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• hwcontext_vaapi : add a quirk for the missing MemoryType attribute

  30 septembre 2016, par Anton Khirnov

  hwcontext_vaapi : add a quirk for the missing MemoryType attribute
  The Intel binary iHD driver does not support the
  
  VASurfaceAttribMemoryType, so surface allocation will fail when using
  
  it.
  (cherry picked from commit 2124711b950b03c582a119c75f52a87acc32d6ec)
  

  • [DH] doc/APIchanges
  • [DH] libavutil/hwcontext_vaapi.c
  • [DH] libavutil/hwcontext_vaapi.h
  • [DH] libavutil/version.h

• Opening the ALSA microphone port using libavformat

  17 mai 2013, par Kartik Aiyer

  I'm writing a fairly simple application to open the microphone port using the ALSA format on a linux VM. I'm trying to do this using libavformat and other ffmpeg libs ( avutil, avcodec, etc ).

  I followed what ffmpeg was doing ( ffmpeg_opt.c : open_input_file) to open the actual microphone port( hw:0,0). I find the ALSA format using av_find_input_format( "alsa" ) which returns with a AVInputFormat* object.

  I then use this with avformat_open_input.
  I didn't precreate AVFormatContext and load it with any params before the above call ( I rely on it being created in avformat_open_input). This worked and I was able to read packets of the port. However, after a while I was not able to open the port. I added a bunch of debug in the libs and find out that :
  avformat_open_input -> init_input -> ... -> avio_open2 -> ffurl_open ->ffurl_alloc
  the final call to ffurl_alloc goes through all the protocols and tries to see if hw matches any given protocol. This fails.

  I was wondering if anyone has tried opening a mic with the ALSA format using libavformat and other libs, and if they have any tips on how to get this done. Specifically how does ffmpeg translate something like hw:0,0 to the actual device port ?

  P.S : I tried the following line on the command line app
  ffmpeg -f alsa -i hw:0,0 -ac 2 -acodec pcm_s16le output.aac
  this worked for a while and then suddenly stopped working as well with the same kind of problem. Unable to open the protocol.

  I'm not sure what changed and why its not able to open the audio port, but any advice on how also port are opened with the rather different handle of HW:x,x would be much appreciated.

  Alternatively, I realize ffmpeg is a little heavy to just read PCM packets and then encode and I could use a more direct approach by using the aac libs directly. Can anyone recommend a lib or kernel driver that I can use to open the microphone ( given that it is an ALSA card )and read PCM data out of it. ( I'm new to LInux so please forgive me if any of this sounds trivial )

  Thanks
  Kartik

• Cannot find installation of real FFmpeg (which comes with ffprobe)

  29 mars 2023, par Asm Goni

  I was trying to fit a generator into a model and I got this error : 
AssertionError: Cannot find installation of real FFmpeg (which comes with ffprobe).

  



  I have looked over many of the solutions on GitHub and other questions on Stack Overflow but none of them worked for me.

  



  Here is one of the commands I ran :

  



  sudo add-apt-repository ppa:mc3man/trusty-media  
sudo apt-get update  
sudo apt-get install ffmpeg  
sudo apt-get install frei0r-plugins  


  



  pip list also indicates the presence of ffmpeg-1.4

  



  In addition, I tried force reinstalling and updating ffmpeg just in case any dependencies were not installed properly.

  



  I also set the skvideo's path for ffmpeg manually :

  



  skvideo.setFFmpegPath('/usr/local/lib/python3.6/dist-packages/ffmpeg/')


  



  This returns : /usr/local/lib/python3.6/dist-packages/skvideo/__init__.py:306: UserWarning: ffmpeg/ffprobe not found in path: /usr/local/lib/python3.6/dist-packages/ffmpeg/
  warnings.warn("ffmpeg/ffprobe not found in path: " + str(path), UserWarning)

  



  By the way, when I try installing, it also returns this error, I don't know what to do about this :

  



  Get:127 http://archive.ubuntu.com/ubuntu bionic/main amd64 vdpau-driver-all amd64 1.1.1-3ubuntu1 [4,674 B]
Fetched 60.4 MB in 7s (8,769 kB/s)
E: Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/w/wavpack/libwavpack1_5.1.0-2ubuntu1.1_amd64.deb  404  Not Found [IP: 91.189.88.149 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?


  



  I ran apt-get update --fix-missing and that didn't make anything better.

  



  Is there a solution to this ?