libZPlay documentation (Win32)
Use dynamic streams

Simple example using dynamic streams.

This example will show how to use dynamic stream.


Note: In this example we are using buffered stream. This means that all data pushed to stream will be saved into internal buffer. User can destroy original data after call to PushDataToStream function. Also, data used by OpenStream will be buffered into internal memory.

* libZPlay example
* Use dynamic stream.

#include <windows.h>
#include <stdio.h>
#include <conio.h>

#include "libzplay.h"

using namespace libZPlay;

// callback function prototype, need this to get info when dynamic stream needs more data
int  __stdcall  myCallbackFunc(void* instance,
                            void *user_data,
                            TCallbackMessage message,
                            unsigned int param1,
                            unsigned int param2);

unsigned int nOutputDataSize = 0;

int main(int argc, char **argv)
    printf("Play dynamic stream.\n\nPress q to end\n\n");

    // create class instance using class factory.
    ZPlay *player = CreateZPlay();

    // detect stream format
    TStreamFormat format = player->GetFileFormat("test.mp3");
    if(format == sfUnknown)
        printf("Unsupported format\n");
        return 0;

    FILE *in = fopen("test.mp3", "rb"); // open input file
    if(in == NULL)
        printf("Can't open test.mp3.");
        return 0;

    // set callback mechanism to intercept MsgStreamNeedMoreData message
    // send file handle as user parameter to callback function
    player->SetCallbackFunc(myCallbackFunc, (TCallbackMessage) MsgStreamNeedMoreData, in);

    char buffer[10000]; // buffer for stream data
    // load some starting data into memory buffer,
    // this data must contain at least, one valid mp3 frame
    unsigned int read = fread(buffer, 1, 10000, in);

    // open memory stream - buffered, dynamic stream.
    int result = player->OpenStream(1, 1, buffer, read, format);
    if(result == 0)
        // display error message
        printf("Error: %s\n", player->GetError());
        return 0;

    // start playing

    // display position and wait for song end
        // check key press
            int a = getch();
            if(a == 'q' || a == 'Q')
                break; // end program if Q key is pressed

        // get stream status to check if song is still playing
        TStreamStatus status;
        if(status.fPlay == 0)
            break; // exit checking loop

        // get current position
        TStreamTime pos;
        // display position
        printf("Pos: %02u:%02u:%02u:%03u\r", pos.hms.hour, pos.hms.minute, pos.hms.second, pos.hms.millisecond);

        Sleep(300); // wait 300 ms

    // destroy class instance

    fclose(in); // close wave file
    return 0;

int  __stdcall  myCallbackFunc(void* instance, void *user_data, TCallbackMessage message, unsigned int param1, unsigned int param2)
    ZPlay *myplayer = (ZPlay*) instance;

        case MsgStreamNeedMoreData: // stream needs more data
            FILE *in = (FILE*) user_data; // this parameter is set by SetCallbackFunc

            // read next chunk of data from file into memory buffer
            char buffer[10000];
            unsigned int read = fread(buffer, 1, 10000, in);

            // push this memory buffer into stream
            myplayer->PushDataToStream(buffer, read);
        return 0;   

    return 0;


Copyright (c) 2010. Zoran Cindori - All rights reserved.