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• Add audio to video file at specific second in nodejs fluent-ffmpeg

  17 mars 2020, par toljoas

  I have a Video (mp4) and want to add audio to it (mp3).
  The audio should be added at the xth second of the video (meaning the video initially plays for 3 seconds, and only then the audio starts to play, if possible only for a specified duration, but this is not necessary).
  I use the package ’fluent-ffmpeg’.

  I have tried the following :

  const conv = ffmpeg()
  
  
  
  conv.addInput(__dirname + '/screens/screen_%d.png').
  
  addInput(__dirname + '/audio.mp3').setStartTime(3).setDuration(6).
  
  withFpsInput(60).withSize('1920x1080')

  But this sets the start time of the audio itself (meaning the first 6 seconds of the audio are skipped), and sets the duration of the whole video, not merely the audio.

  The question I am asking has already been asked here, but the answer merely shows how to add audio to the video from the start of the video.

  Help is appreciated.

• Why is chrominance lost when i OpenSharedResource from a ffmpeg AVFrame resource ?

  19 avril 2022, par Logoro

  D3D11_TEXTURE2D_DESC texture_desc = {0};&#xA;texture_desc.Width = 640;&#xA;texture_desc.Height = 480;&#xA;texture_desc.MipLevels = 1;&#xA;texture_desc.Format = DXGI_FORMAT_NV12;&#xA;texture_desc.SampleDesc.Count = 1;&#xA;texture_desc.ArraySize = 1;&#xA;texture_desc.Usage = D3D11_USAGE_DEFAULT;&#xA;texture_desc.MiscFlags = D3D11_RESOURCE_MISC_SHARED;&#xA;&#xA;Microsoft::WRL::ComPtr<id3d11texture2d> temp_texture_for_my_device{nullptr};&#xA;my_device->CreateTexture2D(&amp;texture_desc, NULL, &amp;temp_texture_for_my_device);&#xA;&#xA;Microsoft::WRL::ComPtr<idxgiresource> dxgi_resource{nullptr};&#xA;temp_texture_for_my_device.As(&amp;dxgi_resource);&#xA;HANDLE shared_handle = NULL;&#xA;dxgi_resource->GetSharedHandle(&amp;shared_handle);&#xA;dxgi_resource->Release();&#xA;&#xA;Microsoft::WRL::ComPtr<id3d11texture2d> temp_texture_for_ffmpeg_device {nullptr};&#xA;ffmpeg_device->OpenSharedResource(shared_handle, __uuidof(ID3D11Texture2D), (void**)temp_texture_for_ffmpeg_device.GetAddressOf());&#xA;ffmpeg_device_context->CopySubresourceRegion(temp_texture_for_ffmpeg_device.Get(), 0, 0, 0, 0, (ID3D11Texture2D*)ffmpeg_avframe->data[0], (int)ffmpeg_avframe->data[1], NULL);&#xA;ffmpeg_device_context->Flush();&#xA;</id3d11texture2d></idxgiresource></id3d11texture2d>

  


  I copy temp_texture_for_ffmpeg_device to a D3D11_USAGE_STAGING, it's normal, but when i copy temp_texture_for_my_device to a D3D11_USAGE_STAGING, i lost the chrominance data.

  


  When i map the texture to cpu via D3D11_USAGE_STAGING :

  


  temp_texture_for_ffmpeg_device : RowPitch is 768, DepthPitch is 768 * 720.
temp_texture_for_my_device : RowPitch is 1024, DepthPitch is 1024 * 480.

  


  I think there are some different parameters between the two devices(or device context ?), but I don't know what parameters would cause such a difference in behavior.

  


  my_device and my_device_context are created by D3D11On12CreateDevice

  


• Difference between DirectShowSource() and FFmpegSource2() in AviSynth

  29 mars 2024, par MarianD

  For non .avi A/V sources (as .mp3, .mp4, etc.) there are (at least) 2 possibilities for reading those media files in AviSynth (in Windows) :

  



  

  • The built-in media filter DirectShowSource(), using Microsoft's DirectShow media architecture.

  


  • The AviSynth Plugin FFmpegSource2() alias FFMS2() using FFmpeg and nothing else.

  


  



  What are advantages and disadvantages of them ?
  
Which is more reliable, frame / sample accurate, etc.?