using:video_filter_resize
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using:video_filter_resize [2010/04/16 19:53] j.m |
using:video_filter_resize [2012/11/11 08:51] |
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| - | ====== Video filter Resize ====== | ||
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| - | ===== Resize vs MPlayer resize ===== | ||
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| - | //Resize// is a YV12 port of Avisynth resize filter. | ||
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| - | //MPlayer resize// is a port of Michael Niedermayer resize filter, which is used in MPlayer. | ||
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| - | Avisynth resize is slightly more accurate, but MPlayer resize is 3x(nbsp)faster without any perceptible difference. | ||
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| - | The filter dialog config box is the same for both filters. You can direcly enter the new width/height and the resize algorithm or use the slider and the menu. | ||
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| - | In case you enter the values manually, press OK, not Apply, as pressing Apply recomputes the value from the slider position. | ||
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| - | ===== Resize function ===== | ||
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| - | Three resize methods are proposed: | ||
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| - | * **Bilinear:** Tends to smooth the picture, but makes the video //easier// to encode. Appropriate for downsizing. | ||
| - | * **Bicubic:** Keeps sharpness and thus makes the video //harder// to encode (leads more easily to blocking-artifacts). Recommended for enlarging. | ||
| - | * **Lanczos:** Produces a very sharp picture and keeps a lot of details. Use it for HQ encodings at high bitrates. | ||
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| - | Remember: Sharp pictures look nice in preview, but they can cause problems when the video is encoded (especially at low bitrates). So don't rely on the preview only. Encode a short sample and check the encoded video! | ||
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| - | ===== Aspect ratio ===== | ||
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| - | The aspect ratio is very important for proper resizing. If the source is MPEG-1/2, you can be almost sure that the source aspect ratio is 4:3 or 16:9. AVI files are most commonly 1:1. | ||
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| - | So to resize properly a widescreen DVD for example to MPEG-4 AVI (e.g. encoded with XviD), select 16:9 for source and 1:1 for destination. | ||
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| - | The framerate is also important. 4:3 MPEG has non square pixels, different for PAL and NTSC. So if you resize before altering the framerate you will end up with a differently sized image. | ||
| - | * What is the link between framerate and non-square pixels? This explanation needs more info! | ||
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| - | The //16 round up// checkbox, when checked, will round up the resize value to the closest multiple of 16. | ||
using/video_filter_resize.txt ยท Last modified: 2012/11/11 08:51 (external edit)
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