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• Arecord->FFMPEG works but FFMPEG w/ ALSA stutters ?

  7 février 2017, par user2989813

  I am trying to stream audio from my Pi Zero and my I2s MEMS mic. I would like to stream using FFMPEG and ALSA (which I have already compiled) but I’m running into stuttering issues.

  1. FFMPEG + ALSA

     ~/special/ffmpeg/ffmpeg -report -f alsa -ar 48000 -ac 2 -acodec pcm_s32le -i mic_sv -f lavfi -i testsrc -c:v h264_omx -c:a aac -ab 32k -bufsize 32k -f flv rtmp://209.85.230.23/live2/KEY

  This results in constant stuttering and choppiness.

  2. Arecord piped directly to FFMPEG

     arecord -Dmic_sv -c2 -r48000 -fS32_LE | ~/special/ffmpeg/ffmpeg -report -acodec pcm_s32le -i - -f lavfi -i testsrc -c:v h264_omx  -acodec aac -ab 32k -bufsize 32k -f flv rtmp://209.85.230.23/live2/KEY

  This results in a coherent audio stream, but with skipping every 5 seconds or so.

  3. Arecord recorded to a wav file, piped into FFMPEG

     arecord -Dmic_sv -c2 -r48000 -fS32_LE -twav temp.v &
~/special/ffmpeg/ffmpeg -report -re -i temp.v -f lavfi -i testsrc -c:v h264_omx -ac 2 -acodec aac -ab 32k -bufsize 32k -async 2 -f flv rtmp://209.85.230.23/live2/KEY

  This results in a perfect audio stream.

  I don’t know why #3 works but #2 and #1 cause problems. Any suggestions ?

• Send 2 different feeds to ffserver from ffmpeg

  30 avril 2015, par Niklas Tampier Holmgren

  I’m currently working in a project where I have to stream 2 webcams streams from a computer to another through a TCP connection, I can stream 1 without problem :

  using

  ffserver.conf :

              HTTPPort 8090
  
              HTTPBindAddress 0.0.0.0
  
              MaxClients 40
  
              MaxBandwidth 30000
  
  
  
              CustomLog -
  
              NoDaemon
  
  
  
              <stream>
  
              Format status
  
              ACL allow localhost
  
              ACL allow 192.168.0.0 192.168.255.255
  
              </stream>
  
  
  
             #feed for camera 1
  
             <feed>
  
             File /tmp/webcam1.ffm
  
             FileMaxSize 100M
  
             </feed>
  
  
  
             #feed for camera 2
  
             <feed>
  
             File /tmp/webcam2.ffm
  
             FileMaxSize 100M
  
             </feed>
  
  
  
            #stream for feed 1
  
            <stream>
  
            Feed webcam1.ffm
  
            Format mjpeg
  
            VideoSize 1280x720
  
            VideoFrameRate 30
  
            Preroll 0
  
            NoAudio
  
            Strict -1
  
            </stream>
  
  
  
            #stream for feed2
  
            <stream>
  
            Feed webcam2.ffm
  
            Format mjpeg
  
            VideoSize 1280x720
  
            VideoFrameRate 30
  
            Preroll 0
  
            NoAudio
  
            Strict -1
  
            </stream>

  command to run ffserver :

            ffserver /etc/ffserver.conf

  command to feed ffserver :

           ffmpeg -v 2 -r 20 -f video4linux2 -i /dev/video0 http://localhost/webcam1.ffm

  and it works perfect, but when I try to run the other feed :

           ffmpeg -v 2 -r 20 -f video4linux2 -i /dev/video1 http://localhost/webcam2.ffm

  I can see just the second stream and the first one do not work anymore.
  some idea ?

• FFMPEG make adjustment on first frame

  30 avril 2022, par iDeveloper

  I am using FFMPEG library to convert images to video file in my software program.

  


  Here frameRate is 1 or 5. So, I need a dynamic image based on time for first 5 seconds. So, in the images folder if there is more than 10 images then I set frameRate as 5 for else frame rate is 1

  


  Algorithm :

  


  let startNumber: Int
let blackFrame  = self.sourceURL.appendingPathComponent("TIME_STAMP.jpg", isDirectory: false)
    
    if FileManager.default.fileExists(atPath: blackFrame.path){
       
        let data = try! Data(contentsOf: blackFrame)
        
        try? FileManager.default.removeItem(at: blackFrame)

        if frameRate == "1"{
            
            startNumber = 20
            
            for i in 20...24{
                
                let url = sourceURL.appendingPathComponent("img\(i).jpg", isDirectory: false)
                try? data.write(to: url)
            }
            
        }else{
            
            startNumber = 0
            for i in 0...24{
                
                let url = sourceURL.appendingPathComponent("img\(i).jpg", isDirectory: false)
                try? data.write(to: url)
            }
        }
        
    }else{
        
        startNumber = 25
    }
 
    let arguments: [String] = [
        "-y",
        "-framerate", frameRate,
        "-start_number",  "\(startNumber)",
        "-i", "\(sourceURL.path)/img%0d.jpg",
        "-c:v", "libx264",
        "-crf", "28",
        outputURL.path
    ]


  


  This is how I am constructing the arguments. It's working perfect on fast systems. but for slow systems the creation of custom time image takes time than the FFMPEG execution. So, the output video file is mixed of various frames instead of 1....N ;

  


  So, I don't want to create the 5 or 25 images each time. Instead can am I able to set frame rate for first image only ? or is there any alternative ?

  


  Thank you !