Task: Question Generation
Input (English): CD-Vs are not to be confused with Video CDs (which are all-digital and can only be played on VCD players, DVD players, CD-i players, computers, and later-model LaserDisc players, such as the DVL series from Pioneer that can also play DVDs). CD-Vs can only be played back on LaserDisc players with CD-V capability. VSDs were the same as CD-Vs, but without the audio CD tracks. CD-Vs were somewhat popular for a brief time worldwide, but soon faded from view. VSDs were popular only in Japan and other parts of Asia, and were never fully introduced to the rest of the world.
Output (English): What were VSDs lacking that CD-Vs included?