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• configure.ac : Remove unused config flags

  4 décembre 2016, par Erik de Castro Lopo

  configure.ac : Remove unused config flags
  FLAC__NO_SSE_OS and FLAC__SSE_OS.
  Patch-from : "lvqcl.mail" <lvqcl.mail@gmail.com>
  

  • [DH] configure.ac

• How to process video stream ?

  27 avril 2016, par sharpener

  I would like to ask some experienced multimedia professional how to proceed with following task :

  Given URL provides video stream and we would like to get access to decoded frames (byte stream in memory) in managed Win7+ application (C#). We don’t want to render/present the frames the standard way. The video format is known but not fixed (might get changed between two successive sessions, but we will know the parameters).

  So far, I have found there are several methods and I have build following picture in my mind :

  1. ffmpeg wrapper
     • Pros
       1. Self contained (no dependency to windows technologies)
       2. Powerful
     • Cons
       1. Little more complex to understand
       2. Lot of different wrapping variants (FFmpeg.NET, ffmpeg-sharp, ffmpeg-shard, FFmpeg.AutoGen, ...)
  2. DirectShow wrapper
     • Pros
       1. Widely used/supported technology (variaous filters freely available)
       2. Nice/detailed documentation on MSDN
     • Cons
       1. Quite old
       2. Considered obsolete from the point of author’s view (available only for desktop model on runtime >= Win8)
  3. MediaFoundation wrapper
     • Pros
       1. Theoretical successor of DirectShow, so should be available in the future
     • Cons
       1. Seems to be not as good as DirectShow
       2. Not very popular, limited "community" support
  4. FFmpegInterop wrapper
     • Pros
       1. Microsoft’s open source wrapper alternative
     • Cons
       1. Not available for runtime < Win8

• Audio video duration matching for infinite dash loop pseudo live

  19 janvier 2020, par Massimo Vantaggio

  May I ask help to understand how to match audio and video duration during ffmpeg encoding for a concatenation of videos destined to an infinite loop mpeg dash transmission (mp4box).

  My issue happen during ffmpeg encoding :

  first step for audio encoding and timebase uniformity of each video before the concat/encode process :

  ffmpeg -y -i "$f" -c copy -video_track_timescale 90k -c:a aac -b:a 384k -ar 44100 -ac 2 -shortest -af aresample=async=1 ../buffer/${NAME}_buffer.mp4

  Then concat/encode process in order to get total duration in seconds multiple of closed GOP
  for example : cutting 373.5 duration to obtain 372.000 duration :

  ffmpeg -f concat -safe 0 -y -i list.txt -loop 1 -i ../logo/logo.png -c:a copy -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 4800k -maxrate 9600k -bufsize 19200k -profile:v main -crf 22 -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=1920:1080,setsar=1" -t $TOTDUR 1080set.mp4 

  the result

  VIDEO FORMAT CONTAINER DURATION:
  
  372.000000
  
  VIDEO STREAM DURATION:
  
  372.000000
  
  AUDIO FORMAT CONTAINER DURATION:
  
  372.006000

  I need help to understand why the audio duration counts 6 ms more than video duration and how to fix it.
  I read about loop_stream should help ?
  Thanks a lot !

  Below the videos info :

  Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isomavc1
  
      creation_time   : 2007-05-09T07:55:25.000000Z
  
    Duration: 00:01:29.22, start: 0.000000, bitrate: 7490 kb/s
  
      Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1920x816, 7403 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
  
      Metadata:
  
        creation_time   : 2007-05-09T07:55:25.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 94 kb/s (default)
  
      Metadata:
  
        creation_time   : 2007-05-09T07:55:29.000000Z
  
        handler_name    : GPAC ISO Audio Handler
  
  
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isomavc1
  
      creation_time   : 2007-07-17T09:18:37.000000Z
  
      genre           : Trailer
  
      artist          : Fox
  
      title           : The Simpsons Movie
  
      date            : 2007
  
    Duration: 00:02:17.25, start: 0.000000, bitrate: 8591 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x800, 8486 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
  
      Metadata:
  
        creation_time   : 2007-07-17T09:18:37.000000Z
  
        handler_name    : GPAC ISO Video Handler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, 5.1, fltp, 107 kb/s (default)
  
      Metadata:
  
        creation_time   : 2007-07-17T09:18:45.000000Z
  
        handler_name    : GPAC ISO Audio Handler
  
      Stream #0:2: Video: mjpeg (Progressive), yuvj420p(pc, bt470bg/unknown/unknown), 101x150 [SAR 72:72 DAR 101:150], 90k tbr, 90k tbn, 90k tbc (attached pic)
  
  
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: mp42isomavc1
  
      creation_time   : 2013-12-01T03:59:56.000000Z
  
      genre           : Trailer
  
      artist          : Warner Bros.
  
      title           : Gravity - 2K Trailer
  
      encoder         : HandBrake 0.9.9 2013051800
  
      date            : 2013
  
    Duration: 00:02:27.07, start: 0.000000, bitrate: 20296 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 2048x858, 20149 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
  
      Metadata:
  
        creation_time   : 2013-12-01T03:59:56.000000Z
  
        encoder         : JVT/AVC Coding
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 153 kb/s (default)
  
      Metadata:
  
        creation_time   : 2013-12-01T03:59:56.000000Z
  
      Stream #0:2: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 102x150 [SAR 72:72 DAR 17:25], 90k tbr, 90k tbn, 90k tbc (attached pic)