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• Trouble with ffmpeg on mac os catalina 10.15.3

  27 décembre 2020, par Scuds

  I had ffmpeg installed before upgrading my os to catalina. When I tried to re-encode a video it complained with this message

  



  dyld: Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib
  Referenced from: /usr/local/bin/ffmpeg
  Reason: image not found
zsh: abort      ffmpeg


  



  I found out openssl isn't used in catalina in favor for libressl.. 
I did a brew search openssl and found I have openssl@1.1 not 1.0.0

  



  I'm weary about messing around with the version of openssl because so many other programs depend on it and I don't want to screw up my system..

  



  My question is how can I get ffmpeg to run on my system ? Mac os catalina 10.15.3

  


• dcadsp : Add a new method, qmf_32_subbands

  15 juillet 2013, par Ben Avison

  dcadsp : Add a new method, qmf_32_subbands
  This does most of the work formerly carried out by
  
  the static function qmf_32_subbands() in dcadec.c.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/dcadec.c
  • [DH] libavcodec/dcadsp.c
  • [DH] libavcodec/dcadsp.h

• set MediaRecorder to record 1 frame every N seconds

  19 août 2022, par The Blind Hawk

  Summary

  


  I have a version of my code already working on Chrome and Edge, but I need some fixes for it to work on Safari.
  
My objective is to record around 25 minutes and download a timelapse version of the recording.
  
final product requirements :

  


  speed: 3fps
length: ~25s

(I need to record one frame every 20 seconds for 25 mins)


  


  this.secondStream settings :

  


  this.secondStream = await navigator.mediaDevices.getUserMedia({
    audio: false,
    video: {width: 430, height: 430, facingMode: "user"}
});


  


  My code for IOS so far :

  


          startIOSVideoRecording: function() {
            console.log("setting up recorder");
            var self = this;
            this.data = [];

            if (MediaRecorder.isTypeSupported('video/mp4')) {
                // IOS does not support webm, so I will be using mp4
                var options = {mimeType: 'video/mp4', videoBitsPerSecond : 1000000};
            } else {
                console.log("ERROR: mp4 is not supported, trying to default to webm");
                var options = {mimeType: 'video/webm'};
            }
            console.log("options settings:");
            console.log(options);

            this.recorder = new MediaRecorder(this.secondStream, options);

            this.recorder.ondataavailable = function(evt) {
                if (evt.data && evt.data.size > 0) {
                    self.data.push(evt.data);
                    console.log('chunk size: ' + evt.data.size);
                }
            }

            this.recorder.onstop = function(evt) {
                console.log('recorder stopping');
                var blob = new Blob(self.data, {type: "video/mp4"});
                self.download(blob, "mp4");
                self.sendMail(videoBlob);
            }

            console.log("finished setup, starting")
            this.recorder.start(1200);

            function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms));}

            async function looper() {
                // I am trying to pick one second every 20 more or less
                await sleep(500);
                self.recorder.pause();
                await sleep(18000);
                self.recorder.resume();
                looper();
            }
            looper();
        },


  


  Issues

  


  Only one call to getUserMedia()

  


  I am already using this.secondstream elsewhere, and I need the settings to stay as they are for the other functionality.
  
On Chrome and Edge, I could just call getUserMedia() again with different settings, and the issue would be solved, but on IOS calling getUserMedia() a second time kills the first stream.
  
The settings that I was planning to use (works for Chrome and Edge) :

  


  navigator.mediaDevices.getUserMedia({
    audio: false,
    video: { 
        width: 360, height: 240, facingMode: "user", 
        frameRate: { min:0, ideal: 0.05, max:0.1 } 
    },
}


  


  The timelapse library I am using does not support mp4 (ffmpeg as alternative ?)

  


  I am forced to use mp4 on IOS apparently, but this does not allow me to use the library I was relying on so I need an alternative.
  
I am thinking of using ffmpeg but cannot find any documentation to make it interact with the blob before the download.
  
I do not want to edit the video after downloading it, but I want to be able to download the already edited version, so no terminal commands.

  


  MediaRecorder pause and resume are not ideal

  


  On Chrome and Edge I would keep one frame every 20 seconds by setting the frameRate to 0.05, but this does not seem to work on IOS for two reasons.
  
First one is related to the first issue of not being able to change the settings of getUserMedia() without destroying the initial stream in the first place.
  
And even after changing the settings, It seems that setting the frame rate below 1 is not supported on IOS. Maybe I wrote something else wrong, but I was not able to open the downloaded file.
  
Therefore I tried relying on pausing and resuming the MediaRecorder, but this brings forth another two issues :
  
I am currently saving 1 second every 20 seconds and not 1 frame every 20 seconds, and I cannot find any workarounds.
  
Pause and Resume take a little bit of time, making the code unreliable, as I sometimes pick 2/20 seconds instead of 1/20, and I have no reliability that the loop is actually running every 20 seconds (might be 18 might be 25).