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• Checking if a video has a sound even if it has an audio codec ?

  19 janvier 2023, par Sreenivasan

  I am new to intermediate python and I am trying to find if a downloaded video has sound, every video I download has an audio codec but I want to get the decibel of sound that audio has in that particular video.

  


  For example, this 'FFmpeg' command line script allows me to get the full info :

  


  ffmpeg -hide_banner -i testvideo.mp4 -af volumedetect -vn -f null - 2>&1


  


  this yields the below result in my command prompt(windows user here with win 11)

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'testvideo.mp4':

Metadata:

major_brand : mp42

minor_version : 0

compatible_brands: mp42mp41isomavc1

creation_time : 2022-04-12T23:21:45.000000Z

Duration: 00:00:40.58, start: 0.000000, bitrate: 4104 kb/s

Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1920x1080, 3846 kb/s, 29.97 fps, 29.97 tbr, 30k tbn (default)

Metadata:

creation_time : 2022-04-12T23:21:45.000000Z

handler_name : L-SMASH Video Handler

vendor_id : [0][0][0][0]

encoder : AVC Coding

Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 253 kb/s (default)

Metadata:

creation_time : 2022-04-12T23:21:45.000000Z

handler_name : L-SMASH Audio Handler

vendor_id : [0][0][0][0]

Stream mapping:

Stream #0:1 -> #0:0 (aac (native) -> pcm_s16le (native))

Press [q] to stop, [?] for help

Output #0, null, to 'pipe:':

Metadata:

major_brand : mp42

minor_version : 0

compatible_brands: mp42mp41isomavc1

encoder : Lavf59.35.100

Stream #0:0(und): Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s (default)

Metadata:

creation_time : 2022-04-12T23:21:45.000000Z

handler_name : L-SMASH Audio Handler

vendor_id : [0][0][0][0]

encoder : Lavc59.56.100 pcm_s16le

size=N/A time=00:00:40.55 bitrate=N/A speed=1.22e+03x

video:0kB audio:7608kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

[Parsed_volumedetect_0 @ 0000026609be08c0] n_samples: 3895296

[Parsed_volumedetect_0 @ 0000026609be08c0] mean_volume: -91.0 dB

[Parsed_volumedetect_0 @ 0000026609be08c0] max_volume: -91.0 dB

[Parsed_volumedetect_0 @ 0000026609be08c0] histogram_91db: 3895296


  


  As you can see there are 'parsed_volumedetect' values with dB which has a mean value of -91 dB which means the audio has no sound, i.e., the video has audio but there is no sound.

  


  Now I am trying to do the same in python and I want to get just the mean volume value to be stored in a variable so that I can check if the video has any sound in it.

  


  I have seen the subprocess codes so far but when I try to run my code in VS-Code - python 3.11 :

  


  import subprocess    
result = subprocess.run(["ffmpeg", "-hide_banner", "-af", "volumedetect", "-vn", "-f", "null", "testvideo1.mp4"],
    stdout=subprocess.PIPE,
    stderr=subprocess.STDOUT,
    shell=True)
    print(result.stdout)


  


  It says that :

  


  PS C:\Users\balaj\OneDrive\Documents\Programming language\python files> c:; cd 'c:\Users\balaj\OneDrive\Documents\Programming language\python files'; & 'C:\Python311\python.exe' 'c:\Users\balaj\.vscode\extensions\ms-python.python-2022.20.2\pythonFiles\lib\python\debugpy\adapter/../..\debugpy\launcher' '51760' '--' 'c:\Users\balaj\OneDrive\Documents\Programming language\python files\devproject\sample.py'

b"Output #0, null, to 'testvideo1.mp4':\r\nOutput file #0 does not contain any stream\r\n"


  


  Any help is much appreciated. Sorry for the long post... TIA !!!

  


  Just a quick update :
The result is the same for video files that have sound(I tested in VLC) and don't have sound.

  


  Another update :
I have changed the subprocess.runcode to the exact same as I called in the cmd windows :

  


  result = subprocess.run(["ffmpeg", "-hide_banner","-i","testvideo-sound.mp4", "-af", "volumedetect", "-vn", "-f", "null", "-2>&1"]


  


  Now the result is this :

  


  b'The handle could not be duplicated\r\nduring redirection of handle 1.\r\n'


  


• Getting ffserver && ffmpeg to work of Debian with Logitech C270 [closed]

  14 mars 2013, par Joseph Baldwin Roberts

  I'm having real trouble getting my webcam to work and I wonder if anyone can help. Im running Raspian on a raspberry pi.

  When I run lsusb I get :

  pi@raspberrycar ~ $ lsusb
  
  Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
  
  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
  
  Bus 001 Device 004: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
  
  Bus 001 Device 005: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
  
  Bus 001 Device 006: ID 046d:0825 Logitech, Inc. Webcam C270

  When I run v412-ctl —all I get :

  pi@raspberrycar ~ $ v4l2-ctl --all
  
  Driver Info (not using libv4l2):
  
          Driver name   : uvcvideo
  
          Card type     : UVC Camera (046d:0825)
  
          Bus info      : usb-bcm2708_usb-1.2.4
  
          Driver version: 3.6.11
  
          Capabilities  : 0x04000001
  
                  Video Capture
  
                  Streaming
  
  Format Video Capture:
  
          Width/Height  : 640/480
  
          Pixel Format  : 'YUYV'
  
          Field         : None
  
          Bytes per Line: 1280
  
          Size Image    : 614400
  
          Colorspace    : SRGB
  
  Crop Capability Video Capture:
  
          Bounds      : Left 0, Top 0, Width 640, Height 480
  
          Default     : Left 0, Top 0, Width 640, Height 480
  
          Pixel Aspect: 1/1
  
  Video input : 0 (Camera 1: ok)
  
  Streaming Parameters Video Capture:
  
          Capabilities     : timeperframe
  
          Frames per second: 5.000 (5/1)
  
          Read buffers     : 0

  When I run v412-ctl —list-formats I get :

  pi@raspberrycar ~ $ v4l2-ctl --list-formats
  
  ioctl: VIDIOC_ENUM_FMT
  
          Index       : 0
  
          Type        : Video Capture
  
          Pixel Format: 'YUYV'
  
          Name        : YUV 4:2:2 (YUYV)
  
  
  
          Index       : 1
  
          Type        : Video Capture
  
          Pixel Format: 'MJPG' (compressed)
  
          Name        : MJPEG

  My ffserver settings file is /etc/ffserver.conf

  Port 80
  
  BindAddress 0.0.0.0
  
  MaxClients 10
  
  MaxBandwidth 50000
  
  NoDaemon
  
  
  
  <feed>
  
  file /tmp/webcam.ffm
  
  FileMaxSize 10M
  
  </feed>
  
  
  
  <stream>
  
  Feed webcam.ffm
  
  Format mpeg
  
  VideoSize 640x480
  
  VideoFrameRate 10
  
  VideoBitRate 2000
  
  VideoQMin 1
  
  VideoQMax 10
  
  </stream>
  
  
  
  <stream>
  
  Format status
  
  
  
  ACL allow 192.168.2.0 192.168.2.255
  
  </stream>

  My ffmpeg run string is /usr/sbin/webcam.sh

  ffserver -f /etc/ffserver.conf & ffmpeg -v verbose -r 5 -s 640x480 -f video4linux2 -i /dev/video0 http://localhost/webcam.ffm

  When I run this is the output :

  pi@raspberrycar ~ $ sudo /usr/sbin/webcam.sh
  
  ffmpeg version 1.0.5ffserver version 1.0.5 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar 14 2013 18:37:40 with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
   Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar 14 2013 18:37:40 with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
    configuration:
  
    libavutil      51. 73.101 / 51. 73.101
  
    configuration:
  
    libavutil      51. 73.101 / 51. 73.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 15.100 /  0. 15.100
  
    libswresample   0. 15.100 /  0. 15.100
  
  [video4linux2,v4l2 @ 0xfa5620] [3]Capabilities: 4000001

  I can see the stream on the status page and my webcam light is on but it never loads. Does anyone know what I am doing wrong ?

  Thanks in advance

  Joe

• Restoring corrupted video after recovery

  22 août 2019, par Harold.Demure

  I have recently recovered the content of an old drive of mine using photorec.

  To my surprise, photorec recovered a lot of files with non-video extensions (.sqlite, .apple, .pdf, .torrent...) that contain fragments of video. I can see these fragments only using mplayer/mencoder (quicktime and vlc cannot). Some of the files are even hundreds of megabyte large, but mplayer only shows me a few seconds of the video.

  Is there any script/data carving tool that I can use to see if I can recover more video fragments from these files ? I am not afraid of trying solutions that require some coding or manual inspection (e.g., search for headers via hex editors).

  Thank you for your help, any suggestion is highly appreciated.
  Harol.