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• Ffmpeg transcoding video .vob (vcodec MPEG-2)

  5 mai 2017, par Aminesrine

  I want to transcode a file .vob to get the bitrate 1500 with 16/9 ratio I execute this command ffmpeg

  ffmpeg -i /path/video.vob -vcodec libx264 -vf scale=1280:-2 -strict experimental -b:v 1308k -b:a 192k -ar 44100 -r 25 /path/video_1500.mp4 2>&1
  

  But I got a video with size: 1280 x 1024. What options I should add to my command ffmpeg?

• How to let FFMpeg 'see' self-registered DShow filters

  5 mai 2017, par user7967599

  I'm trying to capture screen and voice/sound with ffmpeg. First I installed screen-capture-recorder and it includes 2 virtual dshow filters, after installation, ffmpeg could discover the 2:

  ffmpeg -list_devices true -f dshow -i dummy
  ffmpeg version N-45279-g6b86dd5... 
  [dshow @ 03ACF580] DirectShow video devices
  [dshow @ 03ACF580]  "Integrated Camera"
  [dshow @ 03ACF580]  "screen-capture-recorder"
  [dshow @ 03ACF580] DirectShow audio devices
  [dshow @ 03ACF580]  "Internal Microphone (Conexant 2"
  [dshow @ 03ACF580]  "virtual-audio-capturer"
  dummy: Immediate exit requested
  

  In order to customize the audio capturer, I compiled the source for "virtual-audio-capturer" and registered it with regsvr32. But this time ffmpeg could not find the registered filter. What steps should I add to let ffmpeg aware of the new filter?

  P.S. the registered filter could be listed with GraphStudioNext in category "Audio Capture Sources".

• x264 Encoding use x264_picture_clean crash

  5 mai 2017, par Wong Sam

  When I use iphone encoding CMSampleBufferRef To H264, it offen crash at x264_picture_clean I dont't know how to deal it

  enter image description here

  x264_picture_t* pPic_in; 
  

  here is my init about pPic_in

  pPic_in = (x264_picture_t*)malloc(sizeof(x264_picture_t));
  pPic_out = (x264_picture_t*)malloc(sizeof(x264_picture_t));
  
  x264_picture_init(pPic_out);
  
  x264_picture_init(pPic_in);
  x264_picture_alloc(pPic_in, csp, pParam->i_width, pParam->i_height);
  
  pPic_in->img.i_stride[0] = width;
  pPic_in->img.i_stride[1] = width / 2;
  pPic_in->img.i_stride[2] = width / 2;
  pPic_in->img.i_plane = 3;
  

  and i set data here

      picture_buf = yuv420_data;
      pPic_in->img.plane[0] = picture_buf;
      pPic_in->img.plane[1] = picture_buf + y_size;
      pPic_in->img.plane[2] = picture_buf + y_size*5/4;
  

  it looks well , when i run it on my iphone,but sometimes it will crash at

  x264_picture_clean
  

  here is more detail abuot pPic_in when crash occer enter image description here

  Thank u very much

• Adjust MP3 Files Volume and save it to new file [duplicate]

  5 mai 2017, par Gio Vanno

  This question already has an answer here:

  • Mute specified sections of an audio file using ffmpeg 1 answer

  I'm trying to make an audio-editing app here This program can adjust(increase and decrease) the mp3 file volume at the specific time(adjust start time and finish time, example: from 00:10 to 00:20) and we can save it to a new mp3 file.

  my questions is:

  -Does ffmpeg work for it?

  -is there any alternative besides ffmpeg?

  Thank you

• ffmpeg colorspace conversion speed

  5 mai 2017, par Mikhail Novikov

  I am running 2 ffmpeg commands on a fairly fast, GPU-enabled machine (AWS g2.2xlarge instance):

  ffmpeg -i ./in.mp4 -s 1280x720 -r 30 -an -f rawvideo -pix_fmt yuv420p - | cat - >/dev/null
  

  gives 524fps while

  ffmpeg -i ./in.mp4 -s 1280x720 -r 30 -an -f rawvideo -pix_fmt argb - | cat - >/dev/null
  

  just 101... it just shouldn't, couldn't take as much as 8ms per frame on a modern CPU, let alone GPU!

  What am i doing wrong and how can i improve speed of this?

  PS: Now this is truly ridiculous!

  ffmpeg -i ./in.mp4 -s 1280x720 -r 30 -an -f rawvideo -pix_fmt yuv420p - | ffmpeg -s 1280x720 -r 30 -an -f rawvideo -pix_fmt yuv420p -i - -s 1280x720 -r 30 -an -f rawvideo -pix_fmt argb - | cat - >/dev/null
  

  makes 275 fps! which is by far not perfect, but something i can live with.

  why?

  Thanks!