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• What ffmpeg command to use to convert a list of unsigned integers into an audio file ?

  21 mars 2019, par John

  I have a file that contains a list of about forty thousand integers that are space delimited, with each integer between the value of 0 and 255. It is this file here :

  https://github.com/johnlai2004/sound-project/blob/master/integers.txt

  If you connect a speaker to an ESP32 breakout board, then run this list of integers through the digital to analog converter at a frequency of 24kHz, you will hear the sentence, "That’s not the post that you missed."

  What I want to know is how do you use FFMPEG to convert this list of integers into a sound file that other computer can play to hear the same phrase ? I tried this command :

  ffmpeg -f u8 -ac 1 -ar 24000 -i integers.txt -y audio.wav

  But my audio.wav just sounds like white noise. I tried a few other values for -f and for -ar, but all I hear are different frequencies of white noise and maybe some extra buzzing.

  Is it possible to use ffmpeg to translate my list of integers into an audio file for other computers to play ? If so, what’s the correct ffmpeg command to do this ?

  OTHER NOTES

  If it helps, this is the sketch file that I upload to an ESP32 if I want to hear the audio :

  https://github.com/johnlai2004/sound-project/blob/master/play-audio.ino

  In short, the file looks like this :

  #define speakerPin 25                          //The pins to output audio on. (9,10 on UNO,Nano)
  
  #define bufferTotal 1347
  
  #define buffSize 32
  
  
  
  byte buffer[bufferTotal][buffSize];
  
  int buffItemN = 0;
  
  int bufferN = 0;
  
  
  
  hw_timer_t * timer = NULL;
  
  portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
  
  
  
  void IRAM_ATTR onTimer() {
  
    portENTER_CRITICAL_ISR(&timerMux);
  
  
  
  
  
    byte v = buffer[bufferN][buffItemN];
  
    dacWrite(speakerPin,v);
  
  
  
    buffItemN++;
  
  
  
    if(buffItemN >= buffSize){                                      //If the buffer is empty, do the following
  
      buffItemN = 0;                                              //Reset the sample count
  
      bufferN++;
  
      if(bufferN >= bufferTotal)
  
        bufferN = 0;
  
    }
  
  
  
    portEXIT_CRITICAL_ISR(&timerMux);
  
  
  
  }
  
  
  
  void setup() {      
  
  
  
  /* buffer records */
  
  buffer[0][0]=88;  // I split the long list of integers and load it into a 2D array
  
  buffer[0][1]=88;
  
  buffer[0][2]=86;
  
  buffer[0][3]=85;
  
  //etc....
  
  buffer[1346][28]=94;
  
  buffer[1346][29]=92;
  
  buffer[1346][30]=92;
  
  buffer[1346][31]=95;
  
  
  
  
  
  /* end buffer records */
  
  
  
    timer = timerBegin(0, 80, true);
  
    timerAttachInterrupt(timer, &onTimer, true);
  
    timerAlarmWrite(timer, 41, true);
  
    timerAlarmEnable(timer);
  
  
  
  }
  
  
  
  void loop() {
  
  
  
  }

  The buffer... is the list of integers found in the integers.txt file.

• QT6.5 QtMultimedia ffmpeg problems

  4 avril 2023, par sethsource

  So i've waited until the full stable release of QT6.5 as instructed by many people from previous posts. I'm still facing the same issues.

  


  playing rtsp video is still not working. MediaPlayer status gives me "invalid media" and errorstring gives me "could not open file"

  


  this code works perfectly on linux. this is a WINDOWS ONLY problem that needs to be fixed.

  


  Running latest qt6.5 release as of 4/3/23. running MSVC2019 with cmake.

  


  import QtQuick
import QtMultimedia

Window {
    width: 1280
    height: 720
    visible: true

    MediaPlayer {
        id: player
        source: Qt.resolvedUrl("rtsp://192.168.2.18/h264_stream")
        audioOutput: AudioOutput {}
        videoOutput: videoOutput
        onErrorOccurred: console.log(errorString)
    }

    VideoOutput {
        id: videoOutput
        anchors.fill: parent
        anchors.margins: 20

    }

    Component.onCompleted: {
        player.play()
    }
}


  


• Can I have time stamps on my screen recording [closed]

  27 décembre 2023, par user23160856

  I have been looking around for a way to add timestamps with dates on my screen records (I am using a Mac and have recorded them via cmd + 5). I ran into an issue of not having timestamps on the recordings which I need for a project and I have to have the timestamps on the vid recordings.

  


  I saw a few places where ffmpeg is a good option. I have managed to install it. However im unsure if theres a way for me to include the timestamps on my previous recording or would I need to record a brand new vid with ffmpeg's screen record options and if yes, I don't see any that boasts of such an option. Hoping someone is able to assist !

  


  I have downloaded ffmpeg and tried this string on a prerecorded screen recording

  


   ffmpeg -i <input /> -vf "drawtext=text=&#x27;%{localtime\:%T}&#x27;" -f flv <output>&#xA;</output>

  


  I was successful but theres 2 issues. I need the date stamp and time stamp. The second issue was that it gave it the time stamp at the current time of conversion and not the time of the recording.

  


  I am fairly new to these aspects and open to learning more !