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• Revision 1fc70e47cd : Adds code for corner detection and ransac This code is to start experiments wit

  7 février 2015, par Deb Mukherjee

  Changed Paths :
   Add /vp9/encoder/vp9_corner_detect.c

  
   Add /vp9/encoder/vp9_corner_detect.h

  
   Add /vp9/encoder/vp9_corner_match.c

  
   Add /vp9/encoder/vp9_corner_match.h

  
   Add /vp9/encoder/vp9_global_motion.c

  
   Add /vp9/encoder/vp9_global_motion.h

  
   Add /vp9/encoder/vp9_ransac.c

  
   Add /vp9/encoder/vp9_ransac.h

  
   Modify /vp9/vp9cx.mk

  
  
  Adds code for corner detection and ransac

  This code is to start experiments with global motion models.

  The corner detection can be either fast_9 or Harris.
  Corner matching is currently based on normalized correlation.
  Three flavors of ransac are used to estimate either a
  homography (8-param), or an affine model (6-param) or a
  rotation-zoom only affine model (4-param).

  The highest level API for the library is in vp9_global_motion.h,
  where there are two functions - one for computing a single model
  and another for computing multiple models up to a maximum number
  provided or until a desired inlier probability is achieved.

  Change-Id : I3f9788ec2dc0635cbc65f5c66c6ea8853cfcf2dd

• Transcode video using celery and ffmpeg in django

  28 octobre 2015, par Robin

  I would like to transcode user uploaded videos using celery. I think first I should upload the video, and spawn a celery task for transcoding.

  Maybe something like this in the tasks.py :

  subprocess.call('ffmpeg -i path/.../original path/.../output')

  Just completed First steps with celery, so confused how to do so in the views.py and tasks.py. Also is it a good solution ? I would really appreciate your help and advice. Thank you.

  models.py :

  class Video(models.Model):
  
      user = models.ForeignKey(User)
  
      title = models.CharField(max_length=100)
  
      original = models.FileField(upload_to=get_upload_file_name)
  
      mp4_480 = models.FileField(upload_to=get_upload_file_name, blank=True, null=True)
  
      mp4_720 = models.FileField(upload_to=get_upload_file_name, blank=True, null=True)
  
      privacy = models.CharField(max_length=1,choices=PRIVACY, default='F')
  
      pub_date = models.DateTimeField(auto_now_add=True, auto_now=False)

  my incomplete views.py :

  @login_required
  
  def upload_video(request):
  
      if request.method == 'POST':
  
          form = VideoForm(request.POST, request.FILES)
  
          if form.is_valid():
  
              if form.cleaned_data:
  
                  user = request.user
  
                  #
  
                  #
  
                  # No IDEA WHAT TO DO NEXT
  
                  #
  
                  #
  
                  return HttpResponseRedirect('/')
  
  
  
      else:
  
          form = VideoForm()
  
          return render(request, 'upload_video.html', {
  
              'form':form
  
              })

• CMTimeGetSeconds doesn't get the right video duration

  26 février 2015, par JLCastillo

  some users don’t get the right duration of videos they capture with their own device. The funny thing is others do actually see it right, using the same device models and OS version. Anyway, we observed it in a iPhone 5c 7.1.2 and an iPhone 5s 8.1.3.

  This code works for most users, but not all :

  ALAssetRepresentation *representation = [mediaObject.asset defaultRepresentation];
  
  NSURL *url = [representation url];
  
  NSDictionary *options = @{ AVURLAssetPreferPreciseDurationAndTimingKey : @YES };
  
  AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:options];
  
  videoDurationTime = CMTimeGetSeconds(avAsset.duration);

  I asked them to send the input videos, and this is the output from "ffmpeg -i"

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'bug_duration1.MOV':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 0
  
      compatible_brands: qt
  
      creation_time   : 2015-02-23 08:30:01
  
      encoder         : 8.1.3
  
      encoder-eng     : 8.1.3
  
      date            : 2015-02-23T16:30:01+0800
  
      date-eng        : 2015-02-23T16:30:01+0800
  
      model           : iPhone 5s
  
      model-eng       : iPhone 5s
  
      make            : Apple
  
      make-eng        : Apple
  
    Duration: 00:00:03.67, start: 0.000000, bitrate: 16793 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 16719 kb/s, 29.99 fps, 29.97 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2015-02-23 08:30:01
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 61 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-02-23 08:30:01
  
        handler_name    : Core Media Data Handler

  The video is detected with a duration of several minutes. Did anybody face this problem before ?

  Thanks in advance.