Consumer electronics devices such as digital cameras, camcorders, and portable DVD players use 3.5 mm connectors for composite video and audio output. Typically, a TRS connection is used for mono unbalanced audio plus video, and a TRRS connection for stereo unbalanced audio plus video.
TRS means Tip Ring Sleeve (3-pole) and TRRS means Tip Ring Ring Sleeve (4-pole).
TRS (3-pole)
TRS is commonly used for stereo headphones, mono headsets, stereo microphones, auxiliary cables, etc.
TRRS (4-pole)
TRRS is commonly used for stereo headsets, such as cell phone headsets with an inline microphone, audio/video cables with stereo audio, etc.