output.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003 M. Bakker, Ahead Software AG, http://www.nero.com
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through [e-mail].
**
** $Id: output.c,v 1.42 2004/09/04 14:56:28 menno Exp $
**/

#include "common.h"
#include "structs.h"

#include "output.h"
#include "decoder.h"

#ifndef FIXED_POINT


#define FLOAT_SCALE (1.0f/(1<<15))

#define DM_MUL REAL_CONST(0.3203772410170407) // 1/(1+sqrt(2) + 1/sqrt(2))
#define RSQRT2 REAL_CONST(0.7071067811865475244) // 1/sqrt(2)


static INLINE real_t get_sample(real_t **input, uint8_t channel, uint16_t sample,
                                uint8_t down_matrix, uint8_t *internal_channel)
{
    if (!down_matrix)
        return input[internal_channel[channel]][sample];

    if (channel == 0)
    {
        return DM_MUL * (input[internal_channel[1]][sample] +
            input[internal_channel[0]][sample] * RSQRT2 +
            input[internal_channel[3]][sample] * RSQRT2);
    } else {
        return DM_MUL * (input[internal_channel[2]][sample] +
            input[internal_channel[0]][sample] * RSQRT2 +
            input[internal_channel[4]][sample] * RSQRT2);
    }
}

#ifndef HAS_LRINTF
#define CLIP(sample, max, min) \
if (sample >= 0.0f)            \
{                              \
    sample += 0.5f;            \
    if (sample >= max)         \
        sample = max;          \
} else {                       \
    sample += -0.5f;           \
    if (sample <= min)         \
        sample = min;          \
}
#else
#define CLIP(sample, max, min) \
if (sample >= 0.0f)            \
{                              \
    if (sample >= max)         \
        sample = max;          \
} else {                       \
    if (sample <= min)         \
        sample = min;          \
}
#endif

#define CONV(a,b) ((a<<1)|(b&0x1))

static void to_PCM_16bit(NeAACDecHandle hDecoder, real_t **input,
                         uint8_t channels, uint16_t frame_len,
                         int16_t **sample_buffer)
{
    uint8_t ch, ch1;
    uint16_t i;

    switch (CONV(channels,hDecoder->downMatrix))
    {
    case CONV(1,0):
    case CONV(1,1):
        for(i = 0; i < frame_len; i++)
        {
            real_t inp = input[hDecoder->internal_channel[0]][i];

            CLIP(inp, 32767.0f, -32768.0f);

            (*sample_buffer)[i] = (int16_t)lrintf(inp);
        }
        break;
    case CONV(2,0):
        if (hDecoder->upMatrix)
        {
            ch  = hDecoder->internal_channel[0];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch][i];

                CLIP(inp0, 32767.0f, -32768.0f);

                (*sample_buffer)[(i*2)+0] = (int16_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int16_t)lrintf(inp0);
            }
        } else {
            ch  = hDecoder->internal_channel[0];
            ch1 = hDecoder->internal_channel[1];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch ][i];
                real_t inp1 = input[ch1][i];

                CLIP(inp0, 32767.0f, -32768.0f);
                CLIP(inp1, 32767.0f, -32768.0f);

                (*sample_buffer)[(i*2)+0] = (int16_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int16_t)lrintf(inp1);
            }
        }
        break;
    default:
        for (ch = 0; ch < channels; ch++)
        {
            for(i = 0; i < frame_len; i++)
            {
                real_t inp = get_sample(input, ch, i, hDecoder->downMatrix, hDecoder->internal_channel);

                CLIP(inp, 32767.0f, -32768.0f);

                (*sample_buffer)[(i*channels)+ch] = (int16_t)lrintf(inp);
            }
        }
        break;
    }
}

static void to_PCM_24bit(NeAACDecHandle hDecoder, real_t **input,
                         uint8_t channels, uint16_t frame_len,
                         int32_t **sample_buffer)
{
    uint8_t ch, ch1;
    uint16_t i;

    switch (CONV(channels,hDecoder->downMatrix))
    {
    case CONV(1,0):
    case CONV(1,1):
        for(i = 0; i < frame_len; i++)
        {
            real_t inp = input[hDecoder->internal_channel[0]][i];

            inp *= 256.0f;
            CLIP(inp, 8388607.0f, -8388608.0f);

            (*sample_buffer)[i] = (int32_t)lrintf(inp);
        }
        break;
    case CONV(2,0):
        if (hDecoder->upMatrix)
        {
            ch = hDecoder->internal_channel[0];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch][i];

                inp0 *= 256.0f;
                CLIP(inp0, 8388607.0f, -8388608.0f);

                (*sample_buffer)[(i*2)+0] = (int32_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int32_t)lrintf(inp0);
            }
        } else {
            ch  = hDecoder->internal_channel[0];
            ch1 = hDecoder->internal_channel[1];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch ][i];
                real_t inp1 = input[ch1][i];

                inp0 *= 256.0f;
                inp1 *= 256.0f;
                CLIP(inp0, 8388607.0f, -8388608.0f);
                CLIP(inp1, 8388607.0f, -8388608.0f);

                (*sample_buffer)[(i*2)+0] = (int32_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int32_t)lrintf(inp1);
            }
        }
        break;
    default:
        for (ch = 0; ch < channels; ch++)
        {
            for(i = 0; i < frame_len; i++)
            {
                real_t inp = get_sample(input, ch, i, hDecoder->downMatrix, hDecoder->internal_channel);

                inp *= 256.0f;
                CLIP(inp, 8388607.0f, -8388608.0f);

                (*sample_buffer)[(i*channels)+ch] = (int32_t)lrintf(inp);
            }
        }
        break;
    }
}

static void to_PCM_32bit(NeAACDecHandle hDecoder, real_t **input,
                         uint8_t channels, uint16_t frame_len,
                         int32_t **sample_buffer)
{
    uint8_t ch, ch1;
    uint16_t i;

    switch (CONV(channels,hDecoder->downMatrix))
    {
    case CONV(1,0):
    case CONV(1,1):
        for(i = 0; i < frame_len; i++)
        {
            real_t inp = input[hDecoder->internal_channel[0]][i];

            inp *= 65536.0f;
            CLIP(inp, 2147483647.0f, -2147483648.0f);

            (*sample_buffer)[i] = (int32_t)lrintf(inp);
        }
        break;
    case CONV(2,0):
        if (hDecoder->upMatrix)
        {
            ch = hDecoder->internal_channel[0];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch][i];

                inp0 *= 65536.0f;
                CLIP(inp0, 2147483647.0f, -2147483648.0f);

                (*sample_buffer)[(i*2)+0] = (int32_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int32_t)lrintf(inp0);
            }
        } else {
            ch  = hDecoder->internal_channel[0];
            ch1 = hDecoder->internal_channel[1];
            for(i = 0; i < frame_len; i++)
            {
                real_t inp0 = input[ch ][i];
                real_t inp1 = input[ch1][i];

                inp0 *= 65536.0f;
                inp1 *= 65536.0f;
                CLIP(inp0, 2147483647.0f, -2147483648.0f);
                CLIP(inp1, 2147483647.0f, -2147483648.0f);

                (*sample_buffer)[(i*2)+0] = (int32_t)lrintf(inp0);
                (*sample_buffer)[(i*2)+1] = (int32_t)lrintf(inp1);
            }
        }
        break;
    default:
        for (ch = 0; ch < channels; ch++)
        {
            for(i = 0; i < frame_len; i++)
            {
                real_t inp = get_sample(input, ch, i, hDecoder->downMatrix, hDecoder->internal_channel);

                inp *= 65536.0f;
                CLIP(inp, 2147483647.0f, -2147483648.0f);

                (*sample_buffer)[(i*channels)+ch] = (int32_t)lrintf(inp);
            }
        }
        break;