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• ffmpeg have unmet dependencies (Ubuntu20) [closed]

  10 août 2024, par mojiang

  when installing ffmpeg with ubuntu20(fosal), it have conflict dependencies :

  


  # sudo apt-get install ffmpeg
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 ffmpeg : Depends: libavdevice58 (= 7:4.2.7-0ubuntu0.1) but it is not going to be installed
          Depends: libavfilter7 (= 7:4.2.7-0ubuntu0.1)
          Depends: libavformat58 (= 7:4.2.7-0ubuntu0.1) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.


  


  I solved it by install the reason of conflit library with a specific version, may be someone will need the solution.

  


  step 1. fix-broken

  


  sudo apt --fix-broken install
Reading package lists... Done
Building dependency tree       
Reading state information... Done


  


  step2. find the reason of unmet dependencies :

  


  # sudo apt install libavdevice58=7:4.2.7-0ubuntu0.1 libavfilter7=7:4.2.7-0ubuntu0.1 libavformat58=7:4.2.7-0ubuntu0.1
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libavformat58 : Depends: libchromaprint1 (>= 1.3.2) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.


  


  Here the problem is from libchromaprint1

  


  step3. find candidate versions of libchromaprint1(conflict reason)

  


  # apt-cache policy libchromaprint1
libchromaprint1:
  Installed: (none)
  Candidate: 1.5.1-1~20.04.sav0
  Version table:
     1.5.1-1~20.04.sav0 500
        500 http://ppa.launchpad.net/savoury1/multimedia/ubuntu focal/main amd64 Packages
     1.4.3-3build1 500
        500 http://mirrors.cloud.aliyuncs.com/ubuntu focal/universe amd64 Packages
        500 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages


  


  step4. install the old version of libchromaprint1 to solve the conflicts

  


  # sudo apt install libchromaprint1=1.4.3-3build1
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  libchromaprint1
0 upgraded, 1 newly installed, 0 to remove and 223 not upgraded.
Need to get 37.6 kB of archives.


  


  step5. reinstall ffmpeg

  


  # sudo apt install ffmpeg
Reading package lists... Done
Building dependency tree       
Reading state information... Done


  


  Done. the reason of conflict is that the latest version of libraries have conflict, by install old version of the conflicted ones to solve it.

  


• FFmpeg function avformat_open_input for USB video device throws exception : No such file or directory

  8 juin, par ffvideoner

  Windows & C# & FFmpeg.AutoGen

  


  I used the ffmpeg-function (from library FFmpeg.AutoGen) to show video from rtsp-stream :

  


  ffmpeg.avformat_open_input(&pFormatContext, "rtsp://127.0.0.1:8554/abc", iformat, null);


  


  It works right.

  


  Now I want to use this function for USB video device.

  


  FFmpeg outputs this device name :

  


  ffmpeg -list_devices true -f dshow -i dummy

[dshow @ 0000000000163000] "GENERAL WEBCAM" (video)


  


  This is how I'm trying to get the video :

  


  string deviceName = "GENERAL WEBCAM";


  


  or

  


  string deviceName = "video=GENERAL WEBCAM";

ffmpeg.avformat_open_input(&pFormatContext, deviceName, ffmpeg.av_find_input_format("dshow"), null);


  


  For both variants of device names, I get an error :

  


  No such file or directory.


  


  But here it works :

  


  ffmpeg -video_size 1280x720 -framerate 30 -f dshow -i video="GENERAL WEBCAM":audio="Microphone (3- GENERAL WEBCAM)" -c:v libx264 -crf 30 -preset ultrafast ffmpegvideo.mp4


  


  Why doesn't avformat_open_input work with video device name ?

  


• ffmpeg utility vs direct libav* capabilities

  15 avril 2015, par ransh

  I would like to ask some general question about ffmpeg utility.
  When it is documented in ffmpeg wiki’s :
  https://www.ffmpeg.org/general.html
  That it support some feature (for example jpeg2000), does it mean that only ffmpeg utility support this feature, or does it mean that using directly the libraries in the ffmpeg repository (through libav*, libavcodecand , libopenjpeg, and other external libraries which are part of ffmpeg) will also support this feature as well ?

  Thank you very much,

  Ran