atom_rtp.cpp

/*
 * 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):
 *      Dave Mackie     dmackie@cisco.com
 */

#include "src/impl.h"

namespace mp4v2 {
namespace impl {

///////////////////////////////////////////////////////////////////////////////

MP4RtpAtom::MP4RtpAtom(MP4File &file)
        : MP4Atom(file, "rtp ")
{
    // The atom type "rtp " is used in two complete unrelated ways
    // i.e. it's real two atoms with the same name
    // To handle that we need to postpone property creation until
    // we know who our parent atom is (stsd or hnti) which gives us
    // the context info we need to know who we are
}

void MP4RtpAtom::AddPropertiesStsdType()
{
    AddReserved(*this, "reserved1", 6); /* 0 */

    AddProperty( /* 1 */
        new MP4Integer16Property(*this, "dataReferenceIndex"));

    AddProperty( /* 2 */
        new MP4Integer16Property(*this, "hintTrackVersion"));
    AddProperty( /* 3 */
        new MP4Integer16Property(*this, "highestCompatibleVersion"));
    AddProperty( /* 4 */
        new MP4Integer32Property(*this, "maxPacketSize"));

    ExpectChildAtom("tims", Required, OnlyOne);
    ExpectChildAtom("tsro", Optional, OnlyOne);
    ExpectChildAtom("snro", Optional, OnlyOne);
}

void MP4RtpAtom::AddPropertiesHntiType()
{
    MP4StringProperty* pProp =
        new MP4StringProperty(*this, "descriptionFormat");
    pProp->SetFixedLength(4);
    AddProperty(pProp); /* 0 */

    AddProperty( /* 1 */
        new MP4StringProperty(*this, "sdpText"));
}

void MP4RtpAtom::Generate()
{
    ASSERT(m_pParentAtom);
    if (!strcmp(m_pParentAtom->GetType(), "stsd")) {
        AddPropertiesStsdType();
        GenerateStsdType();
    } else if (!strcmp(m_pParentAtom->GetType(), "hnti")) {
        AddPropertiesHntiType();
        GenerateHntiType();
    } else {
        log.warningf("%s: \"%s\": rtp atom in unexpected context, can not generate",
                     __FUNCTION__, GetFile().GetFilename().c_str() );
    }
}

void MP4RtpAtom::GenerateStsdType()
{
    // generate children
    MP4Atom::Generate();

    ((MP4Integer16Property*)m_pProperties[1])->SetValue(1);
    ((MP4Integer16Property*)m_pProperties[2])->SetValue(1);
    ((MP4Integer16Property*)m_pProperties[3])->SetValue(1);
}

void MP4RtpAtom::GenerateHntiType()
{
    MP4Atom::Generate();

    ((MP4StringProperty*)m_pProperties[0])->SetValue("sdp ");
}

void MP4RtpAtom::Read()
{
    ASSERT(m_pParentAtom);
    if (!strcmp(m_pParentAtom->GetType(), "stsd")) {
        AddPropertiesStsdType();
        ReadStsdType();
    } else if (!strcmp(m_pParentAtom->GetType(), "hnti")) {
        AddPropertiesHntiType();
        ReadHntiType();
    } else {
        log.verbose1f("rtp atom in unexpected context, can not read");
    }

    Skip(); // to end of atom
}

void MP4RtpAtom::ReadStsdType()
{
    MP4Atom::Read();
}

void MP4RtpAtom::ReadHntiType()
{
    ReadProperties(0, 1);

    // read sdp string, length is implicit in size of atom
    uint64_t size = GetEnd() - m_File.GetPosition();
    char* data = (char*)MP4Malloc(size + 1);
    ASSERT(data != NULL);
    m_File.ReadBytes((uint8_t*)data, size);
    data[size] = '\0';
    ((MP4StringProperty*)m_pProperties[1])->SetValue(data);
    MP4Free(data);
}

void MP4RtpAtom::Write()
{
    if (!strcmp(m_pParentAtom->GetType(), "hnti")) {
        WriteHntiType();
    } else {
        MP4Atom::Write();
    }
}

void MP4RtpAtom::WriteHntiType()
{
    // since length of string is implicit in size of atom
    // we need to handle this specially, and not write the terminating \0
    MP4StringProperty* pSdp = (MP4StringProperty*)m_pProperties[1];
    pSdp->SetFixedLength((uint32_t)strlen(pSdp->GetValue()));
    MP4Atom::Write();
    pSdp->SetFixedLength(0);
}

///////////////////////////////////////////////////////////////////////////////

}
} // namespace mp4v2::impl