File:Ntsc video timing.png

A visualization of the NTSC PPU's video output signal, using different colors to denote each part of the signal.

• Cyan is the horizontal blanking pulse
• Dark blue is the "back porch" after HBlank
  • Yellow is the colorburst signal
• Red is the visible output region, including the left and right border
  • Bright green is the grayscale pulse (at cycle 326)
  • Bright red is where the background and sprites are actually visible
  • The black dot delinates cycle 0 (0, 0) according to the PPU Frame Timing Diagram
• Orange is the "front porch" before HBlank
• Magenta is the vertical blanking pulse
• Dark green is the surrounding vertical blanking region (and the sync separator)
  • The orange dot indicates when the PPU skips a dot on odd frames (339, 261)