mb1 
Anmeldungsdatum: 06.06.2001
Beiträge: 3708
Wohnort: München
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 Beitrag 4 - Verfasst am: Fr Jul 26, 2002 7:59 Titel: |
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Wieso klappt das denn nicht ?
| Zitat: | | ChangeFPS changes the frame rate by deleting or duplicating frames to preserve playback speed. |
Das sollte doch genau das verlangte machen ...
ConvertFPS ist nur in avisynth 1.0beta7 verfügbar
| Zitat: | ConvertFPS
ConvertFPS( new_rate [, zone = nlines ] [, vbi = nlines ] [, clip ] )
ConvertFPS() is a video filter for Avisynth. It is available as of Avisynth 1.0beta7.
The filter attempts to convert the frame rate of clip to new_rate without dropping or inserting frames, providing a smooth conversion with results similar to those of standalone converter boxes. The output will have (almost) the same duration as clip, but the number of frames will change proportional to the ratio of target and source frame rates.
The filter has two operating modes. If the optional argument zone is not present, it will blend adjacent video frames, weighted by a blend factor proportional to the frames' relative timing ("Blend Mode"). If zone is present, it will switch from one video frame to the next ("Switch Mode") whenever a new source frame begins, that is, usually somewhere in the middle of a target frame. Switch Mode assumes that the output will be shown on a TV where each frame is scanned from top to bottom. The parameter zone specifies the height of the transition region in which the current frame will be blended into the next.
Blend Mode will cause visible, although slight, blurring of motion. This is a typical artifact of frame rate conversion and can be seen on commercial video tapes and TV programs as well. When working with interlaced video, it is important to let the filter operate on individual fields, not on the interlaced frames. (See Examples below.)
Switch Mode is an attempt to avoid motion blurring, but comes at the expense of slight flicker and motion artifacts. Horizontal and vertical pans may show a slight wobble. Still frames from this conversion show "broken" or "bent" vertical lines in moving scenes. Scene transitions may occur in the middle of a frame. Nevertheless, the results do look less blurry than in "Blend Mode".
Neither mode is perfect. Which one to choose depends on personal preference and on the footage to be converted. Switch Mode is probably only suitable if the output will be shown on a TV, not on a computer screen.
Frame rate conversion is inherently difficult. This filter implements two common methods used by commercial Prosumer-level converter systems. The results are typically quite good. More sophisticated systems employ motion interpolation algorithms, which are difficult to get right, but, if done right, do yield superior results.
Footage converted with this filter should not be converted again. Blurriness builds up quickly in subsequent generations.
The audio data are not touched by this filter. Audio will remain synchronized, although the length of the audio data may slightly differ from that of the video data after the conversion. This is because the output can only contain an integer number of frames. This effect will be more pronounced for shorter clips. The difference in length should be ignored.
Parameters
new_rate Target frame rate. Can be integer or floating point number. In Blend Mode, new_rate must be at least 2/3 (66.7%) of the source frame rate, or an error will occur. This is to prevent frame skipping. If you need to slow down the frame rate more than that, use Switch Mode.
zone (Optional) If specified, puts the filter into Switch Mode. Integer number greater or equal to zero. If zero, the filter will perform a hard switch, that is, it will immediately display the next frame below the switch line. If greater than zero, specifies the height (in lines) of the transition zone, where one frame is gradually blended into the next. zone=80 yields good results for full-size video (480/576 active lines). The transition is done in the same way as in PeculiarBlend(). zone must be less or equal than the number of lines of the target frame that correspond to the duration of the source frame. This is typically 5/6 or 6/5 of the target frame height, that is, a few hundred lines. An error occurs if a larger value is chosen.
vbi (Optional) In Switch Mode, specifies that the filter should apply a timing correction for the vertical blanking interval (VBI). Integer number greater than zero, indicating the height of the VBI of the target frames, in lines. Typically vbi=49 for PAL and vbi=45 for NTSC, but these values are not critical. Ignored in Blend Mode.
Examples NTSC->PAL conversion
AVISource("NTSC_clip.avi") # Get clip
Bob() # Separate fields and interpolate them to full height.
BicubicResize(768,576) # Resize to PAL square-pixel frame size. (Use 720,576 for CCIR.)
ConvertFPS(50) # Convert field rate to PAL, using Blend Mode.
SeparateFields.SelectEvery(4,0,3) # Undo Bob, even field first. Use SelectEvery(4,1,2) for odd field first.
Weave # Finish undoing Bob.
This example will also work with frame-based NTSC material, even with telecined film (movies). For film material, however, you will get better results by using an inverse-telecine filter and speeding up the frame rate from 23.976 to 25fps. Limitations Currently requires YUY2 input.
Bugs Not all parameter values are checked for sanity. |
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mb1
Prophet Mohammed:
"Ein für den Wissenserwerb verbrachter Tag ist Gott lieber als 100 Kriege für Gott." |
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