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• x86util : import MOVHL macro

  11 février 2017, par James Darnley

  x86util : import MOVHL macro
  Originally committed to x264 in 1637239a by Henrik Gramner who has
  
  agreed to re-license it as LGPL.  Original commit message follows.
      x86 : Avoid some bypass delays and false dependencies
      A bypass delay of 1-3 clock cycles may occur on some CPUs when transitioning
  
      between int and float domains, so try to avoid that if possible.
  

  • [DH] libavutil/x86/x86util.asm

• Manipulate video with ffmpeg without losing quality

  17 août 2016, par TheChymera

  I am rotating a video with ffmpeg with the following code :

  ffmpeg -i nd750_a0040.MOV -vf "transpose=dir=clock, transpose=dir=clock" out.mkv

  The resulting file is almost 10x smaller than the input.
  I have found this question which addresses a related question and suggsts passing to ffmpeg the codec and bitrate obtained from the following :

  bitratev="$(ffmpeg -i "$1" -f null - |& grep video: | awk -F'[:|kB]' '{print $2}')"
  
  codecv="$(ffprobe -loglevel error -select_streams v:0 -show_entries stream=codec_name -of default=nk=1:nw=1 "$1")"

  however, both of these commands give me the same output for both files : 2643 and h264 respectively.
  Am I correct in assuming that ffmpeg keeps these values the same for the output - by default ?

  However, if I inspect the files with ffmpeg -i I get different bitrate values :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'nd750_a0040.MOV':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537331968
  
      compatible_brands: qt  niko
  
      creation_time   : 2016-06-18 04:28:03
  
    Duration: 00:15:40.74, start: 0.000000, bitrate: 11569 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, smpte170m/bt709/bt470m), 1920x1080, 10029 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 2016-06-18 04:28:03
  
      Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 2 channels, s16, 1536 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-06-18 04:28:03

  and

  Input #0, matroska,webm, from 'out.mkv':
  
    Metadata:
  
      COMPATIBLE_BRANDS: qt  niko
  
      MAJOR_BRAND     : qt  
  
      MINOR_VERSION   : 537331968
  
      ENCODER         : Lavf56.40.101
  
    Duration: 00:15:40.74, start: 0.000000, bitrate: 1445 kb/s
  
      Stream #0:0(eng): Video: h264 (High), yuvj420p(pc), 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
  
      Metadata:
  
        CREATION_TIME   : 2016-06-18 04:28:03
  
        LANGUAGE        : eng
  
        ENCODER         : Lavc56.60.100 libx264
  
        DURATION        : 00:15:40.742000000
  
      Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        CREATION_TIME   : 2016-06-18 04:28:03
  
        LANGUAGE        : eng
  
        ENCODER         : Lavc56.60.100 libvorbis
  
        DURATION        : 00:15:40.743000000

  So I have a few questions :

  • Which bitrate is the correct one for each video ?
  • Is all of the information loss between these two files covered by the bitrate (or does ffmpeg by default change other things that lead to a lower file size as well - if so, what ?) ?
  • How do I make sure nothing else changes but the container format and the rotation ?

• FFmpeg for marking time video based on a reference date

  3 août 2016, par Denio Mariz

  I am trying to mark a timestamp in a video using Drawtext filter.
  FFmpeg easily marks timestamps based on localtime, gmtime or even PTS. However, I want to assign a reference time (start time) for the timestamp in order to represent the time the video was recorded (not encoded).

  Reading the documentation, I found that option "basetime" can be used for this purpose. However it seems that is not working or I am missing something.

  The command line I am using is :

  ffmpeg -y -i input.mp4 -filter_complex drawtext="fontfile=/tmp/UbuntuMono-B.ttf: fontsize=36: fontcolor=yellow: box=1: boxcolor=black@0.4: text='Wall Clock Time\: %{gmtime\:%Y-%m-%d %T}': basetime=1456007118" output.mp4

  By using basetime=1456007118", it was expected the start time was set to ’02/20/2016 20:25:18’ since 1456007118 is the UTC time for that time and date :

  date -d '02/20/2016 20:25:18' +"%s" # format MM/DD/AAAA hh:mm:ss
  
  1456007118

  However, no error is issued by FFMpeg and the video is marked with current GMT, ignoring "basetime" option.

  Any hint ?
  Thanks.

  Complete information about FFmpeg version and output is :

     ffmpeg -y -i /home/denio/Videos/Interstellar_2014_Trailer_4_5.1-1080p-HDTN.mp4 -filter_complex drawtext="fontfile=/tmp/UbuntuMono-B.ttf: fontsize=36: fontcolor=yellow: box=1: boxcolor=black@0.4: text='Wall Clock Time\: %{gmtime\:%Y-%m-%d %T}': basetime=1470226363" /tmp/x.mp4
   ffmpeg version 3.1.1 Copyright (c) 2000-2016 the FFmpeg developers
     built with gcc 5.3.1 (Ubuntu 5.3.1-14ubuntu2.1) 20160413
     configuration: --enable-libxavs --enable-bzlib --enable-libfaac --enable-libfreetype --enable-libfontconfig --enable-libmp3lame --enable-libschroedinger --enable-libspeex --enable-libvorbis --enable-libx264 --enable-libx265 --enable-libxvid --enable-zlib --enable-x11grab --enable-static --enable-pthreads --enable-gpl --enable-nonfree --enable-version3 --disable-ffserver --enable-libgsm --enable-librtmp --enable-libvpx --enable-libschroedinger --enable-libopencore-amrnb --enable-libopenjpeg
     libavutil      55. 28.100 / 55. 28.100
     libavcodec     57. 48.101 / 57. 48.101
     libavformat    57. 41.100 / 57. 41.100
     libavdevice    57.  0.101 / 57.  0.101
     libavfilter     6. 47.100 /  6. 47.100
     libswscale      4.  1.100 /  4.  1.100
     libswresample   2.  1.100 /  2.  1.100
     libpostproc    54.  0.100 / 54.  0.100
   ...
   ...