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• ffmpeg doesn't always create wave picture

  17 février 2017, par Sean

  @LordNeckbeard and other ffmpeg experts,

  can you please help me with generating wave picture. the following command works perfectly on some videos and it doesn’t on other videos :

  ffmpeg  -i "input.mp4" -filter_complex "[0:a]aformat = channel_layouts = mono, compand = gain = -6, showwavespic = s = 1920x384: colors =red|blue[fg]; color = s = 1920x384: color =#444444, drawgrid = width = 38:height = 38:color =#555555@0.5[bg]; [bg][fg]overlay = format = rgb, drawbox = x = (iw - w) / 2:y = (ih - h) / 2:w = iw:h = 2:color =#000000@0.4" -vframes 1  "output.png" 

  when working, it generates the following wave pic :
  working example

  on other videos, it shows the grid but it seems that the wave signal is hidden behind the grid

  wave hidden behind the grid

  Your help is greatly appreciated !

  Thank you,
  Sean.

• ffmpeg : Considers AVPixelFormat as Int ?

  16 mars 2014, par jamie_y

  I would like to use a function ff_load_image.

  program.c

  #include "../ffmpeg/libavfilter/lavfutils.h"
  
  
  
  int main ()
  
  {
  
    uint8_t* data;
  
  
  
    int linesize, width, height, log_ctx;
  
  
  
    int i = ff_load_image(&data, &linesize, &width, &height, AV_PIX_FMT_RGB24, "blue.jpg", &log_ctx);
  
  }

  This compiles, but gives a warning.

  program.c: In function 'main':
  
  program.c:11: warning: passing argument 5 of 'ff_load_image' makes pointer from integer without a cast
  
  ../ffmpeg/libavfilter/lavfutils.h:39: note: expected 'enum AVPixelFormat *' but argument is of type 'int'

  When I run the program, it segment faults. I can't think of any other way to specify a pixel format. Why would ffmpeg think AV_PIX_FMT_RGB8 is an integer ? It's obviously an AVPixelFormat.

• ffmpeg is dropping frames of second video in concat

  17 juin 2018, par bugwheels94

  I did a screen share and when sharing the screen I minimized the sharing window so the video that I am sharing has some thing weird going on. Seeking does not work on mplayer but works on VLC. However, when doing the concat

  ffmpeg -i test.webm -f lavfi -i color=c=blue:s=1366x768:d=71 \
  
  -filter_complex "[0]scale=w='min(1366\, iw)':h='min(768\, ih)':force_original_aspect_ratio=decrease,\
  
  pad=width=1366:height=768:x=(ow-iw)/2:y=(oh-ih)/2,setsar=1/1[v1];\
  
  [1][v1]concat=n=2[v]" -map [v] -qscale 7 result.mp4

  The webm video of length 155 seconds is not showing complete. Ideally the result should be 71 + 156 = 227 but I am getting 155 seconds and the webm video of concat being cropped.

  If I reverse the concat order to [v1][1]concat=n=2[v] then everything is perfect at 227 seconds

  Download test.webm

  May you please tell me about what might be wrong here ? Thanks