Save an AVFrame as a JPEG file using FFmpeg

save_frame_as_jpeg.c

int save_frame_as_jpeg(AVCodecContext *pCodecCtx, AVFrame *pFrame, int FrameNo) {
    AVCodec *jpegCodec = avcodec_find_encoder(AV_CODEC_ID_JPEG2000);
    if (!jpegCodec) {
        return -1;
    }
    AVCodecContext *jpegContext = avcodec_alloc_context3(jpegCodec);
    if (!jpegContext) {
        return -1;
    }

    jpegContext->pix_fmt = pCodecCtx->pix_fmt;
    jpegContext->height = pFrame->height;
    jpegContext->width = pFrame->width;

    if (avcodec_open2(jpegContext, jpegCodec, NULL) < 0) {
        return -1;
    }
    FILE *JPEGFile;
    char JPEGFName[256];

    AVPacket packet = {.data = NULL, .size = 0};
    av_init_packet(&packet);
    int gotFrame;

    if (avcodec_encode_video2(jpegContext, &packet, pFrame, &gotFrame) < 0) {
        return -1;
    }

    sprintf(JPEGFName, "dvr-%06d.jpg", FrameNo);
    JPEGFile = fopen(JPEGFName, "wb");
    fwrite(packet.data, 1, packet.size, JPEGFile);
    fclose(JPEGFile);

    av_free_packet(&packet);
    avcodec_close(jpegContext);
    return 0;
}