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• Two videos playing, how to crop the second video in FFmpeg

  14 janvier 2021, par Rorlingur

  I'm totally new to FFmpeg and I'm still learning.

  


  I've been trying to combine two videos into one. Where there is a "main" video that plays and a secondary video that is much smaller in the corner.

  


  I have managed to figure out almost everything on my own except for how to crop the smaller corner video by half. My goal is to crop/cut the corner video so it will only show the right half of the video but I can't seem to make it work, any help/tips would be much appreciated !

  


  ffmpeg -ss 00:04:10.10 -i corner.m4v -vf "movie=main.mkv [in1]; [in]scale=iw/4:ih/4, pad=0*iw:ih[in0]; [in1][in0] overlay=main_w/1.334:550 [out]" -b:v 3500k out.mkv


  


  The above is what I currently have that works, the only thing that is missing is cropping the corner video.

  


• Washed out colours when converting MOV to WEBM using FFMPEG

  16 octobre 2023, par pyefacepoker

  I'm trying to convert a simple animation from MOV to WEBM so it can be used as an OBS alert for my Twitch stream.

  


  However, when I convert using FFMPEG, the colour is slightly washed out.

  


  As you can see on the left red line, the right half (WEBM) is washed out compared to the left half (MOV).

  


  This is what i'm currently using :

  


  ffmpeg -i "file_name.mov" -c:v libvpx-vp9 -lossless 1 -auto-alt-ref 0 "file_name.webm"


  


  I was not expecting the colour to be slightly washed out.

  


  Is there anyway to ensure that the WEBM, once converted from the MOV file does not lose its colour ?

  


  Many thanks.

  


• Continuous RTSP stream recording with ffmpeg. Can I optimize it to not damage the SD card ?

  10 juillet 2019, par Mona

  I have got an IP camera with RTSP stream. I decided to record the stream using ffmpeg (version 3.2.14-1 deb9u1) on the Odroid-N2 device with Armbian. I have created a .sh script which is launched by Croon every minute. It checks if the ffmpeg recording is active for selected camera and also deletes files older than 7 days :

  #!/bin/bash
  
  RecordPathAndFind='/home/mona/CameraRecordings/Camera1/'
  
  SegmentTime=900
  
  MinutesAfterDeleteOldFiles=10080
  
  DaysSecurityLimit=31
  
  
  
  tempoutput=$(ps aux | grep ffmpeg | grep $RecordPathAndFind)
  
  if [ ${#tempoutput} -ge 5 ];
  
  then
  
        echo "FFMPEG with record command is already running. Skipping.\n"
  
  else
  
        echo "FFMPEG with record command is not running. Starting now...\n"
  
        FFMPEGSTART=$(su - mona -c "cd /home/mona; /usr/bin/screen -dmS ffmpegcamera1 ffmpeg -rtsp_transport udp -i 'rtsp://admin:password@192.168.1.xxx:554/onvif1' -vcodec copy -c:a aac -map 0 -f segment -segment_time $(echo $SegmentTime) -segment_format mp4 -strftime 1 $(echo $RecordPathAndFind)%Y-%m-%d_%H-%M-%S.mp4")
  
  fi
  
  
  
  currenthourminutes=$(date +%M)
  
  if [ "$currenthourminutes" == "00" ]; then
  
      echo "Current Minute is 00. Checking for old files to delete.\n"
  
      FILESDELETECOMMAND=$(find $(echo $RecordPathAndFind) -maxdepth 1 -type f -mmin +$(echo $MinutesAfterDeleteOldFiles) -mtime -$(echo $DaysSecurityLimit) -name '*.mp4' -ls -exec rm {} \;)
  
  else
  
      echo "Current Minute is NOT 00. Skipping.\n"
  
  fi

  The script works fine, but I’m afraid of the life of the SD card in this device. I detected that ffmpeg is continuously writing the mp4 file (file size grows all the time). I think it would be better if ffmpeg waited for 1MiB before flushing it to disk.

  I tried different ffmpeg settings (adding "blocksize", "flush_packets", "reorder_queue_size" and few others I can’t recall now), unfortunately it didn’t change anything. The mp4 file size was increasing all the time (even by few KBs).

  The first question is : Should I be worried about the microSD card life when ffmpeg is all the time writing the file (current environment) ?

  The second question is : Are there any other ffmpeg optimization settings which I missed ?

  If my fears regarding the SD card life are correct, can you please recommend some other things which I could add to my script (or change in system) in order to increase the life of micro SD cards (or USB sticks) used for recording purposes ? I was thinking about using the ramdisk, and then manually move the files, however this could cause files loss in case of system reboot, hang, or power outage.