Recherche avancée

Sur d’autres sites (6375)

• 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 to kurento rtp stream choppy video issue

  29 juillet 2020, par ahmetsarias

  I use ffmpeg to make an rtp stream to kurento media server and then send it to browsers via webrtc.

  


  ffmpeg (h264 RTP) -> Kurento -> (h264 WebRTC) Browser

  


  I'm capturing virtual xorg display.
This is my ffmpeg command :

  


  ffmpeg -y -v info -fflags +genpts -f x11grab -draw_mouse 0 -r 25 -s 1280x720 -thread_queue_size 4096 -i :0.0+0,0 -an -c:v libx264 -preset veryfast -crf 25 -g 50 -pix_fmt yuv420p -maxrate 2976k -bufsize 5952k -ssrc 112233 -payload_type 103 -tune zerolatency -f rtp rtp://172.16.1.115:40258

  


  This is my fake sdp offer used in negotiation with kurento RtpEndpoint

  


  v=0
o=- 0 0 IN IP4 127.0.0.1
s=Stream
c=IN IP4 127.0.0.1
t=0 0
m=video 9 RTP/AVP 103
a=rtpmap:103 H264/90000
a=fmtp:103 packetization-mode=1
a=sendonly
a=direction:active
a=ssrc:112233 cname:user@example.com 


  


  Here is the problem :

  


  Some I-frames are choppy on bottom half slice of the frame while others have no problem.

  


  It is sometimes corrected when another I-frame has arrived, but mostly choppy.

  


  When choppiness happened, Kms log says :

  


  


  kmsutils kmsutils.c:483:gap_detection_probe:kmsagnosticbin2-108:sink Stream gap detected, timestamp : 0:51:22.574766908, duration : 0:00:00.000008237

  


  


  Normal stream (No choppy at all)

  


  

  


  Choppy stream

  


  

  


  When it is corrected with an I-Frame (Sometimes it happens)

  


  

  


  I have no clue about what could lead the issue.

  


  Things that I tried to solve the problem.

  


  

  • Adding ?pkt_size=1000 (1100,900,1200. Since the mtu in kurento is 1200 default)

  


  • Changing -crf to different values in between 18-35

  


  • Changing -preset between medium and ultrafast

  


  • Changing framerate

  


  • Changing gop length (When i lower the gop length -More I-Frames- choppiness become shorter in duration but more frequent)

  


  • When I disable sliced-threads, there is no issue with bottom side but whole screen freezes in same scenario

  


  


  Any help would be appreciated. Thanks.

  


• How to ffmpeg a PNG image sequence in multiple subdirs to one mp4 ?

  17 août 2021, par MikeEcho

  I am trying desperately to get this working.

  


  I have multiple files in the format of : lago_20210817_1200.png, lago_20210817_1201.png and so on.

  


  I am having a folder for each day of the year. eg. lago_20210817_1200.png is the folder 2021, subfolder 08, subfolder 17.

  


  I have tried many different approaches :

  


  

  • ffmpeg -f concat -i filelist.txt -r 25 output.mp4

  


  • ffmpeg -f concat -i <(find '/home/user/lago/2021/08/*.png') -r 25 output.mp4

  &#xA;

  &#xA;

  But no approach seems to work !

  &#xA;

  I tried to create a filelist with :

  &#xA;

  find . -name '*.png' -exec echo "file '{}'" \;|sort -h|sort


  &#xA;

  the result looked promising

  &#xA;

  file './lago_20210813_1959.png'
file './lago_20210813_2000.png'
file './lago_20210813_2001.png'


  &#xA;

  I am getting very different error messages...

  &#xA;

  DTS -230584300921369, next:40000 st:0 invalid dropping
PTS -230584300921369, next:40000 invalid dropping st:0
DTS -230584300921369, next:40000 st:0 invalid dropping


  &#xA;

  or

  &#xA;

  [concat @ 0x562531fe6c80] Unsafe file name './lago_20210813_2155.png'


  &#xA;

  Could anyone lead me in the right direction, i am desperate.

  &#xA;

  ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100


  &#xA;