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• Block artifacts in extracted frame using ffmpeg

  28 août 2020, par 12.yakir

  I'm extracting a single frame from a video with :

  


  ffmpeg -ss 60 -i video.mov -vframes 1 a.jpg


  


  which produces this :

I tried manipulating the pix_fmt and the quality of the q:v 2 to no avail. Note that elsewhere in the video (i.e. not at 60 seconds, but before or after) no such artifacts are visible.

  


  The one thing that helped a little is averaging across multiple frames (adapted from here for 15 frames) :

  


  -vf tmix=frames=15:weights="1 1 1 1 1 1 1 1 1 1 1 1 1 1 1",select='not(mod(n\,15))'


  


  which looks better :

But still, it took a whole 15 frames to get this, and you can still see the artifacts.

  


  Is there a better way to deal with this kind of noise ?

  


  Thank you in advance !

  


  Here are the stats of this video :

  


  ffmpeg version n4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.1.0 (GCC)
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librav1e --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Downloads/20191130_1h_ICE_2.6m_B9.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 0
    compatible_brands: qt  
    creation_time   : 2020-03-29T09:24:30.000000Z
  Duration: 00:07:04.83, start: 0.000000, bitrate: 9891 kb/s
    Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 260 kb/s (default)
    Metadata:
      creation_time   : 2020-03-29T09:24:30.000000Z
      handler_name    : Core Media Audio
    Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 9632 kb/s, 24.38 fps, 25 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      creation_time   : 2020-03-29T09:24:30.000000Z
      handler_name    : Core Media Video
      encoder         : H.264
File 'a.jpg' already exists. Overwrite? [y/N] y
Stream mapping:
  Stream #0:1 -> #0:0 (h264 (native) -> mjpeg (native))
Press [q] to stop, [?] for help
[swscaler @ 0x55a5393a9a40] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to 'a.jpg':
  Metadata:
    major_brand     : qt  
    minor_version   : 0
    compatible_brands: qt  
    encoder         : Lavf58.45.100
    Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc (default)
    Metadata:
      creation_time   : 2020-03-29T09:24:30.000000Z
      handler_name    : Core Media Video
      encoder         : Lavc58.91.100 mjpeg
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/A
frame=    1 fps=0.0 q=9.3 Lsize=N/A time=00:00:00.04 bitrate=N/A dup=1 drop=1 speed=0.0984x    
video:207kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown


  


• How to compress video size without changing much quality and without changing framerate (Ffmpeg) ?

  19 septembre 2020, par WebDiva

  I am using this command to compress my videos :

  


  ffmpeg -y -i video.mp4 -vcodec libx264 -crf 24 -preset ultrafast compressed.mp4



  


  Although it works okay, there is a slight increase in duration because I am changing the framerate of videos, and we need the video to be the exact duration. Is there a way to compress videos without changing the framerate ? any help would be appreciated. Thank you.

  


  Log :

  


  ffmpeg version git-2020-08-31-4a11a6f Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.2.1 (GCC) 20200805
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libgsm --enable-librav1e --enable-libsvtav1 --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 58.100 / 56. 58.100
  libavcodec     58.101.101 / 58.101.101
  libavformat    58. 51.101 / 58. 51.101
  libavdevice    58. 11.101 / 58. 11.101
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1600498063375.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2020-09-19T06:47:54.000000Z
    com.android.version: 10
  Duration: 00:00:10.53, start: 0.000000, bitrate: 4613 kb/s
    Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p(tv, bt709), 776x1440, 4611 kb/s, SAR 1:1 DAR 97:180, 19.11 fps, 16.42 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      creation_time   : 2020-09-19T06:47:54.000000Z
      handler_name    : VideoHandle
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 000001e25a673ac0] using SAR=1/1
[libx264 @ 000001e25a673ac0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 000001e25a673ac0] profile Constrained Baseline, level 3.2, 4:2:0, 8-bit
[libx264 @ 000001e25a673ac0] 264 - core 161 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=16 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=24.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, mp4, to 'compressed.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    com.android.version: 10
    encoder         : Lavf58.51.101
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 776x1440 [SAR 1:1 DAR 97:180], q=-1--1, 16.42 fps, 12608 tbn, 16.42 tbc (default)
    Metadata:
      creation_time   : 2020-09-19T06:47:54.000000Z
      handler_name    : VideoHandle
      encoder         : Lavc58.101.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
frame=  181 fps= 95 q=-1.0 Lsize=    5244kB time=00:00:10.96 bitrate=3918.2kbits/s dup=1 drop=29 speed=5.76x
video:5243kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.030269%
[libx264 @ 000001e25a673ac0] frame I:1     Avg QP:21.00  size: 92845
[libx264 @ 000001e25a673ac0] frame P:180   Avg QP:22.42  size: 29306
[libx264 @ 000001e25a673ac0] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 000001e25a673ac0] mb P  I16..4: 35.6%  0.0%  0.0%  P16..4: 39.9%  0.0%  0.0%  0.0%  0.0%    skip:24.6%
[libx264 @ 000001e25a673ac0] coded y,uvDC,uvAC intra: 34.6% 31.8% 2.5% inter: 28.7% 17.1% 0.7%
[libx264 @ 000001e25a673ac0] i16 v,h,dc,p: 38% 18% 20% 23%
[libx264 @ 000001e25a673ac0] i8c dc,h,v,p: 48% 17% 25%  9%
[libx264 @ 000001e25a673ac0] kb/s:3894.93


  


• Trim off N bytes from audio file using SoX / FFmpeg etc, on Windows ?

  17 novembre 2020, par Rinaldo Jonathan

  My team accidentally on purpose clicked NO when Audacity asked to save the recording. So I left with bunch of *.au files, after using recovery program.

  


  Some of them did have header and still open-able with audacity itself (example : this one), and some other are just complete nonsense, sometimes having the header filled with text from random javascript or HTML code (like this one). Probably hard disk half overwritten with browser cache ? I don't know. And at this point, I almost don't care.

  


  The audacity is on default settings, with sample rate 44100Hz. I can open a-113.au using audacity, from standard open files. I also was able to achieve open files using "Open RAW files" from Audacity, using this settings :

  


  

  


  so I assume header takes 12384 bytes.

  


  Now, how do I trim 12384 bytes from the file when opened as RAW, with either SoX or ffmpeg ? because if I open it as RAW with 0 offset (default settings), it will add the header as a noise.

  


  Current ffmpeg command I used : ffmpeg.exe  -f f32le -ar 44.1k -ac 1 -i  source destination
  
Current sox command I used : sox -t raw --endian little --rate 44100 -b 1 -b 32 --encoding floating-point  %%A "converted/%%~nxA.wav"
  
Both still have header as a noise in the converted files.