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• Best way to record a HTML Canvas/WebGL animation server-side into a video ?

  19 novembre 2022, par Abhinav

  I have a set of animations which I can make in Canvas (fabric.js) or WebGL (three.js). I need to record them automatically, server-side, through a script and output a video file.

  



  The animations include :
  

  



  

  1. Pictures
     

  


  2. Videos (with audio)
     

  


  3. Other animations/effects

  


  



  I have researched a lot during last few months on this.

  



  Results
  
1. Use PhantomJS + FFMPEG
  
Run HTML Canvas animations on headless browser(PhantomJS) and record with FFMPEG. Here the issue is PhantomJS supports neither WebGL nor Video element. http://phantomjs.org/supported-web-standards.html

  
2. Use Websockets to send data back to server using DataURL
  
Here again, we will need to run the animations on browser (which we can't because we have to do everything on server).

  
3. Use node-canvas
  
This is a library by TJ Holowaychuk which allows rendering HTML Canvas on Node.js. But it has its own limitations plus I haven't really explored this field much. 
(If someone could shed more light on this library)

  



  If anyone has done it before or can guide me somewhere useful.
  
All we need to do is use some data to create animations and record it into a video, everything on server side.

  


• With apulsator in ffempeg - How do I make so one side does not completely become silent ?

  3 avril 2022, par corgrath

  I am trying to learn more about signal processing and the apulsator effect in ffmpeg.

  


  http://ffmpeg.org/ffmpeg-filters.html#apulsator

  


  With the most default example :

  


  ffmpeg -y -i input.mp3 -af "apulsator=hz=0.0625:timing=hz:mode=sine" output.mp3

  


  You can clearly hear that the sound travels from left to right and then back to left, as expected.

  


  However, I am trying to understand how/if it is possible that sound volume does not completely becomes silent, but perhaps 10% of the volume, while the other side gets 90%.

  


  What I am trying to achieve is that one side does not completely becomes silent.

  


  If this cannot be achieved solely by the apulsator settings, what other effects or ways can I achieve this using ffmpeg ?

  


  Any advice is appreciated !

  


• FFmpeg uses xface to merge videos without transition effects

  30 avril 2024, par soapbar

  ffmpeg -i ./first.mp4 -i ./first.mp4 -filter_complex "xfade=transition=circlecrop:duration=1:offset=4,format=yuv420p" -y output.mp4

  


  FFMPEG version 6.1.1, the video is generated normally without any error prompts, but the generated video does not have any transition effects.

  


  output

  


  
ffmpeg version 6.1.1-tessus  https://evermeet.cx/ffmpeg/  Copyright (c) 2000-2023 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration : —cc=/usr/bin/clang —prefix=/opt/ffmpeg —extra-version=tessus —enable-avisynth —enable-fontconfig —enable-gpl —enable-libaom —enable-libass —enable-libbluray —enable-libdav1d —enable-libfreetype —enable-libgsm —enable-libmodplug —enable-libmp3lame —enable-libmysofa —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenh264 —enable-libopenjpeg —enable-libopus —enable-librubberband —enable-libshine —enable-libsnappy —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libtwolame —enable-libvidstab —enable-libvmaf —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libwebp —enable-libx264 —enable-libx265 —enable-libxavs —enable-libxml2 —enable-libxvid —enable-libzimg —enable-libzmq —enable-libzvbi —enable-version3 —pkg-config-flags=—static —disable-ffplay
  libavutil      58. 29.100 / 58. 29.100
  libavcodec     60. 31.102 / 60. 31.102
  libavformat    60. 16.100 / 60. 16.100
  libavdevice    60.  3.100 / 60.  3.100
  libavfilter     9. 12.100 /  9. 12.100
  libswscale      7.  5.100 /  7.  5.100
  libswresample   4. 12.100 /  4. 12.100
  libpostproc    57.  3.100 / 57.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './first.mp4' :
  Metadata :
    major_brand : isom
    minor_version : 512
    compatible_brands : isomiso2avc1mp41
    encoder : Lavf61.1.100
  Duration : 00:00:05.00, start : 0.000000, bitrate : 110 kb/s
  Stream #0:0[0x1](und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1080x1920 [SAR 4095:4096 DAR 36855:65536], 109 kb/s, SAR 14317:14320 DAR 128853:229120, 0.20 fps, 0.20 tbr, 16384 tbn (default)
    Metadata :
      handler_name : VideoHandler
      vendor_id : [0][0][0][0]
      encoder : Lavc61.3.100 libx264
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from './first.mp4' :
  Metadata :
    major_brand : isom
    minor_version : 512
    compatible_brands : isomiso2avc1mp41
    encoder : Lavf61.1.100
  Duration : 00:00:05.00, start : 0.000000, bitrate : 110 kb/s
  Stream #1:0[0x1](und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1080x1920 [SAR 4095:4096 DAR 36855:65536], 109 kb/s, SAR 14317:14320 DAR 128853:229120, 0.20 fps, 0.20 tbr, 16384 tbn (default)
    Metadata :
      handler_name : VideoHandler
      vendor_id : [0][0][0][0]
      encoder : Lavc61.3.100 libx264
Stream mapping :
  Stream #0:0 (h264) -> xfade
  Stream #1:0 (h264) -> xfade
  format:default -> Stream #0:0 (libx264)
Press [q] to stop, [?] for help
[libx264 @ 0x7f9f99fc87c0] using SAR=4095/4096
[libx264 @ 0x7f9f99fc87c0] using cpu capabilities : MMX2 SSE2Fast SSSE3 SSE4.2
[libx264 @ 0x7f9f99fc87c0] profile High, level 4.0, 4:2:0, 8-bit
[libx264 @ 0x7f9f99fc87c0] 264 - core 164 r3172 c1c9931 - H.264/MPEG-4 AVC codec - Copyleft 2003-2023 - 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=1 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 'output.mp4' :
  Metadata :
    major_brand : isom
    minor_version : 512
    compatible_brands : isomiso2avc1mp41
    encoder : Lavf60.16.100
  Stream #0:0 : Video : h264 (avc1 / 0x31637661), yuv420p(tv, progressive), 1080x1920 [SAR 14317:14320 DAR 128853:229120], q=2-31, 0.20 fps, 16384 tbn
    Metadata :
      encoder : Lavc60.31.102 libx264
    Side data :
      cpb : bitrate max/min/avg : 0/0/0 buffer size : 0 vbv_delay : N/A
[out#0/mp4 @ 0x7f9f99fc74c0] video:72kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead : 1.190217%
frame=    2 fps=0.0 q=-1.0 Lsize=      73kB time=00:00:05.00 bitrate= 118.9kbits/s speed=45.5x    
[libx264 @ 0x7f9f99fc87c0] frame I:1     Avg QP:12.25  size : 72527
[libx264 @ 0x7f9f99fc87c0] frame P:1     Avg QP:13.77  size :   216
[libx264 @ 0x7f9f99fc87c0] mb I  I16..4 : 51.4% 34.9% 13.8%
[libx264 @ 0x7f9f99fc87c0] mb P  I16..4 :  0.0%  0.0%  0.0%  P16..4 :  0.8%  0.0%  0.0%  0.0%  0.0%    skip:99.2%
[libx264 @ 0x7f9f99fc87c0] 8x8 transform intra:34.9% inter:0.0%
[libx264 @ 0x7f9f99fc87c0] coded y,uvDC,uvAC intra : 9.2% 9.6% 6.9% inter : 0.0% 0.6% 0.0%
[libx264 @ 0x7f9f99fc87c0] i16 v,h,dc,p : 79% 20%  2%  0%
[libx264 @ 0x7f9f99fc87c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu :  1% 97%  2%  0%  0%  0%  0%  0%  0%
[libx264 @ 0x7f9f99fc87c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu : 36% 32% 10%  3%  3%  3%  4%  3%  4%
[libx264 @ 0x7f9f99fc87c0] i8c dc,h,v,p : 80% 15%  4%  0%
[libx264 @ 0x7f9f99fc87c0] Weighted P-Frames : Y:0.0% UV:0.0%
[libx264 @ 0x7f9f99fc87c0] kb/s:58.19