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• how can I assign unique AVFoundation camera device names ?

  28 avril 2023, par mcgregor94086

  Short summary :
I have a USB multi-camera array device. According to system_profiler, each of these webcams share the same name : "USB Camera". I have no unique name I can use with FFMPEG AVFoundation and get images from that specific camera. How can I tell FFMPEG the specific camera that I want (each has a unique USB path that I normally use to identify a specific camera.

  


  I can solve this problem on Linux, but I can't figure out how to do it on macOS.

  


  How I might do this on Linux
I know the unique USB Path to each camera, and I would like to use this to assign a unique Name that I can address using FFMPEG when taking images. On Linux I can use the udev system to make those assignments,

  


  In Linux, I can reassign a new unique camera name using /etc/udev/rules.d/60-v4l.rules. with something like this :

  


  SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_1, ENVID_V4L_PRODUCT="Cam_00"
SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_3, ENVID_V4L_PRODUCT="Cam_01"
...

  


  More details :
Of course macOS doesn't work this way, as it uses AVFoundation to address video devices.

  


  When I attach the device I see that 16 new cameras now appear when I type query system_profiler SPCameraDataType, it prints the output shown further below

  


  You may notice that there are 16 cameras all named "USB Camera :" but system_profiler is reporting that each has a "Unique ID :" that is different for each camera. This Unique ID is composed of a unique USB Path (e.g. '0x1441311') concatenated with the "Vendor ID" ('00bda') and product ID ('5829') all expressed in hexadecimal.

  


  Unfortunately, this means every camera has the same generic name in iPhoto, and when specifying the input camera in FFMPEG with AVFoundation syntax, I can't seem to indicate which specific camera I want.

  


  I want to take 1 photo from each camera in a specific order. I have a table that maps each camera's USB Path to a desired name that would make it easy for me to trigger the camera captures in the sequence I desire.

  


  In Linux, I can reassign a new unique camera name using /etc/udev/rules.d/60-v4l.rules.

  


  SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_1, ENVID_V4L_PRODUCT="Cam_00"
SUBSYSTEMS=="usb", ENVID_VENDOR_ID=="0bda", ENVID_MODEL_ID=="5829", ENVID_PATH_TAG==platform-fd500000_pcie-0000_01_00_0-usb_1_4_5_1_3_1_3, ENVID_V4L_PRODUCT="Cam_01"
...

  


  % system_profiler SPCameraDataType

  


  Camera :

  


  USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131100bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144200000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141400bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121200bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121400bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144133000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144131200bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141100bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144143000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144121300bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144110000bda5829

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144141200bda5829

FaceTime HD Camera (Built-in):

  Model ID: UVC Camera VendorID_1452 ProductID_34068
  Unique ID: 0x8020000005ac8514

USB Camera:

  Model ID: UVC Camera VendorID_3034 ProductID_22569
  Unique ID: 0x144300000bda5829


  


  MacBook Pro, OS X 10.11
Posted on Apr 27, 2023 10:49 PM
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how can I assign unique AVFoundation camera device names ?
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• Facing delay in mic audio while using ffmpeg with h264_nvenc encoder [closed]

  30 avril 2023, par Aniket Bose

  I am trying to capture my windows10 desktop with desktop duplication api and on-gpu D3D11 textures, in the form of ffmpeg D3D11VA frames @60 fps. Required command is given here. On top of that I am trying to also intercept my mic audio. For that I am using this command,

  


  ffmpeg -init_hw_device d3d11va -filter_complex ddagrab=framerate=60 -f dshow -i audio="Microphone (High Definition Audio Device)" -c:v h264_nvenc -rc vbr -cq 24 -qmin 24 -qmax 24 -profile:v main -b:v 0K output.mp4


  


  After the desktop capture process when I am watching output.mp4 I am facing an audio delay. More Precisely my mic audio is coming after 28/29 video frames. ie. (28/60)*1000 = 466 ms delay in audio.

  


  I tried to capture @30fps but no improvement. Now I am getting 14 frames delay ie. (14/30)*1000 = 466 ms delay in audio.

  


  After some research I came to know about keyframe intervals. at default h264_nvenc uses 200 sec keyframe interval. So i tried to lower that with the -g option of h264_nvenc encoder. No improvement here too.

  


  One possible solution could be to delay my video using -itsoffset option. These stack overflow and superuser solutions only work with pre-recorded videos,

  


  ffmpeg delay video in overlay

  


  In ffmpeg, how to delay only the audio of a .mp4 video without converting the audio ?

  


  But I am capturing and encoding on the go (ie. at same time).

  


  I am a novice at video editing and ffmpeg. I am using latest release build from gyan.dev.

  


  ffmpeg version 6.0-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: 
--enable-gpl --enable-version3 --enable-static --disable-w32threads 
--disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls 
--enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma 
--enable-libsnappy --enable-zlib --enable-librist --enable-libsrt 
--enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray 
--enable-libcaca --enable-sdl2 --enable-libaribb24 --enable-libdav1d 
--enable-libdavs2 --enable-libuavs3d --enable-libzvbi --enable-librav1e 
--enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 
--enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl 
--enable-libopenjpeg --enable-libvpx --enable-mediafoundation 
--enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi 
--enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg 
--enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec 
--enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 
--enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo 
--enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug 
--enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame 
--enable-libshine --enable-libtheora --enable-libtwolame 
--enable-libvo-amrwbenc --enable-libilbc --enable-libgsm 
--enable-libopencore-amrnb --enable-libopus --enable-libspeex 
--enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite 
--enable-libmysofa --enable-librubberband --enable-libsoxr 
--enable-chromaprint
  libavutil      58.  2.100 / 58.  2.100
  libavcodec     60.  3.100 / 60.  3.100
  libavformat    60.  3.100 / 60.  3.100
  libavdevice    60.  1.100 / 60.  1.100
  libavfilter     9.  3.100 /  9.  3.100
  libswscale      7.  1.100 /  7.  1.100
  libswresample   4. 10.100 /  4. 10.100
  libpostproc    57.  1.100 / 57.  1.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...


  


• FFmpeg with m3u8 playlist : Invalid data found when processing input [closed]

  15 mai 2023, par anthnyprschka

  I get the following error when I try to open a playlist with FFmpeg :

  


  ffmpeg version 2023-03-05-git-912ac82a3c-essentials_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
  libavutil      58.  3.100 / 58.  3.100
  libavcodec     60.  6.100 / 60.  6.100
  libavformat    60.  4.100 / 60.  4.100
  libavdevice    60.  2.100 / 60.  2.100
  libavfilter     9.  4.100 /  9.  4.100
  libswscale      7.  2.100 /  7.  2.100
  libswresample   4. 11.100 /  4. 11.100
  libpostproc    57.  2.100 / 57.  2.100
playlist.m3u8: Invalid data found when processing input


  


  Command I use :

  


  ffmpeg [-allowed_extensions ALL] -i playlist.m3u8 -c copy playlist.mp4


  


  Playlist file :

  


  #EXTM3U
#EXTINF:-1,0
https://20230515.s3.eu-central-1.amazonaws.com/output0000f.mp4
#EXTINF:-1,1
https://20230515.s3.eu-central-1.amazonaws.com/output0001f.mp4
#EXTINF:-1,2
https://20230515.s3.eu-central-1.amazonaws.com/output0002f.mp4


  


  The playlist plays fine in VLC player