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• ffmpeg QSV hardware encoder with x11grab screen capture

  11 janvier 2020, par Toby Eggitt

  I believe I have built ffmpeg with support for my motherboard’s Intel graphics processor chip, but I have not succeeded in showing this working in any way. My goal is to use it for screen capture (the ffmpeg I built does capture screen successfully using the software encoding, but this is far too slow to be useful—it manages about 12fps at a very modest quality).

  My main problem—I think—is that I don’t know how to use these encoders, the examples I found all fail, which makes me suspect that what I’ve built is broken in some way. However, I also have no idea how I can verify that I built this correctly, but the following are true :

  • The five components that I built to get to this all compiled without
    errors (they were libva, gmmlib, intel-media-driver, libmfx, and
    ffmpeg
  • The output of ffmpeg -encoders includes four encoders with _qsv in
    their names including h264_qsv
  • Most of the commands I have tried result in output of this form :

      [h264_qsv @ 0x55ef1dc72040] Low power mode is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current frame rate is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current picture structure is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current resolution is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] Current pixel format is unsupported
  
      [h264_qsv @ 0x55ef1dc72040] some encoding parameters are not supported by the QSV runtime. Please double check the input parameters.
  
      Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  I have the impression this thing might be fussy about many parameters of this sort but have no idea where to find out what it would like. Any suggestions at all, how to verify it, or better yet, how to issue a command that captures screen and encodes with the hardware, would be most welcome.

• FFmpeg - MJPEG decoding - getting different values

  27 décembre 2016, par ahmadh

  I have a set of JPEG frames which I am muxing into an avi, which gives me a mjpeg video. This is the command I run on the console :

  ffmpeg -y -start_number 0 -i %06d.JPEG -codec copy vid.avi

  When I try to demux the video using ffmpeg C api, I get frames which are slightly different in values. Demuxing code looks something like this :

  AVFormatContext* fmt_ctx = NULL;
  
  AVCodecContext* cdc_ctx = NULL;
  
  AVCodec* vid_cdc = NULL;
  
  int ret;
  
  unsigned int height, width;
  
  
  
  ....
  
  // read_nframes is the number of frames to read
  
  output_arr = new unsigned char [height * width * 3 * 
  
                                  sizeof(unsigned char) * read_nframes];
  
  
  
  avcodec_open2(cdc_ctx, vid_cdc, NULL);
  
  
  
  int num_bytes;
  
  uint8_t* buffer = NULL;
  
  const AVPixelFormat out_format = AV_PIX_FMT_RGB24;
  
  
  
  num_bytes = av_image_get_buffer_size(out_format, width, height, 1);
  
  buffer = (uint8_t*)av_malloc(num_bytes * sizeof(uint8_t));
  
  
  
  AVFrame* vid_frame = NULL;
  
  vid_frame = av_frame_alloc();
  
  AVFrame* conv_frame = NULL;
  
  conv_frame = av_frame_alloc();
  
  
  
  av_image_fill_arrays(conv_frame->data, conv_frame->linesize, buffer, 
  
                       out_format, width, height, 1);
  
  
  
  struct SwsContext *sws_ctx = NULL;
  
  sws_ctx = sws_getContext(width, height, cdc_ctx->pix_fmt,
  
                           width, height, out_format,
  
                           SWS_BILINEAR, NULL,NULL,NULL);
  
  
  
  int frame_num = 0;
  
  AVPacket vid_pckt;
  
  while (av_read_frame(fmt_ctx, &vid_pckt) >=0) {
  
      ret = avcodec_send_packet(cdc_ctx, &vid_pckt);
  
      if (ret < 0)
  
          break;
  
  
  
      ret = avcodec_receive_frame(cdc_ctx, vid_frame);
  
      if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
  
          break;
  
      if (ret >= 0) {
  
          // convert image from native format to planar GBR
  
          sws_scale(sws_ctx, vid_frame->data, 
  
                    vid_frame->linesize, 0, vid_frame->height, 
  
                    conv_frame->data, conv_frame->linesize);
  
  
  
          unsigned char* r_ptr = output_arr + 
  
              (height * width * sizeof(unsigned char) * 3 * frame_num);
  
          unsigned char* g_ptr = r_ptr + (height * width * sizeof(unsigned char));
  
          unsigned char* b_ptr = g_ptr + (height * width * sizeof(unsigned char));
  
          unsigned int pxl_i = 0;
  
  
  
          for (unsigned int r = 0; r < height; ++r) {
  
              uint8_t* avframe_r = conv_frame->data[0] + r*conv_frame->linesize[0];
  
              for (unsigned int c = 0; c < width; ++c) {
  
                  r_ptr[pxl_i] = avframe_r[0];
  
                  g_ptr[pxl_i]   = avframe_r[1];
  
                  b_ptr[pxl_i]   = avframe_r[2];
  
                  avframe_r += 3;
  
                  ++pxl_i;
  
              }
  
          }
  
  
  
          ++frame_num;
  
  
  
          if (frame_num >= read_nframes)
  
              break;
  
      }
  
  }
  
  
  
  ...

  In my experience around two-thirds of the pixel values are different, each by +-1 (in a range of [0,255]). I am wondering is it due to some decoding scheme FFmpeg uses for reading JPEG frames ? I tried encoding and decoding png frames, and it works perfectly fine.

  In short my goal is to get the same pixel by pixel values for each JPEG frame as I would I have gotten if I was reading the JPEG images directly. Here is the stand-alone code I used. It includes cmake files to build code, and a couple of jpeg frames with the converted avi file to test this problem. (give —filetype png to test the png decoding).

• FFMPEG gives an error for rtp_mpegts on fedora

  6 mars 2017, par chaitanya kiran

  While executing below ffmpeg command on fedora 21 i m facing "Requested output format ’rtp_mpegts’ is not a suitable output format" ; whereas same works on Ubuntu any ideas please.

  ffmpeg -f v4l2 -i /dev/video0 -s 720x480 -pix_fmt yuv420p -vcodec h264 -r 30 -g 15 -ar 0 -streamid 0:48 -bf 2  -f rtp_mpegts rtp://239.0.32.0:50000

  ffmpeg version 2.4.11 Copyright (c) 2000-2015 the FFmpeg developers
  built on Aug 26 2015 19:46:08 with gcc 4.9.2 (GCC) 20150212 (Red Hat
  4.9.2-6) configuration : —prefix=/usr —bindir=/usr/bin —datadir=/usr/share/ffmpeg —incdir=/usr/include/ffmpeg —libdir=/usr/lib —mandir=/usr/share/man —arch=i686 —optflags=’-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong —param=ssp-buffer-size=4 -grecord-gcc-switches -m32 -march=i686 -mtune=atom -fasynchronous-unwind-tables’ —enable-bzlib —disable-crystalhd —enable-frei0r —enable-gnutls —enable-ladspa —enable-libass —enable-libcdio —enable-libdc1394 —disable-indev=jack —enable-libfreetype —enable-libgsm —enable-libmp3lame —enable-openal —enable-opencl —enable-libopencv —enable-libopenjpeg —enable-libopus —enable-libpulse —enable-libschroedinger —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libvorbis —enable-libv4l2 —enable-libvpx —enable-libx264 —enable-libx265 —enable-libxvid —enable-x11grab —enable-avfilter —enable-avresample —enable-postproc —enable-pthreads —disable-static —enable-shared —enable-gpl —disable-debug —disable-stripping —shlibdir=/usr/lib —cpu=i686 —enable-runtime-cpudetect libavutil 54. 7.100 / 54. 7.100 libavcodec 56. 1.100 / 56. 1.100 libavformat 56. 4.101 /
  56. 4.101 libavdevice 56. 0.100 / 56. 0.100 libavfilter 5. 1.100 / 5. 1.100 libavresample 2. 1. 0 / 2. 1. 0 libswscale 3. 0.100 / 3. 0.100 libswresample 1. 1.100 /
  1. 1.100 libpostproc 53. 0.100 / 53. 0.100 Input #0, video4linux2,v4l2, from ’/dev/video0’ : Duration : N/A, start :
  554538.584009, bitrate : 199065 kb/s
  Stream #0:0 : Video : rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, 199065 kb/s, 6 fps, 6 tbr, 1000k tbn, 1000k tbc

  [NULL @ 0x8e94d00] Requested output format ’rtp_mpegts’ is not a suitable output format rtp ://239.0.32.0:50000 : Invalid argument