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• How to copy other frame buffer with ffmpeg ?

  23 avril 2023, par wrabbit

  I have a question for frame copy with other position.

  


  I got a 1280640 decoded frame (YUV420) from h264/mp4 and I wanna merge 4 frame to 25601280 frame buffer . as below.

  


  

  


  The code is like this but does not working.

  


  /* pCodecCtx and pFrame for decoded frame information */
int Encoding2JPEG( AVCodecContext *pCodecCtx, AVFrame *pFrame, int FrameNo, int Quality) {
    int gotFrame;

    /* New Context for JPEG encoding */
    AVCodec *jpeg_codec = NULL;
    AVCodecContext *jpeg_ctx =NULL;
    int ret;
    AVPacket *packet;
    packet = av_packet_alloc();
    if(!packet)
    {
            printf("alloc fail!\n");
            return -1;
    }

    if(frame)
            printf("received frame for encoding %3"PRId64"\n", frame->pts);

    pFrame_gather = av_frame_alloc();
    if(!pFrame_gather)
    {
            printf("Could not allocate gater frame!\n");
            return -1;
    }

    pFrame_gather->format = pCodecCtx->pix_fmt;
    pFrame_gather->width = pCodecCtx->width*2;
    pFrame_gather->height = pCodecCtx->height*2;

    if ( av_frame_get_buffer(pFrame_gather, 0) < 0)
            printf("Could not allocate the gather frame data!\n");

    /* Buffer Clear */
    ptrdiff_t linesize[4] = { frame->linesize[0], 0, 0, 0 };
    if( av_image_fill_black ( pFrame_gather->data, linesize, pCodecCtx->pix_fmt, \
                    AVCOL_RANGE_JPEG , pFrame_gather->width, pFrame_gather->height) != 0 )
            printf("image clear error!\n");

    ret = av_frame_make_writable(pFrame_gather);
    if( ret <0)
                    printf("writeable set fail!\n");

     /* set position of destination */
    int top_band =0;
    int left_band=200;

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(pCodecCtx->pix_fmt);
     int y_shift;
     int x_shift;
     int max_step[4];

     if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)
      return -1;

     y_shift = desc->log2_chroma_h;
     x_shift = desc->log2_chroma_w;
     av_image_fill_max_pixsteps(max_step, NULL, desc);
 
     /* Y Data */
     memcpy( pFrame_gather->data[0] + (top_band * pFrame->linesize[0]) + left_band,\
         frame->data[0] , pCodecCtx->width*pCodecCtx->height);
     /* U Data */
     memcpy ( pFrame_gather->data[1] + ((top_band >> y_shift) * pFrame->linesize[1]) + \
          (left_band >> x_shift), frame->data[1], pCodecCtx->width/2*pCodecCtx->height/2);
     /* V DAta */
     memcpy ( pFrame_gather->data[2] + ((top_band >> y_shift) * pFrame->linesize[2]) \
          + (left_band >> x_shift), frame->data[2], pCodecCtx->width/2*pCodecCtx->height/2);

     /* unref variable .... */
     ....
 }


  


  Upper source code is something wring. It does not working.
How to memory copy with position ?

  


• Java infinite video stream loop

  30 juin 2021, par Jason Roufael

  i wanna add a loop to make the process go in an infinite loop so the video can keep repeating itself

  


  try {&#xA;var processBuilder = new ProcessBuilder();&#xA;List<string> cmds=new ArrayList&lt;>();&#xA;cmds.add("ffmpeg.exe");&#xA;cmds.add("-i");&#xA;cmds.add("C:\\ffmpeg\\bin\\inpiit.mp4");&#xA;cmds.add("-vcodec");&#xA;cmds.add("libx264");&#xA;cmds.add("-acodec");&#xA;cmds.add("mp2");&#xA;cmds.add("-f");&#xA;cmds.add("mpegts");&#xA;cmds.add("udp://224.5.5.5:1234?pkt_size=1316");&#xA;processBuilder.command(cmds);&#xA;var process = processBuilder.start();&#xA;&#xA;} catch(IOException ex) {&#xA;&#xA;ex.printStackTrace(); &#xA;</string>

  


  }

  


• Is there any way to add drawtext filter in video at the last 3 seconds by enable function in ffmpeg

  26 juillet 2021, par Daksh

  I wanna ask that I want to add drawtext filter to the video in last 3 seconds only, may the video of any length like 2 minutes or 20 minutes, whatever. I want it in Python format.