/*----------------------------------------------------------------------
|   main
+---------------------------------------------------------------------*/
int
main(int argc, char** argv)
{
    if (argc != 2) {
        PrintUsageAndExit();
    }
    const char* input_filename  = argv[1];
    
    // open the input
    AP4_ByteStream* input = NULL;
    AP4_Result result = AP4_FileByteStream::Create(input_filename, AP4_FileByteStream::STREAM_MODE_READ, input);
    if (AP4_FAILED(result)) {
        fprintf(stderr, "ERROR: cannot open input file (%s)\n", input_filename);
        return 1;
    }
        
    // get the movie
    AP4_File* file = new AP4_File(*input, AP4_DefaultAtomFactory::Instance, true);
    AP4_Movie* movie = file->GetMovie();
    
    AP4_Atom* atom = NULL;
    do {
        // process the next atom
        result = AP4_DefaultAtomFactory::Instance.CreateAtomFromStream(*input, atom);
        if (AP4_SUCCEEDED(result)) {
            printf("atom size=%lld\n", atom->GetSize());
            if (atom->GetType() == AP4_ATOM_TYPE_MOOF) {
                AP4_ContainerAtom* moof = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
                if (moof) {
                    // remember where we are in the stream
                    AP4_Position position = 0;
                    input->Tell(position);
        
                    // process the movie fragment
                    ProcessMoof(movie, moof, input, position-atom->GetSize(), position+8);

                    // go back to where we were before processing the fragment
                    input->Seek(position);
                }
            } else {
                delete atom;
            }            
        }
    } while (AP4_SUCCEEDED(result));
    
    // cleanup
    delete file;
    input->Release();

    return 0;                                            
}
Example #2
0
/*----------------------------------------------------------------------
|   AP4_LinearReader::AdvanceFragment
+---------------------------------------------------------------------*/
AP4_Result
AP4_LinearReader::AdvanceFragment()
{
    AP4_Result result;
     
    // go the the start of the next fragment
    result = m_FragmentStream->Seek(m_NextFragmentPosition);
    if (AP4_FAILED(result)) return result;

    // read atoms until we find a moof
    assert(m_HasFragments);
    if (!m_FragmentStream) return AP4_ERROR_INVALID_STATE;
    do {
        AP4_Atom* atom = NULL;
        result = AP4_DefaultAtomFactory::Instance.CreateAtomFromStream(*m_FragmentStream, atom);
        if (AP4_SUCCEEDED(result)) {
            if (atom->GetType() == AP4_ATOM_TYPE_MOOF) {
                AP4_ContainerAtom* moof = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
                if (moof) {
                    // remember where we are in the stream
                    AP4_Position position = 0;
                    m_FragmentStream->Tell(position);
        
                    // process the movie fragment
                    result = ProcessMoof(moof, position-atom->GetSize(), position+8);
                    if (AP4_FAILED(result)) return result;

                    // compute where the next fragment will be
                    AP4_UI32 size;
                    AP4_UI32 type;
                    m_FragmentStream->Tell(position);
                    result = m_FragmentStream->ReadUI32(size);
                    if (AP4_FAILED(result)) return AP4_SUCCESS; // can't read more
                    result = m_FragmentStream->ReadUI32(type);
                    if (AP4_FAILED(result)) return AP4_SUCCESS; // can't read more
                    if (size == 0) {
                        m_NextFragmentPosition = 0;
                    } else if (size == 1) {
                        AP4_UI64 size_64 = 0;
                        result = m_FragmentStream->ReadUI64(size_64);
                        if (AP4_FAILED(result)) return AP4_SUCCESS; // can't read more
                        m_NextFragmentPosition = position+size_64;
                    } else {
                        m_NextFragmentPosition = position+size;
                    }
                    return AP4_SUCCESS;
                } else {
                    delete atom;
                }
            } else {
                delete atom;
            }            
        }
    } while (AP4_SUCCEEDED(result));
        
    return AP4_ERROR_EOS;
}
Example #3
0
/*----------------------------------------------------------------------
|       AP4_StsdAtom::AP4_StsdAtom
+---------------------------------------------------------------------*/
AP4_StsdAtom::AP4_StsdAtom(AP4_SampleTable* sample_table) :
    AP4_ContainerAtom(AP4_ATOM_TYPE_STSD, 4+AP4_FULL_ATOM_HEADER_SIZE, true)
{
    AP4_Cardinal sample_description_count = sample_table->GetSampleDescriptionCount();
    m_SampleDescriptions.EnsureCapacity(sample_description_count);
    for (AP4_Ordinal i=0; i<sample_description_count; i++) {
        // clear the cache entry
        m_SampleDescriptions.Append(NULL);

        // create an entry for the description
        AP4_SampleDescription* sample_description = sample_table->GetSampleDescription(i);
        AP4_Atom* entry = sample_description->ToAtom();
        m_Children.Add(entry);

        // update the size
        m_Size += entry->GetSize();
    }
}
/*----------------------------------------------------------------------
|   AP4_Processor::MuxStream
+---------------------------------------------------------------------*/
AP4_Result
AP4_Processor::MuxStream(
	AP4_Array<AP4_ByteStream *> &input,
	AP4_ByteStream& output,
	AP4_UI08		partitions,
	AP4_AtomFactory& atom_factory)
{
	AP4_Result		result;
	AP4_UI64		stream_offset = 0;

	if (partitions & 1)
	{
		// read all atoms.
		// keep all atoms except [mdat]
		// keep a ref to [moov]
		// put [moof] atoms in a separate list
		AP4_AtomParent              top_level;
		AP4_Array<AP4_MoovAtom*>	moov;
		AP4_Size					track_count(0);

		for(AP4_Size streamid(0); streamid < input.ItemCount(); ++streamid)
		{
			for (AP4_Atom* atom = NULL; AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(*input[streamid], atom)); input[streamid]->Tell(stream_offset))
			{
				if (atom->GetType() == AP4_ATOM_TYPE_MFRA) {
					delete atom;
					continue;
				}
				else if (atom->GetType() == AP4_ATOM_TYPE_SIDX) {
					delete atom;
					continue;
				}
				else if (atom->GetType() == AP4_ATOM_TYPE_SSIX) {
					delete atom;
					continue;
				}
				if (streamid == 0)
					top_level.AddChild(atom);
				else if (atom->GetType() != AP4_ATOM_TYPE_MOOV)
					delete atom;
				if (atom->GetType() == AP4_ATOM_TYPE_MOOV)
				{
					moov.Append(AP4_DYNAMIC_CAST(AP4_MoovAtom,atom));
					break;
				}
			}
			if (moov.ItemCount() == streamid)
				return AP4_ERROR_INVALID_FORMAT;
			
			while (AP4_SUCCEEDED(moov[streamid]->DeleteChild(AP4_ATOM_TYPE_PSSH, 0)));

			// Remove tracks we cannot handle
			for (AP4_List<AP4_TrakAtom>::Item *item(moov[streamid]->GetTrakAtoms().FirstItem()); item;)
				if (!item->GetData()->FindChild("mdia/minf/stbl"))
					moov[streamid]->GetTrakAtoms().Remove(item);
				else
					item = item->GetNext();
			track_count += moov[streamid]->GetTrakAtoms().ItemCount();
		}

		// initialize the processor
		if (AP4_FAILED(result = Initialize(top_level, *input[0]))) 
			return result;

		// process the tracks if we have a moov atom
		m_TrackData.SetItemCount(track_count);
		m_StreamData.SetItemCount(input.ItemCount());
	
		//NormalizeTREX(mvex, 0, m_TrackCounts[0], m_TrackCounts[1]);
		AP4_Cardinal internal_index(0);
		AP4_ContainerAtom *mvex_base(0);
		AP4_List<AP4_TrakAtom>::Item *item = NULL;

		for (AP4_Size streamid(0); streamid < input.ItemCount(); ++streamid)
		{
			m_StreamData[streamid].trackStart = internal_index;
			m_StreamData[streamid].stream = input[streamid];
			if (streamid)
				moov[0]->AddTrakAtoms(moov[streamid]->GetTrakAtoms(), item);
			else
				item = moov[streamid]->GetTrakAtoms().FirstItem();

			for (; item; item = item->GetNext())
			{
				PERTRACK &track_data(m_TrackData[internal_index]);
				track_data.original_id = item->GetData()->GetId();
				item->GetData()->SetId(track_data.new_id = internal_index + 1);

        if (AP4_MdhdAtom* mdhd = AP4_DYNAMIC_CAST(AP4_MdhdAtom, item->GetData()->FindChild("mdia/mdhd")))
          track_data.timescale = mdhd->GetTimeScale();
        else
          track_data.timescale = 1;
        
        AP4_ContainerAtom *mvex = AP4_DYNAMIC_CAST(AP4_ContainerAtom, moov[streamid]->GetChild(AP4_ATOM_TYPE_MVEX, 0));
				if (!mvex)
					return AP4_ERROR_INVALID_FORMAT;
				
				if (!item->GetData()->GetDuration())
				{
					AP4_MehdAtom *mehd(AP4_DYNAMIC_CAST(AP4_MehdAtom, mvex->GetChild(AP4_ATOM_TYPE_MEHD, 0)));
					item->GetData()->SetDuration(mehd? mehd->GetDuration():0);
				}
				
				AP4_TrexAtom *trex(NULL);
				unsigned int index(0);
				for (; !trex && (trex = AP4_DYNAMIC_CAST(AP4_TrexAtom, mvex->GetChild(AP4_ATOM_TYPE_TREX, index++)));)
					if(trex->GetTrackId() != track_data.original_id)
						trex = NULL;
				if (!trex)
					return AP4_ERROR_INVALID_FORMAT;

				if (mvex_base)
				{
					trex = AP4_DYNAMIC_CAST(AP4_TrexAtom, trex->Clone());
					mvex_base->AddChild(trex);
				}
				else
					mvex_base = mvex;
				trex->SetTrackId(track_data.new_id);

				track_data.track_handler = CreateTrackHandler(item->GetData(), trex);
				track_data.track_handler->ProcessTrack();
				track_data.streamId = streamid;
				++m_StreamData[streamid].trackCount;
				++internal_index;
			}
		}
		// We don't need the other moovs anymore.....
		moov.SetItemCount(1);

		AP4_MvhdAtom *mvhd(AP4_DYNAMIC_CAST(AP4_MvhdAtom, moov[0]->GetChild(AP4_ATOM_TYPE_MVHD, 0)));
		if (!mvhd->GetDuration())
		{
			AP4_MehdAtom *mehd(AP4_DYNAMIC_CAST(AP4_MehdAtom, mvex_base->GetChild(AP4_ATOM_TYPE_MEHD, 0)));
			mvhd->SetDuration(mehd ? mehd->GetDuration() : 0);
		}

		// finalize the processor
		Finalize(top_level);

		// calculate the size of all atoms combined
		AP4_UI64 atoms_size = 0;
		top_level.GetChildren().Apply(AP4_AtomSizeAdder(atoms_size));

		// write all atoms
		top_level.GetChildren().Apply(AP4_AtomListWriter(output));
		m_MoovAtom = moov[0];
		m_MoovAtom->Detach();
	}

	if (partitions & 2)
	{
		// process the fragments, if any
		result = AP4_SUCCESS;
		AP4_Array<AP4_UI64> moof_positions, mdat_positions;
		moof_positions.SetItemCount(input.ItemCount());
		mdat_positions.SetItemCount(input.ItemCount());

		for (;;)
		{
			AP4_ContainerAtom *moof = NULL;
			AP4_UI32 track_index(0);
			
#if 0			
      for (AP4_Cardinal streamid(0); streamid < input.ItemCount(); ++streamid)
			{
				AP4_Atom* atom = NULL;
				if (AP4_SUCCEEDED(input[streamid]->Tell(stream_offset)) && AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(*input[streamid], atom)))
				{
					if (atom->GetType() != AP4_ATOM_TYPE_MOOF)
						return AP4_ERROR_INVALID_FORMAT;
					
					moof_positions[streamid] = stream_offset;
					mdat_positions[streamid] = stream_offset + atom->GetSize() + +AP4_ATOM_HEADER_SIZE;

					if (moof)
					{
						int index(0);
						for (; AP4_Atom* child = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom)->GetChild(AP4_ATOM_TYPE_TRAF, index++);)
							moof->AddChild(child->Clone());
						delete atom;
					}
					else
						moof = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
					NormalizeTRAF(AP4_DYNAMIC_CAST(AP4_ContainerAtom, moof), m_StreamData[streamid].trackStart,
						m_StreamData[streamid].trackStart + m_StreamData[streamid].trackCount, track_index);
				}
				else
					delete atom;
			}
#else
      double mindts(9999999999.0);
      AP4_Cardinal nextStream(~0);
      for (AP4_Cardinal track(0); track < m_TrackData.ItemCount(); ++track)
        if ((double)m_TrackData[track].dts / m_TrackData[track].timescale  < mindts)
        {
          mindts = (double)m_TrackData[track].dts / m_TrackData[track].timescale;
          nextStream = m_TrackData[track].streamId;
        }
      
      AP4_Atom* atom = NULL;
      if (AP4_SUCCEEDED(result = input[nextStream]->Tell(stream_offset)) && AP4_SUCCEEDED(result = atom_factory.CreateAtomFromStream(*input[nextStream], atom)))
      {
        if (atom->GetType() != AP4_ATOM_TYPE_MOOF)
          return AP4_ERROR_INVALID_FORMAT;
			} else if (atom)
				return result;

      moof_positions[nextStream] = stream_offset;
      mdat_positions[nextStream] = stream_offset + atom->GetSize() + +AP4_ATOM_HEADER_SIZE;

      moof = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
      NormalizeTRAF(AP4_DYNAMIC_CAST(AP4_ContainerAtom, moof), m_StreamData[nextStream].trackStart,
        m_StreamData[nextStream].trackStart + m_StreamData[nextStream].trackCount, track_index);
#endif
			if (!moof)
				break;
			
			if (AP4_FAILED(result = ProcessFragment(moof, NULL, 0, output, moof_positions, mdat_positions)))
				return result;
			
			delete moof;
			moof = NULL;
		}

		// cleanup
		m_TrackData.Clear();
		m_StreamData.Clear();
	}

	return AP4_SUCCESS;
}
/*----------------------------------------------------------------------
|   AP4_Processor::Process
+---------------------------------------------------------------------*/
AP4_Result
AP4_Processor::Process(AP4_ByteStream&   input, 
                       AP4_ByteStream&   output,
                       AP4_ByteStream*   fragments,
                       ProgressListener* listener,
                       AP4_AtomFactory&  atom_factory)
{
    // read all atoms.
    // keep all atoms except [mdat]
    // keep a ref to [moov]
    // put [moof] atoms in a separate list
    AP4_AtomParent              top_level;
    AP4_MoovAtom*               moov = NULL;
    AP4_ContainerAtom*          mfra = NULL;
    AP4_SidxAtom*               sidx = NULL;
    AP4_List<AP4_AtomLocator>   frags;
    AP4_UI64                    stream_offset = 0;
    bool                        in_fragments = false;
    unsigned int                sidx_count = 0;
    for (AP4_Atom* atom = NULL;
        AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(input, atom));
        input.Tell(stream_offset)) {
        if (atom->GetType() == AP4_ATOM_TYPE_MDAT) {
            delete atom;
            continue;
        } else if (atom->GetType() == AP4_ATOM_TYPE_MOOV) {
            moov = AP4_DYNAMIC_CAST(AP4_MoovAtom, atom);
            if (fragments) break;
        } else if (atom->GetType() == AP4_ATOM_TYPE_MFRA) {
            mfra = AP4_DYNAMIC_CAST(AP4_ContainerAtom, atom);
            continue;
        } else if (atom->GetType() == AP4_ATOM_TYPE_SIDX) {
            // don't keep the index, it is likely to be invalidated, we will recompute it later
            ++sidx_count;
            if (sidx == NULL) {
                sidx = AP4_DYNAMIC_CAST(AP4_SidxAtom, atom);
            } else {
                delete atom;
                continue;
            }
        } else if (atom->GetType() == AP4_ATOM_TYPE_SSIX) {
            // don't keep the index, it is likely to be invalidated
            delete atom;
            continue;
        } else if (!fragments && (in_fragments || atom->GetType() == AP4_ATOM_TYPE_MOOF)) {
            in_fragments = true;
            frags.Add(new AP4_AtomLocator(atom, stream_offset));
			break;
        }
        top_level.AddChild(atom);
    }

    // check that we have at most one sidx (we can't deal with multi-sidx streams here
    if (sidx_count > 1) {
        top_level.RemoveChild(sidx);
        delete sidx;
        sidx = NULL;
    }
    
    // if we have a fragments stream, get the fragment locators from there
    if (fragments) {
        stream_offset = 0;
        for (AP4_Atom* atom = NULL;
            AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(*fragments, atom));
            fragments->Tell(stream_offset)) {
            if (atom->GetType() == AP4_ATOM_TYPE_MDAT) {
                delete atom;
                continue;
            }
            frags.Add(new AP4_AtomLocator(atom, stream_offset));
        }
    }
    
    // initialize the processor
    AP4_Result result = Initialize(top_level, input);
    if (AP4_FAILED(result)) return result;

    // process the tracks if we have a moov atom
    AP4_Array<AP4_SampleLocator> locators;
    AP4_Cardinal                 track_count       = 0;
    AP4_List<AP4_TrakAtom>*      trak_atoms        = NULL;
    AP4_LargeSize                mdat_payload_size = 0;
    AP4_SampleCursor*            cursors           = NULL;
    if (moov) {
        // build an array of track sample locators
        trak_atoms = &moov->GetTrakAtoms();
        track_count = trak_atoms->ItemCount();
        cursors = new AP4_SampleCursor[track_count];
		m_TrackData.SetItemCount(track_count);
		m_StreamData.SetItemCount(1);
		m_StreamData[0].stream = &input;

		unsigned int index = 0;
        for (AP4_List<AP4_TrakAtom>::Item* item = trak_atoms->FirstItem(); item; item=item->GetNext()) {
            AP4_TrakAtom* trak = item->GetData();

            // find the stsd atom
            AP4_ContainerAtom* stbl = AP4_DYNAMIC_CAST(AP4_ContainerAtom, trak->FindChild("mdia/minf/stbl"));
            if (stbl == NULL) continue;
            
            // see if there's an external data source for this track
            AP4_ByteStream* trak_data_stream = &input;
            for (AP4_List<ExternalTrackData>::Item* ditem = m_ExternalTrackData.FirstItem(); ditem; ditem=ditem->GetNext()) {
                ExternalTrackData* tdata = ditem->GetData();
                if (tdata->m_TrackId == trak->GetId()) {
                    trak_data_stream = tdata->m_MediaData;
                    break;
                }
            }
			AP4_ContainerAtom *mvex = AP4_DYNAMIC_CAST(AP4_ContainerAtom, moov->GetChild(AP4_ATOM_TYPE_MVEX));
			AP4_TrexAtom*      trex = NULL;
			if (mvex) {
				for (AP4_List<AP4_Atom>::Item* item = mvex->GetChildren().FirstItem(); item; item = item->GetNext()) {
					AP4_Atom* atom = item->GetData();
					if (atom->GetType() == AP4_ATOM_TYPE_TREX) {
						trex = AP4_DYNAMIC_CAST(AP4_TrexAtom, atom);
						if (trex && trex->GetTrackId() == trak->GetId()) 
							break;
						trex = NULL;
					}
				}
			}
			// create the track handler    
            m_TrackData[index].track_handler	= CreateTrackHandler(trak, trex);
			m_TrackData[index].new_id = trak->GetId();

			cursors[index].m_Locator.m_TrakIndex   = index;
            cursors[index].m_Locator.m_SampleTable = new AP4_AtomSampleTable(stbl, *trak_data_stream);
            cursors[index].m_Locator.m_SampleIndex = 0;
            cursors[index].m_Locator.m_ChunkIndex  = 0;
            if (cursors[index].m_Locator.m_SampleTable->GetSampleCount()) {
                cursors[index].m_Locator.m_SampleTable->GetSample(0, cursors[index].m_Locator.m_Sample);
            } else {
                cursors[index].m_EndReached = true;
            }

            index++;            
        }

        // figure out the layout of the chunks
        for (;;) {
            // see which is the next sample to write
            AP4_UI64 min_offset = (AP4_UI64)(-1);
            int cursor = -1;
            for (unsigned int i=0; i<track_count; i++) {
                if (!cursors[i].m_EndReached &&
                    cursors[i].m_Locator.m_Sample.GetOffset() <= min_offset) {
                    min_offset = cursors[i].m_Locator.m_Sample.GetOffset();
                    cursor = i;
                }
            }

            // stop if all cursors are exhausted
            if (cursor == -1) break;

            // append this locator to the layout list
            AP4_SampleLocator& locator = cursors[cursor].m_Locator;
            locators.Append(locator);

            // move the cursor to the next sample
            locator.m_SampleIndex++;
            if (locator.m_SampleIndex == locator.m_SampleTable->GetSampleCount()) {
                // mark this track as completed
                cursors[cursor].m_EndReached = true;
            } else {
                // get the next sample info
                locator.m_SampleTable->GetSample(locator.m_SampleIndex, locator.m_Sample);
                AP4_Ordinal skip, sdesc;
                locator.m_SampleTable->GetChunkForSample(locator.m_SampleIndex,
                                                         locator.m_ChunkIndex,
                                                         skip, sdesc);
            }
        }

        // update the stbl atoms and compute the mdat size
        int current_track = -1;
        int current_chunk = -1;
        AP4_Position current_chunk_offset = 0;
        AP4_Size current_chunk_size = 0;
        for (AP4_Ordinal i=0; i<locators.ItemCount(); i++) {
            AP4_SampleLocator& locator = locators[i];
            if ((int)locator.m_TrakIndex  != current_track ||
                (int)locator.m_ChunkIndex != current_chunk) {
                // start a new chunk for this track
                current_chunk_offset += current_chunk_size;
                current_chunk_size = 0;
                current_track = locator.m_TrakIndex;
                current_chunk = locator.m_ChunkIndex;
                locator.m_SampleTable->SetChunkOffset(locator.m_ChunkIndex, current_chunk_offset);
            } 
            AP4_Size sample_size;
            TrackHandler* handler = m_TrackData[locator.m_TrakIndex].track_handler;
            if (handler) {
                sample_size = handler->GetProcessedSampleSize(locator.m_Sample);
                locator.m_SampleTable->SetSampleSize(locator.m_SampleIndex, sample_size);
            } else {
                sample_size = locator.m_Sample.GetSize();
            }
            current_chunk_size += sample_size;
            mdat_payload_size  += sample_size;
        }

        // process the tracks (ex: sample descriptions processing)
        for (AP4_Ordinal i=0; i<track_count; i++) {
            TrackHandler* handler = m_TrackData[i].track_handler;
            if (handler)
				handler->ProcessTrack();
        }
    }

    // finalize the processor
    Finalize(top_level);

    if (!fragments) {
        // calculate the size of all atoms combined
        AP4_UI64 atoms_size = 0;
        top_level.GetChildren().Apply(AP4_AtomSizeAdder(atoms_size));

        // see if we need a 64-bit or 32-bit mdat
        AP4_Size mdat_header_size = AP4_ATOM_HEADER_SIZE;
        if (mdat_payload_size+mdat_header_size > 0xFFFFFFFF) {
            // we need a 64-bit size
            mdat_header_size += 8;
        }
        
        // adjust the chunk offsets
        for (AP4_Ordinal i=0; i<track_count; i++) {
            AP4_TrakAtom* trak;
            trak_atoms->Get(i, trak);
            trak->AdjustChunkOffsets(atoms_size+mdat_header_size);
        }

        // write all atoms
        top_level.GetChildren().Apply(AP4_AtomListWriter(output));

        // write mdat header
        if (mdat_payload_size) {
            if (mdat_header_size == AP4_ATOM_HEADER_SIZE) {
                // 32-bit size
                output.WriteUI32((AP4_UI32)(mdat_header_size+mdat_payload_size));
                output.WriteUI32(AP4_ATOM_TYPE_MDAT);
            } else {
                // 64-bit size
                output.WriteUI32(1);
                output.WriteUI32(AP4_ATOM_TYPE_MDAT);
                output.WriteUI64(mdat_header_size+mdat_payload_size);
            }
        }        
    }
    
    // write the samples
    if (moov) {
        if (!fragments) {
#if defined(AP4_DEBUG)
            AP4_Position before;
            output.Tell(before);
#endif
            AP4_Sample     sample;
            AP4_DataBuffer data_in;
            AP4_DataBuffer data_out;
            for (unsigned int i=0; i<locators.ItemCount(); i++) {
                AP4_SampleLocator& locator = locators[i];
                locator.m_Sample.ReadData(data_in);
                TrackHandler* handler = m_TrackData[locator.m_TrakIndex].track_handler;
                if (handler) {
                    result = handler->ProcessSample(data_in, data_out);
                    if (AP4_FAILED(result)) return result;
                    output.Write(data_out.GetData(), data_out.GetDataSize());
                } else {
                    output.Write(data_in.GetData(), data_in.GetDataSize());            
                }

                // notify the progress listener
                if (listener) {
                    listener->OnProgress(i+1, locators.ItemCount());
                }
            }

#if defined(AP4_DEBUG)
            AP4_Position after;
            output.Tell(after);
            AP4_ASSERT(after-before == mdat_payload_size);
#endif
		}
		else
			m_StreamData[0].stream = fragments;
        
        // find the position of the sidx atom
        AP4_Position sidx_position = 0;
		if (sidx) {
			for (AP4_List<AP4_Atom>::Item* item = top_level.GetChildren().FirstItem();
				item;
				item = item->GetNext()) {
				AP4_Atom* atom = item->GetData();
				if (atom->GetType() == AP4_ATOM_TYPE_SIDX) {
					break;
				}
				sidx_position += atom->GetSize();
			}
		}
        
        // process the fragments, if any
		AP4_Array<AP4_Position> moof_offsets, mdat_offsets;
		moof_offsets.SetItemCount(1);
		mdat_offsets.SetItemCount(1);

		while (frags.ItemCount() > 0)
		{
			for (AP4_List<AP4_AtomLocator>::Item *locator(frags.FirstItem()); locator; locator = locator->GetNext())
			{
				AP4_ContainerAtom *moof(AP4_DYNAMIC_CAST(AP4_ContainerAtom, locator->GetData()->m_Atom));
				moof_offsets[0] = locator->GetData()->m_Offset;
				mdat_offsets[0] = moof_offsets[0] + moof->GetSize() + AP4_ATOM_HEADER_SIZE;

				result = ProcessFragment(moof, sidx, sidx_position, output, moof_offsets, mdat_offsets);
				if (AP4_FAILED(result))
					return result;
			}
			frags.DeleteReferences();

			AP4_Atom* atom = NULL;
			input.Tell(stream_offset);
			if (AP4_SUCCEEDED(atom_factory.CreateAtomFromStream(input, atom)))
			{
				if (atom->GetType() == AP4_ATOM_TYPE_MOOF)
					frags.Add(new AP4_AtomLocator(atom, stream_offset));
				else
					delete atom;
			}
		}

		// update the mfra if we have one
		if (mfra) {
			for (AP4_List<AP4_Atom>::Item* mfra_item = mfra->GetChildren().FirstItem(); mfra_item; mfra_item = mfra_item->GetNext())
			{
				if (mfra_item->GetData()->GetType() != AP4_ATOM_TYPE_TFRA)
					continue;
				AP4_TfraAtom* tfra = AP4_DYNAMIC_CAST(AP4_TfraAtom, mfra_item->GetData());
				if (tfra == NULL)
					continue;
				AP4_Array<AP4_TfraAtom::Entry>& entries = tfra->GetEntries();
				AP4_Cardinal entry_count = entries.ItemCount();
				for (unsigned int i = 0; i<entry_count; i++) {
					entries[i].m_MoofOffset = FindFragmentMapEntry(entries[i].m_MoofOffset);
				}
			}
		}

        // update and re-write the sidx if we have one
        if (sidx && sidx_position) {
            AP4_Position where = 0;
            output.Tell(where);
            output.Seek(sidx_position);
            result = sidx->Write(output);
            if (AP4_FAILED(result)) return result;
            output.Seek(where);
        }
        
        if (!fragments) {
            // write the mfra atom at the end if we have one
            if (mfra) {
                mfra->Write(output);
            }
        }
        
        // cleanup
        for (AP4_Ordinal i=0; i<track_count; i++)
            delete cursors[i].m_Locator.m_SampleTable;
        m_TrackData.Clear();
        delete[] cursors;
    }

    // cleanup
    frags.DeleteReferences();
    delete mfra;
    
    return AP4_SUCCESS;
}
/*----------------------------------------------------------------------
|   Mp4ParserOutput_SetSampleDescription
+---------------------------------------------------------------------*/
static BLT_Result
Mp4ParserOutput_SetSampleDescription(Mp4ParserOutput* self, 
                                     unsigned int     indx)
{
    // if we had a decrypter before, release it now
    delete self->sample_decrypter;
    self->sample_decrypter = NULL;
    
    // check that the audio track is of the right type
    AP4_SampleDescription* sample_desc = self->track->GetSampleDescription(indx);
    if (sample_desc == NULL) {
        ATX_LOG_FINE("no sample description for track");
        return BLT_ERROR_INVALID_MEDIA_FORMAT;
    }
    // handle encrypted tracks
    BLT_Result result = Mp4ParserOutput_ProcessCryptoInfo(self, sample_desc);
    if (BLT_FAILED(result)) return result;
    
    // update the generic part of the stream info
    BLT_StreamInfo stream_info;
    stream_info.id            = self->track->GetId();
    stream_info.duration      = self->track->GetDurationMs();
    stream_info.mask = BLT_STREAM_INFO_MASK_ID |
                       BLT_STREAM_INFO_MASK_DURATION;
    
    // deal with audio details, if this is an audio track
    AP4_AudioSampleDescription* audio_desc = dynamic_cast<AP4_AudioSampleDescription*>(sample_desc);
    if (audio_desc) {
        ATX_LOG_FINE("sample description is audio");
        stream_info.type          = BLT_STREAM_TYPE_AUDIO;
        stream_info.channel_count = audio_desc->GetChannelCount();
        stream_info.sample_rate   = audio_desc->GetSampleRate();
        stream_info.mask |= BLT_STREAM_INFO_MASK_TYPE          |
                            BLT_STREAM_INFO_MASK_CHANNEL_COUNT |
                            BLT_STREAM_INFO_MASK_SAMPLE_RATE;
    } else if (self == &self->parser->audio_output) {
        ATX_LOG_FINE("expected audio sample description, but did not get one");
        return BLT_ERROR_INVALID_MEDIA_FORMAT;
    }

    AP4_VideoSampleDescription* video_desc = dynamic_cast<AP4_VideoSampleDescription*>(sample_desc);
    if (video_desc) {
        ATX_LOG_FINE("sample description is video");
        stream_info.type     = BLT_STREAM_TYPE_VIDEO;
        stream_info.width    = video_desc->GetWidth();
        stream_info.height   = video_desc->GetHeight();
        stream_info.mask |= BLT_STREAM_INFO_MASK_TYPE     |
                            BLT_STREAM_INFO_MASK_WIDTH    |
                            BLT_STREAM_INFO_MASK_HEIGHT;
    } else if (self == &self->parser->video_output) {
        ATX_LOG_FINE("expected video sample descriton, but did not get one");
        return BLT_ERROR_INVALID_MEDIA_FORMAT;
    }
    
    AP4_MpegSampleDescription* mpeg_desc = NULL;
    if (sample_desc->GetType() == AP4_SampleDescription::TYPE_MPEG) {
        ATX_LOG_FINE("sample description is of type MPEG");
        mpeg_desc = dynamic_cast<AP4_MpegSampleDescription*>(sample_desc);
    }
    if (mpeg_desc) {
        stream_info.data_type       = mpeg_desc->GetObjectTypeString(mpeg_desc->GetObjectTypeId());
        stream_info.average_bitrate = mpeg_desc->GetAvgBitrate();
        stream_info.nominal_bitrate = mpeg_desc->GetAvgBitrate();
        stream_info.mask |= BLT_STREAM_INFO_MASK_AVERAGE_BITRATE |
                            BLT_STREAM_INFO_MASK_NOMINAL_BITRATE |
                            BLT_STREAM_INFO_MASK_DATA_TYPE;
    }
    
    // setup the output media type
    AP4_DataBuffer  decoder_info;
    BLT_MediaTypeId media_type_id = BLT_MEDIA_TYPE_ID_NONE;
    AP4_UI32        format_or_object_type_id = 0;
    if (mpeg_desc) {
        decoder_info.SetData(mpeg_desc->GetDecoderInfo().GetData(),
                             mpeg_desc->GetDecoderInfo().GetDataSize());
        media_type_id = self->mp4_es_type_id;
        format_or_object_type_id = mpeg_desc->GetObjectTypeId();
    } else {
        // here we have to be format-specific for the decoder info
        stream_info.data_type = AP4_GetFormatName(sample_desc->GetFormat());
        stream_info.mask |= BLT_STREAM_INFO_MASK_DATA_TYPE;
        format_or_object_type_id = sample_desc->GetFormat();
        if (sample_desc->GetFormat() == AP4_SAMPLE_FORMAT_AVC1) {
            // look for an 'avcC' atom
            AP4_AvccAtom* avcc = static_cast<AP4_AvccAtom*>(sample_desc->GetDetails().GetChild(AP4_ATOM_TYPE_AVCC));
            if (avcc) {
                // pass the avcc payload as the decoder info
                decoder_info.SetData(avcc->GetRawBytes().GetData(),
                                     avcc->GetRawBytes().GetDataSize());
            } 
        } else if (sample_desc->GetFormat() == AP4_SAMPLE_FORMAT_ALAC) {
            // look for an 'alac' atom (either top-level or inside a 'wave') 
            AP4_Atom* alac = sample_desc->GetDetails().GetChild(AP4_SAMPLE_FORMAT_ALAC);
            if (alac == NULL) {
                AP4_ContainerAtom* wave = dynamic_cast<AP4_ContainerAtom*>(sample_desc->GetDetails().GetChild(AP4_ATOM_TYPE_WAVE));
                if (wave) {
                    alac = wave->GetChild(AP4_SAMPLE_FORMAT_ALAC);
                }
            }
            if (alac) {
                // pass the alac payload as the decoder info
                AP4_MemoryByteStream* mbs = new AP4_MemoryByteStream((AP4_Size)alac->GetSize());
                alac->WriteFields(*mbs);
                decoder_info.SetData(mbs->GetData(), mbs->GetDataSize());                
                mbs->Release();
            } 
        }
        
        media_type_id = self->iso_base_es_type_id;
    }
    BLT_Mp4MediaType* media_type = NULL;
    unsigned int struct_size = decoder_info.GetDataSize()?decoder_info.GetDataSize()-1:0;
    if (audio_desc) {
        struct_size += sizeof(BLT_Mp4AudioMediaType);
        BLT_Mp4AudioMediaType* audio_type = (BLT_Mp4AudioMediaType*)ATX_AllocateZeroMemory(struct_size);;
        audio_type->base.stream_type    = BLT_MP4_STREAM_TYPE_AUDIO;
        audio_type->channel_count       = audio_desc->GetChannelCount();
        audio_type->sample_rate         = audio_desc->GetSampleRate();
        audio_type->decoder_info_length = decoder_info.GetDataSize();
        if (decoder_info.GetDataSize()) {
            ATX_CopyMemory(&audio_type->decoder_info[0], decoder_info.GetData(), decoder_info.GetDataSize());
        }
        media_type = &audio_type->base;
    } else {
        struct_size += sizeof(BLT_Mp4VideoMediaType);
        BLT_Mp4VideoMediaType* video_type = (BLT_Mp4VideoMediaType*)ATX_AllocateZeroMemory(struct_size);
        video_type->base.stream_type    = BLT_MP4_STREAM_TYPE_VIDEO;
        video_type->width               = video_desc->GetWidth();
        video_type->height              = video_desc->GetHeight();
        video_type->decoder_info_length = decoder_info.GetDataSize();
        if (decoder_info.GetDataSize()) {
            ATX_CopyMemory(&video_type->decoder_info[0], decoder_info.GetData(), decoder_info.GetDataSize());
        }
        media_type = &video_type->base;
    }
    media_type->base.id                  = media_type_id;
    media_type->base.extension_size      = struct_size-sizeof(BLT_MediaType); 
    media_type->format_or_object_type_id = format_or_object_type_id;
    self->media_type = &media_type->base;
    self->sample_description_index = indx;
    
    // final update to the stream info
    BLT_Stream_SetInfo(ATX_BASE(self->parser, BLT_BaseMediaNode).context, &stream_info);
    
    // enable the track in the linear reader if we have one
    if (self->parser->input.reader) {
        self->parser->input.reader->EnableTrack(self->track->GetId());
    }
    
    return BLT_SUCCESS;    
}