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• ffmpeg audio - video sync issue (audio ahead of video) - while screen recording using x11grab

  12 juillet 2023, par maheshg

  While screen-recording using the below ffmpeg options I consistently get audio ahead of video, delay is in the order of few seconds

  


  ffmpeg cmd :

  


  ffmpeg -y -f x11grab -thread_queue_size 1024 -draw_mouse 0 -video_size 1920x1080 -i :0 -f pulse -thread_queue_size 1024 -i default -c:v libx264 -threads 0 -preset faster -c:a flac -async 1 -vsync 1 -crf 30 -crf_max 33 -f matroska output.mkv

  


  ffprobe output below :

  


  $ ffprobe demo.mkv 
ffprobe version 3.4.4-1~16.04.york0 Copyright (c) 2007-2018 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
  configuration: --prefix=/usr --extra-version='1~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, matroska,webm, from 'demo.mkv':
  Metadata:
    ENCODER         : Lavf57.71.100
  Duration: 01:00:31.93, start: 0.000000, bitrate: 416 kb/s
    Stream #0:0: Video: h264 (High), yuv420p(progressive), 1920x1080, 29.97 fps, 29.97 tbr, 1k tbn, 59.94 tbc (default)
    Metadata:
      ENCODER         : Lavc57.89.100 libx264
      DURATION        : 01:00:31.928000000
    Stream #0:1: Audio: flac, 48000 Hz, stereo, s16 (default)
    Metadata:
      ENCODER         : Lavc57.89.100 flac
      DURATION        : 01:00:30.912000000


  


  I have even tried using avoid_negative_ts flag, but it didnt help with the sync issue.

  


  


  OS : Ubuntu-18.04

  


  ffmpeg version : 3.4

  


  


  Update : (with ffmpeg-4.0)
I have since split this process into 2 parts and tried as shown below (quality is better, but audio/video sync is still an issue)

  


  # STEP-1: screen recording
/usr/bin/ffmpeg -y -f x11grab -thread_queue_size 1024 -draw_mouse 0 \
-video_size 1920x1080 -i :91141925 -f pulse -thread_queue_size 1024 \
-i virtual_sink.monitor -c:v libx264rgb -threads 0 -preset ultrafast \
-c:a flac -ac 1 -crf 0 -f matroska output.mkv

# STEP-2: audio/video encoding
/usr/bin/ffmpeg -y -i output.mkv -c:v libx264 -threads 0 \
-preset faster -pix_fmt yuv420p -c:a copy -ac 1 -crf 25 \
-f matroska final_output.mkv


  


  STEP-1 uses much less CPU during screen recording, but audio is still ahead of video. the display I am using is xvfb one in STEP-1 (since, this is a headless machine in the cloud)

  


  Also, i have tried flags -filter_complex aresample=44100 -vsync 1 in STEP-1 to no avail.

  


  Can someone please help !

  


  


  Update 2 : (with latest ffmpeg from git master)

  


  IT WORKED ! THANKS @llogan for the helpful comments.

  


  


• stream 0, timescale not set when concat video using ffmpeg

  17 février 2018, par no name

  I have 2 video which i want to add them together so i make a text file which contains the file names

  file No-fade_25fps.mp4
  
  file video.mp4

  then i start using this command

  ffmpeg -f concat -i ffmpeg-sound.txt -c copy final_output.mp4

  the problem is i got this from ffmpeg

      [mov,mp4,m4a,3gp,3g2,mj2 @ 0561dbc0] stream 0, timescale not set
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0561dbc0] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from 'out.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 464 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 464 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Metadata:
  
        creation_time   : 2018-02-09T10:36:18.000000Z
  
        handler_name    : Core Media Video
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 72:72 DAR 16:9], 90k tbr, 90k tbn, 90k tbc
  
  Output #0, mp4, to 'final_output.mp4':
  
    Metadata:
  
      encoder         : Lavf58.7.100
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 464 kb/s, 25 fps, 25 tbr, 12800 tbn, 25 tbc
  
      Metadata:
  
        creation_time   : 2018-02-09T10:36:18.000000Z
  
        handler_name    : Core Media Video
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 05c3e940] Auto-inserting h264_mp4toannexb bitstream filter
  
  frame= 8194 fps=0.0 q=-1.0 Lsize=    2254kB time=46:35:51.68 bitrate=   0.1kbits/s speed=1.19e+006x
  
  video:2157kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 4.486598%

  the result give me a video mp4 file with a long duration like 46:33:20 and it not work, and iam sure that both videos have same reslution.
  what i tried is to use this command to convert the video

  ffmpeg -y -i No-fade_25fps.mp4 -r 25 -s 1280x720 -c:v libx264 -b:v 3M -strict -2 -movflags faststart destination.mp4

  and when i concate them again it worked and give me result mp4 file which have a right duration and worked fine but without a sound, because the first video file i use is muted no sound in it and second one contains a sound.
  my question is how to concate those videos togther without this problem also what make the video have the problem of this long duration and when i convert them using the command line it worked ?
  first video info which is No-fade_25fps.mp4

      [mov,mp4,m4a,3gp,3g2,mj2 @ 03e05000] stream 0, timescale not set
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'No-fade_25fps.mp4':
  
    Metadata:
  
      major_brand     : M4V
  
      minor_version   : 1
  
      compatible_brands: M4V M4A mp42isom
  
      creation_time   : 2018-02-09T10:36:18.000000Z
  
      keywords        : tunepro,orange
  
      album_artist    : Kiran Khan
  
      description     : This video is about new tunepro
  
      artist          : Kiran Khan
  
      title           : new tunepro
  
    Duration: 00:00:06.48, start: 0.000000, bitrate: 497 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 464 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
  
      Metadata:
  
        creation_time   : 2018-02-09T10:36:18.000000Z
  
        handler_name    : Core Media Video
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 72:72 DAR 16:9], 90k tbr, 90k tbn, 90k tbc
  
  At least one output file must be specified

  second video video.mp4

      Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.7.100
  
    Duration: 00:05:21.28, start: 0.000000, bitrate: 181 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 1280x720 [SAR 1:1 DAR 16:9], 45 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, s16p, 127 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler

  what i want is to add any number of videos togthers without a problems like this they all have same reslution and frame per second is there something else need to be checked before i start merge videos ?
  Update
  this what i get when i use the command without copy codec

  [mov,mp4,m4a,3gp,3g2,mj2 @ 058ddb80] stream 0, timescale not set
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 058ddb80] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from 'out.txt':
  
    Duration: N/A, start: 0.000000, bitrate: 464 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 464 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Metadata:
  
        creation_time   : 2018-02-09T10:36:18.000000Z
  
        handler_name    : Core Media Video
  
      Stream #0:1: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 72:72 DAR 16:9], 90k tbr, 90k tbn, 90k tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 05937d00] using SAR=1/1
  
  [libx264 @ 05937d00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
  
  [libx264 @ 05937d00] profile High, level 3.1
  
  [libx264 @ 05937d00] 264 - core 155 r2901 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'final_output.mp4':
  
    Metadata:
  
      encoder         : Lavf58.7.100
  
      Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc
  
      Metadata:
  
        creation_time   : 2018-02-09T10:36:18.000000Z
  
        handler_name    : Core Media Video
  
        encoder         : Lavc58.9.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 058ddb80] Auto-inserting h264_mp4toannexb bitstream filtered=3.41x
  
  More than 1000 frames duplicated

  and it stop like it’s in infinite loop

• How encrypt video file using ffmpeg with a single file output

  9 décembre 2016, par Akshay Kumar

  I am trying to encrypt a video(mp4) file having a single file output. Here is the command that I use :
  ffmpeg -i -c:v libx264 -preset slow -hls_list_size 0 -hls_key_info_file encrypt.keyinfo -f hls -hls_playlist_type vod -hls_time 20 -threads 0 .
  However when I play the generated m3u8 file in safari the video stop for seconds(timer goes on) and resume after few seconds. This is happens multiple times in a single video playback.
  Can anyone help me to encode video file with single output file.

  Full command :

  /usr/local/bin/ffmpeg -i MJ.mp4 -c:v libx264  -preset slow -hls_list_size 0 -hls_key_info_file encrypt.keyinfo -f hls -hls_playlist_type vod -hls_flags single_file -hls_time 20  -threads 0 encrypted15.m3u8

  It’s corresponding console output :

  ffmpeg version 3.2.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libavresample   3.  1.  0 /  3.  1.  0
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'MJ.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf54.63.104
  
    Duration: 00:04:43.21, start: 0.000000, bitrate: 1070 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 938 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [libx264 @ 0x7f8930818200] using SAR=1/1
  
  [libx264 @ 0x7f8930818200] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 0x7f8930818200] profile High, level 3.1
  
  Output #0, hls, to 'encrypted15.m3u8':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf57.56.100
  
      Stream #0:0(und): Video: h264 (libx264), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 90k tbn, 25 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
        encoder         : Lavc57.64.101 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1(und): Audio: aac (LC), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc57.64.101 aac
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame= 7079 fps= 64 q=-1.0 Lsize=N/A time=00:04:43.21 bitrate=N/A speed=2.55x
  
  video:30401kB audio:4156kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  
  [libx264 @ 0x7f8930818200] frame I:66    Avg QP:16.19  size: 44529
  
  [libx264 @ 0x7f8930818200] frame P:2496  Avg QP:20.09  size:  7995
  
  [libx264 @ 0x7f8930818200] frame B:4517  Avg QP:21.77  size:  1823
  
  [libx264 @ 0x7f8930818200] consecutive B-frames:  5.7% 10.3% 52.4% 31.6%
  
  [libx264 @ 0x7f8930818200] mb I  I16..4: 34.7% 39.2% 26.0%
  
  [libx264 @ 0x7f8930818200] mb P  I16..4:  4.8%  7.0%  0.7%  P16..4: 31.6%  7.1%  2.6%  0.0%  0.0%    skip:46.2%
  
  [libx264 @ 0x7f8930818200] mb B  I16..4:  0.4%  0.4%  0.0%  B16..8: 24.8%  1.6%  0.1%  direct: 0.9%  skip:71.8%  L0:39.4% L1:57.4% BI: 3.2%
  
  [libx264 @ 0x7f8930818200] 8x8 transform intra:52.6% inter:73.7%
  
  [libx264 @ 0x7f8930818200] direct mvs  spatial:99.9% temporal:0.1%
  
  [libx264 @ 0x7f8930818200] coded y,uvDC,uvAC intra: 23.4% 41.8% 12.7% inter: 3.8% 6.4% 0.3%
  
  [libx264 @ 0x7f8930818200] i16 v,h,dc,p: 40% 25% 12% 23%
  
  [libx264 @ 0x7f8930818200] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 28% 16% 36%  2%  3%  4%  4%  3%  4%
  
  [libx264 @ 0x7f8930818200] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 19% 14%  5%  8%  7%  8%  6%  6%
  
  [libx264 @ 0x7f8930818200] i8c dc,h,v,p: 49% 21% 21%  8%
  
  [libx264 @ 0x7f8930818200] Weighted P-Frames: Y:6.7% UV:6.2%
  
  [libx264 @ 0x7f8930818200] ref P L0: 66.8% 10.5% 12.6%  4.9%  5.1%  0.2%  0.0%
  
  [libx264 @ 0x7f8930818200] ref B L0: 82.4% 12.1%  4.5%  1.0%
  
  [libx264 @ 0x7f8930818200] ref B L1: 99.2%  0.8%
  
  [libx264 @ 0x7f8930818200] kb/s:879.53
  
  [aac @ 0x7f8930811e00] Qavg: 7830.089