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• Ream-time watermarking with MPEG-DASH

  14 juillet 2016, par Calvin W.

  In the system, I want to add a unique watermark (e.g. IP address of client and time stamp) into the video that he/she want to watch.

  But when I handled it with OpenCV, it spent 25 minute with a 15-min video. And I need to transcode to mp4 with ffmpeg.

  Now I’m trying the watermark function of ffmpeg, bit it still needs some time.

  It it possible to send the video to client side with MPEG-DASH while transcoding it with ffmpeg ?

  System spec :(Amazon EC2 c3.xlarge)
  Intel Xeon E5-2680 v2 (Ivy Bridge) - 4 vCPU
  7.5G RAM
  40GB SSD
  Ubuntu 14.04 LTS
  OpenCV2.4.13
  ffmpeg 3.1.1
  

  code :

  import cv2
  
  import sys
  
  import time
  
  from datetime import datetime as dt
  
  
  
  # frame of input video
  
  fps = float(sys.argv[4])
  
  # encode to AVC
  
  fourcc = cv2.cv.CV_FOURCC('A', 'V', 'C', '1')
  
  # transparency of text
  
  alpha = 0.1
  
  beta = 1 - alpha
  
  
  
  # input video
  
  cap = cv2.VideoCapture(sys.argv[3])
  
  
  
  # current frame index, start from 0
  
  frameIndex = 0
  
  
  
  # get input video's width/height
  
  width = int(cap.get(cv2.cv.CV_CAP_PROP_FRAME_WIDTH))
  
  height = int(cap.get(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT))
  
  
  
  # config output (error using .mp4)
  
  out = cv2.VideoWriter('output.avi', fourcc, fps, (width, height))
  
  
  
  # access time
  
  timeStr = dt.fromtimestamp(time.time()).strftime('%Y-%m-%d %H:%M:%S')
  
  
  
  requestIP = sys.argv[1]
  
  username = sys.argv[2]
  
  text = "%s %s %s" % (requestIP, username, timeStr)
  
  
  
  
  
  # start loading video
  
  while(cap.isOpened()):
  
      ret, frame = cap.read()
  
      if ret:
  
          # add text between 10s - 20s
  
          if frameIndex > time10 and frameIndex < time20:
  
              # clone a new frame to add text
  
              overlay = frame.copy()
  
              cv2.putText(overlay, text, (100, 100), cv2.FONT_HERSHEY_PLAIN, 0.5, (255, 255, 255))
  
              # combine both frame and make text transparent
  
              cv2.addWeighted(overlay, alpha, frame, beta, 0, frame)
  
          # write frame to output
  
          out.write(frame)
  
          frameIndex += 1
  
      # wait for next frame
  
      if cap.get(cv2.cv.CV_CAP_PROP_POS_FRAMES) == cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT):
  
          break
  
  # End of video
  
  # release
  
  cap.release()
  
  out.release()

• FFMPEG segment live video for DASH

  23 décembre 2014, par static

  I’m trying to stream live capture of desktop to my own server, which shall create an MPD with segment template for use with dash.js player.
  Using the following command i managed to get it working
  

  ffmpeg -rtbufsize 6M -f x11grab -s 1366x768 -r 10 -i :0.0 -flags +global_header \
  
  -vcodec libvpx -deadline realtime -profile:v 0 -keyint_min 1 -g 1 -cpu-used 0 \
  
  -vb 1200k -qmin 10 -qmax 42 -threads 4 -bufsize 6000k -slices 4 -map 0 -an \
  
  -f stream_segment -segment_time 2 -segment_format webm **/streams

  The output :

  Input #0, x11grab, from ':0.0': Duration: N/A, start: 1419329032.549498, bitrate: N/A
  
  Stream #0:0: Video: rawvideo (BGRA / 0x41524742), bgra, 1366x768, 10 fps, 10 tbr, 1000k tbn, 10 tbc
  
  [libvpx@ 0x23ccf60] v1.3.0 Output #0, stream_segment, ssegment, to /streams/d':
  
  Metadata:
  
  encoder : Lavf56.15.102
  
  Stream #0:0: Video: vp8 (libvpx), yuva420p, 1366x768, q=10-42, 1200 kb/s, 10 fps, 1k tbn, 10 tbc
  
  Metadata: encoder: Lavc56.13.100 libvpx
  
  Stream mapping: Stream #0:0 -> #0:0 (rawvideo (native) -> vp8 (libvpx))
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0x23ac0c0] Warning: data is not aligned! This can lead to a speedloss
  
  frame= 2839 fps= 10 q=0.0 Lsize=N/A time=00:04:43.90 bitrate=N/A
  
  video:135246kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

  If I increase the number of frames to produce better quality, the latency drastically increases and the stream is not in sync with the MPD. This is caused by the fact that keyframes are created at every frame -keyint_min 1 -g 1 because otherwise and error MEDIA_ERR_SRC_NOT_SUPPORTED is thrown by the player. This is probably because a keyframe must be found at the beginning of each segment.

  Could ffmpeg be used to generate keyframes as the first frame in each segment ? I try different values for -keyint_min x -g y, for example number of frames but with no result (probably because the number of frames stabilized after a couple a seconds, so the first 2-3 segments were produced with inconsistent number of frames, so all the keyframes were introduced in wrong positions in the segments).

• Rails 5 with Carrierwave and S3 - creating multiple video formats for DASH streaming works but mpd file breaks

  22 novembre 2019, par Milind

  what I am doing -
  i have a Rails 5 app for video streaming(DASH MPEG) that uses FFMPEG to get encoded stream videos by converting any single video into multiple videos of multiple bit rates/size and primarily also MPD FILE that can be played easily on html video player, which i have already tested by manually running the ffmpeg scripts on the console that generates all the files.However, I want to automate this process and hence carrierwave comes into the pictures.
  Here, i use carrierwave to generate different versions(size/bitrate) of videos(mp4/webm) to upload to s3 but during running the version, where all the versions are successfully created in tmp folder, only the last version(mpd) that needs to create .mpd file, carrierwave creates a mp4 video file and just replaces the extension instead of actually creating the mpd file.

  So in the aws s3(screenshot added below), i can see my all versions and mpd file , but that mpd file which must be xml file is actually a mp4 video file or uploaded version file itself.
  I have also tried to create new file during the process, but it never works.
  Has some one encountered this problem ?

  any help will be greatly appreciated ?

  Ny code snippets below - model,uploader,output of script on the console during upload, s3 screenshot

     ##### models/video.rb ##########
  
  
  
      mount_uploader :video, VideoUploader  
  
  
  
     ####### uploaders/video_uploader.rb #########
  
  
  
      class VideoUploader < CarrierWave::Uploader::Base
  
  
  
  
  
      include CarrierWave::MiniMagick
  
      include CarrierWave::Video
  
      include CarrierWave::Video::Thumbnailer
  
      include ::CarrierWave::Backgrounder::Delay
  
  
  
      ####### for streaming ..first get the audio and then convert the input video into multiple bitrates/scale #######
  
  
  
      ###first get audio and then get all different versions of same video
  
      version :video_audio do
  
        process :get_audio
  
  
  
        def get_audio
  
          `ffmpeg -y -i "#{file.path}" -c:a aac -ac 2 -ab 128k -vn video_audio.mp4`
  
        end
  
  
  
          def full_filename(for_file)
  
            "video_audio.mp4"
  
          end
  
  
  
          def filename
  
            "video_audio.mp4"
  
          end        
  
      end 
  
  
  
      ####### similar to the above i have various version like ...#########
  
  
  
      version :video_1080 do...end
  
      version :video_720 do... end
  
      version :video_480 do ...end
  
      ...and so on..and all these versions are successfully created and uploaded to s3, however..in next version ...show it also creates a video file whereas i need a simple mpd file ONLY.
  
  
  
           ###this is where even after everything works, in S3, i can see a video file of version mpd and not actual mpd file
  
           version :mpd  do
  
             process :get_manifest
  
                ###here in the command below, the video.mpd file is successfully obtained but its uploaded as video.mpd file of added/uploaded video file and not a new mpd file
  
                ###tried with ffmpeg -f webm_dash_manifest -i too, but s3 still shows a mp4 file
  
                `MP4Box -dash 1000 -rap -frag-rap -profile onDemand -out video.mpd video_1080.mp4 video_720.mp4 video_480.mp4 video_360.mp4 video_240.mp4 video_audio.mp4 `
  
  
  
             end
  
            end
  
  
  
           ######### sidekiq console output - successful mpd is generated ################
  
                DASH-ing files - single segment
  
                Subsegment duration 1.000 - Fragment duration: 1.000 secs
  
                Splitting segments and fragments at GOP boundaries
  
                DASHing file video_1080.mp4
  
                DASHing file video_720.mp4                                  
  
                DASHing file video_480.mp4                                  
  
                DASHing file video_360.mp4                                  
  
                DASHing file video_240.mp4                                  
  
                DASHing file video_audio.mp4                                
  
               \[DASH\] Generating MPD at time 2019-11-22T00:01:59.872Z      
  
                mpd_1mb.mp4
  
                mpd_video.mpd

  this is what the uploaded files looks on s3, notice the video.mpd, its a mp4 video file just like others which should have been a simple mpd file of not more than 2kb.

  Is there something that I am missing ?
  Can Carrierwave do this or is it not made for this ?
  Do I have to write a callback and then programmatically upload files to s3, if carrierwave is not helping in this regard ?

  Kindly provide any suggestion or useful advice so that I can move ahead.