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• DXGI Desktop Duplication : encoding frames to send them over the network

  31 août 2018, par prazuber

  I’m trying to write an app which will capture a video stream of the screen and send it to a remote client. I’ve found out that the best way to capture a screen on Windows is to use DXGI Desktop Duplication API (available since Windows 8). Microsoft provides a neat sample which streams duplicated frames to screen. Now, I’ve been wondering what is the easiest, but still relatively fast way to encode those frames and send them over the network.

  The frames come from AcquireNextFrame with a surface that contains the desktop bitmap and metadata which contains dirty and move regions that were updated. From here, I have a couple of options :

  1. Extract a bitmap from a DirectX surface and then use an external library like ffmpeg to encode series of bitmaps to H.264 and send it over RTSP. While straightforward, I fear that this method will be too slow as it isn’t taking advantage of any native Windows methods. Converting D3D texture to a ffmpeg-compatible bitmap seems like unnecessary work.
  2. From this answer : convert D3D texture to IMFSample and use MediaFoundation’s SinkWriter to encode the frame. I found this tutorial of video encoding, but I haven’t yet found a way to immediately get the encoded frame and send it instead of dumping all of them to a video file.

  Since I haven’t done anything like this before, I’m asking if I’m moving in the right direction. In the end, I want to have a simple, preferably low latency desktop capture video stream, which I can view from a remote device.

  Also, I’m wondering if I can make use of dirty and move regions provided by Desktop Duplication. Instead of encoding the frame, I can send them over the network and do the processing on the client side, but this means that my client has to have DirectX 11.1 or higher available, which is impossible if I would want to stream to a mobile platform.

• Anomalie #2424 : bug sur la migration de la table spip_urls de spip2 à spip3

  6 décembre 2011, par Alexandre C

  Je confirme que le problème persiste pour moi sur des mises à jour d’articles, entrainant aussi le bug sur les rubriques mères, sur un SPIP 3.0.0-beta [18754]

• How to avoid that Mediafilesegmenter cuts the last frames ?

  26 avril 2021, par Alexander Khitev

  We use ffmpeg and mediafilesegmenter for creating HLS video, we also created shell script for convenience. I noticed one issue that if we use original video with float duration, for example 10.602 seconds mediafilesegmenter cuts some last frames. How can I fix it ? Or what other tools can I use to create HLS ? Thanks !

  


  ffmpeg -i movie.mp4 -vb 500K movie-500K.mp4
ffmpeg -i movie.mp4 -vb 1500K movie-1500K.mp4

mkdir small
mkdir big

mediafilesegmenter -f small -A -B segment -t 1 movie-500K.mp4
mediafilesegmenter -f big -A -B segment -t 1 movie-1500K.mp4
mv movie-500K.plist small/movie-500K.plist
mv movie-1500K.plist big/movie-1500K.plist

variantplaylistcreator -r -o prog_index.m3u8 small/prog_index.m3u8 small/movie-500K.plist big/prog_index.m3u8 big/movie-1500K.plist