Sur d’autres sites (5575)

• Can any part of an ffmpeg command use expressions ?

  6 avril 2022, par corgrath

  I am still learning how expressions work with ffmpeg, whether any part of a command can be using expression or not.

  


  As an example, I have this command :

  


  ffmpeg -y -i input.mp3 -af "sofalizer=sofa=ClubFritz1.sofa:type=freq:radius=2:speakers='FL 45|FR 45|BL 45|BR 45'" output.mp3

  


  (The file CubFritz1.sofa can by the way be downloaded here)

  


  Which basically applies the sofalizer effect and specify that each channel should be heard / come from, the left side (45 degrees) of the audio.

  


  This works as expected.

  


  However, I cannot seem to get expressions working in the command at all.

  


  For example this :

  


  ffmpeg -y -i input.mp3 -af "sofalizer=sofa=ClubFritz1.sofa:type=freq:radius=2:speakers='FL if(0, 45, 45)'|'FR if(0, 45, 45)'|'BL if(0, 45, 45)'|'BR if(0, 45, 45)'" output.mp3

  


  Which does an if(0, 45, 45) as a test, so regardless the outcome should be 45, right ?

  


  However, when I run this command, it does not seem to work anymore, meaning the sound is not purely coming from the left side.

  


  I have even tried changing the location of the single ' in the command without luck :

  


  ffmpeg -y -i input.mp3 -af "sofalizer=sofa=ClubFritz1.sofa:type=freq:radius=2:speakers=FL 'if(0, 45, 45)'|FR 'if(0, 45, 45)'|BL 'if(0, 45, 45)'|BR 'if(0, 45, 45)'" output.mp3

  


  My question is, what are the rules for getting expressions working in an ffmpeg command ?

  


  How would the command be rewritten so that the if(0, 45, 45) works ?

  


• FFMPEG- how to set presentation timestamp of a second video while merging a second video side-by-side with a first video

  14 octobre 2020, par Sankalpa Sarkar

  I was trying to merge a second video into a first video, side-by-side in a stacked fashion as a self-interest work. The twist is the video is a recording of a video call, where a second user might join at a later stage than the first user. The cumulative recording of the video call must reflect that the second user joins at a later stage than the first user. For this, I am using this code :

  


  DIFF=$(($start_ts-$BASEts))
DIFFms=`echo "scale=0;$DIFF/1000" | bc`
DIFFs=`echo "scale=4;$DIFF/1000000" | bc`
ffmpeg -i $a.webm -i b.webm -filter_complex \
    "[0]pad=2*iw:1*ih[l];[1]setpts=PTS-STARTPTS+$DIFFs/TB[1v]; [l][1v]overlay=x=W/2[v]; \
    [1]adelay=$DIFFms|$DIFFms[1a]; \
    [0][1a]amix=inputs=2[a]" \
    -map "[v]" -map "[a]" -vcodec libvpx -cpu-used -5 -deadline realtime finalOutput.webm


  


  However, the error being thrown here is :

  


  [Parsed_setpts_1 @ 0x55ada9df1dc0] [Eval @ 0x7ffff35acb60] Undefined constant or missing '(' in '/TB'
[Parsed_setpts_1 @ 0x55ada9df1dc0] Error while parsing expression 'PTS-STARTPTS+/TB'
[AVFilterGraph @ 0x55ada9d6c2a0] Error initializing filter 'setpts' with args 'PTS-STARTPTS+/TB'
Error initializing complex filters.
Invalid argument


  


  It is unable to read the $DIFFs variable at all, is what I figured. Can anybody help me out here ?

  


• Can not use the jsmpeg in react "Unexpected use of 'self'"

  5 mai 2020, par Muhammad Anas Khan

  code that i want to convert in React

  



   &#xA;    &#xA;    <code class="echappe-js">&lt;script type=&quot;text/javascript&quot; src='http://stackoverflow.com/feeds/tag/jsmpeg.min.js'&gt;&lt;/script&gt;&#xA;&#xA;    &lt;script type=&quot;text/javascript&quot;&gt;&amp;#xA;      var canvas = document.getElementById(&quot;videoCanvas&quot;);&amp;#xA;      console.log(document.location.hostname);&amp;#xA;     var url = &quot;ws://localhost:9999/&quot;;&amp;#xA;    &lt;/script&gt;&#xA;    &#xA;&#xA;

  



  Can not change it to react format.When i try to convert it is giving jsmpeg error 
i.e

  



  code that i tried but get an error

  



  import React from &#x27;react&#x27;;&#xA;import ReactDOM from &#x27;react-dom&#x27;;&#xA;import "./jsmpeg.min.js"&#xA;const App =()=>{&#xA;    return(&#xA;        <h1>Hello</h1>&#xA;    )&#xA;}&#xA;&#xA;&#xA;ReactDOM.render(<app></app>,document.getElementById(&#x27;root&#x27;));&#xA;

  



  Error

  



  /src/jsmpeg.min.js
Line 606:9 : Unexpected use of 'self' no-restricted-globals
 Line 2771:13 : Expected an assignment or function call and instead saw an expression no-unused-expressions

  



  Search for the keywords to learn more about each error.