A high-resolution audio format approved by the DVD Forum in 1999. Designed as an optical disc format with higher-quality sound than a CD, DVD-Audio never caught on. Neither did SACD, a competing next-generation music format (see SACD). However music in DVD-Audio resolutions is available via download (see high-resolution audio). Like CDs, DVD-Audio uses PCM encoding. It supports 16, 20 and 24-bit samples at sampling rates of 44.1, 48, 88.2, 96, 176.4 and 192 kHz, compared to 16-bit samples at 44.1 kHz for CDs. Offering two channels at the highest rates and six channels at lower rates, the front speaker channels can be sampled higher than the rear channels. DVD-Audio supports other coding systems on alternate tracks, such as Dolby Digital, DTS and DSD. Video, Graphics, Text and CD Music DVD-Audio also holds video, graphics and text in the Video Zone, located at the outer edge of the disc. It follows the DVD-Audio zone that starts at the center. A Flip Disc placed DVD-Audio titles on one side and the same music in CD format on the other. See high-resolution audio, MLP and DVD.