[FFmpeg-devel] Creating a AVFrame from a QVideoFrame

Mike Nelson mike at realrunners.com
Sat Jun 7 15:52:12 CEST 2014

I'm struggling with converting a QVideoFrame (QT) into a AVFrame in order
to encode video coming from a webcam.

Documentation for QVideoFrame:

I understand the basics of image formats, stride and such but I'm missing
something. This is what I've got so far, adapted from a libav example (

static void fill_yuv_image(const QVideoFrame &frame, AVFrame *pict,
int frame_index, int width, int height)


    pict->pts = frame.startTime() * 1000000.0; // time_base is 1/1000000

    pict->width = frame.width();

    pict->height = frame.height();

    pict->format = STREAM_PIX_FMT; //todo: get this from the frame

    pict->data[0] = (uint8_t*)frame.bits();

    pict->linesize[0] = frame.bytesPerLine();


After which I'm attempting to encode:

AVPacket pkt;

        int got_packet_ptr = 0;

        int success = avcodec_encode_video2(c, &pkt, picture, &got_packet_ptr);

        /* if zero size, it means the image was buffered */

        if (success == 0) {

            /* write the compressed frame in the media file */

            ret = av_interleaved_write_frame(oc, &pkt);

        } else {

            ret = 0;


It's returning an error about the stride not matching. Any help would
be greatly appreciated. Thanks!

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