Apollo
Apollo is an MP3 player for audiophiles
Apollo 37 only decodes MP3 and WAV files. But it does it extremely well so that Apollo is almost certainly the best existing MP3 player - thought to provide the best possible decoding quality for audiophiles. It features extremely optimized MP3-decoding routines. Because of its high quality, many radio stations use this freely available program as well as owners of high-end HiFi equipment. The playback with such a program requires high quality MP3-files. The author of Apollo recommends the use of the lame encoder for the creation of suitable MP3-files with the "-V 0 --vbr-new" switches set.
Why does Apollo sound so good?
The sound quality has always been an important factor when making decisions in the Apollo decoder code. Recent addition of 32-bit and 24-bit output has resulted in further improvements in the quality. To prove this, the difference of Apollo 37 24-bit output to the MPEG-1 audio layer 3 (MP3)compliance test reference signal (ISO/IEC 11172-4) has been measured. The results for Apollo 37zm 24-bit output are RMS level 7.169×10−10 and maximum difference 1.192×10−7.
For comparison, the same values for the latest MAD decoder (MPEG Audio Decoder 0.15.1b) built with accuracy optimizations enabled and 24-bit output without dithering are RMS level 8.804×10−8 and maximum difference 4.768×10−7. The difference is quite obvious and favorable to Apollo: RMS level is over a hundred times the one produced by Apollo 37 and the maximum difference is four times the one by Apollo (interestingly the results for MAD 0.11.4b seem to be somewhat better than for the latest one but they are still worse than Apollo's). Actually, the maximum difference of Apollo's output is the smallest possible deviation in 24-bit data, the only smaller possible value would be zero. This means that at any time, Apollo's output is either exactly the same as the reference output or differs from it by the smallest unit expressible in 24-bit data. Of course, this only goes for the provided test signal, but it should give some picture about the sound quality.
