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• How to avoid audio sample 16bit clipping after equalization ?

  28 mai 2013, par testCoder

  I have samples which come from ffmpeg, very often it is 16 bit samples (short type), i have used iir band pass filter with dbGain as described here, after filtering i sometimes got a short type overflow and result of it is some noise when calculated sample value go out from 32767/-32767, Is any way to escape audio pcm sample clipping. May be exists any approaches ?

  I have googled but not found any worked example ?

  UPDATE

  When i cast transfer function calculation result to integer and check overflow then noise still occurs: :

  int result = A1 * ((int) Rx) + A2 * ((int) Rxx) + A3 * ((int) Rxxx)
  
                      - B1 * ((int) Ryy) - B2 * ((int) Ryyy);
  
  if (result > 32767)
  
      result = 32767;
  
  if (result < -32700)
  
      result = -32700;
  
  y = (short) result;

• ffmpeg cannot open connection tcp ://a.rtmp.youtube.com

  13 mars 2024, par Hiji Deui

  I want to live stream using ffmpeg, when live on Facebook it runs normally, but when I live on YouTube there is an error, is there anything wrong with the command I entered ? even though the command is the same as live on Facebook, but only the RTMP link has been changed

  


  


  


  ffmpeg -re -i out.mp4 -c:v copy -c:a aac -ar 44100 -ab 128k -ac 2 -strict -2 -flags +global_header -bsf:a aac_adtstoasc -bufsize 3000k -f flv "rtmp://a.rtmp.youtube.com/live2/my-key-streaming"

  


  


  



  and the output is

  


  


  


  ffmpeg version N-55112-g7eb9cf593e-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 61.100 / 56. 61.100
  libavcodec     58.114.100 / 58.114.100
  libavformat    58. 64.100 / 58. 64.100
  libavdevice    58. 11.103 / 58. 11.103
  libavfilter     7. 91.100 /  7. 91.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    creation_time   : 2020-12-26T11:13:27.000000Z
    com.android.version: 10
  Duration: 00:00:03.27, start: 0.000000, bitrate: 21344 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, unknown/bt470bg/unknown), 1920x1080, 20225 kb/s, SAR 1:1 DAR 16:9, 29.99 fps, 30.01 tbr, 90k tbn, 180k tbc (default)
    Metadata:
      rotate          : 90
      creation_time   : 2020-12-26T11:13:27.000000Z
      handler_name    : VideoHandle
    Side data:
      displaymatrix: rotation of -90.00 degrees
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2020-12-26T11:13:27.000000Z
      handler_name    : SoundHandle
[tcp @ 0x58bf880] Connection to tcp://a.rtmp.youtube.com:1935 failed: Connection timed out
[rtmp @ 0x5893140] Cannot open connection tcp://a.rtmp.youtube.com:1935
rtmp://a.rtmp.youtube.com/live2/my-key: Connection timed out

  


  


  



  how to fix this, btw i use vps, sorry, my english so bad and this is the first time i asked on this website

  


• Why i'm failing to download mp4 file using youtube-dl in python

  9 décembre 2019, par Joao

  Python noob :(

  I created a script that downloads any youtube video.

  Then the script inserts a subtitle into the video and that works fine.

  However, I have a problem, I can’t make the script always download the video in mp4. Most of the time it is downloaded in mkv and i can’t understand why that happens and how can I change the code in order to always download the video in the format I prefer.

  The function in charge to download the video is this one :

  def video_download():
  
      #global resolution
  
      try:
  
          print(linkvideo)
  
          ydl_opts = {
  
              'format': 'bestvideo[ext=mp4]+bestaudio/best',
  
              'outtmpl': video_id+"."+'%(ext)s'
  
              #'bestvideo': 'mp4',
  
              #'bestaudio': 'm4a',
  
              #'ext': 'mp4'
  
          }
  
          with youtube_dl.YoutubeDL(ydl_opts) as ydl:
  
              ydl.download([linkvideo])
  
              result = ydl.extract_info("{}".format(linkvideo))
  
              title = result.get("id", None)
  
              videoext = result.get("ext", None)
  
              resolution = result.get("resolution", None)
  
      except:
  
          print("falhou")
  
          pass
  
      global ficheiro
  
      ficheiro2 = str(title)+"."+"mkv"
  
      ficheiro =""
  
      for i in ficheiro2:
  
          if (i == '"' or i =="'" or i =="/"):
  
              pass
  
          else:
  
              ficheiro += i

  Can any one help me ? Thanks in advance.

  I got it, thanks to everyone who tried to help me.

  The problem is this : when we try to download any video with the opts i’ve selected, youtube-dl will download the best video/audio combination in the same file, so I’ve added the following in my code :

  ytdl = YoutubeDL()
  
      result = ytdl.extract_info(linkvideo, download=False)
  
      formats = result['formats']
  
      formato = ""
  
      formatoaudio =  ""
  
      extaudio = ""
  
      for format in formats:
  
          if format['format_note'] == "1080p" and format['ext'] == "mp4":
  
              print(format)
  
              formato = (format['format_id'])
  
              break
  
          else:
  
              print("no 1080p mp4?!")
  
  
  
      if formato == "":
  
          for format in formats:
  
              if format['format_note'] == "720p" and format['ext'] == "mp4":
  
                  print(format)
  
                  formato = (format['format_id'])
  
                  break
  
              else:
  
                  print("no 720p mp4")

  Then I did the same to the sound file, checking if there is any m4a or webm sound file. To finish I’m joining both files using FFmpeg.

  Maybe this is not the best solution, but I’m still learning. :)

  Thank you all