dex Otaku Posted November 14, 2004 Report Share Posted November 14, 2004 (This is related to the thread about the MD deck with 20-bit playback.) Why do some MDs claim 20+bit recording and playback? Lossy formats such as mp3, atrac, &c. use various transform methods to convert data from linear PCM [time-domain] to the frequency-domain. Fourier transforms, discrete cosine and modified cosine transforms, &c. tend to be the most common wasy of doing this. What this means, in English, is that once the original PCM data is compressed, it doesn't even have a bit-resolution per se - at least, not in the conventional PCM sense. While the sampling rate has to be locked [or resampling done] between all stages of encoding/decoding, the bit depth is actually kind of irrelevant. As long as the codec knows how to handle more bits, what you'll end up with is a slightly more accurate encoding. And when I say slightly, I'd opine that it's so slight as to be marginal, but still maybe measurable. Likewise, when decoding you can do so to any bit depth, with higher bit depths getting marginally better accuracy [as long as they're properly dithered adn noise-shaped] from the decoder. This does not mean that you can decode something at a higher resolution and get better results than what originally went into the encoder, however. GIGO - Garbage In, Garbage Out; if you rip a CD [16 bit audio] and then decode it as 20-bit, all you're doing is getting a more accurate decoding of the compressed format it's in. You can NOT get something better than the original. It's LOSSY, remember? In the end, I personally consider this a huge non-issue; since 95% of source material out there now is quantised to 16-bits, the differences that higher-resolution playback equipment can make are negligible at best. It would be better to concern ourselves with proper dither &c. Quote Link to comment Share on other sites More sharing options...
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