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• Compressing videos from a smartphone

  21 septembre 2019, par fejesjoco

  I have a Nexus 6p with the stock camera. It’s set to record at 1080p, 30fps. Here’s a 5 second sample (11 MB).

  Videos from this phone come out at about 17 Mbps on average. I tried to compress it with ffmpeg with -c:v libx264 -crf 23 -preset veryslow, the result comes out at about 5.5 MB, which is about 9 Mbps.

  I think this bitrate is a bit too much. When I look at torrent file listings, I can see high quality videos at 3 GB in size on average, and if such a movie is 90 minutes long on average, that is about 4-5 Mbps which sounds okay.

  I’m wondering, why the big difference ? I can notice that my video is noisy/grainy (which is expected from a phone), and that might reduce compressibility. I tried a few ffmpeg filters, like hqdn3d and atadenoise, but the noise mostly remained (maybe I didn’t play with it enough). Then I figured, the video is also shaky (which is also expected), and that might reduce compressibility too (and even makes temporal noise filtering less effective). I tried to stabilize it with the deshake filter, but that didn’t help either.

  I know I could just limit the bandwidth to whatever I like, but there must be a reason why ffmpeg thinks it needs a high bandwidth to maintain a certain quality, and a lower bandwidth would just decrease the quality.

  Why do these videos have such a high bitrate ? What’s the best way to compress them more while keeping or even increasing their quality ?

• A *hot* Piwik Community Meetup 2015 !

  10 août 2015 — Community

  Last weekend I arrived in Germany to attend the Piwik Community Meetup 2015 and now I am in Poland. I joined Piwik PRO back in May as enterprise support project coordinator in North America. I am now writing this from the Piwik PRO main office in Wrocław, where I’ll be working from for the next two weeks.

  The meetup was HOT in every sense ! Berlin temperatures reached 35 degrees (celsius), as I finally meet in person several long-time, dedicated Piwik community contributors.

  

  Meetup preparation in Berlin, photo by M. Zawadziński, licensed under CC-BY-SA 4.0

  Pictures from the meetup preparation sessions
  

  In the first leg of my trip I was in Berlin to meet Piwik community members and Piwik PRO staff to prepare for the 2015 annual Piwik community meetup. These are my notes taken during the meeting at the request of one of my colleagues. I also relayed live on Framasphère, Twitter and IRC.

  

  Community discussion at the meetup, photo by D.Czajka, licensed under CC-BY-SA 4.0

  More pictures from the Piwik meetup
  

  This was harder than I expected, as I took notes with my laptop, pictures with my phone, wrote live to social media (using the Android Diaspora Native Web App), and used my laptop to relay on IRC. Going forward this requires better preparation, I was glad I had a few links and pictures ready before hand but it really requires intense focus to achieve this. I am glad presenters were patient when I requested repeating some of the ideas they shared. I am also a bit disappointed not much happened in IRC.

  Two day preparation sessions

  The discussions and session we had during the two days prior to the meetup are available here.

  We gathered in rented apartments in Berlin, this reminded me very much of similar community gatherings and perhaps of BarCamp and, at a much smaller scale, UDS sessions.

  

  Piwik Pizza !, photo by F. Rodríguez, licensed under CC-BY-SA 4.0

  A list of ideas of topics was initially submitted, we then proceeded to have scheduled sessions for open discussion. Several people shared their concern there was no possible remote participation which led to making public the Trello boards used/linked here.

  Note : The Trello links below still have action items and notes that are pending bug report / feature requests filing which should happen over the coming weeks. Most importantly, many action items will need identifying leads for different community team including Translations and Documentation, and better coordination of coming community engagement.

  Monday sessions consisted of the following subjects :

  • What are Piwik values & how to communicate them ? (see below for details)
  • How to encourage and recognize new external contributors ?
  • How could we double the Piwik userbase ?
  • How Community can organise help resources

  On Tuesday we met again to discuss the following subjects :

  • Piwik Long Term support (LTS)
  • How do Piwik.org (project) and Piwik PRO (company) sit together / are organized ? – An important part of this session was about having better communication channels and improving the new team page (bug #8520 and bug #8519, respectively)
  • Improving usability of Piwik e.g. for new users – this last session was not held has we ran out of time and prepared to go to the meetup venue.

  Some more details about individual preparation sessions

  What are Piwik values & how to communicate them ?

  The main subjects in this session were important changes proposed in the project mission and values. This was edited directly on on the wiki page on GitHub, some of the changes can be seen by comparing revisions.

  Piwik mission statement (bug #7376)

  “To create the leading Free and open source analytics platform, and to support global organisations and communities to keep full control over their data.”

  Our values

  • Openness
  • Freedom
  • Transparency
  • Data ownership
  • Privacy
  • Kaizen (改善) : continuous improvement

  This was also presented by Matthieu Aubry at the meetup and is published in the Roadmap page. Bringing more visibility and perhaps having a top page for Mission and Values was also brought up.

  Meetup agenda and notes

  The official agenda is available here.

  Many Piwik PRO employees stayed in Berlin for the meetup, and we had good participation although less than last year in Munich as my colleagues told me. Some were consultants, others staff from public organizations, universities, etc. In retrospect considering the very hot weather and summer holidays the attendance was good. I was very happy to arrive at the beautiful Kulturbrauerei and enter the air-conditioned Soda Club. T-Shirts were waiting for all attendees and free drinks (non-alcohol !) were welcome

• 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