works (thought i have to use it for both), not as smooth as vcl but its workin (i have to click on fit source one time) besides i dont really know what to do with those crappy 480x576 streams 480x576 autozoom to 768x576 or somethin like 480x576 encode to 640x480 or even 768x576 Last edited by fatxy; 29th September 2005 at 21:27. |
19th January 2006, 17:12 | #17 | Link |
Squeeze it!
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Full TV PAL is 768x576 @ 52.000µs @ 14,7692307Mhz (= quadra pixels)
ITU samplingrate is 13,5 Mhz (= squarepixels) 14,7692307/13,5 = 1,094017 = TV PAR @ 13.5Mhz used by a SAP or ... 52.000µs * 13.5Mhz = 702 active pixels at square pixels 52.000µs * 14,7692307Mhz = 768 active pixels at quadra pixels 768/702 equals 128/117 equals 1,094017 Last edited by Inc; 19th January 2006 at 17:15. |
19th January 2006, 18:26 | #18 | Link |
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That's fine for anamorphic encodes with pixel frame width of 702....
However, if you want to generate spec PAL video files with a target aspect ratio of 4:3 based on a pixel frame width of 720, I would recommend you use the following calculation: - 768/720 = Lowest fraction = 16/15 (Decimal = 1.094017) However, if you want to generate spec PAL video files with a target aspect ratio of 16:9 based on a pixel frame width of 720, I would recommend you use the following calculation: - 1024/720 = Lowest fraction = 64/45 (Decimal = 1.422222) Cheers
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19th January 2006, 18:55 | #19 | Link |
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What would you suggest for NTSC Analogue captures with a width of 720 or 704 pixels?
For example, I have an analogue capture at 720x480 which I crop to 720x360 to remove letterboxing, the resize back to 720x480 anamorphic. Using the cropped resolution: 16.9 = 1.7777 -> (1.7777x360)/720 = ~640/720 = 0.888 640/720 equals 8/9 equals 0.8888 This doesn't look right. EDIT: This of course assumes the original pixel width is actually 720 and not at all taking into account things like what my ATI AIW 8500's capture window is etc etc. Last edited by Piper; 19th January 2006 at 19:04. |
19th January 2006, 19:45 | #20 | Link | |
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Quote:
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