C++ AP4_Atom::Write方法代码示例

//.........这里部分代码省略.........
    // filter tracks if required
    if (Options.audio_only) {
        AP4_Track* track = movie->GetTrack(AP4_Track::TYPE_AUDIO);
        if (track == NULL) {
            fprintf(stderr, "--audio option specified, but no audio track found\n");
            return 1;
        }
        Options.track_filter = track->GetId();
    } else if (Options.video_only) {
        AP4_Track* track = movie->GetTrack(AP4_Track::TYPE_VIDEO);
        if (track == NULL) {
            fprintf(stderr, "--video option specified, but no video track found\n");
            return 1;
        }
        Options.track_filter = track->GetId();
    } else if (Options.track_id) {
        AP4_Track* track = movie->GetTrack(Options.track_id);
        if (track == NULL) {
            fprintf(stderr, "--track-id option specified, but no such track found\n");
            return 1;
        }
        Options.track_filter = track->GetId();
    }
    
    // save the init segment
    AP4_ByteStream* output = NULL;
    result = AP4_FileByteStream::Create(Options.init_segment_name, AP4_FileByteStream::STREAM_MODE_WRITE, output);
    if (AP4_FAILED(result)) {
        fprintf(stderr, "ERROR: cannot open output file (%d)\n", result);
        return 1;
    }
    AP4_FtypAtom* ftyp = file->GetFileType(); 
    if (ftyp) {
        result = ftyp->Write(*output);
        if (AP4_FAILED(result)) {
            fprintf(stderr, "ERROR: cannot write ftyp segment (%d)\n", result);
            return 1;
        }
    }
    if (Options.track_filter) {
        AP4_MoovAtom* moov = movie->GetMoovAtom();
        
        // only keep the 'trak' atom that we need
        AP4_List<AP4_Atom>::Item* child = moov->GetChildren().FirstItem();
        while (child) {
            AP4_Atom* atom = child->GetData();
            child = child->GetNext();
            if (atom->GetType() == AP4_ATOM_TYPE_TRAK) {
                AP4_TrakAtom* trak = (AP4_TrakAtom*)atom;
                AP4_TkhdAtom* tkhd = (AP4_TkhdAtom*)trak->GetChild(AP4_ATOM_TYPE_TKHD);
                if (tkhd && tkhd->GetTrackId() != Options.track_filter) {
                    atom->Detach();
                    delete atom;
                }
            }
        }

        // only keep the 'trex' atom that we need
        AP4_ContainerAtom* mvex = AP4_DYNAMIC_CAST(AP4_ContainerAtom, moov->GetChild(AP4_ATOM_TYPE_MVEX));
        if (mvex) {
            child = mvex->GetChildren().FirstItem();
            while (child) {
                AP4_Atom* atom = child->GetData();
                child = child->GetNext();
                if (atom->GetType() == AP4_ATOM_TYPE_TREX) {
                    AP4_TrexAtom* trex = AP4_DYNAMIC_CAST(AP4_TrexAtom, atom);

/*----------------------------------------------------------------------
|   main
+---------------------------------------------------------------------*/
int
main(int argc, char** argv)
{
    if (argc < 4) {
        PrintUsageAndExit();
    }
    
    // parse arguments
    const char* atom_path       = NULL;
    const char* input_filename  = NULL;
    const char* output_filename = NULL;
    bool        payload_only    = false;
    char* arg;
    while ((arg = *++argv)) {
        if (!strcmp(arg, "--payload-only")) {
            payload_only = true;
        } else if (atom_path == NULL) {
            atom_path = arg;
        } else if (input_filename == NULL) {
            input_filename = arg;
        } else if (output_filename == NULL) {
            output_filename = arg;
        } else {
            fprintf(stderr, "ERROR: invalid command line argument (%s)\n", arg);
            return 1;
        }
    }

    // check arguments
    if (atom_path == NULL) {
        fprintf(stderr, "ERROR: missing atom path\n");
        return 1;
    }
    if (input_filename == NULL) {
        fprintf(stderr, "ERROR: missing input filename\n");
        return 1;
    }
    if (output_filename == NULL) {
        fprintf(stderr, "ERROR: missing output filename\n");
        return 1;
    }

	// create the input stream
    AP4_Result result;
    AP4_ByteStream* input = NULL;
    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;
    }

    // parse the atoms
    AP4_AtomParent top_level;
    AP4_Atom* atom;
    AP4_AtomFactory& atom_factory = AP4_DefaultAtomFactory::Instance;
    while (atom_factory.CreateAtomFromStream(*input, atom) == AP4_SUCCESS) {
        top_level.AddChild(atom);
    }

    // release the input
    input->Release();

    // find the atom
    atom = top_level.FindChild(atom_path);
    if (atom == NULL) {
        fprintf(stderr, "ERROR: atom '%s' not found\n", atom_path);
        return 1;
    }

    // create the output stream
    AP4_ByteStream* output = NULL;
    result = AP4_FileByteStream::Create(output_filename, AP4_FileByteStream::STREAM_MODE_WRITE, output);
    if (AP4_FAILED(result)) {
        fprintf(stderr, "ERROR: cannot open output file (%s)\n", output_filename);
        return 1;
    }

    // write the atom
    if (payload_only) {
        atom->WriteFields(*output);
    } else {
        atom->Write(*output);
    }

    // cleanup
    output->Release();

    return 0;
}