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• Unknown V4L2 pixel format equivalent for yuva420p with ffmpeg and v4l2loopback

  7 février 2019, par Kim

  I am trying to use filter_complex from ffmpeg to stich several video input together into one output.

  I use v4l2loopback to create a virtual video device :

  sudo modprobe v4l2loopback video_nr=90

  In this example, i first try with only one camera :

  v4l2-ctl --device=/dev/video0 --info gives the following output :

  Driver Info (not using libv4l2):
  
          Driver name   : uvcvideo
  
          Card type     : HD USB Camera
  
          Bus info      : usb-0000:00:14.0-13.2
  
          Driver version: 4.10.17
  
          Capabilities  : 0x84200001
  
                  Video Capture
  
                  Streaming
  
                  Extended Pix Format
  
                  Device Capabilities
  
          Device Caps   : 0x04200001
  
                  Video Capture
  
                  Streaming
  
                  Extended Pix Format
  
  Priority: 2
  
  Video input : 0 (Camera 1: ok)
  
  Format Video Capture:
  
          Width/Height      : 640/480
  
          Pixel Format      : 'YUYV'
  
          Field             : None
  
          Bytes per Line    : 1280
  
          Size Image        : 614400
  
          Colorspace        : sRGB
  
          Transfer Function : Default
  
          YCbCr Encoding    : Default
  
          Quantization      : Default
  
          Flags             :
  
  Crop Capability Video Capture:
  
          Bounds      : Left 0, Top 0, Width 640, Height 480
  
          Default     : Left 0, Top 0, Width 640, Height 480
  
          Pixel Aspect: 1/1
  
  Selection: crop_default, Left 0, Top 0, Width 640, Height 480
  
  Selection: crop_bounds, Left 0, Top 0, Width 640, Height 480
  
  Streaming Parameters Video Capture:
  
          Capabilities     : timeperframe
  
          Frames per second: 30.000 (30/1)
  
          Read buffers     : 0
  
                       brightness (int)    : min=0 max=15 step=1 default=8 value=8
  
                         contrast (int)    : min=0 max=15 step=1 default=8 value=8
  
                       saturation (int)    : min=0 max=15 step=1 default=7 value=7
  
                              hue (int)    : min=-10 max=10 step=1 default=0value=0
  
   white_balance_temperature_auto (bool)   : default=1 value=1
  
                            gamma (int)    : min=1 max=10 step=1 default=7 value=7
  
                             gain (int)    : min=0 max=0 step=0 default=0 value=0
  
             power_line_frequency (menu)   : min=0 max=2 default=2 value=2
  
        white_balance_temperature (int)    : min=2800 max=6500 step=1 default=2800 value=2800 flags=inactive
  
                        sharpness (int)    : min=0 max=15 step=1 default=6 value=6
  
           backlight_compensation (int)    : min=0 max=1 step=1 default=0 value=0
  
                    exposure_auto (menu)   : min=0 max=3 default=3 value=3
  
                exposure_absolute (int)    : min=4 max=5000 step=1 default=625 value=625 flags=inactive
  
                   focus_absolute (int)    : min=0 max=21 step=1 default=16 value=16 flags=inactive
  
                       focus_auto (bool)   : default=1 value=1

  Then i use this command to ouput /dev/video0 to /dev/video90 on the left side with a specific resolution :

  ffmpeg -loglevel verbose -y \
  
    -f v4l2 -thread_queue_size 512 -i /dev/video0 \
  
    -filter_complex "nullsrc=size=960x240 [base]; \
  
            [0:v] format=pix_fmts=yuva420p, setpts=PTS-STARTPTS, scale=320x240 [left]; \
  
            [base][left] overlay=shortest=1" \
  
    -f v4l2 /dev/video90

  Which results in the following error :

  [v4l2 @ 0x55fa67d02f60] Unknown V4L2 pixel format equivalent for yuva420p
  
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  
  Error initializing output stream 0:0 --
  
  Conversion failed!

  Full logs :

  ffmpeg version 3.4.4-1~16.04.york0 Copyright (c) 2000-2018 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
  
    WARNING: library configuration mismatch
  
    avcodec     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 --enable-version3 --disable-doc --disable-programs --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libtesseract --enable-libvo_amrwbenc
  
    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
  
  [video4linux2,v4l2 @ 0x55fa67cfca00] fd:5 capabilities:84200001
  
  [video4linux2,v4l2 @ 0x55fa67cfca00] Querying the device for the current frame size
  
  [video4linux2,v4l2 @ 0x55fa67cfca00] Setting frame size to 640x480
  
  Input #0, video4linux2,v4l2, from '/dev/video0':
  
    Duration: N/A, start: 273229.829138, bitrate: 147456 kb/s
  
      Stream #0:0: Video: rawvideo, 1 reference frame (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
  
  [Parsed_nullsrc_0 @ 0x55fa67d00680] size:960x240 rate:25/1 duration:-1.000000 sar:1/1
  
  [Parsed_scale_3 @ 0x55fa67d02240] w:320 h:240 flags:'bilinear' interl:0
  
  Stream mapping:
  
    Stream #0:0 (rawvideo) -> format
  
    overlay -> Stream #0:0 (rawvideo)
  
  Press [q] to stop, [?] for help
  
  [Parsed_nullsrc_0 @ 0x55fa67cfc760] size:960x240 rate:25/1 duration:-1.000000 sar:1/1
  
  [Parsed_scale_3 @ 0x55fa67d055c0] w:320 h:240 flags:'bilinear' interl:0
  
  [graph 0 input from stream 0:0 @ 0x55fa67d06a40] w:640 h:480 pixfmt:yuyv422 tb:1/1000000 fr:30/1 sar:0/1 sws_param:flags=2
  
  [auto_scaler_0 @ 0x55fa67d05d80] w:iw h:ih flags:'bilinear' interl:0
  
  [Parsed_format_1 @ 0x55fa67d04360] auto-inserting filter 'auto_scaler_0' between the filter 'graph 0 input from stream 0:0' and the filter 'Parsed_format_1'
  
  [auto_scaler_0 @ 0x55fa67d05d80] w:640 h:480 fmt:yuyv422 sar:0/1 -> w:640 h:480 fmt:yuva420p sar:0/1 flags:0x2
  
  [Parsed_format_1 @ 0x55fa67d04360] TB:0.000001 FRAME_RATE:30.000000 SAMPLE_RATE:nan
  
  [Parsed_scale_3 @ 0x55fa67d055c0] w:640 h:480 fmt:yuva420p sar:0/1 -> w:320 h:240 fmt:yuva420p sar:0/1 flags:0x2
  
  [Parsed_overlay_4 @ 0x55fa67d05e80] main w:960 h:240 fmt:yuva420p overlay w:320 h:240 fmt:yuva420p
  
  [Parsed_overlay_4 @ 0x55fa67d05e80] [framesync @ 0x55fa67d05fa8] Selected 1/1000000 time base
  
  [Parsed_overlay_4 @ 0x55fa67d05e80] [framesync @ 0x55fa67d05fa8] Sync level 2
  
  [v4l2 @ 0x55fa67d02f60] Unknown V4L2 pixel format equivalent for yuva420p
  
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  
  Error initializing output stream 0:0 --
  
  Conversion failed!

  What I tried and didn’t work :

  • use -f h264 for the output, which ends in a av_interleaved_write_frame(): Invalid argument error

• Data Privacy Day 2021 : Five ways to embrace privacy into your business

  27 janvier 2021, par Matomo Core Team — Community, Privacy

  Welcome to Data Privacy Day 2021 !

  This year we are excited to announce that we are participating as a #PrivacyAware Champion for DPD21 through the National Cyber Security Alliance. This means that on this significant day we are in partnership with hundreds of other organisations and businesses to share a unified message that empowers individuals to “Own Your Privacy” and for organisations to “Respect Privacy.”

  "Last year dawned a new era in the way many businesses operate from a traditional office work setting to a remote working from home environment for employees. This now means it’s more important than ever for your employees to understand how to take ownership of their privacy when working online."

  As a Data Privacy Day #PrivacyAware Champion we would like to provide some practical tips and share examples of how the Matomo team helps employees be privacy aware.

  

  Five ways to embrace privacy into your business

  1. Create a privacy aware culture within your business

  • Get leadership involved.
  • Appoint privacy ambassadors within your team. 
  • Create a privacy awareness campaign where you educate employees on your company privacy policy. 
  • Share messages about privacy around the office/or in meetings online, on internal message boards, in company newsletters, or emails. 
  • Teach new employees their role in your privacy culture and reinforce throughout their career.

  2. Organise privacy awareness training for your employees

  • Invite outside speakers to talk to employees about why privacy matters. 
  • Engage staff by asking them to consider how privacy and data security applies to the work they do on a daily basis.
  • Encourage employees to complete online courses to gain a better understanding of how to avoid privacy risks.

  3. Help employees manage their individual privacy

  • Better security and privacy behaviours at home will translate to better security and privacy practices at work. 
  • Teach employees how to update their privacy and security settings on personal accounts.
  • Use NCSA’s privacy settings page to help them get started

  4. Add privacy to the employee’s toolbox

  • Give your employees actual tools they can use to improve their privacy, such as company-branded camera covers or privacy screens for their devices, or virtual private networks (VPNs) to secure their connections.

  5. Join Matomo and we’ll be your web analytics experts

  • At Matomo, ensuring our users and customers that their privacy is protected is not only a core component of the work we do, it’s why we do what we do ! Find out how.

  Want to find out more about data privacy download your free DPD 2021 Champion Toolkit and read our post on “Why is privacy important”.

  Team Matomo

  2021 Data Privacy Day Toolkit

  Your guide to Data Privacy Day, January 28, 2021

  Free Download

• Announcing the first free software Blu-ray encoder

  25 avril 2010, par Dark Shikari — blu-ray, x264

  For many years it has been possible to make your own DVDs with free software tools. Over the course of the past decade, DVD creation evolved from the exclusive domain of the media publishing companies to something basically anyone could do on their home computer.

  But Blu-ray has yet to get that treatment. Despite the “format war” between Blu-ray and HD DVD ending over two years ago, free software has lagged behind. “Professional” tools for Blu-ray video encoding can cost as much as $100,000 and are often utter garbage. Here are two actual screenshots from real Blu-rays : I wish I was making this up.

  But today, things change. Today we take the first step towards a free software Blu-ray creation toolkit.

  Thanks to tireless work by Kieran Kunyha, Alex Giladi, Lamont Alston, and the Doom9 crowd, x264 can now produce Blu-ray-compliant video. Extra special thanks to The Criterion Collection for sponsoring the final compliance test to confirm x264′s Blu-ray compliance.

  With x264′s powerful compression, as demonstrated by the incredibly popular BD-Rebuilder Blu-ray backup software, it’s quite possible to author Blu-ray disks on DVD9s (dual-layer DVDs) or even DVD5s (single-layer DVDs) with a reasonable level of quality. With a free software encoder and less need for an expensive Blu-ray burner, we are one step closer to putting HD optical media creation in the hands of the everyday user.

  To celebrate this achievement, we are making available for download a demo Blu-ray encoded with x264, containing entirely free content !

  On this Blu-ray are the Open Movie Project films Big Buck Bunny and Elephant’s Dream, available under a Creative Commons license. Additionally, Microsoft has graciously provided about 6 minutes of lossless HD video and audio (from part of a documentary project) under a very liberal license. This footage rounds out the Blu-ray by adding some difficult live-action content in addition to the relatively compressible CGI footage from the Open Movie Project. Finally, we used this sound sample, available under a Creative Commons license.

  You may notice that the Blu-ray image is only just over 2GB. This is intentional ; we have encoded all the content on the disk at appropriate bitrates to be playable from an ordinary 4.7GB DVD. This should make it far easier to burn a copy of the Blu-ray, since Blu-ray burners and writable media are still relatively rare. Most Blu-ray players will treat a DVD containing Blu-ray data as a normal Blu-ray disc. A few, such as the Playstation 3, will not, but you can still play it as a data disc.

  Finally, note that (in accordance with the Blu-ray spec) the disc image file uses the UDF 2.5 filesystem, which may be incompatible with some older virtual drive and DVD burning applications. You’ll also need to play it on an actual Blu-ray player if you want to get the menus and such working correctly. If you’re looking to play it on a PC, a free trial of Arcsoft TMT is available here.

  What are you waiting for ? Grab a copy today !

  UPDATE : Here is an AVCHD-compliant version of the above, which should work better when burned on a DVD-5 instead of a BD-R. (mirror)
  

  What’s left before we have a fully free software Blu-ray creation toolkit ? Audio is already dealt with ; AC3 audio (aka Dolby Digital), the format used in DVD, is still supported by Blu-ray, and there are many free software AC3 encoders. The primary missing application is a free software Blu-ray authoring tool, to combine the video and audio streams to create a Blu-ray file structure with the menus, chapters, and so forth that we have all come to expect. But the hardest part is dealt with : we can now create compatible video and audio streams.

  In the meantime, x264 can be used to create streams to be authored using Blu-Print, Scenarist, Encore or other commercial authoring tools.

  More detailed documentation on the new Blu-ray support and how to use it can be found in the official commit message. Do keep in mind that you have to export to raw H.264 (not MKV or MP4) or else the buffering information will be slightly incorrect. Finally, also note that the encoding settings given as an example are not a good choice for general-purpose encoding : they are intentionally crippled by Blu-ray restrictions, which will significantly reduce compression for ordinary non-Blu-ray encoding.

  In addition to Blu-ray support, the aforementioned commit comes with a lot of fun extras :

  x264 now has native variable-framerate ratecontrol, which makes sure your encodes get a correct target bitrate and proper limiting of maximum bitrate even if the duration of every frame is different and the “framerate” is completely unknown. This helps a lot when encoding from variable-framerate container formats such as FLV and WMV, along with variable-framerate content such as anime.

  x264 now supports pulldown (telecine) in much the same fashion as it is handled in MPEG-2. The calling application can pass in flags representing how to display a frame, allowing easy transcoding from MPEG-2 sources with pulldown, such as broadcast television. The x264 commandline app contains some examples of these (such as the common 3:2 pulldown pattern).

  x264 now also exports HRD timing information, which is critical for compliant transport stream muxing. There is currently an active project to write a fully DVB-compatible free software TS muxer that will be able to interface with x264 for a seamless free software broadcast system. It will likely also be possible to repurpose this muxer as part of a free software Blu-ray authoring package.

  All of this is now available in the latest x264.

  http://mirror05.x264.nl/Dark/bluray%20fail.png