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• Alternate 2 videos with ffmpeg

  2 juin 2012, par enzo.rivello

  Here is the problem :

  i got 2 videos, and 3 intervals ;
  i need to create one video by mixing this 2 videos switching video A to B at interval 1, B to A at interval 2 and again A to B at interval 3.

  Switching needs to be done along the audio files .

  Right now the only solution i came up was to cut the 2 videos and then chain them in the right order, but i was asking if there's a more elegant way to do this !

  Thank you everyone in advance !

• how to scale video using ffmpeg with -filter_complex

  7 juillet 2020, par JuraganFilm

  im trying to encode my video with watermark and subtitles , i and i have this codes that work for watermark and subtitles

  


  ffmpeg -hide_banner -i $video -i $TITLE.ass -loop 1 -i $WATERMARK -loop 1 -i $LOGO -filter_complex "[${videomap}]drawtext=text='${TEXT}':fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf:y=h-line_h-100:x=w-(t-${MARQUE})*w/15:y='10':enable='lt(mod(t\,1000)\,100)':fontcolor=orange:fontsize=${FONT}:shadowx=${SHADOWX}:shadowy=${SHADOWY},ass=$TITLE.ass[FID1];[FID1][2:v]overlay=10:${WATERMARKPOSITION}:repeatlast=0:enable='between(t,300,600)'[FID3];[3:v]fade=in:st=1200:d=1.6:alpha=1,fade=out:st=107998:d=1.6:alpha=1[FID6];[FID3][FID6]overlay=10:5:repeatlast=0:enable='between(t,1200,187922)'" -c:v libx264 -x264-params "no-deblock=0:ref=2:weightp=2:chroma_qp_offset=0:keyint=50:keyint_min=5:bframes=3:b_pyramid=1:b-adapt=2:subme=7:b_bias=0:direct=1:weightb=1:open_gop=0:scenecut=40::threads=7:lookahead_threads=1" -b:v 500k -minrate 500k -maxrate 600k -bufsize 1200k -pix_fmt yuv420p -preset ultrafast -profile:v baseline -level:v 3.0 -c:a copy -vf "scale=trunc(oh*a/2)*2:480:flags=bicubic" -use_editlist 0 -movflags faststart -metadata title="${INFOVID} - Visit us @ ${WEBSITE}" -strict -2 -f mp4 -y "${output}/$TITLE-480p.mp4"


  


  and now im trying to scale the video to 480p quality , i've tried using

  


  -vf "scale=trunc(oh*a/2)*2:480"


  


  and also add :flags=bicubic but still i got error .

  


  how to scale video with -filter_complex from those code above ?

  


  thank you before !

  


• Enable cache on ffmpeg to record streaming

  13 mars 2020, par james

  now I’m using steamlink and ffmpeg to record streams and save them to a file, many times the video file saved have so much lag. I found this link https://www.reddit.com/r/Twitch/comments/62601b/laggy_stream_on_streamlinklivestreamer_but_not_on/
  where they claim that the lag problem occurs from the fact of not having the cache enabled on the player.
  I tried putting options -hls_allow_cache allowcache -segment_list_flags cache with the result that the ffmpeg process starts for 8seconds more or less, after which it ends and starts again immediately afterwards without returning a video file,if I don’t put those two options the video is recorded correctly but most of the time with some lag.

  Obviously if I visit streaming from the browser I have no lag problem

  this is the code

  from streamlink import Streamlink, NoPluginError, PluginError
  
  streamlink = Streamlink()
  
  #this code is just a snippet, it is inside a while loop to restart the process
  
  try:
  
      streams = streamlink.streams(m3u8_url)
  
      stream_url = streams['best'].url
  
      #note hls options not seem to work
  
      ffmpeg_process = Popen(
  
          ["ffmpeg", "-hide_banner", "-loglevel", "panic", "-y","-hls_allow_cache", "allowcache", "-segment_list_flags", "cache","-i", stream_url, "-fs", "10M", "-c", "copy",
  
          "-bsf:a", "aac_adtstoasc", fileName])
  
  
  
      ffmpeg_process.wait()
  
  
  
  except NoPluginError:
  
      print("noplugin")
  
  
  
  except PluginError:
  
      print("plugin")
  
  
  
  except Exception as e:
  
      print(e)

  what are the best options to enable the cache and limit the lag as much as possible ?