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• Video frame difference with FFMPEG

  18 octobre 2018, par StepTNT

  I need to compute the frame differences between a source video and a compressed one.
  For now I’m using OpenCV with Java, by extracting each frame and doing a simple difference, but it’s quite slow (working a 0.5 fps, meaning that a 500 frames video will take more than 15 mins) so I was thinking to move to FFMPEG.

  FFMPEG feels a lot faster (everything’s done under 1 minute) but it has one big issue that makes the results useless : when compressing the source file, done with FFMPEG too, an extra gray frame is added at the beginning and this fakes the results because different frames are compared.

  This is what I’m doing now (knowing that the extra frame messes it all) :

  ffmpeg -y -i src.avi -i compressed.avi -filter_complex "blend=all_mode=difference,hue=s=0" -c:v libx264 -crf 18 -c:a copy difference.avi

  To fix the frame issue I was trying to remove the first frame by re-encoding the compressed video with this command

  ffmpeg -y -ss 0.02 -i compressed.mpg -an -f mpeg2video compressed-cut.mpg"

  (Note that -ss is 0.02 because it’s a 50 fps video, so I did 1/FPS as suggested here)

  But I get this response

  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

  So, finally, the question is : since extracting all the frames and then compute differences with OpenCV is really slow, how can I use FFMPEG to produce a video containing the difference between two sources while keeping in mind that one of them has an extra frame at the beginning ?

  EDIT : I wanted to avoid posting endless console outputs but since you asked for it, here we go.

  1) Encoding

  Input

  ffmpeg -i "720p50_mobcal_ter.avi" -an -f mpeg2video -y "720p50_mobcal_ter.mpg"

  Output

  ffmpeg version N-76684-g1fe82ab Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  6.100 / 55.  6.100
  
    libavcodec     57. 15.100 / 57. 15.100
  
    libavformat    57. 14.100 / 57. 14.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 15.100 /  6. 15.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, avi, from '720p50_mobcal_ter.avi':
  
    Metadata:
  
      encoder         : Lavf57.14.100
  
    Duration: 00:00:10.08, start: 0.000000, bitrate: 552974 kb/s
  
      Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1280x720, 554059 kb/s, SAR 1:1 DAR 16:9, 50 fps, 50 tbr, 50 tbn, 50 tbc
  
  Output #0, mpeg2video, to '720p50_mobcal_ter.mpg':
  
    Metadata:
  
      encoder         : Lavf57.14.100
  
      Stream #0:0: Video: mpeg2video, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 50 fps, 50 tbn, 50 tbc
  
      Metadata:
  
        encoder         : Lavc57.15.100 mpeg2video
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> mpeg2video (native))
  
  Press [q] to stop, [?] for help
  
  frame=   41 fps=0.0 q=31.0 size=     984kB time=00:00:00.78 bitrate=10330.5kbits/frame=   80 fps= 78 q=31.0 size=    1323kB time=00:00:01.56 bitrate=6948.1kbits/frame=  124 fps= 80 q=31.0 size=    1725kB time=00:00:02.44 bitrate=5790.0kbits/frame=  168 fps= 81 q=31.0 size=    2084kB time=00:00:03.32 bitrate=5142.8kbits/frame=  212 fps= 81 q=31.0 size=    2482kB time=00:00:04.20 bitrate=4841.4kbits/frame=  255 fps= 82 q=31.0 size=    2840kB time=00:00:05.06 bitrate=4597.2kbits/frame=  296 fps= 82 q=31.0 size=    3133kB time=00:00:05.88 bitrate=4364.5kbits/frame=  338 fps= 82 q=24.8 size=    3453kB time=00:00:06.72 bitrate=4209.2kbits/frame=  382 fps= 82 q=31.0 size=    3723kB time=00:00:07.60 bitrate=4013.4kbits/frame=  426 fps= 83 q=31.0 size=    4005kB time=00:00:08.48 bitrate=3869.1kbits/frame=  470 fps= 83 q=24.8 size=    4276kB time=00:00:09.36 bitrate=3742.5kbits/frame=  504 fps= 83 q=31.0 Lsize=    4469kB time=00:00:10.06 bitrate=3639.3kbits/s
  
  video:4469kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%

  This adds the extra grey frame at the beginning, it just duplicates the first one

  2) Removing first frame

  Input

  ffmpeg -y -i "720p50_mobcal_ter.mpg" -an -f mpeg2video -vf select=gte(n\,1) "CUT-720p50_mobcal_ter.mpg"

  Output

  ffmpeg version N-76684-g1fe82ab Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  6.100 / 55.  6.100
  
    libavcodec     57. 15.100 / 57. 15.100
  
    libavformat    57. 14.100 / 57. 14.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 15.100 /  6. 15.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, mpegvideo, from '720p50_mobcal_ter.mpg':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: mpeg2video (Main), yuv420p(tv), 1280x720 [SAR 1:1 DAR 16:9], max. 104857 kb/s, 50 fps, 50 tbr, 1200k tbn, 100 tbc
  
  Output #0, mpeg2video, to 'CUT-720p50_mobcal_ter.mpg':
  
    Metadata:
  
      encoder         : Lavf57.14.100
  
      Stream #0:0: Video: mpeg2video, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 50 fps, 50 tbn, 50 tbc
  
      Metadata:
  
        encoder         : Lavc57.15.100 mpeg2video
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg2video (native) -> mpeg2video (native))
  
  Press [q] to stop, [?] for help
  
  frame=  255 fps=0.0 q=31.0 size=    2781kB time=00:00:05.10 bitrate=4467.3kbits/frame=  503 fps=0.0 q=31.0 Lsize=    4415kB time=00:00:10.08 bitrate=3588.5kbits/s
  
  video:4415kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%

  3) Frame difference

  Input

  ffmpeg -y -i "720p50_mobcal_ter.avi" -i "CUT-720p50_mobcal_ter.mpg" -filter_complex "blend=all_mode=difference,hue=s=0" -c:v libx264 -crf 18 -c:a copy "DIFF-720p50_mobcal_ter.mpg"

  Output

  ffmpeg version N-76684-g1fe82ab Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55.  6.100 / 55.  6.100
  
    libavcodec     57. 15.100 / 57. 15.100
  
    libavformat    57. 14.100 / 57. 14.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 15.100 /  6. 15.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, avi, from '720p50_mobcal_ter.avi':
  
    Metadata:
  
      encoder         : Lavf57.14.100
  
    Duration: 00:00:10.08, start: 0.000000, bitrate: 552974 kb/s
  
      Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1280x720, 554059 kb/s, SAR 1:1 DAR 16:9, 50 fps, 50 tbr, 50 tbn, 50 tbc
  
  Input #1, mpegvideo, from 'CUT-720p50_mobcal_ter.mpg':
  
    Duration: N/A, bitrate: N/A
  
      Stream #1:0: Video: mpeg2video (Main), yuv420p(tv), 1280x720 [SAR 1:1 DAR 16:9], max. 104857 kb/s, 50 fps, 50 tbr, 1200k tbn, 100 tbc
  
  [libx264 @ 000002784dbeb980] using SAR=1/1
  
  [libx264 @ 000002784dbeb980] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 000002784dbeb980] profile High, level 3.2
  
  [mpeg @ 000002784dbeaf20] VBV buffer size not set, using default size of 130KB
  
  If you want the mpeg file to be compliant to some specification
  
  Like DVD, VCD or others, make sure you set the correct buffer size
  
  Output #0, mpeg, to 'D:\DOWNLOADS\TMP\Video TDI\AVI\DIFF-720p50_mobcal_ter.mpg':
  
    Metadata:
  
      encoder         : Lavf57.14.100
  
      Stream #0:0: Video: h264 (libx264), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 50 fps, 90k tbn, 50 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.15.100 libx264
  
  Stream mapping:
  
    Stream #0:0 (rawvideo) -> blend:top
  
    Stream #1:0 (mpeg2video) -> blend:bottom
  
    hue -> Stream #0:0 (libx264)
  
  Press [q] to stop, [?] for help
  
  frame=  504 fps= 39 q=-1.0 Lsize=   32182kB time=00:00:10.04 bitrate=26258.5kbits/s
  
  video:32061kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.377054%
  
  [libx264 @ 000002784dbeb980] frame I:30    Avg QP:19.69  size:149974
  
  [libx264 @ 000002784dbeb980] frame P:299   Avg QP:23.28  size: 69423
  
  [libx264 @ 000002784dbeb980] frame B:175   Avg QP:24.48  size: 43280
  
  [libx264 @ 000002784dbeb980] consecutive B-frames: 30.6% 69.4%  0.0%  0.0%
  
  [libx264 @ 000002784dbeb980] mb I  I16..4: 18.3% 51.4% 30.4%
  
  [libx264 @ 000002784dbeb980] mb P  I16..4:  0.6%  5.6%  2.4%  P16..4: 35.9% 22.9% 15.6%  0.0%  0.0%    skip:17.0%
  
  [libx264 @ 000002784dbeb980] mb B  I16..4:  0.2%  0.5%  0.3%  B16..8: 49.5% 12.4%  5.6%  direct:15.5%  skip:16.1%  L0:47.8% L1:42.1% BI:10.1%
  
  [libx264 @ 000002784dbeb980] 8x8 transform intra:57.5% inter:38.5%
  
  [libx264 @ 000002784dbeb980] coded y,uvDC,uvAC intra: 90.7% 0.0% 0.0% inter: 50.3% 0.0% 0.0%
  
  [libx264 @ 000002784dbeb980] i16 v,h,dc,p: 32% 23% 35% 10%
  
  [libx264 @ 000002784dbeb980] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 11% 11% 41%  7%  5%  6%  5%  6%  8%
  
  [libx264 @ 000002784dbeb980] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 14% 23%  8%  7%  7%  7%  7%  8%
  
  [libx264 @ 000002784dbeb980] i8c dc,h,v,p: 100%  0%  0%  0%
  
  [libx264 @ 000002784dbeb980] Weighted P-Frames: Y:33.8% UV:0.0%
  
  [libx264 @ 000002784dbeb980] ref P L0: 58.1% 16.3% 14.2%  9.4%  2.0%
  
  [libx264 @ 000002784dbeb980] ref B L0: 79.3% 20.7%
  
  [libx264 @ 000002784dbeb980] kb/s:26056.02

  The second command made everything work while the second one in the first part didn’t (the one with the -ss option), so I could be quite happy about it but I’m not that sure if FFMPEG duplicates the first frame for every video or if it’s just related to the one I’m using now, so it could be better to start off with a compressed video that has the same frame count of the original one.

  So let’s get to one final question : why does FFMPEG add a duplicated first frame at the beginning of the compressed video and how can I avoid that ?

• Why do you need analytics for your WordPress ?

  7 avril 2020, par Joselyn Khor — Analytics Tips, Plugins
  Not many people know this, but having a WordPress analytics tool gives you a competitive advantage. It’s also essential to the growth of your website. For many businesses, websites are the main driver of revenue and sales. In the case of blogs, it’s your first chance to make a lasting impression.

  Now, maybe you’ve heard of Google Analytics or even the privacy-friendly alternative, Matomo Analytics, but have never tried them ? These are analytics platforms that help you understand your website traffic and visitors. (You can find these platforms as plugins in the WordPress directory !)

  They’re important because the insights you get help you determine what changes to make to improve your website. Without them you could face a tougher time figuring out what’s working, what the issues are (and solving them before they get out of hand), and making sure you’re taking your website in the right direction. 

  WordPress analytics gives you an understanding of what’s actually going on.

  How does a WordPress analytics plugin benefit your website ?

  What this means for you is getting a toolkit to learn how to get more sales or followers and subscribers (aka conversions in analytics terms). 

  By getting insights into user behaviour, content performance, and how you can optimise your website, you can reach more of your goals, like increasing sales or growing your audience.

  A WordPress analytics tool helps you get more traffic to your site

  You get a range of features which tell you which acquisition channels are working for you like – social media, search engines, and other websites mentioning you. This helps you make an informed decision on where to focus energies (or spend) to get more of the ideal people coming through to your website. 

  

  Example : Looking through your acquisition channels and seeing that Reddit drives a lot of traffic through to your website. Since this channel seems to be working for you, you could then spend more time on Reddit posts to increase traffic.

  But getting more traffic isn’t all there is to it. Once they land on your site, you want them to stay for a little longer so they are intrigued by what you’re offering. Be it a product, or awesome content.

  Which leads us to …

  Increasing engagement by learning about visitor behaviour

  When you get a solid number of visitors on your website, it’s good to then learn about how they behave on your site. A WordPress analytics tool helps with engagement since you’re seeing what’s appealing to them, and what isn’t.

   Increasing engagement is good for a few reasons. 

  • You end up speaking the language of your readers. 
  • You can make a difference with the information you’re putting out. 
  • You get loyal customers and believers in your organisation. 

  With more engaged visitors, you can build trust with them and eventually be able to convince them that your product, service, or blog is needed in their lives.

  

  Example : Looking through entry and exit pages to see what first impression is making them stay, and what impression is making them leave. This helps you redirect efforts to give your website a better chance of getting visitors to stay longer.

  Improving your content and engagement can lead to more conversions

  After you get visitors engaged, it’s time to convert. 

  Whether you have an ecommerce site or freelance blog, you’ll need to know how to boost conversions. This simply means getting people to achieve more of the actions you’re wanting them to take on your site. Like subscribing to your newsletter or adding items to a cart.

  With conversion optimization features, you’re finding out how well your website is designed to get buyers through a journey to conversion. 

  

  Example : Say you’ve created a newsletter sign up page, but you’re not getting as many sign ups as you’d like. With a web analytics tool, you can look into it further. A funnels feature could tell you how they’re getting to that page. If people can’t find your page, that could be reason for low conversion rates. Or, maybe you are getting people landing on this page, but you can’t tell why they’re not signing up. Try setting up a heatmap to see how far they’re scrolling down your page to the sign up section. Through these conversion optimization features, you can make tweaks that significantly improve conversions.

  So, how does the Matomo Analytics for WordPress plugin help with all of this ?

  

  Matomo Analytics for WordPress is a free web analytics plugin that gives you access to all the features mentioned above, right in your own WordPress dashboard. It’s completely free to use and is handy for users of all skill levels. From beginners right through to advanced analysts. 

  You get to move through all the stages to increase traffic, increase engagement, and convert. By using Matomo for WordPress, you put yourself in a better position to track all the needed data from your WordPress website. 

  You have this toolkit to improve your website for free, with a few clicks ! 

  By getting useful insights like visitors, acquisitions, bounce rates etc. you gain a new perspective on how to improve your website so it’s better at doing what you created it to do. Getting these insights also means giving yourself the confidence to do what’s best for your website in a data-driven way. 

  With all this knowledge, you can be competitive, or grow enough that you’re leaving your competitors in the dust. 

• Video becomes choppy when the order in the hstack filter is changed

  25 octobre 2018, par Mayank

  I have a FFmpeg command wherein I am merging 2 videos side by side using hstack filter. When I place first video on the right hand side and second video on the left hand side, the final merged video is perfect in quality and plays smoothly.

  However, when I swap the order in hstack filter, the final video is very choppy.

  Can someone please let me know the issue in this command ? Many thanks in advance.

  Also, the file size of the non working file is almost double than that of working file. Can you explain why ?

  Here is the working command :

  ffmpeg -i 1_a.opus -i 2_a.opus -itsoffset 0.024 -i 1_v.mp4 -itsoffset 0.113 -i 2_v.mp4 -filter_complex "[1:a]adelay=15646|15646[a1]; [0:a][a1]amix; [3:v]trim=0:15.646,geq=0:128:128[silence]; [3:v]fifo[3v]; [silence][3v]concat[3_v_silence]; [3_v_silence][2:v]hstack" -preset ultrafast -y n_m_bars_try2.mp4

  output :

  ffmpeg version 4.0.2-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  
    configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg
  
    libavutil      56. 14.100 / 56. 14.100
  
    libavcodec     58. 18.100 / 58. 18.100
  
    libavformat    58. 12.100 / 58. 12.100
  
    libavdevice    58.  3.100 / 58.  3.100
  
    libavfilter     7. 16.100 /  7. 16.100
  
    libswscale      5.  1.100 /  5.  1.100
  
    libswresample   3.  1.100 /  3.  1.100
  
    libpostproc    55.  1.100 / 55.  1.100
  
  Input #0, ogg, from '1_a.opus':
  
    Duration: 00:01:03.82, start: -0.020000, bitrate: 37 kb/s
  
      Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp
  
  Input #1, ogg, from '2_a.opus':
  
    Duration: 00:00:52.40, start: -0.020000, bitrate: 44 kb/s
  
      Stream #1:0: Audio: opus, 48000 Hz, stereo, fltp
  
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from '1_v.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.12.100
  
    Duration: 00:01:03.85, start: 0.000000, bitrate: 2644 kb/s
  
      Stream #2:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 2633 kb/s, 333 fps, 333 tbr, 10656 tbn, 666 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Input #3, mov,mp4,m4a,3gp,3g2,mj2, from '2_v.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.12.100
  
    Duration: 00:00:52.32, start: 0.000000, bitrate: 861 kb/s
  
      Stream #3:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 860 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Stream mapping:
  
    Stream #0:0 (opus) -> amix:input0
  
    Stream #1:0 (opus) -> adelay
  
    Stream #2:0 (h264) -> hstack:input1
  
    Stream #3:0 (h264) -> trim
  
    Stream #3:0 (h264) -> fifo
  
    amix -> Stream #0:0 (aac)
  
    hstack -> Stream #0:1 (libx264)
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 0x528d600] using SAR=1/1
  
  [libx264 @ 0x528d600] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowShuffle
  
  [libx264 @ 0x528d600] profile Constrained Baseline, level 3.1
  
  [libx264 @ 0x528d600] 264 - core 155 r2901 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - 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=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=3 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=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
  
  Output #0, mp4, to 'navid_mayank_bars_try2.mp4':
  
    Metadata:
  
      encoder         : Lavf58.12.100
  
      Stream #0:0: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        encoder         : Lavc58.18.100 aac
  
      Stream #0:1: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1280x480 [SAR 1:1 DAR 8:3], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
  
      Metadata:
  
        encoder         : Lavc58.18.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  frame= 1704 fps= 42 q=-1.0 Lsize=   14440kB time=00:01:08.12 bitrate=1736.5kbits/s dup=3 drop=21229 speed=1.69x    
  
  video:13448kB audio:953kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.269503%
  
  [aac @ 0x52b8680] Qavg: 22255.799
  
  [libx264 @ 0x528d600] frame I:7     Avg QP:16.29  size: 46284
  
  [libx264 @ 0x528d600] frame P:1697  Avg QP:18.36  size:  7924
  
  [libx264 @ 0x528d600] mb I  I16..4: 100.0%  0.0%  0.0%
  
  [libx264 @ 0x528d600] mb P  I16..4:  1.8%  0.0%  0.0%  P16..4: 31.0%  0.0%  0.0%  0.0%  0.0%    skip:67.2%
  
  [libx264 @ 0x528d600] coded y,uvDC,uvAC intra: 29.9% 59.3% 17.5% inter: 13.4% 24.6% 0.8%
  
  [libx264 @ 0x528d600] i16 v,h,dc,p: 36% 29% 18% 17%
  
  [libx264 @ 0x528d600] i8c dc,h,v,p: 42% 25% 21% 11%
  
  [libx264 @ 0x528d600] kb/s:1616.23

  Non working command :

  ffmpeg -i 1_a.opus -i 2_a.opus -itsoffset 0.024 -i 1_v.mp4 -itsoffset 0.113 -i 2_v.mp4 -filter_complex "[1:a]adelay=15646|15646[a1]; [0:a][a1]amix; [3:v]trim=0:15.646,geq=0:128:128[silence]; [3:v]fifo[3v]; [silence][3v]concat[3_v_silence]; [2:v][3_v_silence]hstack" -preset ultrafast -y m_n_bars_try2.mp4

  output :

  ffmpeg version 4.0.2-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  
    configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg
  
    libavutil      56. 14.100 / 56. 14.100
  
    libavcodec     58. 18.100 / 58. 18.100
  
    libavformat    58. 12.100 / 58. 12.100
  
    libavdevice    58.  3.100 / 58.  3.100
  
    libavfilter     7. 16.100 /  7. 16.100
  
    libswscale      5.  1.100 /  5.  1.100
  
    libswresample   3.  1.100 /  3.  1.100
  
    libpostproc    55.  1.100 / 55.  1.100
  
  Input #0, ogg, from '1_a.opus':
  
    Duration: 00:01:03.82, start: -0.020000, bitrate: 37 kb/s
  
      Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp
  
  Input #1, ogg, from '2_a.opus':
  
    Duration: 00:00:52.40, start: -0.020000, bitrate: 44 kb/s
  
      Stream #1:0: Audio: opus, 48000 Hz, stereo, fltp
  
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from '1_v.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.12.100
  
    Duration: 00:01:03.85, start: 0.000000, bitrate: 2644 kb/s
  
      Stream #2:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 2633 kb/s, 333 fps, 333 tbr, 10656 tbn, 666 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Input #3, mov,mp4,m4a,3gp,3g2,mj2, from '2_v.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf58.12.100
  
    Duration: 00:00:52.32, start: 0.000000, bitrate: 861 kb/s
  
      Stream #3:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 860 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
  Stream mapping:
  
    Stream #0:0 (opus) -> amix:input0
  
    Stream #1:0 (opus) -> adelay
  
    Stream #2:0 (h264) -> hstack:input0
  
    Stream #3:0 (h264) -> trim
  
    Stream #3:0 (h264) -> fifo
  
    amix -> Stream #0:0 (aac)
  
    hstack -> Stream #0:1 (libx264)
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 0x6d21600] using SAR=1/1
  
  [libx264 @ 0x6d21600] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowShuffle
  
  [libx264 @ 0x6d21600] profile Constrained Baseline, level 5.1
  
  [libx264 @ 0x6d21600] 264 - core 155 r2901 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - 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=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=3 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=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
  
  Output #0, mp4, to 'mayank_navid_bars_try2.mp4':
  
    Metadata:
  
      encoder         : Lavf58.12.100
  
      Stream #0:0: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        encoder         : Lavc58.18.100 aac
  
      Stream #0:1: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1280x480 [SAR 1:1 DAR 8:3], q=-1--1, 333 fps, 10656 tbn, 333 tbc (default)
  
      Metadata:
  
        encoder         : Lavc58.18.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  Past duration 0.999992 too large
  
      Last message repeated 12 times
  
  More than 1000 frames duplicated   33280kB time=00:01:08.03 bitrate=4007.4kbits/s dup=982 drop=1590 speed=0.536x    
  
  frame=22679 fps=177 q=-1.0 Lsize=   33892kB time=00:01:08.10 bitrate=4076.9kbits/s dup=1339 drop=1590 speed=0.531x    
  
  video:32804kB audio:953kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.401324%
  
  [aac @ 0x6d4c680] Qavg: 22255.799
  
  [libx264 @ 0x6d21600] frame I:91    Avg QP:15.31  size: 51639
  
  [libx264 @ 0x6d21600] frame P:22588 Avg QP:18.24  size:  1279
  
  [libx264 @ 0x6d21600] mb I  I16..4: 100.0%  0.0%  0.0%
  
  [libx264 @ 0x6d21600] mb P  I16..4:  0.2%  0.0%  0.0%  P16..4: 13.0%  0.0%  0.0%  0.0%  0.0%    skip:86.8%
  
  [libx264 @ 0x6d21600] coded y,uvDC,uvAC intra: 44.9% 54.0% 29.9% inter: 2.0% 10.9% 0.1%
  
  [libx264 @ 0x6d21600] i16 v,h,dc,p: 45% 24% 13% 18%
  
  [libx264 @ 0x6d21600] i8c dc,h,v,p: 51% 20% 18% 11%
  
  [libx264 @ 0x6d21600] kb/s:3945.79