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• Revision 16878 : do not try to get aspect information from source twice in twopass ...

  7 février 2010, par j — Log

  do not try to get aspect information from source twice in twopass mode, fixes bug reported by DuClare ?

• how to have live video streaming using ffmpeg command or using tcl 8.0 script on windows 10 platform [duplicate]

  16 novembre 2017, par M. D. P

  This question is an exact duplicate of :

  • How to stream live-video display from a webcam using FFMPEG command on tcl version 8.0 and windows 7 ?
    
    1 answer
    

  I am able to capture the video and image by using ffmpeg in tcl script, but I want to have live video streaming for my multiple webcams for tcl version 8.0 on windows 10.

  I tryed :

  ffmpeg -f vfwcap -r 25 -i 0 sample.avi

  for video capturing, it works

  ffmpeg -f vfwcap -r 25 -i 0 

  and I tried this for live video streaming by it didn’t http://wiki.tcl.tk/40194
  So what will be the right command for live video streaming.

  exec [list ffmpeg -f dshow -t 00:00:10 -i "video=Integrated Webcam" -b 5000k -s 1280x720 c :/test/sample-a.avi] &

  also tried with this, still not working

• FFmpeg output video file much smaller than uncompressed input audio file, using option to preserve original audio quality

  17 mars 2021, par Jan

  I attempt to create a video slideshow from a number of image files and an audio file in 2 steps :

  


  

  1. Create a temporary video file from a sequence of image files

  


  2. Add an audio file to the temporary video file with a delay of 5 seconds

  


  


  The audio file is an uncompressed stereo wav file, encoded with a sample rate of 44100 Hz and a bit depth of 32 bits, with a size of 40.1 MB. To preserve the lossless quality of the input audio file I use the option -c:a aac -b:a 192k as per Slideshow Wiki. However, the final output video file has a size of only 4.49 MB.

  


  How can the output video file be about 10 times smaller than the input audio file and still preserve the original lossless quality ?

  


  My code :

  


  ffmpeg -f concat -i slide-sequence.txt -c:v libx264 -r 30 -filter_complex format=yuv420p temp.mp4
ffmpeg -i temp.mp4 -i audio.wav -af "adelay=5000|5000" -c:v copy -c:a aac -b:a 192k out.mp4