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• Alias Artifacts

  26 avril 2013, par Multimedia Mike — General

  Throughout my own life, I have often observed that my own sense of nostalgia has a window that stretches about 10-15 years past from the current moment. Earlier this year, I discovered the show “Alias” and watched through the entire series thanks to Amazon Prime Instant Video (to be fair, I sort of skimmed the fifth and final season which I found to be horribly dull, or maybe franchise fatigue had set in). The show originally aired from 2001-2006 so I found that it fit well within the aforementioned nostalgia window.

  
  
  

  But what was it, exactly, about the show that triggered nostalgia ? The computers, of course ! The show revolved around spies and espionage and cutting-edge technology necessarily played a role. The production designer for the series must have decided that Unix/Linux == awesome hacking and so many screenshots featured Linux.

  Since this is still nominally a multimedia blog, I’ll start of the screenshot recon with an old multimedia player. Here is a vintage Mac OS desktop running an ancient web browser (probably Netscape) that’s playing a full-window video (probably QuickTime embedded directly into the browser).

  
  

  

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  Let’s jump right into the Linux side of things. This screenshot makes me particularly sentimental since this is exactly what a stock Linux/KDE desktop looked like circa 2001-2003 and is more or less what I would have worked with on my home computer at the time :

  
  

  

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  Studying that screenshot, we see that the user logs in as root, even to the desktop environment. Poor security practice ; I would expect better from a bunch of spooks.

  Echelon
  Look at the terminal output in the above screenshot– it’s building a program named Echelon, an omniscient spy tool inspired by a real-world surveillance network of the same name. In the show, Echelon is used to supply plot-convenient intelligence. At one point, some antagonists get their hands on the Echelon source code and seek to compile it. When they do, they will have access to the vast surveillance network. If you know anything about how computers work, don’t think about that too hard.

  Anyway, it’s interesting to note that Echelon is a properly autotool’d program– when the bad guys finally got Echelon, installation was just a ‘make install’ command away. The compilation was very user-friendly, though, as it would pop up a nice dialog box showing build progress :

  
  

  

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  Examining the build lines in both that screenshot and the following lines, we can see that Echelon cares about files such as common/db_err.c and bt_curadj.c :

  
  

  

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  A little googling reveals that these files both belong to the Berkeley DB library. That works ; I can imagine a program like this leveraging various database packages.

  Computer Languages
  The Echelon source code stuff comes from episode 2.11 : “A Higher Echelon”. While one faction had gotten a hold of the actual Echelon source code, a rival faction had abducted the show’s resident uber-nerd and, learning that they didn’t actually receive the Echelon code, force the nerd to re-write Echelon from scratch. Which he then proceeds to do…

  
  

  

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  The code he’s examining there appears to be C code that has something to do with joystick programming (JS_X_0, JS_Y_1, etc.). An eagle-eyed IMDb user contributed the trivia that he is looking at the file /usr/include/Linux/joystick.h.

  Getting back to the plot, how could the bad buys possibly expect him to re-write a hugely complex piece of software from scratch ? You might think this is the height of absurdity for a computer-oriented story. You’ll be pleased to know that the writers agreed with that assessment since, when the program was actually executed, it claimed to be Echelon, but that broke into a game of Pong (or some simple game). Suddenly, it makes perfect sense why the guy was looking at the joystick header file.

  This is the first bit of computer-oriented fun that I captured when I was watching the series :

  
  

  

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  This printout purports to be a “mainframe log summary”. After some plot-advancing text about a security issue, it proceeds to dump out some Java source code.

  SSH
  Secure Shell (SSH) frequently showed up. Here’s a screenshot in which a verbose ‘ssh -v’ connection has just been closed, while a telnet command has apparently just been launched (evidenced by “Escape character is ‘^]’.”) :

  
  

  

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  This is followed by some good old Hollywood Hacking in which a free-form database command is entered through any available command line interface :

  
  

  

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  I don’t remember the episode details, but I’m pretty sure the output made perfect sense to the character typing the command. Here’s another screenshot where the SSH client pops up an extra-large GUI dialog element to notify the user that it’s currently negotiating with the host :

  
  

  

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  Now that I look at that screenshot a little more closely, it appears to be a Win95/98 program. I wonder if there was an SSH client that actually popped up that gaudy dialog.

  There’s a lot of gibberish in this screenshot and I wish I had written down some details about what it represented according to the episode’s plot :

  
  

  

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  It almost sounds like they were trying to break into a network computer. Analyzing MD5 structure… public key synthesized. To me, the funniest feature is the 7-digit public key. I’m a bit rusty on the math of the RSA cryptosystem, but intuitively, it seems that the public and private keys need to be of roughly equal lengths. I.e., the private key in this scenario would also be 7 digits long.

  Gadgets
  Various devices and gadgets were seen at various junctures in the show. Here’s a tablet computer from back when tablet computers seemed like fantastical (albeit stylus-requiring) devices– the Fujitsu Stylistic 2300 :

  
  

  

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  Here’s a videophone from an episode that aired in 2005. The specific model is the Packet8 DV326 (MSRP of US$500). As you can see from the screenshot, it can do 384 kbps both down and up.

  
  

  

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  I really regret not writing down the episode details surrounding this gadget. I just know that it was critical that the good guys get it and keep from falling into the hands of the bad guys.

  
  

  

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  As you can see, the (presumably) deadly device contains a Samsung chip and a Lexar chip. I have to wonder what device the production crew salvaged this from (probably just an old cell phone).

  Other Programs

  The GIMP photo editor makes an appearance while scrubbing security camera footage, and serves as the magical Enhance Button (at least they slung around the term “gamma”) :

  
  

  

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  I have no idea what MacOS-based audio editing program this is. Any ideas ?

  
  

  

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  FTP shows up in episode 2.12, “The Getaway”. It’s described as a “secure channel” for communication, which is quite humorous to anyone versed in internet technology.

  
  

  

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• Video encoder & segmenter for HLS VoD poor quality

  10 juillet 2017, par Murilo

  I am trying to encode and segment video for HLS on demand(VoD).
  I am using the following code for such :

  ffmpeg -i 20170706_174314.mp4 -c 24 \
  
          -vcodec libx264 -acodec aac -ac 1 -strict -2 -b:v 128k \
  
          -profile:v baseline -maxrate 400k -bufsize 1835k \
  
          -hls_time 10 -hls_playlist_type vod -vsync 1 \
  
          video_chunks/index1.m3u8 \
  
          -c 24 -vcodec libx264 -acodec aac -ac 1 -strict -2 -b:v 128k \
  
          -profile:v baseline -maxrate 700k -bufsize 1835k \
  
          -hls_time 10 -hls_playlist_type vod -vsync 1 \
  
          video_chunks/index2.m3u8

  I tried this other code also just for segmenting but had the same exactly problem :

  ffmpeg -i 20170706_174314.mp4 \
  
  -c:a libmp3lame -ar 48000 -ab 64k  -c:v libx264 -b:v 128k -flags \ 
  
  -global_header -map 0 -f segment \
  
  -segment_list video_chunks/test.m3u8 -segment_time 10 -segment_format mpegts \
  
  video_chunks/segment_%05d.ts

  Later on I create another playlist with bandwidth separators to call on the two other playlists generated with the code above.

  This code was working great on some videos but yesterday I recorded a video with my Samsung J7 Prime phone to test since the videos will be generated by phone and this video was poorly encoded. The quality sucks and some parts of the video turned Black&White.

  Another thing I noticed on this video is that the following message kept appearing in loop until the end of the encoding&segmenting process.

  Past duration X too large

  Where X is a decimal really close to

  0.675316

  The link to the video is below :

  Dropbox Link

  My FFmpeg version :

  ffmpeg --version
  
  ffmpeg version N-86482-gbc40674 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.1.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 66.100 / 55. 66.100
  
    libavcodec     57. 99.100 / 57. 99.100
  
    libavformat    57. 73.100 / 57. 73.100
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 92.100 /  6. 92.100
  
    libswscale      4.  7.101 /  4.  7.101
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100

  SO : Windows 10

  EDIT1 : Link to the output
  If you see the output it might be worth saying I am also seeing the message

  VBV underflow(Frame X, -Y bits)

• FFmpeg Time Lapse from Sources with Long Frozen Tail End

  5 juillet 2019, par Rich_F

  My source for inputs into FFmpeg is either one AVI file or a concat of many of them. Either way my resulting timelapse file has a long tail of frames that are a repeat of a single frame. It’s like a very long freeze frame is resulting on the end of my output file.

  I’m on an older Mac Pro so I can’t update my FFmpeg. I have a laptop that has a newer version and I get the same there as well. I’m not sure if it’s because my source files are AVI or not.

  ffmpeg version 4.1.1 Copyright (c) 2000-2019 the FFmpeg developers
  
      built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
      configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags=-I/System/Library/Frameworks/JavaVM.framework/Versions/Current/Headers/ --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
      libavutil      56. 22.100 / 56. 22.100
  
      libavcodec     58. 35.100 / 58. 35.100
  
      libavformat    58. 20.100 / 58. 20.100
  
      libavdevice    58.  5.100 / 58.  5.100
  
      libavfilter     7. 40.101 /  7. 40.101
  
      libavresample   4.  0.  0 /  4.  0.  0
  
      libswscale      5.  3.100 /  5.  3.100
  
      libswresample   3.  3.100 /  3.  3.100
  
      libpostproc    55.  3.100 / 55.  3.100
  
  [avi @ 0x7fa82080c800] sample size (1) != block align (2)
  
  Guessed Channel Layout for Input Stream #0.1 : mono
  
  Input #0, avi, from 'concat:16460001.AVI|16460002.AVI|16460003.AVI|16460004.AVI|16460005.AVI|16460006.AVI|16460007.AVI|16460008.AVI|16460009.AVI|16460010.AVI|16460011.AVI|16460012.AVI|16460013.AVI|16460014.AVI|16460015.AVI|16460016.AVI|16460017.AVI|16460018.AVI|16460019.AVI|16460020.AVI|16460021.AVI':
  
      Duration: 00:10:02.00, start: 0.000000, bitrate: 365923 kb/s
  
          Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc, bt470bg/unknown/unknown), 1280x720, 30 fps, 30 tbr, 30 tbn, 30 tbc
  
          Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 32000 Hz, mono, s16, 512 kb/s
  
  Stream mapping:
  
      Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
  
      Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 0x7fa82082cc00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
  
  [libx264 @ 0x7fa82082cc00] profile High, level 3.1
  
  [libx264 @ 0x7fa82082cc00] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=16 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to 'out.mp4':
  
      Metadata:
  
          encoder         : Lavf58.20.100
  
          Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuvj420p(pc, progressive), 1280x720, q=-1--1, 16 fps, 16384 tbn, 16 tbc
  
          Metadata:
  
              encoder         : Lavc58.35.100 libx264
  
          Side data:
  
              cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
          Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 32000 Hz, mono, fltp, 69 kb/s
  
          Metadata:
  
              encoder         : Lavc58.35.100 aac
  
  frame= 1962 fps=1.2 q=-1.0 Lsize=  136725kB time=03:24:07.00 bitrate=  91.5kbits/s dup=0 drop=365448 speed=7.41x
  
  video:31548kB audio:103624kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.149437%
  
  [libx264 @ 0x7fa82082cc00] frame I:10    Avg QP:18.74  size: 62176
  
  [libx264 @ 0x7fa82082cc00] frame P:514   Avg QP:21.24  size: 30528
  
  [libx264 @ 0x7fa82082cc00] frame B:1438  Avg QP:22.74  size: 11121
  
  [libx264 @ 0x7fa82082cc00] consecutive B-frames:  1.4%  2.0%  2.0% 94.6%
  
  [libx264 @ 0x7fa82082cc00] mb I  I16..4:  2.1% 97.2%  0.7%
  
  [libx264 @ 0x7fa82082cc00] mb P  I16..4:  2.0% 33.3%  0.1%  P16..4: 37.7% 12.0% 10.4%  0.0%  0.0%    skip: 4.5%
  
  [libx264 @ 0x7fa82082cc00] mb B  I16..4:  0.7% 11.5%  0.0%  B16..8: 29.1%  4.8%  1.3%  direct:12.0%  skip:40.6%  L0:47.5% L1:42.9% BI: 9.6%
  
  [libx264 @ 0x7fa82082cc00] 8x8 transform intra:94.3% inter:83.0%
  
  [libx264 @ 0x7fa82082cc00] coded y,uvDC,uvAC intra: 73.4% 66.7% 8.5% inter: 25.9% 46.8% 2.2%
  
  [libx264 @ 0x7fa82082cc00] i16 v,h,dc,p: 17% 33% 26% 24%
  
  [libx264 @ 0x7fa82082cc00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 13% 23% 51%  1%  2%  1%  4%  1%  2%
  
  [libx264 @ 0x7fa82082cc00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 21% 19%  5%  8%  7% 13%  5%  5%
  
  [libx264 @ 0x7fa82082cc00] i8c dc,h,v,p: 46% 29% 23%  2%
  
  [libx264 @ 0x7fa82082cc00] Weighted P-Frames: Y:47.5% UV:19.3%
  
  [libx264 @ 0x7fa82082cc00] ref P L0: 45.0% 13.8% 20.6% 15.7%  5.0%
  
  [libx264 @ 0x7fa82082cc00] ref B L0: 61.1% 30.4%  8.5%
  
  [libx264 @ 0x7fa82082cc00] ref B L1: 85.8% 14.2%
  
  [libx264 @ 0x7fa82082cc00] kb/s:2107.54
  
  [aac @ 0x7fa82081ea00] Qavg: 130.084

  I’ve read this thread and tried to follow it :

  Create time lapse video from other video

  Here are some trials I’ve attempted before, all with the same output :

  # ffmpeg -y -i $mov -vf framestep=10,setpts=N/FRAME_RATE/TB,fps=2 -r 30 $out
  
  # ffmpeg -y -i $mov -vf framestep=10,setpts=.01*PTS -r 30 $out
  
  # ffmpeg -y -i $mov -vf framestep=10,setpts=.1*PTS -r 30 $out
  
  # ffmpeg -y -i "concat:16460001.AVI|16460002.AVI|16460003.AVI|16460004.AVI|16460005.AVI|16460006.AVI|16460007.AVI|16460008.AVI|16460009.AVI|16460010.AVI|16460011.AVI|16460012.AVI|16460013.AVI|16460014.AVI|16460015.AVI|16460016.AVI|16460017.AVI|16460018.AVI|16460019.AVI|16460020.AVI|16460021.AVI" -vf framestep=10,setpts=.05*PTS -r 30 $out
  
  ffmpeg -y -i "concat:16460001.AVI|16460002.AVI|16460003.AVI|16460004.AVI|16460005.AVI|16460006.AVI|16460007.AVI|16460008.AVI|16460009.AVI|16460010.AVI|16460011.AVI|16460012.AVI|16460013.AVI|16460014.AVI|16460015.AVI|16460016.AVI|16460017.AVI|16460018.AVI|16460019.AVI|16460020.AVI|16460021.AVI" -r 16 -filter:v "setpts=0.01*PTS" out.mp4

  Am I overlooking something ? I’m trying to speed up the inputs into a single file to quickly review incoming security footage. How can I do this without the super long useless tail at the end ?