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• ffmpeg - embed metadata that updates regularly in video

  11 juillet 2018, par ketil

  I have a video that was recorded with an ROV, or an underwater drone if you will. There video is stored in raw H.264, and lots of data is logged during a dive, like temperature, depth, pitch/roll/yaw, etc. Each log entry is timestamped with seconds since epoch.

  Copying the raw H264 into an mp4 container at the correct framerate is easy, but I’d like to create a video that displays some or all of the metadata. I’d like to automate the process, so that I can come back from a trip and run a conversion batch tool that applies the metadata from new dives into the new video recordings. I’m hoping to avoid manual steps.

  What are my options to display details on the video ? Displaying text on the video is a common thing to do, but it isn’t as clear to me how I could update it every few seconds based on an epoch timestamp from the logs. If I use -vf and try to use frame ranges for when to display each value, that’ll be a very long filter. Would it help somehow if I generate an overlay video first ? I don’t see how that will be much easier, though.

  Examples of some of the details I am hoping to embed are :

  • depth
  • temperature
  • pitch, roll and yaw, perhaps by using "sprites" that can be rotated based on the logged rotation around each axis

  Here’s a small sample of some of the logged data :

  1531168847.588000000 depth: 5.7318845
  
  1531168848.229000000 attitude.calc.roll: -178.67145730705903
  
  1531168848.229000000 attitude.calc.pitch: 8.89832326120461
  
  1531168848.598000000 pressure.fluid_pressure_: 1598.800048828125
  
  1531168848.898000000 temp.water.temperature.temperature_: 13.180000305175781
  
  1531168849.229000000 attitude.calc.roll: -177.03372656909875
  
  1531168849.229000000 attitude.calc.pitch: 3.697970708364904
  
  1531168849.605000000 pressure.fluid_pressure_: 1594.0999755859375
  
  1531168850.235000000 attitude.calc.yaw: 19.87041354690573
  
  1531168850.666000000 pressure.fluid_pressure_: 1593.300048828125

  The various values are logged at fairly irregular intervals, and they are not all updated at the same time.

  I can massage the data into any necessary format. I also have a timestamp (epoch based) of when each recording started, so I can calculate approximate frame numbers as necessary. I have been searching for ways to apply the epoch timestamp to the video (PTS, RTCTIME/RTCSTART), without luck so far. If I manage that, I imagine use of the enable filter might be easier, but I’m still not sure very very long video filters are the way to go.

• Installation of FFMPEG for Python in WIndows

  10 février 2024, par user3587175

  I'm trying to use this python video converter and I couldn't even run the test. I read in the manual that I had to install FFMPEG separately so I did (I created the folder in C :\, the enviroment variable "path" and tested it and worked) but still doesn't work.

  



  When I run the command :

  



  python setup.py test


  



  I get this :

  



  Traceback (most recent call last):&#xA;  File "setup.py", line 51, in <module>&#xA;    packages=[&#x27;converter&#x27;],&#xA;  File "C:\Python27\lib\distutils\core.py", line 151, in setup&#xA;    dist.run_commands()&#xA;  File "C:\Python27\lib\distutils\dist.py", line 953, in run_commands&#xA;    self.run_command(cmd)&#xA;  File "C:\Python27\lib\distutils\dist.py", line 972, in run_command&#xA;    cmd_obj.run()&#xA;  File "setup.py", line 20, in run&#xA;    raise Exception(&#x27;tests failed&#x27;)&#xA;Exception: tests failed&#xA;</module>

  



  When I run this example code :

  



  from converter import Converter
c = Converter()

info = c.probe('test1.ogg')

conv = c.convert('test1.ogg', '/tmp/output.mkv', {
    'format': 'mkv',
    'audio': {
        'codec': 'mp3',
        'samplerate': 11025,
        'channels': 2
    },
    'video': {
        'codec': 'h264',
        'width': 720,
        'height': 400,
        'fps': 15
    }})

for timecode in conv:
    print "Converting (%f) ...\r" % timecode


  



  I get this :

  



  Traceback (most recent call last):&#xA;  File "C:\Users\USER\worspace_pyth\cosa\prueba1.py", line 3, in <module>&#xA;    c=Converter()&#xA;  File "C:\Python27\converter\__init__.py", line 27, in __init__&#xA;    ffprobe_path=ffprobe_path)&#xA;  File "C:\Python27\converter\ffmpeg.py", line 345, in __init__&#xA;    raise FFMpegError("ffmpeg binary not found: " &#x2B; self.ffmpeg_path)&#xA;converter.ffmpeg.FFMpegError: ffmpeg binary not found: ffmpeg&#xA;</module>

  



  I can't understand what else I need to do for this to work. Thanks for your help.

  


• avformat/utils : function to get the formatted ntp time

  7 mai 2018, par Vishwanath Dixit

  avformat/utils : function to get the formatted ntp time
  This utility function creates 64-bit NTP time format as per the RFC
  
  5905.
  
  A simple explaination of 64-bit NTP time format is here
  
  http://www.beaglesoft.com/Manual/page53.htm
  

  • [DH] libavformat/internal.h
  • [DH] libavformat/utils.c