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• Issue creating video with FFmpeg from Gource output

  16 avril 2013, par user1832408

  I'm trying to create a video with FFmpeg from Gource output but FFmpeg fails for some reason. I have no idea why as the error message is quite general. Does anyone have any ideas ? Is the Gource output perhaps invalid ?

  set GOURCE=C:\Program Files\Gource\0.39
  
  set FFMPEG=C:\Program Files\FFmpeg\20130412-git-694fa00-win32-static\bin
  
  set SOURCE=src
  
  
  
  "%GOURCE%\gource.exe" -1280x720 -o gource.ppm %SOURCE%
  
  "%FFMPEG%\ffmpeg.exe" -y -r 60 -f image2pipe -vcodec ppm -i gource.ppm -vcodec libx264 -preset ultrafast -crf 1 -threads 0 -bf 0 -v verbose gource.x264.avi

  FFmpeg output

  ffmpeg version N-52045-g694fa00 Copyright (c) 2000-2013 the FFmpeg developers
    built on Apr 12 2013 16:54:51 with gcc 4.8.0 (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-libcaca —enable-libfreetype —enable-libgsm —enable-libilbc —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-libvo-aacenc —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxavs —enable-libxvid —enable-zlib
    libavutil      52. 26.100 / 52. 26.100
    libavcodec     55.  2.100 / 55.  2.100
    libavformat    55.  2.100 / 55.  2.100
    libavdevice    55.  0.100 / 55.  0.100
    libavfilter     3. 53.101 /  3. 53.101
    libswscale      2.  2.100 /  2.  2.100
    libswresample   0. 17.102 /  0. 17.102
    libpostproc    52.  3.100 / 52.  3.100
  [image2pipe @ 003bade0] Stream #0 : not enough frames to estimate rate ; consider increasing probesize
  Input #0, image2pipe, from 'gource.ppm' :
    Duration : N/A, bitrate : N/A
      Stream #0:0 : Video : ppm, rgb24, 1280x720, 60 tbr, 60 tbn, 60 tbc
  [graph 0 input from stream 0:0 @ 003bbb60] w:1280 h:720 pixfmt:rgb24 tb:1/60 fr:60/1 sar:0/1 sws_param:flags=2
  [auto-inserted scaler 0 @ 003bbaa0] w:0 h:0 flags :'0x4' interl:0
  [format @ 003bb4e0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'Parsed_null_0' and the filter 'format'
  [graph 0 input from stream 0:0 @ 003bbb60] TB:0.016667 FRAME_RATE:60.000000 SAMPLE_RATE:nan
  [auto-inserted scaler 0 @ 003bbaa0] w:1280 h:720 fmt:rgb24 sar:0/1 -> w:1280 h:720 fmt:yuv444p sar:0/1 flags:0x4
  No pixel format specified, yuv444p for H.264 encoding chosen.
  Use -pix_fmt yuv420p for compatibility with outdated media players.
  [libx264 @ 003bc980] using cpu capabilities : MMX2 SSE2Fast LZCNT
  [libx264 @ 003bc980] profile High 4:4:4 Predictive, level 3.2, 4:4:4 8-bit
  Output #0, avi, to 'gource.x264.avi' :
    Metadata :
      ISFT : Lavf55.2.100
      Stream #0:0 : Video : h264 (H264 / 0x34363248), yuv444p, 1280x720, q=-1—1, 60 tbn, 60 tbc
  Stream mapping :
    Stream #0:0 -> #0:0 (ppm -> libx264)
  Press [q] to stop, [?] for help
  frame=   17 fps=0.0 q=0.0 size=      43kB time=00:00:00.21 bitrate=1614.1kbits/s    
  frame=   33 fps= 32 q=0.0 size=     164kB time=00:00:00.48 bitrate=2777.5kbits/s    
  frame=   48 fps= 31 q=0.0 size=     277kB time=00:00:00.73 bitrate=3093.0kbits/s    
  gource.ppm : Input/output error
  No more output streams to write to, finishing.
  frame=   48 fps= 30 q=2358879.0 Lsize=     324kB time=00:00:00.80 bitrate=3313.9kbits/s
  video:317kB audio:0kB subtitle:0 global headers:0kB muxing overhead 2.112279%
  
  [libx264 @ 003bc980] frame I:1     Avg QP : 0.00  size : 10560
  
  [libx264 @ 003bc980] frame P:47    Avg QP : 0.00  size :  6680
  
  [libx264 @ 003bc980] mb I  I16..4 : 100.0%  0.0%  0.0%
  
  [libx264 @ 003bc980] mb P  I16..4 :  0.5%  0.0%  0.0%  P16..4 :  1.9%  0.0%  0.0%  0.0%  0.0%    skip:97.5%
  
  [libx264 @ 003bc980] coded y,u,v intra : 3.7% 1.1% 1.2% inter : 1.4% 0.5% 0.6%
  
  [libx264 @ 003bc980] i16 v,h,dc,p : 93%  4%  2%  0%
  
  [libx264 @ 003bc980] kb/s:3245.31
  

• Solving The XVD Puzzle

  15 avril 2012, par Multimedia Mike — General, multimedi archaeology, silicon valley, vg2, xvd, zygo

  I downloaded a multimedia file a long time ago (at least, I strongly suspected it was a multimedia file which is why I downloaded it). It went by the name of ‘lamborghini_850kbps.vg2′. I have had it in my collection for at least 7 years. I couldn’t remember where I found it. I downloaded it before it occurred to me to take notes about this sort of stuff.

  I found myself staring at the file again today and Googled the filename. This led me to a few Japanese sites which also contained working URLs for a few more .vg2 samples. Some other clues led me to a Russian language forum where someone had linked to a site that had Win32 codec modules that could process the files. The site was defunct but the Internet Archive Wayback Machine kept a copy for me, as well as copies of several more .vg2 samples from a defunct Japanese site previously involved with this codec.

  Sometimes this internet technology works really well. But I digress.

  Anyway, through all this, I finally found a clue : XVD. and wouldn’t you know, there is already a basic page on the MultimediaWiki describing the technology. In fact, while VG2 is a custom container, the MultimediaWiki states that the video component has a FourCC of VGMV, and there is already a file named VGMV.avi in the root V-codecs/ samples directory, something I vow to correct (that’s a big pet peeve of mine– putting samples in the root V-codecs/ or A-codecs/ directories).

  XVD… XVD… XVD… why does that sound so familiar ? Oh, of course ; there is a company named XVD and they have an office in the Bay Area which I have passed on numerous occasions, like this morning :

  
  <

  Someone originally connected with the multimedia technology in question operates a website which contains an unofficial history of the XVD tech. At first, I was wondering if the technology was completely defunct (and should therefore be open sourced). But if XVD’s solutions page (dated 2010) is to be believed, the technology is still in service, and purported to be better than H.264 and VC-1 : “The current generation of XVD video compression technology provides better video quality at any given data rate than standards-based codecs (H.264 or VC-1) with four times lower encoding complexity (when compared with H.264 Main Profile).”

  If they say so. For my part, I’m just happy that I have finally figured out what this lamborghini_850kbps.vg2 is so that I can properly catalog it on the samples site, which I have now done, along with other samples and various codecs modules.

  This episode reminds me that there’s a branch office of Zygo Corporation close to my home (though the headquarters are far, far away). The companies you see in Silicon Valley. Anyway, long-time open source multimedia hackers will no doubt recognize Zygo from the ZyGo FourCC & video codec transported in QuickTime files that was almost decode-able using an H.263 decoder.

  
  
  

  I may never learn what Zygo’s core competency actually is, but I will always remember their multimedia tech every time I run past their office.

• v4l2loopback+ffmpeg input for uvc gadget

  13 mai, par Mosi

  I'm trying to use an MP4 video file as the input for a UVC Gadget setup on my Raspberry Pi 4 Model B, but I'm running into an issue when streaming through V4L2.

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  Goal :

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  To emulate a webcam that streams a looping MP4 video file to a Windows 11 host.

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  My setup :

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  • Hardware : Raspberry Pi 4 Model B

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  • OS : Raspberry Pi OS Lite 64-bit (2025-05-06-raspios-bookworm-arm64-lite)

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  • Kernel : 6.12.25+rpt-rpi-v8

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  • Host System : Windows 11

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  • UVC Gadget version : v0.3.0

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  Workflow :

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  [MP4 Video] → [FFmpeg] → [V4L2 Loopback] → [UVC Gadget] → Windows sees virtual webcam


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  What works :

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  The UVC Gadget works perfectly when I use a real webcam as the source (e.g., /dev/video0). Windows detects the virtual webcam and displays a smooth video stream.

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  The problem :

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  When I try to use an MP4 video file through FFmpeg and send it to the loopback device (/dev/video3), the UVC Gadget fails with the following error :

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  ---

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  Command I'm using :

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  ffmpeg -re -stream_loop -1 -i input.mp4 -vf scale=640:480 \
  -c:v rawvideo -pix_fmt yuyv422 -r 30 -f v4l2 /dev/video3


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  Then I run :

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  sudo uvc-gadget -d /dev/video3 uvc.0


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  Output :

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  bRequestType 21 bRequest 01 wValue 0200 wIndex 0001 wLength 0022
streaming request (req SET_CUR cs 02)
setting commit control, length = 34
Setting format to 0x56595559 640x480
=== Setting frame rate to 30 fps
Starting video stream.
--> [At this point I open the camera on the Windows host]
/dev/video3: 2 buffers requested.
Failed to export buffer 0.
Failed to export buffers on source: Inappropriate ioctl for device (25)


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  ---

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  Things I've tried :

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  • Multiple FFmpeg formats, resolutions, and pixel formats

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  • Various ffmpeg buffer and framerate tweaks

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  • Different UVC Gadget versions

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  • GitHub related projects (showcamera, etc.)

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  • Older Raspberry Pi OS versions

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  Most guides and GitHub projects I found are outdated (5+ years old), and newer methods seem undocumented or incompatible with current kernel/UVC gadget tools.

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  ---

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  My question :

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  How can I stream an MP4 file as a virtual webcam using UVC Gadget without getting ioctl errors ?
  &#xA;Is there a proper way to set up FFmpeg and loopback devices so that UVC Gadget can read the stream correctly ?

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  Any modern working example or tips would be very appreciated. Thanks in advance !

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