Linux command
ppmntsc 命令
文本
涉及管道、覆盖或删除，执行前请先确认路径和参数。
常用示例
Convert to NTSC-safe colors
ppmntsc [input.ppm] > [output.ppm]
Use PAL limits
ppmntsc --pal [input.ppm] > [output.ppm]
Show count of illegal pixels
ppmntsc --verbose [input.ppm] > [output.ppm]
Output only corrected pixels
ppmntsc --correctedonly [input.ppm] > [output.ppm]
说明
ppmntsc adjusts the colors in a PPM image to fall within the legal range for NTSC television broadcast. It tests each pixel and reduces saturation for those outside the legal range, while leaving compliant pixels unchanged. Colors that exceed the NTSC signal limits are clipped to the nearest legal value, preventing artifacts like blooming and color bleeding on broadcast displays. The --pal option switches to PAL broadcast limits instead. The --verbose mode reports how many pixels were illegal, helping assess whether the source image is significantly out of gamut. The filtering options (--legalonly, --illegalonly, --correctedonly) allow isolating specific pixels for analysis. Part of the Netpbm toolkit.
参数
- --pal
- Use PAL broadcast color limits instead of the default NTSC.
- --verbose
- Display a count of illegal pixels found.
- --debug
- Display detailed output listing each illegal color and its corrected version.
- --legalonly
- Output only compliant pixels; replace non-compliant ones with black.
- --illegalonly
- Output only non-compliant pixels uncorrected; replace compliant ones with black.
- --correctedonly
- Output only corrected versions of non-compliant pixels; replace compliant ones with black.
FAQ
What is the ppmntsc command used for?
ppmntsc adjusts the colors in a PPM image to fall within the legal range for NTSC television broadcast. It tests each pixel and reduces saturation for those outside the legal range, while leaving compliant pixels unchanged. Colors that exceed the NTSC signal limits are clipped to the nearest legal value, preventing artifacts like blooming and color bleeding on broadcast displays. The --pal option switches to PAL broadcast limits instead. The --verbose mode reports how many pixels were illegal, helping assess whether the source image is significantly out of gamut. The filtering options (--legalonly, --illegalonly, --correctedonly) allow isolating specific pixels for analysis. Part of the Netpbm toolkit.
How do I run a basic ppmntsc example?
Run `ppmntsc [input.ppm] > [output.ppm]` in a terminal, then adjust file names, paths, flags, or remote targets for your system.
What does --pal do in ppmntsc?
Use PAL broadcast color limits instead of the default NTSC.