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• avfilter/af_silenceremove : add real peak detector

  25 mai 2023, par Paul B Mahol

  avfilter/af_silenceremove : add real peak detector
  Rename old peak detector to more correct name one.
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/af_silenceremove.c
  • [DH] libavfilter/silenceremove_template.c
  • [DH] tests/fate/filter-audio.mak

• Real Time Audio and Video Streaming in C#

  16 novembre 2014, par Nuwan

  I am developing an application which can be used to stream audio and video in real time.
  I can stream in two different ways. I used a capture card to capture live HD stream and
  re send it. And also I need to stream local video file in real time.

  Now I capture video using OpenCV and store frames as bitmaps in blokingCollection bitmap queue.
  After that I encode video frames using ffmpeg (used c# library Nreco) and stored in a queue. Then I send that encoded data through UDP (did not used RTP/RTSP) to omxplayer in raspberry pi and it works very fine.

  Then I captured audio data using ffmpeg
  I used this command to capture and encode audio data.

                   data = ms.ToArray();
  
                   ffMpegTask = ffmpegConverter.ConvertLiveMedia(
  
                          fileName,
  
                          null,
  
                          ms,
  
                          Format.avi,
  
                          new ConvertSettings()
  
                          {                                
  
                              CustomOutputArgs = " -tune zerolatency -ss " + second + " -t " + endTime + " -strict experimental -acodec aac -ab 160k -ac 2 -ar 44100 -vn ",                             
  
                          });
  
                  ffMpegTask.Start();
  
                  ffMpegTask.Stop();
  
                  byte[] data = ms.ToArray();

  After that I saved every audio data packet to queue.

  And I tried to stream these separate audio and video data to omxplayer by using two different
  ports. and received streams by using two omxplayers. And it works fine.

  But what I need to do is multiplex this audio and video stream and send as one stream.
  what I do is first stream two streams as UDP://224.1.1.1:1250(video) and UDP://224.1.1.1:1260(audio)
  then I used nreco invoke method. We can use it to execute ffmpeg commands.

  " -re -i udp://224.1.1.1:1250 -i udp://224.1.1.1:1260 -c copy -f avi udp://224.1.1.1:1270"

  and this works for both audio and video stream but completely out of sync.

  Next thing what I do is creating another ffmpeg ConvertLiveMedia task and write audio and video data
  to that task using write method. And I stream that mux data and received using ffplay. And it plays the stream
  and the sync problem is solved. But sometimes audio and video frames are dropping and then it begins to
  play out of sync.

                  combine = new MemoryStream();
  
                  ffMpegTaskcom = ffmpegConvertercom.ConvertLiveMedia(
  
                          Format.mpeg,
  
                          combine,
  
                          Format.avi,
  
                          new ConvertSettings()
  
                          {
  
                              CustomInputArgs = " ", // windows bitmap pixel format
  
                              CustomOutputArgs = " -threads 7 -c:v libx264 -preset ultrafast -tune zerolatency -strict experimental -profile:v baseline -movflags +faststart -tune film -level 3.0 -tune zerolatency -tune film -pix_fmt yuv420p -g 250 -crf 22 -b:v 4000k -minrate 3000k -maxrate 5000k -acodec aac -ab 160k -ac 2 -ar 44100",
  
  
  
                          });
  
                  ffMpegTaskcom.Start();
  
                  byte[] streamBytesvi = null;
  
                  byte[] streamBytesau = null;
  
                  encodeQueqe.TryDequeue(out streamBytesvi);
  
                  encodeQueqeau.TryDequeue(out streamBytesau);
  
                  ffMpegTaskcom.Write(streamBytesvi, 0, streamBytesvi.Length);
  
                  ffMpegTaskcom.Write(streamBytesau, 0, streamBytesau.Length);
  
  
  
                  //ffMpegTaskcom.Wait();
  
                  ffMpegTaskcom.Stop();

  Now I need to know a good method to deliver audio and video data with synchronization.
  Please tell me what is the wrong I have done or suggest a better way to do this.

  Thank You !

• ffmpeg create video from image that arrive in real time

  13 juillet 2017, par user3469897

  I have a folder in which every second write 30 images (30fps). My goal is to create a video through ffmpeg, via java. It’s possible ?

  Having an initial x-sec delay, my video should add a frame meantime the images arrive in the folder.