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• how to remove multiple parts from a video, using ffmpeg ?

  26 septembre 2023, par jojo

  how to remove multiple parts from a video ?
for example i have a video of one minute and i want to delete following segments :

  


  from second 0.0 to second 10.0
from second 20.0 to second 30.0
from second 40.0 to second 45.0

  


  please remember i want to delete above mentioned segments, the output should not include these segments.
i have already tried all the answers, but they are all joining the trimmed segments, which i don't want.e.g :

  


  ffmpeg -i foo.mp4 -filter_complex "[0:v]trim=duration=30[av];[0:a]atrim=duration=30[aa];[0:v]trim=start=40:end=50,setpts=PTS-STARTPTS[bv];[0:a]atrim=start=40:end=50,asetpts=PTS-STARTPTS[ba];[0:v]trim=start=80,setpts=PTS-STARTPTS[cv];[0:a]atrim=start=80,asetpts=PTS-STARTPTS[ca];[av][aa][bv][ba][cv][ca]concat=n=3:v=1:a=1" out.mp4


  


  thank you.
note :(python version also accepted.)

  


• Merging parts of GOPRO clips with concat filter produces the ffmpeg buffer error

  17 septembre 2023, par Sailor Jerry

  Here is my command line :

  


  ffmpeg -y  -ss 670497ms  -i "GX030058.MP4" -to 25977ms  -i "GX040058.MP4" \
 -filter_complex   \
"[0][1]concat=v=1:a=1 [concv] [conca]" \
 -map [concv] -map [conca] \
 "out.mp4"


  


  it produces the following error and the audio goes out of sync

  


  [out_0_0 @ 0x7fca2d508bc0] 100 buffers queued in out_0_0, something may be wrong.s speed=0.539x    
[out_0_1 @ 0x7fca2d5093c0] 100 buffers queued in out_0_1, something may be wrong.
[out_0_1 @ 0x7fca2d5093c0] 1000 buffers queued in out_0_1, something may be wrong.


  


  If I just issue command :

  


  ffmpeg -y  -ss 670497ms  -i "GX030058.MP4" -to 25977ms  -i "GX040058.MP4" "out.mp4"


  


  Then audio has no problems.

  


  The reason I use the filter, because the actual filter is more complex and also includes adding the overlay to these concatenated clips, but the problem exists even with concat operation only.

  


• Dynamically record parts of a video stream using ffmpeg based on incoming events

  12 septembre 2023, par ganjim

  Say I have a RTSP stream running on some server.

  


  I want to record parts of this video stream based on some events that will come up on my machine.
My goal is to record 10 seconds before up to 10 seconds after the PTS in any received event. Consider that I have a way to synchronize the PTS between the sender and the receiver, but by the time I receive the events, its already streamed and is in the past.
So I either need to have the ffmpeg command running already, or to have buffered streaming video in my memory.

  


  I just added some code with comments as a way to simulate the situation, it is not complete as I still don't have a working solution. But I'm looking to understand if ffmpeg has capabilities for dealing with rtsp streams suitable for this situation.

  


  const { spawn } = require('child_process');

function processEvent(event){
  
  let startTime = event.pts - 10
  let endTime = event.pts + 10

  const ffmpegArgs = [
    '-i', "rtspUrl",
    '-ss', startTime.toString(),
    '-to', endTime.toString(),
    '-c', 'copy',
    '-f', 'mp4',
    `output_${startTime}_${endTime}.mp4` // Output filename
  ];
  // Here it is obviously not possible to give ffmpeg a negative startTime.
  // We either have to have spawned the ffmpeg command and somehow give it a starting time for recording on demand or have a buffering system in place.
  // Having a buffer to store every raw frame and then attach them after endTime is also considerably CPU and memory intensive.
  // Looking for alternative ways to achieve the same output.

  const ffmpegProcess = spawn('ffmpeg', ffmpegArgs, {
    stdio: 'inherit'
  });
}

// Code to simulate the events:
// imagine these pts to be relative to Date.now(), so using negative PTS to show the events are going to be in the past by the time we receive them.
setTimeout(() => {
  const event1= { pts: -30 };
  processEvent(event1);
}, 1000);

setTimeout(() => {
  const event2 = { pts: -20 };
  processEvent(event2);
}, 5000);