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Topic: Psychoacoustic Model in AAC LD (Read 1746 times) previous topic - next topic

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  • wutonglu
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Psychoacoustic Model in AAC LD
Hi, everyone

I have been researching AAC LD and try to build up the codec. But now I knock up against some difficulties, pls help.

The MPEG docs show the psychoacoustic parameters tables in AAC LC, including the w_low, w_high, bval and qsthr that used for bark value and listening threshold calculation.
like this

{ /* w_low */
      0, 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 109, 119, 129, 139, 149,
      160, 171, 182, 193, 205, 217, 229, 242, 255, 269, 283, 298, 313, 329,
      346, 364, 382, 401, 421, 442, 465, 489, 515, 542, 571, 602, 635, 671,
      709, 750, 794, 842, 894, 950, 1010
    },
    { /* w_high */
      8, 17, 26, 35, 44, 53, 62, 71, 80, 89, 98, 108, 118, 128, 138, 148,
      159, 170, 181, 192, 204, 216, 228, 241, 254, 268, 282, 297, 312, 328,
      345, 363, 381, 400, 420, 441, 464, 488, 514, 541, 570, 601, 634, 670,
      708, 749, 793, 841, 893, 949, 1009, 1023
    },
    { /* width */
      9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11,
      12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 17, 18, 18, 19, 20, 21, 23, 24,
      26, 27, 29, 31, 33, 36, 38, 41, 44, 48, 52, 56, 60, 14
    },
    { /* bval */
      0.18, 0.53, 0.89, 1.24, 1.59, 1.94, 2.29, 2.63, 2.98, 3.31, 3.65, 3.99,
      4.35, 4.71, 5.05, 5.39, 5.74, 6.10, 6.45, 6.79, 7.13, 7.48, 7.82, 8.17,
      8.51, 8.85, 9.20, 9.54, 9.88, 10.22, 10.56, 10.91, 11.25, 11.58, 11.91,
      12.24, 12.58, 12.92, 13.26, 13.59, 13.93, 14.26, 14.60, 14.93, 15.27,
      15.60, 15.93, 16.26, 16.60, 16.93, 17.26, 17.47
    },
    { /* qsthr */
      46.82, 46.82, 46.82, 41.82, 41.82, 41.82, 38.82, 38.82, 38.82, 33.82,
      33.82, 34.28, 32.28, 32.28, 32.28, 32.28, 32.69, 32.69, 32.69, 32.69,
      33.07, 33.07, 33.07, 33.42, 33.42, 33.74, 33.74, 34.04, 34.04, 34.32,
      34.58, 34.83, 34.83, 35.06, 35.29, 35.50, 35.89, 36.08, 36.43, 36.59,
      36.90, 37.19, 37.46, 37.84, 38.07, 38.40, 38.71, 39.09, 39.44, 39.76,
      40.06, 33.74
    }

So what about the AAC LD for the frame length 512, is there any partition table?