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• FFMpeg sync timecode with smpte ltc timecode audio signal

  11 avril 2018, par Olivier Rivard

  I’m trying to capture video from a capture card and I’m extracting 30 jpeg per second.

  I will have multiple computer capturing multiple cameras. I want to sync all those camera with a smpte ltc timecode audio signal pass in the audio line in of the camera.

  What would be the best way to set the timecode with that audio timecode using ffmpeg ?

  Here is the command I have which is sync with the timestamp, but sometime some cameras are out of sync because of the clock of the computer :

  ffmpeg -vsync 0 -f dshow -rtbufsize 1500M -video_size 1920x1080 -use_wallclock_as_timestamps 1 -copyts -r 30 -i video="QP0203 PCI, Analog 01 Capture" -r 30 -vf setpts=PTS-STARTPTS -vsync 0 -vframes 1800 name%d.jpeg -c copy -vsync 0 -vframes 1800 -f mkvtimestamp_v2 file.txt

• Estimate time of transcoding video FFMPEG [on hold]

  9 mars 2019, par Anh Vo Nguyen Nhat

  Currently, I want to assign a video transcoding task to a computer in my distributed network. The computer are heterogeneous, so I have to check whether that computing can handle the task fast enough (during a specified deadline). My approach for this is to run many experiments and then based on the statistics I will try to estimate the time when running another task.

  I am trying to predict beforehand the time it takes when transcoding a video (e.g. transcoding 1920x1080 H264 video to 1280x720 VP9) using FFMPEG tool.
  I have used the following features to build a simple neural network to predict the time :
   Video Resolution (Input + Output)
   Video Duration
   Video Codec (Input + Output)
   Video Bitrate
   Video Framerate
   Number of B, I, P frames

  However, the result is not really promising. I want to ask if there is any other way to estimate/predict the time it takes when transcoding a video ? Are there any other features beside the listed that affects the transcoding time ?

• Encode and stream from Xbox 360 kinect using ffmpeg

  17 juin 2015, par user3288346

  I want to live stream content obtained from Kinect onto my internal network.

  I have one physical machine which is my server and has ubuntu 14.04 Server on it. I connect remotely to it. I have installed ffmpeg and ffserver and can encode and stream stored video files on the server. However, I have a few problems when using the Xbox Kinect.

  I have xbox 360 kinect which I have attached through usb. I have followed this https://bitbucket.org/samirmenon/scl-manips-v2/wiki/vision/kinect, however I couldn’t get through the OpenCV part. When I run

  $ cmake-gui ..

  I get

  cmake-gui: cannot connect to X server 

  I don’t have physical access to the machine. Probably, its due to accessing it remotely.

  When I do

  test@cloud-node-2:~/kinnect$ lsusb
  
  Bus 002 Device 006: ID 045e:02ae Microsoft Corp. Xbox NUI Camera
  
  Bus 002 Device 004: ID 045e:02b0 Microsoft Corp. Xbox NUI Motor
  
  Bus 002 Device 005: ID 045e:02ad Microsoft Corp. Xbox NUI Audio
  
  Bus 002 Device 003: ID 0409:005a NEC Corp. HighSpeed Hub
  
  Bus 002 Device 002: ID 0bda:0181 Realtek Semiconductor Corp. 
  
  Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub 

  When I do

  test@cloud-node-2:~/kinnect$ ls -ltrh /dev/video*
  
  ls: cannot access /dev/video*: No such file or directory

  Therefore, I am not able to capture the video using ffmpeg.