mp4meta.cpp

AAC编解码源码

/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is MPEG4IP.
 *
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2001.  All Rights Reserved.
 *
 * Contributor(s):
 *      M. Bakker     mbakker at nero.com
 *
 * Apple iTunes Metadata handling
 */

/**

 The iTunes tagging seems to support any tag field name
 but there are some predefined fields, also known from the QuickTime format

 predefined fields (the ones I know of until now):
 - ﹏am : Name of the song/movie (string)
 - 〢RT : Name of the artist/performer (string)
 - ﹚rt : Name of the writer (string)
 - ゛lb : Name of the album (string)
 - ヾay : Year (4 bytes, e.g. "2003") (string)
 - ﹖oo : Tool(s) used to create the file (string)
 - ヽmt : Comment (string)
 - ゞen : Custom genre (string)
 - trkn : Tracknumber (8 byte string)
           16 bit: empty
           16 bit: tracknumber
           16 bit: total tracks on album
           16 bit: empty
 - disk : Disknumber (8 byte string)
           16 bit: empty
           16 bit: disknumber
           16 bit: total number of disks
           16 bit: empty
 - gnre : Genre (16 bit genre) (ID3v1 index + 1)
 - cpil : Part of a compilation (1 byte, 1 or 0)
 - tmpo : Tempo in BPM (16 bit)
 - covr : Cover art (xx bytes binary data)
 - ---- : Free form metadata, can have any name and any data

**/

#include "mp4common.h"

bool MP4File::GetMetadataByIndex(u_int32_t index,
                                 const char** ppName,
                                 u_int8_t** ppValue, u_int32_t* pValueSize)
{
    char s[256];

    sprintf(s, "moov.udta.meta.ilst.*[%u].data.metadata", index);
    GetBytesProperty(s, ppValue, pValueSize);

    sprintf(s, "moov.udta.meta.ilst.*[%u]", index);
    MP4Atom* pParent = m_pRootAtom->FindAtom(s);
    *ppName = pParent->GetType();

    /* check for free form tagfield */
    if (memcmp(*ppName, "----", 4) == 0)
    {
        u_int8_t* pV;
        u_int32_t VSize = 0;
        char *pN;

        sprintf(s, "moov.udta.meta.ilst.*[%u].name.metadata", index);
        GetBytesProperty(s, &pV, &VSize);

        pN = (char*)malloc((VSize+1)*sizeof(char));
        memset(pN, 0, (VSize+1)*sizeof(char));
        memcpy(pN, pV, VSize*sizeof(char));

        *ppName = pN;
    }

    return true;
}

bool MP4File::CreateMetadataAtom(const char* name)
{
    char s[256];
    char t[256];

    sprintf(t, "udta.meta.ilst.%s.data", name);
    sprintf(s, "moov.udta.meta.ilst.%s.data", name);
    AddDescendantAtoms("moov", t);
    MP4Atom *pMetaAtom = m_pRootAtom->FindAtom(s);

    if (!pMetaAtom)
        return false;

    /* some fields need special flags set */
    if (name[0] == '