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• Playing 120fps in browser between original and re-made video, original is normal speed, new video is slo-mo

  1er mars 2023, par Patrick Vellia

  I used my GoPro Hero10 to record at 4k 120fps on a green screen. This original video plays slo-mo in QuickTime but "normal" speed in the browser. I want it playing normal speed, and if end user wants to slow it down they have the extra frames for that to maintain clarity, which is why I record at 120.

  


  I then used FFMPEG to create an image sequence of the video.

  


  Then I ran Image Magic to create the transparent frames.

  


  Then I put it back together with the following command for a HEVC mov file :

  


  ffmpeg -r 120 -f image2 -i transparent/image_transparent_%08d.png -vcodec hevc_videotoolbox -crf 28 -alpha_quality 1  -tag:v hvc1 output.mov


  


  I am still on an Intel MacBook Pro running FFMPEG 4.6 (as I've found 5+ was buggy with one of my commands a few months ago but can't remember which one, I think it was the videotoolbox).

  


  The GoPro video has the following stream data as input to the FFMPEG :

  


  Duration: 00:00:08.15, start: 0.000000, bitrate: 60160 kb/s
  Stream #0:0(eng): Video: hevc (Main) (hvc1 / 0x31637668), yuvj420p(pc, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 59891 kb/s, 119.88 fps, 119.88 tbr, 120k tbn, 119.88 tbc (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro H.265
      vendor_id       : [0][0][0][0]
      encoder         : GoPro H.265 encoder
      timecode        : 19:05:32:105
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro AAC  
      vendor_id       : [0][0][0][0]
      timecode        : 19:05:32:105
  Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro TCD  
      timecode        : 19:05:32:105
  Stream #0:3(eng): Data: bin_data (gpmd / 0x646D7067), 76 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro MET  


  


  Whereas the re-constructed video has the following data :

  


  Duration: 00:00:08.13, start: 0.000000, bitrate: 763650 kb/s
  Stream #0:0: Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, progressive), 3840x2160 [SAR 1:1 DAR 16:9], 763696 kb/s, 120 fps, 120 tbr, 15360 tbn, 15360 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : FFMP
      encoder         : Lavc58.134.100 hevc_videotoolbo


  


  When this re-constructed video plays in the browser, it is in slow-mo and I need to set the playbackRate to 4.0 for it to play "normally".

  


  Is there something I need to add to the video for the browser to play it at "normal" speed ?

  


• 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).

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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…

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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 ‘^]’.”) :

  
  

  

  Click for larger image

  
  

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

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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 :

  
  

  

  Click for larger image

  
  

  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.

  
  

  

  Click for larger image

  
  

  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.

  
  

  

  Click for larger image

  
  

  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”) :

  
  

  

  Click for larger image

  
  

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

  
  

  

  Click for larger image

  
  

  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.

  
  

  

  Click for larger image

  
  

• FFMPEG Incredibly Slow On Windows Server 2016

  1er août 2019, par Ben Gardner

  I have a t2.small (2GB RAM, 1 vCPU) Amazon EC2 instance running a process using FFMPEG. It runs just fine ( 30 fps) on my computer (i7, 12GB RAM), but at around 2 fps on the server. Here’s the command :

  rescale_command = f'ffmpeg -i {srcVideo} -filter_complex \"scale={owidth}:{oheight}, setsar=1:1, pad={dim[0]}:{dim[1]}:{oofx}:{oofy}\" {destVideo}'

  I’ve tried uninstalling and reinstalling ffmpeg/ffprobe

  Edited per llogan’s request, I’ve also discovered that it’s relatively speedy towards the beginning (I’m rescaling 100 times over the course of the program) and slows down towards the end.

  It utilizes 100% of the CPU even from the beginning, though.

  Example command/output :
  ffmpeg -i media/8-1-2019/hi/dl-107.mp4 -filter_complex "scale=607:1080, setsar=1:1, pad=1920:1080:656:0" media/8-1-2019/hi/sl-107.mp4

  ffmpeg version 3.2 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 5.4.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --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-libschroedinger --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-decklink --enable-zlib
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.100 / 57. 64.100
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'media/8-1-2019/hi/dl-107.mp4':
  
    Metadata:
  
      minor_version   : 512
  
      major_brand     : isom
  
      compatible_brands: isomiso2avc1mp41
  
      comment         : vid:v09044ce0000bks3802jqrog167l3rf0
  
      encoder         : Lavf58.20.100
  
    Duration: 00:00:15.12, start: 0.000000, bitrate: 1046 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 540x960 [SAR 1:1 DAR 9:16], 972 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 64 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  [Parsed_setsar_1 @ 00000000023ac840] num:den syntax is deprecated, please use num/den or named options instead
  
  [Parsed_setsar_1 @ 00000000023ad2c0] num:den syntax is deprecated, please use num/den or named options instead
  
  [libx264 @ 00000000023ad800] using SAR=1/1
  
  [libx264 @ 00000000023ad800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
  
  [libx264 @ 00000000023ad800] profile High, level 4.0
  
  [libx264 @ 00000000023ad800] 264 - core 148 r2721 72d53ab - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - 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=1 lookahead_threads=1 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=25 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 'media/8-1-2019/hi/sl-107.mp4':
  
    Metadata:
  
      minor_version   : 512
  
      major_brand     : isom
  
      compatible_brands: isomiso2avc1mp41
  
      comment         : vid:v09044ce0000bks3802jqrog167l3rf0
  
      encoder         : Lavf57.56.100
  
      Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc (default)
  
      Metadata:
  
        encoder         : Lavc57.64.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc57.64.100 aac
  
  Stream mapping:
  
    Stream #0:0 (h264) -> scale (graph 0)
  
    pad (graph 0) -> Stream #0:0 (libx264)
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=  453 fps=3.6 q=29.0 Lsize=    3016kB time=00:00:15.01 bitrate=1645.7kbits/s speed=0.12x
  
  video:2763kB audio:237kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.576820%
  
  [libx264 @ 00000000023ad800] frame I:6     Avg QP:20.93  size: 38467
  
  [libx264 @ 00000000023ad800] frame P:118   Avg QP:23.12  size: 11624
  
  [libx264 @ 00000000023ad800] frame B:329   Avg QP:25.19  size:  3725
  
  [libx264 @ 00000000023ad800] consecutive B-frames:  1.8%  2.6%  4.6% 90.9%
  
  [libx264 @ 00000000023ad800] mb I  I16..4: 16.4% 76.7%  6.9%
  
  [libx264 @ 00000000023ad800] mb P  I16..4:  2.3%  5.8%  0.9%  P16..4:  9.8%  3.8%  1.6%  0.0%  0.0%    skip:75.7%
  
  [libx264 @ 00000000023ad800] mb B  I16..4:  0.4%  0.7%  0.1%  B16..8:  9.5%  1.6%  0.3%  direct: 0.6%  skip:86.8%  L0:43.0% L1:50.8% BI: 6.2%
  
  [libx264 @ 00000000023ad800] 8x8 transform intra:67.4% inter:78.3%
  
  [libx264 @ 00000000023ad800] coded y,uvDC,uvAC intra: 32.5% 40.1% 9.4% inter: 2.7% 3.9% 0.1%
  
  [libx264 @ 00000000023ad800] i16 v,h,dc,p: 50% 25%  6% 19%
  
  [libx264 @ 00000000023ad800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 38% 11% 27%  3%  3%  5%  3%  6%  3%
  
  [libx264 @ 00000000023ad800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 43% 11% 12%  5%  7%  9%  4%  7%  3%
  
  [libx264 @ 00000000023ad800] i8c dc,h,v,p: 62% 11% 22%  5%
  
  [libx264 @ 00000000023ad800] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 00000000023ad800] ref P L0: 64.4% 14.3% 16.1%  5.2%
  
  [libx264 @ 00000000023ad800] ref B L0: 90.6%  7.5%  2.0%
  
  [libx264 @ 00000000023ad800] ref B L1: 97.7%  2.3%
  
  [libx264 @ 00000000023ad800] kb/s:1496.84
  
  [aac @ 0000000000628120] Qavg: 754.761