Many video devices, such as the Analog Devices ADV7179 DAC, have analog-baseband-TV interfaces for PAL (phase-alternating-line) and NTSC (National Television System Committee) video signals. Unfortunately, these kinds of DACs accept video in inter-laced-image format only, but you may need progressive-scan video instead. Furthermore, many of the progressive-scan images vary in size, which makes it more difficult to convert a progressive-scan image to an interlaced image. Therefore, you need a universal and efficient image buffer, such as SDRAM or DRAM, as a strategy for separating the image field.
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