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• FFMPEG concat causing audio glitches in segments boundaries

  28 mai 2017, par Idan

  I am segmenting a video file to 10sec segments, transcoding each of them and then run a concat to merge them all back together.
  While the whole process works without errors and the final file is valid and playable, I’ve noticed some sort of glitches/interruptions in the audio stream when passing over the original segments boundaries.

  For example, in a 60sec video that was segmented to 10sec segments and stitched back again, the final output will show audio interruptions in 10/20/30/40/50 sec timestamps.

  For segmenting the files I use :

  ffmpeg -y -i $INPUT_FILE -c copy -flags -global_header -segment_time 10 -break_non_keyframes 0 -reset_timestamps 1 -segment_list file_segs.list -segment_list_type ffconcat -write_empty_segments 0 -segment_format mp4  -f segment file_seg-%d.mp4

  And for concat I use :

  ffmpeg -y -f concat -i file_segs.list -c copy -movflags +faststart file_video.mp4

  Transcoding is to libx264 / aac

  What might be the cause ? Is there any way to work around this problem ?

• How can i parse strings as the inputs to subprocess.Popen ?

  26 juillet 2013, par rash

  Here I tried to cut first and second 30sec long video file from "path/connect.flv" to the files output1.flv and output2.flv. It works. I able to concatenate these two files to form a new file "final.flv" of 60sec long. So this works and i am getting the outputs output1.flv [30sec], output2.flv[30sec] and final.flv[1min].

  Here is the python code :

  import subprocess
  
  
  
  ffmpeg_command1 = ["ffmpeg", "-i", "/home/xincoz/test/connect.flv", "-acodec", "copy", "-ss", "00:00:00", "-t", "00:00:30", "/home/xincoz/test/output1.flv"]
  
  
  
  ffmpeg_command2 = ["ffmpeg", "-i", "/home/xincoz/test/connect.flv", "-acodec", "copy", "-ss", "00:00:30", "-t", "00:00:30", "/home/xincoz/test/output2.flv"]
  
  
  
  ffmpeg_command3 = ["mencoder", "-forceidx", "-ovc", "copy", "-oac", "pcm", "-o", "/home/xincoz/test/final.flv", "/home/xincoz/test/output1.flv", "/home/xincoz/test/output2.flv"]
  
  
  
  subprocess.call(ffmpeg_command1)
  
  
  
  subprocess.call(ffmpeg_command2)
  
  
  
  subprocess.Popen(ffmpeg_command3)

  But what i really want is to concatenate two strings out1 and out2 and concatinate these two to a file instead of concatenating "/home/xincoz/test/output1.flv" and "/home/xincoz/test/output2.flv". So how can i parse string out1 and out2 as the inputs to mencoder ? Please edit my code to achieve the result.

  import subprocess,os
  
  
  
  ffmpeg_command = ["ffmpeg", "-i", "/home/xincoz/test/connect.flv", "-acodec", "copy", "-ss", "00:00:00", "-t", "00:00:30","-f", "flv", "pipe:1"]
  
  
  
  p = subprocess.Popen(ffmpeg_command,stdout=subprocess.PIPE)
  
  
  
  out1, err = p.communicate()
  
  
  
  ffmpeg_command1 = ["ffmpeg", "-i", "/home/xincoz/test/connect.flv", "-acodec", "copy", "-ss", "00:00:30", "-t", "00:00:30","-f", "flv", "pipe:1"]
  
  
  
  p1 = subprocess.Popen(ffmpeg_command1,stdout=subprocess.PIPE)
  
  
  
  out2, err1 = p1.communicate()
  
  
  
  ffmpeg_command2 = ["mencoder", "-forceidx", "-ovc", "copy", "-oac", "pcm", "-o", "/home/xincoz/test/final.flv", out1, out2 ]
  
  
  
  p2=subprocess.Popen(ffmpeg_command2)

  Please help me. Thanks a lot in advance.

• AWS MediaConvert generating double length video

  1er mai 2024, par user1hjgjhgjhggjhg

  I am new to aws media convert. I am trying to convert the video but the final output video becomes double the length from the original one. for example if I have a video 30 seconds long, it will create 60 seconds long final video. Below is my son.

  


  {
  "Queue": "arn:aws:mediaconvert:us-west-2:730335xxxxx:queues/Default",
  "UserMetadata": {},
  "Role": "arn:aws:iam::73033541xxxx:role/service-role/MediaConvert_Default_Role",
  "Settings": {
    "TimecodeConfig": {
      "Source": "ZEROBASED"
    },
    "OutputGroups": [
      {
        "Name": "DASH ISO",
        "Outputs": [
          {
            "ContainerSettings": {
              "Container": "MPD"
            },
            "VideoDescription": {
              "CodecSettings": {
                "Codec": "H_264",
                "H264Settings": {
                  "MaxBitrate": 3500000,
                  "RateControlMode": "QVBR",
                  "SceneChangeDetect": "TRANSITION_DETECTION"
                }
              }
            },
            "NameModifier": "_output1"
          }
        ],
        "OutputGroupSettings": {
          "Type": "DASH_ISO_GROUP_SETTINGS",
          "DashIsoGroupSettings": {
            "SegmentLength": 30,
            "Destination": "s3://tutorial/video/",
            "FragmentLength": 2,
            "SegmentControl": "SINGLE_FILE"
          }
        }
      }
    ],
    "FollowSource": 1,
    "Inputs": [
      {
        "AudioSelectors": {
          "Audio Selector 1": {
            "DefaultSelection": "DEFAULT"
          }
        },
        "VideoSelector": {},
        "TimecodeSource": "ZEROBASED",
        "FileInput": "s3://tutorial/video/11 - video.mp4"
      }
    ]
  },
  "BillingTagsSource": "JOB",
  "AccelerationSettings": {
    "Mode": "DISABLED"
  },
  "StatusUpdateInterval": "SECONDS_60",
  "Priority": 0
}


  


  Please help