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• Neutral net or neutered

  4 juin 2013, par Mans — Law and liberty

  In recent weeks, a number of high-profile events, in the UK and elsewhere, have been quickly seized upon to promote a variety of schemes for monitoring or filtering Internet access. These proposals, despite their good intentions of protecting children or fighting terrorism, pose a serious threat to fundamental liberties. Although at a glance the ideas may seem like a reasonable price to pay for the prevention of some truly hideous crimes, there is more than first meets the eye. Internet regulation in any form whatsoever is the thin end of a wedge at whose other end we find severely restricted freedom of expression of the kind usually associated with oppressive dictatorships. Where the Internet was once a novelty, it now forms an integrated part of modern society ; regulating the Internet means regulating our lives.

  Terrorism

  Following the brutal murder of British soldier Lee Rigby in Woolwich, attempts were made in the UK to revive the controversial Communications Data Bill, also dubbed the snooper’s charter. The bill would give police and security services unfettered access to details (excluding content) of all digital communication in the UK without needing so much as a warrant.

  The powers afforded by the snooper’s charter would, the argument goes, enable police to prevent crimes such as the one witnessed in Woolwich. True or not, the proposal would, if implemented, also bring about infrastructure for snooping on anyone at any time for any purpose. Once available, the temptation may become strong to extend, little by little, the legal use of these abilities to cover ever more everyday activities, all in the name of crime prevention, of course.

  In the emotional aftermath of a gruesome act, anything with the promise of preventing it happening again may seem like a good idea. At times like these it is important, more than ever, to remain rational and carefully consider all the potential consequences of legislation, not only the intended ones.

  Hate speech

  Hand in hand with terrorism goes hate speech, preachings designed to inspire violence against people of some singled-out nation, race, or other group. Naturally, hate speech is often to be found on the Internet, where it can reach large audiences while the author remains relatively protected. Naturally, we would prefer for it not to exist.

  To fulfil the utopian desire of a clean Internet, some advocate mandatory filtering by Internet service providers and search engines to remove this unwanted content. Exactly how such censoring might be implemented is however rarely dwelt upon, much less the consequences inadvertent blocking of innocent material might have.

  Pornography

  Another common target of calls for filtering is pornography. While few object to the blocking of child pornography, at least in principle, the debate runs hotter when it comes to the legal variety. Pornography, it is claimed, promotes violence towards women and is immoral or generally offensive. As such it ought to be blocked in the name of the greater good.

  The conviction last week of paedophile Mark Bridger for the abduction and murder of five-year-old April Jones renewed the debate about filtering of pornography in the UK ; his laptop was found to contain child pornography. John Carr of the UK government’s Council on Child Internet Safety went so far as suggesting a default blocking of all pornography, access being granted to an Internet user only once he or she had registered with some unspecified entity. Registering people wishing only to access perfectly legal material is not something we do in a democracy.

  The reality is that Google and other major search engines already remove illegal images from search results and report them to the appropriate authorities. In the UK, the Internet Watch Foundation, a non-government organisation, maintains a blacklist of what it deems ‘potentially criminal’ content, and many Internet service providers block access based on this list.

  While well-intentioned, the IWF and its blacklist should raise some concerns. Firstly, a vigilante organisation operating in secret and with no government oversight acting as the nation’s morality police has serious implications for freedom of speech. Secondly, the blocks imposed are sometimes more far-reaching than intended. In one incident, an attempt to block the cover image of the Scorpions album Virgin Killer hosted by Wikipedia (in itself a dubious decision) rendered the entire related article inaccessible as well as interfered with editing.

  Net neutrality

  Content filtering, or more precisely the lack thereof, is central to the concept of net neutrality. Usually discussed in the context of Internet service providers, this is the principle that the user should have equal, unfiltered access to all content. As a consequence, ISPs should not be held responsible for the content they deliver. Compare this to how the postal system works.

  The current debate shows that the principle of net neutrality is important not only at the ISP level, but should also include providers of essential services on the Internet. This means search engines should not be responsible for or be required to filter results, email hosts should not be required to scan users’ messages, and so on. No mandatory censoring can be effective without infringing the essential liberties of freedom of speech and press.

  Social networks operate in a less well-defined space. They are clearly not part of the essential Internet infrastructure, and they require that users sign up and agree to their terms and conditions. Because of this, they can include restrictions that would be unacceptable for the Internet as a whole. At the same time, social networks are growing in importance as means of communication between people, and as such they have a moral obligation to act fairly and apply their rules in a transparent manner.

  Facebook was recently under fire, accused of not taking sufficient measures to curb ‘hate speech,’ particularly against women. Eventually they pledged to review their policies and methods, and reducing the proliferation of such content will surely make the web a better place. Nevertheless, one must ask how Facebook (or another social network) might react to similar pressure from, say, a religious group demanding removal of ‘blasphemous’ content. What about demands from a foreign government ? Only yesterday, the Turkish prime minister Erdogan branded Twitter ‘a plague’ in a TV interview.

  Rather than impose upon Internet companies the burden of law enforcement, we should provide them the latitude to set their own policies as well as the legal confidence to stand firm in the face of unreasonable demands. The usual market forces will promote those acting responsibly.

  Further reading

  • Tory-Labour pact could save data bill, says Lord Howard
  • Internet companies warn May over ‘snooper’s charter’
  • Snooper’s charter ‘should be replaced by strengthening of existing powers’
  • Exclusive : ‘Snooper’s charter’ would not have prevented Woolwich attack, says MI5
  • Search engines urged to block more online porn sites
  • Why technology must be the solution to child abuse material online
  • Google must take more action to police explicit content, says Vince Cable
  • Facebook bows to campaign groups over ‘hate speech’
  • Facebook sexism campaign attracts thousands online
  • Türkischer Ministerpräsident : Twitter ist eine Plage
  • Valls : « La traque sur Internet doit être une priorité pour nous »
  • La Cnil, futur juge d’Internet
  • “National security matter” : Third agency caught unilaterally blocking web sites

• Converting Real Media with ffmpeg

  7 août 2013, par Eric Arenson

  I have a number of old crusty Real Media files I need to convert and was hoping to write a script to batch process them. I'm able to do a Real Media -> AVI conversion with FFMpegX, but when I try to replicate the conversion with ffmpeg, it always errors out with something like :

  [avi @ 0x10084fa00] Too large number of skipped frames 117425 > 60000

  It may have something to do with the funky format of these Real Media files :

  Duration: 01:28:23.42, start: 0.000000, bitrate: 448 kb/s
  
      Stream #0:0: Data: none, 32 kb/s
  
      Stream #0:1: Data: none, 192 kb/s
  
      Stream #0:2: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:3: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:4: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 8 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:5: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 5 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:6: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 27 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:7: Audio: cook (cook / 0x6B6F6F63), 22050 Hz, mono, fltp, 32 kb/s
  
      Stream #0:8: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 192 kb/s, 30 fps, 30 tbr, 1k tbn, 1k tbc
  
      Stream #0:9: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 136 kb/s, 30 fps, 30 tbr, 1k tbn, 1k tbc
  
      Stream #0:10: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:11: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:12: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:13: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:14: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:15: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 5 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc

  Does anyone have any tips on either how to find out what FFMpegX is doing to make the conversion work, or a better way to go about using ffmpeg to do this ?

  EDIT

  Including the ffmpeg command (thank you to @Mondain for teaching me about the stream mapping !) and output :

  Command :

  ffmpeg -i cc121307pm.rm -map 0:8 -map 0:7 -c:v libx264 -c:a libfaac -b:a 32k test.avi

  Output :

  ffmpeg version 1.2.1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Aug  7 2013 12:29:30 with gcc 4.2.1 (GCC) (Apple Inc. build 5664)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/1.2.1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=/usr/bin/gcc-4.2 --host-cflags='-Os -w -pipe -march=core2 -msse4.1 -mmacosx-version-min=10.6' --host-ldflags=-L/usr/local/lib --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  [rm @ 0x10180f200] Unsupported stream type 00000265
  
  [rm @ 0x10180f200] Unsupported stream type 00000652
  
  [rm @ 0x10180f200] max_analyze_duration 5000000 reached at 5004000 microseconds
  
  Input #0, rm, from 'input.rm':
  
    Metadata:
  
      File ID         : 41deac0f-94fb-3595-325c-c717943bc532
  
      Content Rating  : (PICS-1.1 "http://www.classify.org/safesurf" labels comment "RealProducer Plus 8.5.0.200 Windows" ratings (SS~~000 1))
  
      Modification Date: 12/13/2007 16:26:16
  
      Generated By    : RealProducer Plus 8.5.0.200 Windows
  
      Keywords        : 
  
      Abstract        : 
  
      Target Audiences: 28K Modem (20 Kbps);56K Modem (34 Kbps);256K DSL/Cable Modem (225 Kbps);
  
      Video Quality   : Normal Motion Video
  
      Audio Format    : Voice Only
  
      Creation Date   : 12/13/2007 14:57:49
  
      ASMRuleBook     : #($Bandwidth < 15000),Stream2Bandwidth = 6500, Stream3Bandwidth = 5499;#($Bandwidth >= 15000) && ($Bandwidth < 20000),Stream2Ba
  
      title           : 
  
      author          : 
  
      copyright       : ?2007
  
      comment         : 
  
    Duration: 01:28:23.42, start: 0.000000, bitrate: 448 kb/s
  
      Stream #0:0: Data: none, 32 kb/s
  
      Stream #0:1: Data: none, 192 kb/s
  
      Stream #0:2: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:3: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:4: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 8 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:5: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 5 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:6: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 27 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:7: Audio: cook (cook / 0x6B6F6F63), 22050 Hz, mono, fltp, 32 kb/s
  
      Stream #0:8: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 192 kb/s, 30 fps, 30 tbr, 1k tbn, 1k tbc
  
      Stream #0:9: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 136 kb/s, 30 fps, 30 tbr, 1k tbn, 1k tbc
  
      Stream #0:10: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:11: Audio: sipr (sipr / 0x72706973), 8000 Hz, mono, flt, 6 kb/s
  
      Stream #0:12: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:13: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:14: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 13 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
      Stream #0:15: Video: rv20 (RV20 / 0x30325652), yuv420p, 320x240, 5 kb/s, 15 fps, 15 tbr, 1k tbn, 1k tbc
  
  [libx264 @ 0x101889c00] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64
  
  [libx264 @ 0x101889c00] profile High, level 1.3
  
  Output #0, avi, to 'test.avi':
  
    Metadata:
  
      File ID         : 41deac0f-94fb-3595-325c-c717943bc532
  
      Content Rating  : (PICS-1.1 "http://www.classify.org/safesurf" labels comment "RealProducer Plus 8.5.0.200 Windows" ratings (SS~~000 1))
  
      Modification Date: 12/13/2007 16:26:16
  
      Generated By    : RealProducer Plus 8.5.0.200 Windows
  
      Keywords        : 
  
      Abstract        : 
  
      Target Audiences: 28K Modem (20 Kbps);56K Modem (34 Kbps);256K DSL/Cable Modem (225 Kbps);
  
      Video Quality   : Normal Motion Video
  
      Audio Format    : Voice Only
  
      Creation Date   : 12/13/2007 14:57:49
  
      ASMRuleBook     : #($Bandwidth < 15000),Stream2Bandwidth = 6500, Stream3Bandwidth = 5499;#($Bandwidth >= 15000) && ($Bandwidth < 20000),Stream2Ba
  
      INAM            : 
  
      author          : 
  
      ICOP            : ?2007
  
      ICMT            : 
  
      ISFT            : Lavf54.63.104
  
      Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p, 320x240, q=-1--1, 30 tbn, 30 tbc
  
      Stream #0:1: Audio: aac ([255][0][0][0] / 0x00FF), 22050 Hz, mono, s16, 32 kb/s
  
  Stream mapping:
  
    Stream #0:8 -> #0:0 (rv20 -> libx264)
  
    Stream #0:7 -> #0:1 (cook -> libfaac)
  
  Press [q] to stop, [?] for help
  
  [rm @ 0x10180f200] DATA tag in middle of chunk, file may be broken.
  
  Truncating packet of size 775215378 to 283607526
  
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  input.rm: Input/output error
  
  frame=    0 fps=0.0 q=0.0 Lsize=      10kB time=00:00:00.00 bitrate=N/A    
  
  video:0kB audio:0kB subtitle:0 global headers:0kB muxing overhead inf%
  
  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

• how to detect an connection lost of internet audio stream

  29 novembre 2013, par Meph-

  I'm recording internet audio stream and I want to detect somehow a connection error.
  I tried unplug cable of an internet connection and ffmpeg did nothing. I need to ffmpeg sends error message or raises exception. I have found nothing in ffmpeg documentation.

  Does some parameter exist for it ?

  I use :

  ffmpeg -i http://somestream -acodec copy out.wav