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• ffmpeg copy stream preserving FPS

  10 mars 2017, par James Taylor

  I have a stream that I know is outputting at a certain frame rate (30 FPS). I want to use ffmpeg to make a copy of this stream and save it to disk.

  I have the following command :

  ffmpeg -i http://input/ -c copy -map 0 \
  
      -f segment -strftime 1 -segment_time 900 \
  
      -segment_atclocktime 1 -segment_format mp4 %Y-%m-%d_%H-%M-%S.mp4

  But when I run the command, I see the following :

  frame=   32 fps=3.9 q=-1.0 Lsize=N/A time=00:00:01.27 bitrate=N/A

  Where it appears the FPS is hovers around 4.0 FPS and time moves slower than real time.

  I tried added -re (copy the rate of the input stream) and -r 30 (manually set the rate to 30 FPS) flag specified before the input file, but it didn’t seem to work.

  I also read a similar question here using -framerate 30, but that option doesn’t exist in the man pages and is an Invalid option.

  Any help would be greatly appreciated !

  ---

  So I let the modified command (removing the flags -c copy -map 0) run for exactly 5 minutes. Running ffprobe yields :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2017-03-10_01-09-12.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.2.100
  
    Duration: 00:00:15.43, start: 0.066016, bitrate: 13416 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 1024x768, 13414 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler

  Again, this only produces 15 seconds of video and I can’t seem to get a 1:1 relationship between the input stream of 30 FPS and an output stream also in 30 FPS in real time. Playing the video yields something that’s sped up.

• iOS AVFoundation - is it possible to add text/image into the video via position/motion tracking ?

  22 février 2017, par Pranoy C

  I am aware of how to add text / image overlay into a video on iOS with AVFoundation.

  1. Is there some way to do this using position/motion tracking of certain objects / areas in the video ?

  2. What exactly is this type of video editing feature called ?

  Let’s say I have a video of a car moving from left to right. I want to place an image of another car at the position of the original car so that as the car in the video is moving from left to right, my image follows on top of that car. I would also want this to be properly skewed as the car moves from left to right.

  Another example would be a video of a monitor. And me placing an image on the screen of that monitor.

  Please let me know if I need to explain further.

  Other than iOS is there some other library which is able to do this ? Like ffmpeg ?

• configure.ac : Clean up CFLAGS code

  6 février 2017, par Erik de Castro Lopo

  configure.ac : Clean up CFLAGS code
  Also moves _FORTIFY_SOURCE detection to an M4 macro.
  Patchfrom : David Seifert <soap@gentoo.org>
  

  • [DH] configure.ac
  • [DH] m4/ax_add_fortify_source.m4