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• how to ignore or fix false 'unmet dependencies' error ?

  31 août 2014, par yy502

  OS: LMDE 201403

  I previously installed OpenShot (a video editing software), which depends on libmlt6, and libmlt6 depends on ffmpeg. The chain of dependencies auto-installed just fine.

  Today I compiled and installed the latest ffmpeg v2.3.3 and apt-get starts to complain :

  You might want to run 'apt-get -f install' to correct these:
  
  The following packages have unmet dependencies:
  
   libmlt6 : Depends: ffmpeg (>= 5:0.6.2~) but 2.3.3-1 is to be installed
  
  E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

  Well, I’m sure my compiled version of ffmpeg is newer than whatever version libmlt6 requires, but the package manager does not seem to understand the new version number. How can I ignore or fix false ’unmet dependencies’ error, please ?

  Thanks for your time !

  Edit :

  Executing apt-get -f install would install the ffmpeg from repository to /usr/bin/ and uninstall/overwrite my compiled version of ffmpeg in /usr/local/bin/... not really the solution I’m after...

  Edit2 :

  the auto fix of apt-get will remove my compiled version of ffmpeg as prompted below :

  sudo apt-get install -f
  
  Reading package lists... Done
  
  Building dependency tree       
  
  Reading state information... Done
  
  Correcting dependencies... Done
  
  The following extra packages will be installed:
  
    ffmpeg
  
  Suggested packages:
  
    nvidia-libvdpau1
  
  The following packages will be upgraded:
  
    ffmpeg
  
  1 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.
  
  Need to get 0 B/1,307 kB of archives.
  
  After this operation, 242 MB disk space will be freed.
  
  Do you want to continue? [Y/n] n
  
  Abort.

• Official RealVideo Specifications

  29 juillet 2010, par Multimedia Mike — General

  A little birdie tipped me off to a publicly-accessible URL on the Helix community site (does anyone actually use Helix ?) that contains a bunch of specifications for RealVideo 8 and 9. I have been sifting through the documents to see exactly what they contain as the different files seem to be higher revisions of the same documents. Here is the title, date, and version of each PDF document :

  • RNDecoderPerformanceARM.pdf : Decoder Performance on StrongARM and XScale ; May 12, 2003 ; Version 1.1
  • rv89_decoder_summary.pdf : RealVideo 8/9 Combo Decoder Summary ; October 23, 2002 ; Version 1.0
  • rv9_dec_external_spec_v14.pdf : RealVideo 9 External Specification ; November 7, 2003 ; Version 1.4
  • rv8_dec_external_spec_v20.pdf : RealVideo 8 External Specification ; September 19, 2002 ; Version 2.0
  • RV8DecoderExternalSpecificationv201.pdf : RealVideo 8 External Specification ; October 20, 2006 ; Version 2.01
  • RV8DecoderExternalSpecificationv202.pdf : RealVideo 8 External Specification ; April 23, 2007 ; Version 2.02
  • RV8DecoderExternalSpecificationv203.pdf : RealVideo 8 External Specification ; July 20, 2007 ; Version 2.03
  • RV8DecoderExternalSpecificationv21.pdf : RealVideo 8 External Specification ; September 11, 2007 ; Version 2.1
  • RV9DecoderExternalSpecificationv15.pdf ; RealVideo 9 External Specification ; January 26, 2002 ; Version 1.5
  • RV9DecoderExternalSpecificationv16.pdf ; RealVideo 9 External Specification ; August 17, 2005 ; Version 1.6
  • RV9DecoderExternalSpecificationv18.pdf ; RealVideo 9 External Specification ; September 11, 2007 ; Version 1.8

  Additionally, there is an Excel spreadsheet entitled realvideo-faq.xls that appears to contain some general tech support advice for using Real’s official code. There are also 3 ZIP archives which contain profiling information about the official source code (post processing and entropy decoding top the charts which is no big surprise).

  I guess the latest version of each document (the ones dated September 11, 2007) are worth mirroring. Unfortunately, those latest document versions use a terrible font.

• Python - ffmpeg-like media seeking with requests

  8 janvier 2017, par Will

  Using ffmpeg, times in HTTP media resources, such as videos, can be seeked to very quickly with a command like ffmpeg -ss 00:01:00 -i https://example.com/video.mp4, presumably by downloading the video headers to look for the right byte offset. This means that it is very fast to run operations on a section of video, even if it is hours in.

  What I want to be able to do is to do the same thing but piping into ffmpeg with the requests module with something like (in partial pseudo-code) :

  stream = requests.get(url, stream=True)
  
  start_byte = get_byte_offset(stream, time=60)
  
  stream.seek_to(start_byte)
  
  
  
  process = subprocess.Popen(["ffmpeg", "-i" "pipe:" "out.mp4"], stdin=subprocess.PIPE)
  
  
  
  for chunk in stream.iter_content(chunk_size=64 * 2 ** 10):
  
      process.stdin.write(chunk)
  
  process.stdin.close()

  This would allow me to implement extra checks into the stream that I would normally need to parse ffmpeg for, such as if the stream returns a bad status code such as 404 or 403.

  How might I be able to implement this using the requests, and presumably other, modules ? I suppose the first part is using a tool to parse the video headers.