Other option to set media in Player of Qt

  • Hi,

    I am able to play .h264 binary file using QMediaPlayer in Qt, but in which I give file from local location using

    QMediaPlayer *player;
    QString fileName = "C:/username/test.mp4";

    Only for knowledge : Second application get data from camera and put frame by frame in .h264 file, and my application read data from this file, for time saving purpose and for better performance, I want to catch direct data from buffer and show on a player.

    Now my requirement I have to show on time video of camera, and data come in buffer, so question is, How can I set buffer as a input source of player->setmedia? I don't want to give file location to player->setmedia.


  • Lifetime Qt Champion


    Is that camera visible from QCamera ?

  • @SGaist : I don't know its visible or not, but in our process, there is RTSP client application which try to get frame from camera and put in a .h264 binary file, now I have to catch frame from RTSP client and show on a player on time.

    And ya I can give buffer input to player->setmedia like

    mBuffer = new QBuffer(this);
    const QByteArray &bytArray;
    mPlayer->setMedia(QMediaContent(), mBuffer);

    Now my question is, can I catch my frame in a bytArray? if yes then will it work continue? means one frame come on bytArray then I have to catch second frame in bytArray again and this process will continue.

  • Lifetime Qt Champion

    How are you controlling that RTSP client ? Does it give you access to the frames somehow ?

  • @SGaist : Yes, I can control RTSP client, and this process store frame in a buffer (Char Array). Now I want to show this frame on a screen frame by frame.

  • Lifetime Qt Champion

    What format is that frame ?

  • @SGaist : Char array. its a one type of buffer. and ya every frame has different size.

  • Lifetime Qt Champion

    My question was more: are you getting a decoded uncompressed frame ?

  • @SGaist : yes I decoded it with system decoder... actually I store buffer in one file, and when I play this file in VLC, it play successfully. but qt show only black screen.

    I added some more code...

    QMediaPlayer* player[screen];
    QVideoWidget* vw[screen];
        if (NULL != fpFrames)
                        fwrite(u8NAL, 4, 1, fpFrames);
                        fwrite(streamData->dataBuffer, streamData->dataSize, 1, fpFrames);
                        mBuffer->setData((char *)streamData->dataBuffer,streamData->dataSize);
                        mBuffer->write((char *)streamData->dataBuffer);
                        if(playerFlag == 0){
                            player[0]->setMedia(QMediaContent(), mBuffer);
                            playerFlag = 1;

    In above code I get data from rtsp in streamData->dataBuffer and its type is void*, I store it in QBuffer *mBuffer, and this mBuffer store in one file, which can play in VLC.

    Now when I run this application, application out show some message :
    Buffer::setData: Buffer is open

    *GStreamer; Unable to pause - ""

    QBuffer::setData: Buffer is open

    QBuffer::setData: Buffer is open

    QBuffer::setData: Buffer is open

    QBuffer::setData: Buffer is open........*

    Now help to come out this problem....

  • Lifetime Qt Champion

    You never close mBuffer, hence the Buffer is open error.

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