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• How to get time stamp of closest keyframe before a given timestamp with ffmpeg

  21 mai 2021, par loretoparisi

  To seek to position and get the closest frame I was using

  


  ffprobe -i /path/to.mp3 -show_frames -show_entries frame=pkt_pos -of default=noprint_wrappers=1:nokey=1 -hide_banner -loglevel panic -read_intervals $seconds%+#1


  


  where I specify the start position as :

  


  '-read_intervals', seconds + '%+#1', //Read only 1 packet after seeking to position 01:23


  


  With latest ffprobeversion

  


  $ ffprobe --version
ffprobe version 4.4 Copyright (c) 2007-2021 the FFmpeg developers


  


  it does not work anymore, and I get

  


  N/A


  


  hence the "first", while if I remove the $seconds%+#1 I get all

  


  ffprobe -i /path/to.mp3 -show_frames -show_entries frame=pkt_pos -of default=noprint_wrappers=1:nokey=1 -hide_banner -loglevel panic -read_intervals 20
N/A
1029888
1030306
1030724
1031142
1031560
1031978
1032396
1032814
1033232
1033650
1034068
1034486
1034904
...


  


  How to retrieve the closest frame then not using the read_intervals $seconds%+#1 but read_intervals $seconds only ?

  


• FFMPEG overlay not shown in certain players [closed]

  4 février 2024, par Hamed

  I'm trying to add an overlay to my video using ffmpeg. Here is my command :

  


  ffmpeg -y -i {input_video} -i {overlay_video} -filter_complex "[1:v]trim=start_frame=1991:end_frame=2027,scale=300:1,setpts=PTS-STARTPTS[clip2];[0:v][clip2]overlay=25:25" -map 0:v -map 0:a? -c:v libx264 -crf 20  {output_video}


  


  Now the overlay is added alright, but some video players don't show the overlay video. It's almost as if it's not supported. When I convert the video once more (using any tool, doesn't matter) the overlay is added permanently. How does the process work here ? how can I so called "bake" the overlay onto my input ?

  


• 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.