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• avfilter/formats : Fix double frees and memleaks on error

  7 août 2020, par Andreas Rheinhardt

  avfilter/formats : Fix double frees and memleaks on error
  The formats API deals with lists of channel layouts, sample rates,
  
  pixel formats and sample formats. These lists are refcounted in a way in
  
  which the list structure itself contains pointers to all of its owners.
  
  Furthermore, it is possible for a list to be not owned by anyone yet ;
  
  this status is temporary until the list has been attached to an owner.
  
  Adding an owner to a list involves reallocating the list's list of
  
  owners and can therefore fail.
  In order to reduce the amount of checks and cleanup code for the users
  
  of this API, the API is supposed to be lenient when faced with input
  
  lists that are NULL and it is supposed to clean up if adding an owner
  
  to a list fails, so that a simple use case like
  list = ff_make_format_list(foo_fmts) ;
  
  if ((ret = ff_formats_ref(list, &ctx->inputs[0]->out_formats)) < 0)
  
      return ret ;
  needn't check whether list could be successfully allocated
  
  (ff_formats_ref() return AVERROR(ENOMEM) if it couldn't) and it also
  
  needn't free list if ff_formats_ref() couldn't add an owner for it.
  But the cleaning up after itself was broken. The root cause was that
  
  the refcount was decremented during unreferencing whether or not the
  
  element to be unreferenced was actually an owner of the list or not.
  
  This means that if the above sample code is continued by
  if ((ret = ff_formats_ref(list, &ctx->inputs[1]->out_formats)) < 0)
  
      return ret ;
  and that if an error happens at the second ff_formats_ref() call, the
  
  automatic cleaning of list will decrement the refcount from 1 (the sole
  
  owner of list at this moment is ctx->input[0]->out_formats) to 0 and so
  
  the list will be freed ; yet ctx->input[0]->out_formats still points to
  
  the list and this will lead to a double free/use-after-free when
  
  ctx->input[0] is freed later.
  Presumably in order to work around such an issue, commit
  
  93afb338a405eac0f9e7b092bc26603378bfcca6 restricted unreferencing to
  
  lists with owners. This does not solve the root cause (the above example
  
  is not fixed by this) at all, but it solves some crashs.
  This commit fixes the API : The list's refcount is only decremented if
  
  an owner is removed from the list of owners and not if the
  
  unref-function is called with a pointer that is not among the owners of
  
  the list. Furtermore, the requirement for the list to have owners is
  
  dropped.
  This implies that if the first call to ff_formats_ref() in the above
  
  example fails, the refcount which is initially zero during unreferencing
  
  is not modified, so that the list will be freed automatically in said
  
  call to ff_formats_ref() as every list whose refcount reaches zero is.
  If on the other hand, the second call to ff_formats_ref() is the first
  
  to fail, the refcount would stay at one during the automatic
  
  unreferencing in ff_formats_ref(). The list would later be freed when
  
  its last (and in this case sole) owner (namely
  
  ctx->inputs[0]->out_formats) gets unreferenced.
  The issues described here for ff_formats_ref() also affected the other
  
  functions of this API. E.g. ff_add_format() failed to clean up after
  
  itself if adding an entry to an already existing list failed (the case
  
  of a freshly allocated list was handled specially and this commit also
  
  removes said code). E.g. ff_all_formats() inherited the flaw.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/formats.c

• Origin Crusader Media

  14 février 2012, par Multimedia Mike — Game Hacking

  A gleaming copy of the old Origin game Crusader : No Remorse showed up today :

  
  
  

  Immediately, I delved in expecting to find Xan-encoded AVI files that would play perfectly using FFmpeg/Libav. Instead, I found a directory labeled flics/ that indeed has a lot of AVI files, but not in Xan. The programs attempt to interpret them as raw RGB. The strangest thing is the first frame often looks correct, if upside down :

  
  
  

  The first file I peered inside had the video FourCC ‘RRV1′. Searching for this led me to this discussion forum where people have already been hacking on this very format (Origin games invariably get a heap of lasting love). The forum participants have observed that 3 codecs are in play in this flics/ directory, including ‘RRV1′, ‘RRV2′, and ‘JYV1′, which apparently correspond to the initials of certain developers. The reason that the programs identify the files as raw RGB is because the FourCCs don’t appear everywhere that they’re supposed to. Additionally, there are several trailers for other Origin/EA games stored in Cinepak format elsewhere on the disc.

  It seems that I’m the person who added this title to the Xan wiki page, obviously with no first-hand evidence to back it up. Meanwhile, the forum participants speculate that the files are descended from the old Autodesk FLIC format (which would explain why they live in a directory called flics/). Corroborating strings extracted from the CRUSADER.EXE file include “FlicWait”, “FlicPlayer”, “Flic %s not found.”, “flicpath”, and “FLICPLAY.C”.

  The disc also features a sound/ directory which contains AMF files. Suxen Drol already documented these on the wiki as Asylum Media Format files. The disc contains an ASYLUM.DLL file as well as a utility called MOD2AMF.EXE. The latter works beautifully on a random MOD file I had laying around. The AMF file is a bit larger.

  Samples for all 3 FourCCs can be found here, while the AMF files and associated utilities are here.

• FFpyplayer installation on Raspberry Pi 3

  2 décembre 2017, par id911

  first, I’m quite new to posting questions.

  I’m trying to install FFPyplayer on Raspberry Pi 3 for the past few weeks, and it keeps failing. I’m frustrated beyond words with myself now. If someone can lend a hand, point me in right direction or tell me what steps I’m missing, I’d be very very grateful.
  Below are the steps I followed.

  • sudo apt-get -y install libsdl2-dev libsdl2-mixer-dev python-dev
  • mkdir /ffmpeg_sources

  • export LD_LIBRARY_PATH=$LD_LIBRARY_PATH :$HOME/ffmpeg_build/lib

  • sudo apt-get -y install yasm

  • cd /ffmpeg_sources
  • wget http://www.tortall.net/projects/yasm/releases/yasm-1.3.0.tar.gz
  • tar xzf yasm-1.3.0.tar.gz
  • cd yasm-1.3.0
  • ./configure —prefix="$HOME/ffmpeg_build" —bindir="$HOME/ffmpeg_build/bin"
  • make

  • make install

  • sudo apt-get -y install nasm

  • cd /home/pi/ffmpeg_sources
  • wget http://www.nasm.us/pub/nasm/releasebuilds/2.13.01/nasm-2.13.01.tar.xz
  • tar xf nasm-2.13.01.tar.xz
  • cd nasm-2.13.01
  • ./configure —prefix="/home/pi/ffmpeg_build" ---
    bindir="/home/pi/ffmpeg_build/bin"
  • make

  • make install

  • sudo apt-get -y install libx264-dev

  • cd /ffmpeg_sources
  • wget http://download.videolan.org/pub/x264/snapshots/last_x264.tar.bz2
  • tar xjf last_x264.tar.bz2

  • cd x264-snapshot*

  • PATH="$HOME/ffmpeg_build/bin :$PATH" ./configure —prefix="$HOME/ffmpeg_build" —bindir="$HOME/ffmpeg_build/bin" —enable-shared —extra-cflags="-fPIC" ;

  • PATH="$HOME/ffmpeg_build/bin :$PATH" make

  • make install

  • sudo apt-get -y install libmp3lame-dev

  • sudo apt-get -y install nasm
  • cd /ffmpeg_sources
  • wget http://downloads.sourceforge.net/project/lame/lame/3.99/lame-3.99.5.tar.gz
  • tar xzf lame-3.99.5.tar.gz
  • cd lame-3.99.5
  • ./configure —prefix="$HOME/ffmpeg_build" —enable-nasm —enable-shared
  • make

  • make install

  • sudo apt-get -y install libass-dev libfreetype6-dev libtheora-dev libvorbis-dev

  • cd /ffmpeg_sources
  • wget http://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2
  • tar xjf ffmpeg-snapshot.tar.bz2

  • cd ffmpeg

  • PATH="$HOME/ffmpeg_build/bin :$PATH" -
    PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure —prefix="$HOME/ffmpeg_build" —extra-cflags="-I$HOME/ffmpeg_build/include -fPIC" —extra-ldflags="-L$HOME/ffmpeg_build/lib" —bindir="$HOME/ffmpeg_build/bin" —enable-gpl —enable-libass —enable-libfreetype —enable-libmp3lame —enable-libtheora —enable-libvorbis —enable-libx264 —enable-shared ;

  • PATH="$HOME/ffmpeg_build/bin :$PATH" make

  • make install

  • pip install —upgrade cython nose

  • pip install ffpyplayer

  Reference I used :

  http://matham.github.io/ffpyplayer/installation.html