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• 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 :

  


  

  


• 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"


  


• Anomalie #4555 : Révisions de lien si personne logé

  19 octobre 2020, par b b

  Si mes souvenirs sont bons, quand la personne n’est pas logué c’est son adresse IP qu’on utilise au lieu de l’id_auteur... => Je confirme cf https://git.spip.net/spip/revisions/src/branch/master/inc/revisions.php#L544 ce qui voudrait dire que tu tombes sur un cas où $GLOBALS['visiteur_session']['id_auteur'] passe dans le test en question alors qu’il est undefined oO

  Bref, il faudrait que tu nous donnes les paramètres passés à ajouter_version() dans ton cas d’usage.

  Je suppose que la version cible est la 3.2 ?