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• How concat files URL of S3 using Lambda, Ffmpeg

  4 juillet 2021, par Tính Ngô Quang

  I am trying to concat webm files into 1 file, Then upload file new video to S3
Using S3, ffmpeg/lambda-layer

  


  import subprocess
import shlex
import boto3

def lambda_handler(event, context):
    ffmpeg_cmd = "ffmpeg -safe 0 -f matroska concat"
    ffmpeg_cmd += " -i https://s3demo.s3.ap-northeast-1.amazonaws.com/archives/input/record/mask/ep_1.webm"
    ffmpeg_cmd += " -i https://s3demo.s3.ap-northeast-1.amazonaws.com/archives/input/record/mask/ep_2.webm"
    ffmpeg_cmd += " -c:v copy -af aresample=async=1:first_pts=0 -"

    command1 = shlex.split(ffmpeg_cmd)
    p1 = subprocess.run(command1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    print(p1.stdout)
    print(p1.stderr)
    # resp = s3_client.put_object(Body=p1.stdout, Bucket=s3_source_bucket, Key=s3_destination_filename2)


  


  I get error message :

  


  


  concat : Read-only file system

  


  


  According to the article below, using directory storage but still the same error.
https://stackoverflow.com/a/47323443/2949104

  


  ffmpeg_cmd += " -vcodec copy -acodec copy /tmp/output.webm -y"


  


• FFMPEG Wipe transition one layer over another

  25 juillet 2021, par Dan Weaver

  How to reveal one layer over another with a wipe transition using FFMPEG ?

  


  

  


  NOTE : this is not a slide transition. The top image stays in one position but is gradually revealed over time.

  


  I'd like a technique that can work for top layers with or without transparency and for images, videos or dynamically created sources, like showwavespic.

  


  I tried making a mask animation like so :

  


  

  


  but alphamerge doesn't work as I expected it to and I can't find a blend mode that works with this type of mask.

  


  EDIT : The xfade filter was suggested but it doesn't seem to work with when source has transparency. It renders transparent areas black. Example with transparent source :

  


  

  


  But xfade renders this :

  


  

  


• ffmpeg - prop flicker removal works but ffmpeg insists on changing framerate [closed]

  28 avril 2023, par Mutley Eugenius

  I have been researching how to use FFmpeg to do some fantastic wizardry on my cockpit videos to remove the dramatically distracting propeller, but after many hours now I cannot seem to find a way to get the program to stop stripping more than half the frames. The source video file is 1920 x 1080 @ 60fps and I believe I have my offset right (1/60= 0.0166) but the output video is always coming out at 25 fps. Can't see what element in the code is telling it to do that, or how to change it.

  


  Here's my file :

  


  https://drive.google.com/file/d/1VPttH4PHgUr0uzmsbl4Bcyg5_gAixblA/view?usp=sharing

  


  Here's my code :

  


  ffmpeg -i G:\PropFlicker.mp4 -itsoffset 0.01666 -i G:\PropFlicker.mp4 -filter_complex color=0x202020:s=1920x1080:d=24[mask];[mask][0][1]maskedmax=[out] -map [out] -crf 10 G:\PropNoFlicker.mp4


  


  I have tried adding -r 60 which gives me a 60 fps output file, but the video is still being processed at 25 and it just adds in duplicated frames after processing to pad it out to 60. The rendering shows more dropped frames than rendered frames by about a 3 to 2 ratio which matches frame drops from 60 to 25. I lose my shot fluidity and I get flickery artifacts

  


  What am I missing to get the flicker removal processing done at 60 fps and the output file rendered at 60 fps with the original smoothness ?

  


  I'm also not sure what the :d=24 is doing. I tried d=60, but it made no difference.

  


  I copied original code that I found in this link :

  


  text