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• lavu : add av_gettime_relative()

  12 mai 2014, par Olivier Langlois

  lavu : add av_gettime_relative()
  These functions are using the POSIX clock_gettime() function with the
  
  CLOCK_MONOTONIC clock id. If these are not present on the targeted
  
  platform, the new functions will fallback on using the original realtime functions
  
  av_gettime() and av_usleep().
  Monotonic support can be added on other platforms with their
  
  equivalent native system API eventually if possible.
  Whenever time is requested to measure relative time, the monotonic clock,
  
  when available, is superior to the system realtime clock because it is
  
  not affected by discontinuous jumps in the system time
  In a future step, offering the flexibility to let the user choose between
  
  rt and monotonic clock for avdevices packets will be investigated.
  It is very easy to experience the issues that this patch attempt to address
  
  by rewinding back in the past the system time while ffmpeg is running.
  this is breaking the ffmpeg report printing (ffmepg.c:print_report()) and
  
  the the rate emulator functionality (-re) without the patch.
  Signed-off-by : Olivier Langlois <olivier@trillion01.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/APIchanges
  • [DH] libavutil/time.c
  • [DH] libavutil/time.h
  • [DH] libavutil/version.h

• How to transcode to another video parameters ? [on hold]

  23 mai 2014, par user3668381

  Google, man pages and any docs I found didn t shown anything relevant so...

  I want to be able to concatene video with ffmpeg, this part is simple, but fail (freeze or massive frame dropping) if the videos don t have the same properties.

  But for now, I didn t found anything else but trying to set a lot of options, expecting to get the good properties... But when they aren t rounded down (or up), you just can t set them (tbr, tbn...).

  So my question is, is there any hidden option in ffmpeg to take the properties of another video (so -copy won t work) as the properties of the transcode.

  Illustration :

  This is the video from which I wan t to copy the parameters :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'cdr.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 2013-07-04 11:04:27
  
      encoder         : Lavf54.11.100
  
    Duration: 00:06:26.96, start: 0.000000, bitrate: 804 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 854x480 [SAR 1280:1281 DAR 16:9], 753 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-07-04 11:04:27
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 44 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-07-04 11:04:27
  
        handler_name    : SoundHandler
  
  At least one output file must be specified

  For now, my command is ffmpeg -i video.mp4 -c:v h264 -c:a libfdk_aac -aspect 16:9 -b:v 753k -b:a 44k output.mp4

  But it turn out that output.mp4 reveal :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf55.21.100
  
    Duration: 00:00:07.11, start: 0.046440, bitrate: 685 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 854x480 [SAR 1280:1281 DAR 16:9], 637 kb/s, 15 fps, 15 tbr, 15360 tbn, 30 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 45 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  At least one output file must be specified

  As we can see, audio bitrate is rounded, tbn is off the chart, general bitrate isn t the same and on and on and on...

  Is there any better way but to add options again and again and hope that nothing will be rounded ? Something like ffmpeg -i video.mp4 -use_properties_of model.mp4 output.mp4 ?

• ffplay : support rotated video.

  18 avril 2014, par Clément Bœsch

  ffplay : support rotated video.
  with -f lavfi -i testsrc=s=hd1080 as source :
  
    rotate=90*PI/180  vs transpose=clock :   42fps -> 64fps
  
    rotate=180*PI/180 vs vflip,hflip :       75fps -> 77fps
  
    rotate=270*PI/180 vs transpose=cclock :  43fps -> 63fps
  

  • [DH] configure
  • [DH] doc/ffplay.texi
  • [DH] ffplay.c