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• How can i list all the audio devices on my pc using ffmpeg ? [closed]

  12 octobre 2024, par Daniel Lip

  I'm using ffmpeg version : 2024-07-10

  


  I tried this cmd command after running the cmd as admin.

  


  ffmpeg -list_devices true -f dshow -i dummy


  


  but the result is :

  


  D:\>ffmpeg -list_devices true -f dshow -i dummy
ffmpeg version 2024-07-10-git-1a86a7a48d-essentials_build-www.gyan.dev Copyright (c) 2000-2024 the FFmpeg developers
  built with gcc 13.2.0 (Rev5, 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-libharfbuzz --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --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      59. 28.100 / 59. 28.100
  libavcodec     61. 10.100 / 61. 10.100
  libavformat    61.  5.101 / 61.  5.101
  libavdevice    61.  2.100 / 61.  2.100
  libavfilter    10.  2.102 / 10.  2.102
  libswscale      8.  2.100 /  8.  2.100
  libswresample   5.  2.100 /  5.  2.100
  libpostproc    58.  2.100 / 58.  2.100
[dshow @ 000001c1e700f200] Could not enumerate video devices (or none found).
[dshow @ 000001c1e700f200] Could not enumerate audio only devices (or none found).
[in#0 @ 000001c1e700ee00] Error opening input: Immediate exit requested
Error opening input file dummy.


  


• ffmpeg fast seek not working for MP4 over HTTP

  27 juillet 2024, par Gmanicus

  I'm attempting to download snapshots from a video provided by the U.S House of Representatives :

  


  https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4


  


  I am using fluent-ffmpeg in Node to execute this command :

  


  ffmpeg('https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4')
  .inputOption(`-ss 03:33:33`)
  .outputOptions([
     '-vframes 1'
  ])
  .output('test.png')

// Effectively:
// ffmpeg -ss 03:33:33 -i  -y -vframes 1 test.png


  


  My intention is to fast-seek to the desired timestamp and take a snapshot over HTTP. However, when doing so, the performance is not great. A snapshot takes about 10s per 3hrs of video and seems to increase fairly linearly at that rate.

  


  However, when using ffmpeg on the same video locally, it's super fast ! Sub-500ms regardless of the desired timestamp.

  


  Is there some magic that could be done via ffmpeg options or perhaps some sort of technique with manual requests to get a snapshot at the desired segment of video more efficiently ?

  


• ffmpeg fast seek large MP4 over HTTP

  28 juillet 2024, par Gmanicus

  I'm attempting to download snapshots from a video provided by the U.S House of Representatives :

  


  https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4


  


  I am using fluent-ffmpeg in Node to execute this command :

  


  ffmpeg('https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4')
  .inputOption(`-ss 03:33:33`)
  .outputOptions([
     '-vframes 1'
  ])
  .output('test.png')

// Effectively:
// ffmpeg -ss 03:33:33 -i  -y -vframes 1 test.png


  


  My intention is to fast-seek to the desired timestamp and take a snapshot over HTTP. However, when doing so, the performance is not great. A snapshot takes about 10s per 3hrs of video and seems to increase fairly linearly at that rate.

  


  However, when using ffmpeg on the same video locally, it's super fast ! Sub-500ms regardless of the desired timestamp.

  


  Is there some magic that could be done via ffmpeg options or perhaps some sort of technique with manual requests to get a snapshot at the desired segment of video more efficiently ?