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• bash script fail when a command wait ffmpeg to finish

  5 novembre 2013, par d4r10

  In ubuntu 13.04 have a node.js server that launch for certain events, a script like this :

  #! /bin/bash
  
  ...
  
  ...
  
  
  
  avconv -i "$dir$video" -ss "$ss.000" -t $tt -threads 0 "$folder/$dif.webm"
  
  
  
  y_uid=$(/app/youtube-uploader "$folder/$dif.webm" "$label" "$desc" | grep 'watch' | sed 's/v=/ /g' | awk '{print$2}')
  
  
  
  echo "$y_uid" >> ~/log/yt.log
  
  ...
  
  ...

  if avconv (ffmpeg) process a small file (less then 30 minutes of encoding), the script works fine, but if avconv runs for hours, the next command "...youtube-uploader..." (that is a python based application) doesn't work (but if i try to launch it manually, it will go fine).

  I have also tried to launch the next command inside a loop that check if the variable "$y_uid" is empty, so it will try to repeat youtube-uploader until it find a right value, but it will continue to stay in background and will try forever.. (and it is strange, because if i try to launch the command manually, it works fine..).

  Summarizing, seems like that if avconv run for hours, the avconv process will generate a file that is not recognised or locked or a ghost file for the same script (but is recognised if the command is launched outside the script), if it is a small encoding, it will work fine.

  Unfortunatelly It is difficult to debug or test, because i have every time to wait for hours, please help !

  UPDATE

  I think the problem is related at the buffer size of node.js OR some other buffer that store the standard output of ffmpeg. Just correct

  avconv -i "$dir$video" -ss "$ss.000" -t $tt -threads 0 "$folder/$dif.webm"

  in

  avconv -i "$dir$video" -ss "$ss.000" -t $tt -threads 0 "$folder/$dif.webm" &> /dev/null

  so all the ffmpeg output not full the buffer memory and everythings go well

• Why ANativeWindow_Buffer.stride is different for different devices

  17 août 2020, par user2578525

  I am writing simple video player using ffmpeg for android. Following are the steps I followed

  


  

  1. Read AVFrame from file

  


  2. Convert AVFrame to RGB565 format using sws_scale

  


  3. Get buffer from using av_image_copy_to_buffer

  


  4. Display this buffer to SurfaceView by copying buffer to ANativeWindow_Buffer

  


  


  Most of the videos are playing fine, but there is issue with videos which have lower resolution than window. For ex, when I play a 656x480 video on my OnePlus 7T (2206x1080), video looks distorted. The same video plays fine on emulator (2160x1080).

  


  When I debugged whole pipe, I found that on OP7T, after locking ANativeWindow, ANativeWindow_Buffer.stride was set to 704 instead of 656. For all videos which plays normal, stride is same as width of buffer. The same is not the case with Android emulator.

  


  I did some trials and tried to scale width to 600, then stride jumped to 640 and video was distorted. When I scaled width to 640, video was displayed vertically half correct.

  


  Can anyone help me understand, How stride is calculated ? And What is the reason stride is wrongly calculated ?

  


  I found one same problem here : Simple FFMpeg player for Android
OP mentions that video works fine for 640, 1280, 1920.

  


• Thumbnail is not generated while uploading a video which is downloaded from the same server

  16 avril 2014, par nit3ch

  I am using drupal 7 video module and ffmpeg together to upload video on my site.
  My problem :

  1. Upload a video, everything works fine, thumbnail is generated and video is uploaded successfully
  2. Now download the above uploaded video.
  3. Now Try to upload the same video, on same drupal site.

  Thumbnail is not generating and also I am not able to play the newly uploaded video.
  In all other cases video upload is working fine, I am able to upload same video again and again with no fuss,but when I try to upload the downloaded video , everything goes wrong even if I change the file name after downloading the video and uploading again.

  Please let me know if I am not clear, will try to explain more.