Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Psychoacoustic Model in AAC LD (Read 2873 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

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?