demux.c

alac decoder,内容详细

/*
 * ALAC (Apple Lossless Audio Codec) decoder
 * Copyright (c) 2005 David Hammerton
 * All rights reserved.
 *
 * This is the quicktime container demuxer.
 *
 * http://crazney.net/programs/itunes/alac.html
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 */


#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

#include "stream.h"
#include "demux.h"

typedef struct
{
    stream_t *stream;
    demux_res_t *res;
    long saved_mdat_pos;
} qtmovie_t;


/* chunk handlers */
static void read_chunk_ftyp(qtmovie_t *qtmovie, size_t chunk_len)
{
    fourcc_t type;
    uint32_t minor_ver;
    size_t size_remaining = chunk_len - 8; /* FIXME: can't hardcode 8, size may be 64bit */

    type = stream_read_uint32(qtmovie->stream);
    size_remaining-=4;
    if (type != MAKEFOURCC('M','4','A',' '))
    {
        fprintf(stderr, "not M4A file\n");
        return;
    }
    minor_ver = stream_read_uint32(qtmovie->stream);
    size_remaining-=4;

    /* compatible brands */
    while (size_remaining)
    {
        /* unused */
        /*fourcc_t cbrand =*/ stream_read_uint32(qtmovie->stream);
        size_remaining-=4;
    }
}

static void read_chunk_tkhd(qtmovie_t *qtmovie, size_t chunk_len)
{
    /* don't need anything from here atm, skip */
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    stream_skip(qtmovie->stream, size_remaining);
}

static void read_chunk_mdhd(qtmovie_t *qtmovie, size_t chunk_len)
{
    /* don't need anything from here atm, skip */
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    stream_skip(qtmovie->stream, size_remaining);
}

static void read_chunk_edts(qtmovie_t *qtmovie, size_t chunk_len)
{
    /* don't need anything from here atm, skip */
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    stream_skip(qtmovie->stream, size_remaining);
}

static void read_chunk_elst(qtmovie_t *qtmovie, size_t chunk_len)
{
    /* don't need anything from here atm, skip */
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    stream_skip(qtmovie->stream, size_remaining);
}

/* media handler inside mdia */
static void read_chunk_hdlr(qtmovie_t *qtmovie, size_t chunk_len)
{
    fourcc_t comptype, compsubtype;
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    int strlen;
    char str[256] = {0};

    /* version */
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 1;
    /* flags */
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 3;

    /* component type */
    comptype = stream_read_uint32(qtmovie->stream);
    compsubtype = stream_read_uint32(qtmovie->stream);
    size_remaining -= 8;

    /* component manufacturer */
    stream_read_uint32(qtmovie->stream);
    size_remaining -= 4;

    /* flags */
    stream_read_uint32(qtmovie->stream);
    stream_read_uint32(qtmovie->stream);
    size_remaining -= 8;

    /* name */
    strlen = stream_read_uint8(qtmovie->stream);
    stream_read(qtmovie->stream, strlen, str);
    size_remaining -= 1 + strlen;

    if (size_remaining)
    {
        stream_skip(qtmovie->stream, size_remaining);
    }

}

static int read_chunk_stsd(qtmovie_t *qtmovie, size_t chunk_len)
{
    unsigned int i;
    uint32_t numentries;
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    /* version */
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 1;
    /* flags */
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 3;

    numentries = stream_read_uint32(qtmovie->stream);
    size_remaining -= 4;

    if (numentries != 1)
    {
        fprintf(stderr, "only expecting one entry in sample description atom!\n");
        return 0;
    }

    for (i = 0; i < numentries; i++)
    {
        uint32_t entry_size;
        uint16_t version;

        uint32_t entry_remaining;

        entry_size = stream_read_uint32(qtmovie->stream);
        qtmovie->res->format = stream_read_uint32(qtmovie->stream);
        entry_remaining = entry_size;
        entry_remaining -= 8;

        /* sound info: */

        stream_skip(qtmovie->stream, 6); /* reserved */
        entry_remaining -= 6;

        version = stream_read_uint16(qtmovie->stream);
        if (version != 1)
            fprintf(stderr, "unknown version??\n");
        entry_remaining -= 2;

        /* revision level */
        stream_read_uint16(qtmovie->stream);
        /* vendor */
        stream_read_uint32(qtmovie->stream);
        entry_remaining -= 6;

        /* EH?? spec doesn't say theres an extra 16 bits here.. but there is! */
        stream_read_uint16(qtmovie->stream);
        entry_remaining -= 2;

        qtmovie->res->num_channels = stream_read_uint16(qtmovie->stream);

        qtmovie->res->sample_size = stream_read_uint16(qtmovie->stream);
        entry_remaining -= 4;

        /* compression id */
        stream_read_uint16(qtmovie->stream);
        /* packet size */
        stream_read_uint16(qtmovie->stream);
        entry_remaining -= 4;

        /* sample rate - 32bit fixed point = 16bit?? */
        qtmovie->res->sample_rate = stream_read_uint16(qtmovie->stream);
        entry_remaining -= 2;

        /* skip 2 */
        stream_skip(qtmovie->stream, 2);
        entry_remaining -= 2;

        /* remaining is codec data */

#if 0
        qtmovie->res->codecdata_len = stream_read_uint32(qtmovie->stream);
        if (qtmovie->res->codecdata_len != entry_remaining)
            fprintf(stderr, "perhaps not? %i vs %i\n",
                    qtmovie->res->codecdata_len, entry_remaining);
        entry_remaining -= 4;
        stream_read_uint32(qtmovie->stream); /* 'alac' */
        entry_remaining -= 4;

        qtmovie->res->codecdata = malloc(qtmovie->res->codecdata_len - 8);

        stream_read(qtmovie->stream,
                entry_remaining,
                qtmovie->res->codecdata);
        entry_remaining = 0;

#else
        /* 12 = audio format atom, 8 = padding */
        qtmovie->res->codecdata_len = entry_remaining + 12 + 8;
        qtmovie->res->codecdata = malloc(qtmovie->res->codecdata_len);
        memset(qtmovie->res->codecdata, 0, qtmovie->res->codecdata_len);
        /* audio format atom */
        ((unsigned int*)qtmovie->res->codecdata)[0] = 0x0c000000;
        ((unsigned int*)qtmovie->res->codecdata)[1] = MAKEFOURCC('a','m','r','f');
        ((unsigned int*)qtmovie->res->codecdata)[2] = MAKEFOURCC('c','a','l','a');

        stream_read(qtmovie->stream,
                entry_remaining,
                ((char*)qtmovie->res->codecdata) + 12);
        entry_remaining -= entry_remaining;

#endif
        if (entry_remaining)
            stream_skip(qtmovie->stream, entry_remaining);

        qtmovie->res->format_read = 1;
        if (qtmovie->res->format != MAKEFOURCC('a','l','a','c'))
        {
            /*fprintf(stderr, "expecting 'alac' data format, got %c%c%c%c\n",
                    SPLITFOURCC(qtmovie->res->format));*/
            return 0;
        }
    }

    return 1;
}

static void read_chunk_stts(qtmovie_t *qtmovie, size_t chunk_len)
{
    unsigned int i;
    uint32_t numentries;
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    /* version */
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 1;
    /* flags */
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 3;

    numentries = stream_read_uint32(qtmovie->stream);
    size_remaining -= 4;

    qtmovie->res->num_time_to_samples = numentries;
    qtmovie->res->time_to_sample = malloc(numentries * sizeof(*qtmovie->res->time_to_sample));

    for (i = 0; i < numentries; i++)
    {
        qtmovie->res->time_to_sample[i].sample_count = stream_read_uint32(qtmovie->stream);
        qtmovie->res->time_to_sample[i].sample_duration = stream_read_uint32(qtmovie->stream);
        size_remaining -= 8;
    }

    if (size_remaining)
    {
        fprintf(stderr, "ehm, size remianing?\n");
        stream_skip(qtmovie->stream, size_remaining);
    }
}

static void read_chunk_stsz(qtmovie_t *qtmovie, size_t chunk_len)
{
    unsigned int i;
    uint32_t numentries;
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    /* version */
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 1;
    /* flags */
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    stream_read_uint8(qtmovie->stream);
    size_remaining -= 3;

    /* default sample size */
    if (stream_read_uint32(qtmovie->stream) != 0)
    {
        fprintf(stderr, "i was expecting variable samples sizes\n");
        stream_read_uint32(qtmovie->stream);
        size_remaining -= 4;
        return;
    }
    size_remaining -= 4;

    numentries = stream_read_uint32(qtmovie->stream);
    size_remaining -= 4;

    qtmovie->res->num_sample_byte_sizes = numentries;
    qtmovie->res->sample_byte_size = malloc(numentries * sizeof(*qtmovie->res->sample_byte_size));

    for (i = 0; i < numentries; i++)
    {
        qtmovie->res->sample_byte_size[i] = stream_read_uint32(qtmovie->stream);
        size_remaining -= 4;
    }

    if (size_remaining)
    {
        fprintf(stderr, "ehm, size remianing?\n");
        stream_skip(qtmovie->stream, size_remaining);
    }
}

static int read_chunk_stbl(qtmovie_t *qtmovie, size_t chunk_len)
{
    size_t size_remaining = chunk_len - 8; /* FIXME WRONG */

    while (size_remaining)
    {
        size_t sub_chunk_len;
        fourcc_t sub_chunk_id;

        sub_chunk_len = stream_read_uint32(qtmovie->stream);
        if (sub_chunk_len <= 1 || sub_chunk_len > size_remaining)