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• GPU produces laggy videos with ffmpeg [closed]

  10 août 2023, par Salah M. Wahsh

  I wrote a Powershell script to batch edited many videos. but the gpu renders the videos very laggy.

  


  so I'm trying to batch trim and downsize multiple videos using ffmpeg, it works perfectly when it utilizes the CPU. The problem is the CPU is slow when rendering the videos. So, after I utilized the GPU, the rendering time went down significantly which is great, but all the videos are very laggy for some reason. Anyone faced this issue before ?
My GPU is GTX 1050 3gb, I know it's considered a lower end GPU, but it's weird that it renders all the videos very fast so I recon the GPU don't struggle that much.

  


  this is the powershell script I'm using

  


  `New-Item -Path 'EDITED' -ItemType Directory

foreach ($file in Get-ChildItem -Filter *.mp4) {
    ffmpeg -hwaccel cuvid -c:v h264_cuvid -ss 00:00:00 -i $file.FullName -t 00:00:11 -c:v h264_nvenc -c:a copy -vcodec h264_nvenc -qp 23 ("EDITED/" + $file.Name)
}`


  


• Recording output from tvtime

  26 janvier 2013, par user1533147

  I have been trying to record from the application tvtime, which displays the output from my Pinnacle Dazzle DVC 100. Since tvtime doesn't have recording capabilities I have been trying to figure out how to capture the output from it. Piping apparently doesn't work, nor does using something like the command tvtime > ffmpeg.

  I'm trying to capture its output because tvtime does a great job of outputting at a pretty consistent 59.94 frames per second (FPS). I have tried to duplicate its smoothness by using VLC and the yadif deinterlace filter, but that doesn't quite give the quality tvtime offers. Also I have tried using the avconv command

  avconv -f video4linux2 -i /dev/video0 -f alsa -i hw:2,0 -vcodec mpeg4 -vtag DX50 \
  
  -b 1200k -r 60000/1001 -acodec libmp3lame -ar 48000 -ac 2 -ab 128k \
  
  -vf yadif=0:-1:0,scale=720:406  -y /tmp/test.avi

  but that doesn't seem to help, either.

  So is there a way to record from tvtime at the said FPS, or can I use some other recording software (like mencoder or KDEnlive) to simulate 59.94 FPS ?

• How to write frames to a video file ?

  20 juillet 2019, par Mike Chen

  I am currently writing an application that read frames from camera, modify them, and save them into a video file. I’m planing to do it with ffmpeg. There’s rarely a documentation about ffmpeg. I can’t find a way. Does any know how to do it ?

  I need it to be done on unix, and in C or C++. Does any can provide some instructions ?

  Thanks.

  EDIT :

  Sorry, I haven’t write clearly. I want some developer APIs to write frames to a video file. I open up camera stream, I get every single frame, then I save them into a video file with those APIs available in ffmpeg’s public apis. So using command line tool actually doesn’t help me. And I’ve seen output_example.c under the ffmpeg src folder. It’s pretty great that I may copy some parts of the code directly without change. And I am still looking for a easier way.

  Also, I’m thinking of porting my app to iPhone, as far as I know, only ffmpeg has been ported on iPhone. GStreamer is based on glib, and it’s all GNU stuff. I’m not sure if I can get it work on iPhone. So ffmpeg is still the best choice for now.

  Any comments is appreciated.