Пример #1
0
/*----------------------------------------------------------------------
|   AP4_StsdAtom::AP4_StsdAtom
+---------------------------------------------------------------------*/
AP4_StsdAtom::AP4_StsdAtom(AP4_UI32         size,
                           AP4_UI08         version,
                           AP4_UI32         flags,
                           AP4_ByteStream&  stream,
                           AP4_AtomFactory& atom_factory) :
    AP4_ContainerAtom(AP4_ATOM_TYPE_STSD, size, false, version, flags)
{
    // read the number of entries
    AP4_UI32 entry_count;
    stream.ReadUI32(entry_count);

    // save and switch the factory's context
    atom_factory.PushContext(m_Type);

    // read all entries
    AP4_LargeSize bytes_available = size-AP4_FULL_ATOM_HEADER_SIZE-4;
    for (unsigned int i=0; i<entry_count; i++) {
        AP4_Atom* atom;
        if (AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(stream, 
                                                            bytes_available,
                                                            atom))) {
            atom->SetParent(this);
            m_Children.Add(atom);
        }
    }

    // restore the saved context
    atom_factory.PopContext();

    // initialize the sample description cache
    m_SampleDescriptions.EnsureCapacity(m_Children.ItemCount());
    for (AP4_Ordinal i=0; i<m_Children.ItemCount(); i++) {
        m_SampleDescriptions.Append(NULL);
    }
}
Пример #2
0
/*----------------------------------------------------------------------
|   AP4_MarlinIpmpParser:Parse
+---------------------------------------------------------------------*/
AP4_Result 
AP4_MarlinIpmpParser::Parse(AP4_AtomParent&      top_level, 
                            AP4_ByteStream&      stream,
                            AP4_List<SinfEntry>& sinf_entries,
                            bool                 remove_od_data)
{
    // check the file type
    AP4_FtypAtom* ftyp = AP4_DYNAMIC_CAST(AP4_FtypAtom, top_level.GetChild(AP4_ATOM_TYPE_FTYP));
    if (ftyp == NULL ||
        (ftyp->GetMajorBrand() != AP4_MARLIN_BRAND_MGSV && !ftyp->HasCompatibleBrand(AP4_MARLIN_BRAND_MGSV))) {
        return AP4_ERROR_INVALID_FORMAT;
    }
    
    // check the initial object descriptor and get the OD Track ID
    AP4_IodsAtom* iods = AP4_DYNAMIC_CAST(AP4_IodsAtom, top_level.FindChild("moov/iods"));
    AP4_UI32      od_track_id = 0;
    if (iods == NULL) return AP4_ERROR_INVALID_FORMAT;
    const AP4_ObjectDescriptor* od = iods->GetObjectDescriptor();
    if (od == NULL) return AP4_ERROR_INVALID_FORMAT;
    AP4_EsIdIncDescriptor* es_id_inc = AP4_DYNAMIC_CAST(AP4_EsIdIncDescriptor, od->FindSubDescriptor(AP4_DESCRIPTOR_TAG_ES_ID_INC));
    if (es_id_inc == NULL) return AP4_ERROR_INVALID_FORMAT;
    od_track_id = es_id_inc->GetTrackId();
    
    // find the track pointed to by the descriptor
    AP4_MoovAtom* moov = AP4_DYNAMIC_CAST(AP4_MoovAtom, top_level.GetChild(AP4_ATOM_TYPE_MOOV));
    if (moov == NULL) return AP4_ERROR_INVALID_FORMAT;
    AP4_TrakAtom* od_trak = NULL;
    AP4_List<AP4_TrakAtom>::Item* trak_item = moov->GetTrakAtoms().FirstItem();
    while (trak_item) {
        AP4_TrakAtom* trak = trak_item->GetData();
        if (trak) {
            if (trak->GetId() == od_track_id) {
                od_trak = trak;
            } else {
                sinf_entries.Add(new SinfEntry(trak->GetId(), NULL));
            }
        }
        trak_item = trak_item->GetNext();
    }

    // check that we have found the OD track 
    if (od_trak == NULL) return AP4_ERROR_INVALID_FORMAT;

    // look for the 'mpod' trak references
    AP4_TrefTypeAtom* track_references;
    track_references = AP4_DYNAMIC_CAST(AP4_TrefTypeAtom, od_trak->FindChild("tref/mpod"));
    if (track_references == NULL) return AP4_ERROR_INVALID_FORMAT;

    // create an AP4_Track object from the trak atom and check that it has samples
    AP4_Track* od_track = new AP4_Track(*od_trak, stream, 0);
    if (od_track->GetSampleCount() < 1) {
        delete od_track;
        return AP4_ERROR_INVALID_FORMAT;
    }
    
    // get the first sample (in this version, we only look at a single OD command)
    AP4_Sample od_sample;
    AP4_Result result = od_track->GetSample(0, od_sample);
    if (AP4_FAILED(result)) {
        delete od_track;
        return AP4_ERROR_INVALID_FORMAT;
    }
    
    // adapt the sample data into a byte stream for parsing
    AP4_DataBuffer sample_data;
    od_sample.ReadData(sample_data);
    AP4_MemoryByteStream* sample_stream = new AP4_MemoryByteStream(sample_data);
    
    // look for one ObjectDescriptorUpdate command and 
    // one IPMP_DescriptorUpdate command
    AP4_DescriptorUpdateCommand* od_update = NULL;
    AP4_DescriptorUpdateCommand* ipmp_update = NULL;
    do {
        AP4_Command* command = NULL;
        result = AP4_CommandFactory::CreateCommandFromStream(*sample_stream, command);
        if (AP4_SUCCEEDED(result)) {
            // found a command in the sample, check the type
            switch (command->GetTag()) {
              case AP4_COMMAND_TAG_OBJECT_DESCRIPTOR_UPDATE:
                if (od_update == NULL) {
                    od_update = AP4_DYNAMIC_CAST(AP4_DescriptorUpdateCommand, command);
                }
                break;
                
              case AP4_COMMAND_TAG_IPMP_DESCRIPTOR_UPDATE:
                if (ipmp_update == NULL) {
                    ipmp_update = AP4_DYNAMIC_CAST(AP4_DescriptorUpdateCommand, command);
                }
                break;

              default:
                break;
            }
        }
    } while (AP4_SUCCEEDED(result));
    sample_stream->Release();
    sample_stream = NULL;
    
    // check that we have what we need
    if (od_update == NULL || ipmp_update == NULL) {
        delete od_track;
        return AP4_ERROR_INVALID_FORMAT;
    }
        
    // process all the object descriptors in the od update
    for (AP4_List<AP4_Descriptor>::Item* od_item = od_update->GetDescriptors().FirstItem();
         od_item;
         od_item = od_item->GetNext()) {
        od = AP4_DYNAMIC_CAST(AP4_ObjectDescriptor, od_item->GetData());
        if (od == NULL) continue;

        // find which track this od references
        AP4_EsIdRefDescriptor* es_id_ref;
        es_id_ref = AP4_DYNAMIC_CAST(AP4_EsIdRefDescriptor, od->FindSubDescriptor(AP4_DESCRIPTOR_TAG_ES_ID_REF));
        if (es_id_ref == NULL || 
            es_id_ref->GetRefIndex() > track_references->GetTrackIds().ItemCount() ||
            es_id_ref->GetRefIndex() == 0) {
            continue;
        }
        AP4_UI32 track_id = track_references->GetTrackIds()[es_id_ref->GetRefIndex()-1];
        SinfEntry* sinf_entry = NULL;
        for (AP4_List<SinfEntry>::Item* sinf_entry_item = sinf_entries.FirstItem();
             sinf_entry_item;
             sinf_entry_item = sinf_entry_item->GetNext()) {
            sinf_entry = sinf_entry_item->GetData();
            if (sinf_entry->m_TrackId == track_id) {
                break; // match
            } else {
                sinf_entry = NULL; // no match
            }
        }
        if (sinf_entry == NULL) continue; // no matching entry
        if (sinf_entry->m_Sinf != NULL) continue; // entry already populated
        
        // see what ipmp descriptor this od points to
        AP4_IpmpDescriptorPointer* ipmpd_pointer;
        ipmpd_pointer = AP4_DYNAMIC_CAST(AP4_IpmpDescriptorPointer, od->FindSubDescriptor(AP4_DESCRIPTOR_TAG_IPMP_DESCRIPTOR_POINTER));
        if (ipmpd_pointer == NULL) continue; // no pointer

        // find the ipmp descriptor referenced by the pointer
        AP4_IpmpDescriptor* ipmpd = NULL;
        for (AP4_List<AP4_Descriptor>::Item* ipmpd_item = ipmp_update->GetDescriptors().FirstItem();
             ipmpd_item;
             ipmpd_item = ipmpd_item->GetNext()) {
            // check that this descriptor is of the right type
            ipmpd = AP4_DYNAMIC_CAST(AP4_IpmpDescriptor, ipmpd_item->GetData());
            if (ipmpd == NULL || ipmpd->GetIpmpsType() != AP4_MARLIN_IPMPS_TYPE_MGSV) continue;
            
            // check the descriptor id
            if (ipmpd->GetDescriptorId() == ipmpd_pointer->GetDescriptorId()) {
                break; // match
            } else {
                ipmpd = NULL; // no match
            }
        }
        if (ipmpd == NULL) continue; // no matching entry
        
        // parse the ipmp data into one or more 'sinf' atoms, and keep the one with the
        // right type
        AP4_MemoryByteStream* data = new AP4_MemoryByteStream(ipmpd->GetData().GetData(),
                                                              ipmpd->GetData().GetDataSize());
        AP4_LargeSize bytes_available = ipmpd->GetData().GetDataSize();
        do {
            AP4_Atom* atom = NULL;
            
            // setup the factory with a context so we can instantiate an 'schm'
            // atom with a slightly different format than the standard 'schm'
            AP4_AtomFactory* factory = &AP4_MarlinIpmpAtomFactory::Instance;
            factory->PushContext(AP4_ATOM_TYPE('m','r','l','n'));
            
            // parse the next atom in the stream 
            result = factory->CreateAtomFromStream(*data, bytes_available, atom);
            factory->PopContext();
            if (AP4_FAILED(result) || atom == NULL) break;
            
            // check that what we have parsed is indeed an 'sinf' of the right type
            if (atom->GetType() == AP4_ATOM_TYPE_SINF) {
                AP4_ContainerAtom* sinf = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
                AP4_SchmAtom* schm = AP4_DYNAMIC_CAST(AP4_SchmAtom, sinf->FindChild("schm"));
                if (schm->GetSchemeType()    == AP4_PROTECTION_SCHEME_TYPE_MARLIN_ACBC && 
                    schm->GetSchemeVersion() == 0x0100) {
                    // store the sinf in the entry for that track
                    sinf_entry->m_Sinf = sinf;
                    break;
                }
            }
            delete atom;
        } while (AP4_SUCCEEDED(result));
        data->Release();        
    }
    
    // remove the iods atom and the OD track if required
    if (remove_od_data) {
        od_trak->Detach();
        delete od_trak;
        iods->Detach();
        delete iods;
    }
    
    // cleanup
    delete od_track;
    
    return AP4_SUCCESS;
}