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• avfilter/formats : Remove pointless checks

  11 septembre 2020, par Andreas Rheinhardt

  avfilter/formats : Remove pointless checks
  ff_formats_ref() takes a pointer to an AVFilterFormats and a pointer to
  
  a pointer to an AVFilterFormats as arguments and adds the latter as an
  
  owner to the list pointed to by the former ; the latter is hereby always
  
  the address of a list contained in an AVFilterFormatsConfig and can
  
  therefore not be NULL. So remove the check for whether it is NULL ; also
  
  do the same for ff_channel_layouts_ref().
  Also do the same for the unref functions where argument is never NULL
  
  because it is always the address of an existing lvalue.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/formats.c

• avfilter/af_stereowiden : fix read/write past the end of buffer

  12 juillet 2016, par Alexey Tourbin

  avfilter/af_stereowiden : fix read/write past the end of buffer
  The stereowiden filter uses a buffer, s->buffer[], and a pointer
  
  within the buffer, s->write, to implement inter-channel delays.
  
  The loop which applies the delayed samples turns out to be faulty.
     109      for (n = 0 ; n < in->nb_samples ; n++, src += 2, dst += 2) 
  
     110          const float left = src[0], right = src[1] ;
  
     111          float *read = s->write + 2 ;
  
     112
  
     113          if (read > s->buffer + s->length)
  
     114              read = s->buffer ;
  
     115
  
     116          dst[0] = drymix * left - crossfeed * right - feedback * read[1] ;
  
     117          dst[1] = drymix * right - crossfeed * left - feedback * read[0] ;
  
     118
  
     119          s->write[0] = left ;
  
     120          s->write[1] = right ;
  
     121
  
     122          if (s->write == s->buffer + s->length)
  
     123              s->write = s->buffer ;
  
     124          else
  
     125              s->write += 2 ;
  
     126      
  For one, the buffer gets written past its end in lines 119-120, before
  
  the bound check is done in lines 122-123.  This can be easily confirmed
  
  by valgrind.
  ==3544== Invalid read of size 4
  
  ==3544==    at 0x593B41 : filter_frame (af_stereowiden.c:116)
  
  ==3544==  Address 0xb1b03c4 is 4 bytes after a block of size 7,680 alloc’d
  
  ==3544==
  
  ==3544== Invalid read of size 4
  
  ==3544==    at 0x593B66 : filter_frame (af_stereowiden.c:117)
  
  ==3544==  Address 0xb1b03c0 is 0 bytes after a block of size 7,680 alloc’d
  
  ==3544==
  
  ==3544== Invalid write of size 4
  
  ==3544==    at 0x593B79 : filter_frame (af_stereowiden.c:119)
  
  ==3544==  Address 0xb1b03c0 is 0 bytes after a block of size 7,680 alloc’d
  
  ==3544==
  
  ==3544== Invalid write of size 4
  
  ==3544==    at 0x593B7D : filter_frame (af_stereowiden.c:120)
  
  ==3544==  Address 0xb1b03c4 is 4 bytes after a block of size 7,680 alloc’d
  Also, using two separate pointers, s->write and read = s->write + 2,
  
  does not seem to be well thought out.  To apply the delay of s->buffer[],
  
  it is enough to read the delayed samples at the current position within
  
  the buffer, and then to store new samples at the same current position.
  
  Thus the application of delayed samples can probably be best described
  
  with a single pointer s->cur.
  I also introduce a minor change to ensure that the size of s->buffer[]
  
  is always a multiple of 2.  Since the delay parameter is a float, it is
  
  otherwise possible to trick the code into allocating off-by-one buffer.
  

  • [DH] libavfilter/af_stereowiden.c

• VB Dot Net ffMpeg Network Web Server Cannot Execute JS Ajax Call to Private Web Server When Client is Outside Network

  29 septembre 2019, par Sonbelt

  I have a solution that is using Windows Server 2008 (Web Server), Windows Server 2008 (MS Sql Database Server), Computer with Windows 10 Home with IIS acting as a file server that runs command line calls where ffMpeg converts video files to html5 compliant files and then puts them on the NAS (a WD Network Drive.). Users then use the public website to view the videos streamed from the NAS.

  Windows Server 2008 cannot make a command line call to ffMpeg. If it could the performance hit would be too large.

  In order to get the public web server to call a private web page I’m using an Ajax post call to the file server web site. That site converts the videos and then there is a separate routine that moves the files using the same methodology. In order to get the file server where it can move the files to the NAS I’ve set the application pool identity to a specific user. The public web server is using the Network Service as the identity for the application pool.

  When I run the pages on the public server from behind the firewall where the calling ip address is in the same network the solution works fine but when I use any device or browser when the calling ip address is not in the local network the JS Ajax call to the private web site does not work. No lines appear in the IIS log on the file server.

  I’ve tried changing to the other built in choices and set the identity as the administrator on the public web server. Turned off the public server firewall, turned off the private files server firewalls without success.

  The solution needs to work when the calling ip address is not in the local network. I apologize for long post. Can you help me please ?