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• FFmpeg error - "at least one output file must be specified" [closed]

  7 février 2013, par Derrick Tucker

  I'm having a little trouble, and I feel like the solution is probably starting me in the face.

  ffmpeg -ss 0 -i rawvid.flv -t 33 -vf scale=640x480 -b:21504 test.mpg

  When run, this yells at me that "At least one output file must be specified". I've been knocking me head on the wall for hours now, what am I missing ?

  PS : FFmpeg works fine, and if I remove all of the flags in the statement above, it works.

• record screen with high quality and minimum size in ElectronJS (Windows)

  4 avril 2022, par Seyed Ali Roshan

  as I said in the title, I need to record my screen from an electron app.

  


  my needs are :

  


  

  • high quality (720p or 1080p)

  


  • minimum size

  


  • record audio + screen + mic

  


  • low impact on PC hardware while recording

  


  • no need for any wait after the recorder stopped

  


  


  


  by minimum size I mean about 400MB on 720p and 700MB on 1080p for a 3 to 4 hours recording. we already could achieve this by bandicam and obs and it's possible

  


  


  I already tried :

  


  

  • the simple MediaStreamRecorder API using RecordRTC.Js ; produces huge file sizes, like 1GB per hour for 720p video.

  


  • compressing the output video using FFmpeg ; it can take up to 1 hour for 3 hours recording

  


  • save every chunk with 'ondataavailable' event and right after, run FFmpeg and convert and reduce the size and append all the compressed files (also by FFmpeg) ; there are two problems. 1, because of different PTS but it can be fixed by tunning compress command args. 2, the main problem is the audio data headers are only available in the first chunk and this approach causes a video that only has audio for the first few seconds

  


  • recording the video with FFmpeg itself ; the end-users need to change some things manually (Stereo Mix), the configs are too complex, it causes the whole PC to work slower while recording (like fps drop ; even if I set -threads to 1), in some cases after recording is finished it needs many times to wrap it all up

  


  • searched through the internet to find applications that can be used from the command line ; I couldn't find much, the famous applications like bandicam and obs have command line args but there are not many args to play with and I can't set many options which leads to other problems

  


  


  I don't know what else I can do, please tell me if u know a way or simple tool that can be used through CLI to achieve this and guide me through this

  


• NReco video to bitmaps

  15 octobre 2016, par Christine

  please, how can I convert video to a sequence of bitmaps ? I need every frame one by one and process them in memory (no disc output). I chose NReco.VideoConverter but not sure which method can do this. I understand that $FFMpegConverter .GetVideoThumbnail()$ is uselless, since you can extract image only based on time input. Can I use $FFMpegConverter .ConvertMedia()$ ? Please, how ? I’ve been searching for hours.