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• x264 : How to Correctly Use quant_offsets ?

  25 août 2022, par Eynnzerr

  Suppose I need to encode different regions with different QPs in one frame, i.e. RoI(regions of interest) encoding. I searched all over the internet and was only told that quant_offsets can meet my demand. However, none of them told me exactly how to use it, and I can't find any official documentation about it. I read the source code of x264 and did experiments, and find it only adds an offset to the qp decision x264 has made, rather than exactly set the qp value I want.

  


  Is there a possible way that I can have x264 encode these regions using the qp value I've explictly given instead of adding offsets based on what it decided on its own ? Many thanks !

  


• x264 : How to Correctly Use quant_offsets ?

  25 août 2022, par Eynnzerr

  Suppose I need to encode different regions with different QPs in one frame, i.e. RoI(regions of interest) encoding. I searched all over the internet and was only told that quant_offsets can meet my demand. However, none of them told me exactly how to use it, and I can't find any official documentation about it. I read the source code of x264 and did experiments, and find it only adds an offset to the qp decision x264 has made, rather than exactly set the qp value I want.

  


  Is there a possible way that I can have x264 encode these regions using the qp value I've explictly given instead of adding offsets based on what it decided on its own ? Many thanks !

  


• How to upload object to a bucket in Google Cloud Platform from Python script

  7 juillet 2016, par Bryan

  The goal of this script is to extract audio from a video file using ffmpeg and upload it into a bucket on Google Cloud Platform each time it is called. Eventually I will have to extract audio from a large list of videos, so ideally I would want my script to extract and subsequently upload it into the cloud.

  My confusion is how to use GCP API to upload my object into a bucket. Any advice would be greatly appreciated !

  Link for reference : https://cloud.google.com/storage/docs/json_api/v1/json-api-python-samples#setup-code

  import subprocess
  
  import sys
  
  import re 
  
  
  
  fullVideo = sys.argv[1]
  
  title = re.findall('^([^.]*).*', fullVideo)
  
  title = str(title[0])
  
  subprocess.call('ffmpeg -i ' + fullVideo + ' -vn -ab 128k ' + title + '.flac', shell = True)
  
  
  
  def upload_object(bucket, filename, readers, owners):
  
      service = create_service()
  
  
  
      # This is the request body as specified:
  
      # http://g.co/cloud/storage/docs/json_api/v1/objects/insert#request
  
      body = {
  
          'name': filename,
  
      }
  
  
  
      # If specified, create the access control objects and add them to the
  
      # request body
  
      if readers or owners:
  
          body['acl'] = []
  
  
  
      for r in readers:
  
          body['acl'].append({
  
              'entity': 'user-%s' % r,
  
              'role': 'READER',
  
              'email': r
  
          })
  
      for o in owners:
  
          body['acl'].append({
  
              'entity': 'user-%s' % o,
  
              'role': 'OWNER',
  
              'email': o
  
          })
  
  
  
      # Now insert them into the specified bucket as a media insertion.
  
      # http://g.co/dev/resources/api-libraries/documentation/storage/v1/python/latest/storage_v1.objects.html#insert
  
      with open(filename, 'rb') as f:
  
          req = service.objects().insert(
  
              bucket=bucket, body=body,
  
              # You can also just set media_body=filename, but # for the sake of
  
              # demonstration, pass in the more generic file handle, which could
  
              # very well be a StringIO or similar.
  
              media_body=http.MediaIoBaseUpload(f, 'application/octet-stream'))
  
          resp = req.execute()
  
  
  
      return resp