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• How to use Intel QSV record screen based on ffmpeg

  18 octobre 2020, par zonda

  I want to record my screen with ffmpeg.
  
I succeeded in the normal way.
  
ffmpeg -f gdigrab -framerate 30 -draw_mouse 1 -i desktop -c:v h264 -r 30 -preset ultrafast -tune zerolatency -pix_fmt yuv420p "record.mp4"

  



  But I want use GPU record my screen now.
  
I'm trying to use Intel QSV on ffmpeg.
  
ffmpeg -f gdigrab -framerate 30 -draw_mouse 1 -i desktop -c:v h264_qsv -r 30 -tune zerolatency -pix_fmt yuv420p "record.mp4"

  



  It does not work and show :
  
[h264_qsv @ 0000000000479080] Error initializing the encoder: invalid video parameters (-15)
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

I don't know what happened.

  



  And I'm trying simple way.
  
ffmpeg -i test_input.mp4 -c:v h264_qsv -preset:v faster test_output.mp4
  
It does not work too.

  



  My computer information :
  
acer notebook : TravelMate P243-MG
  
OS : windows 7 64bits
  
CPU : Intel i5-3210M
  
Graphics card : Nvidia GT-630M

  



  Thanks in advance !

  


• FFMPEG and NVENC / HVEC low utilisation

  7 octobre 2018, par Deex

  I did some experiments with NVENC and HEVC encoding. It is working but i see only a low GPU Usage between 20-35%. So i read a about it and found some article that my GTX 1080 can only use two sessions according to https://developer.nvidia.com/video-encode-decode-gpu-support-matrix#Encoder . So my first questions are
  1) how can i find out if this is the reason for the low Utilisation
  2) Is there a way with ffmpeg to use the GPU more efficient
  3) What is about the new updatet NVENC Codec for the Nvidia RTX 2080 TI, does it support more sessions ? Would it be a good idea to use it in SLI for video Encoding in the future because of the buff, or should i look for a Quadro Card ?

  My command is

  ffmpeg -f concat -safe 0 -hwaccel auto -i "D:\-=streaming=-\concats\convertme\index.txt" -i "D:\-=streaming=-\concats\convertme\index.txt" ^
-y -preset slow -c:v hevc_nvenc -preset llhq -rc:v cbr_ld_hq -rc cbr_ld_hq -crf 25 -r 60 -movflags +faststart -c:a copy -pass 1 -2pass -1 "D:\-=streaming=-\concats\x265-website_high.mp4" ^
-y -preset slow -c:v hevc_nvenc -preset llhq -rc:v cbr_ld_hq -rc cbr_ld_hq -crf 25 -r 60 -vf scale=640:360 -movflags +faststart -c:a copy -b:a 128k -pass 1 -2pass -1 "D:\-=streaming=-\concats\x265-website_low.mp4"

  

• How can i transform dvb subtitles into text format using FFMpeg or how can i optimize the dvb burning process ?

  28 octobre 2018, par alexsua

  I am working on a hls transcoder from any format to HLS and I need to encode multiple subtitles with the format "dvbsub" at the same time with the purpose of being selected by a client who interprets the m3u8 HLS playlist.

  The main problem is that burning each dvbsub into a live video stream in this way :

   "-filter_complex "[0:v][0:s:0]overlay[v0];[0:v][0:s:1]overlay[v1];[0:v][0:s:2]overlay[v2];......"

  is a very CPU intensive task. (I have 8 or more dvbsub in the same stream).

  Does Anyone know how to transform each dvbsub into a text format (webvtt for example) or if there is a way to optimize the process ? (I tried to perform this burning process with NVIDIA gpu but I have not achieved any improvement)

  I read about OCR programs which can do the task but after days of research i still dont know how to do that.

  Thanks in advance.