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• avcodec/aacenc : Avoid 0 lambda

  28 mai 2021, par Michael Niedermayer

  avcodec/aacenc : Avoid 0 lambda
  Fixes : Ticket8003
  
  Fixes : CVE-2020-20453
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/aacenc.c

• Prevent ffmpeg from changing the intensity of colors while downscaling the resolution of the video

  29 août 2022, par dravit

  I have a use case where I need to downscale a 716x1280 mp4 video to 358x640 (half of the original). Command that I used is

  


  ffmpeg -i ./input.mp4 -vf "scale=640:640:force_original_aspect_ratio=decrease,pad=ceil(iw/2)*2:ceil(ih/2)*2" ./output.mp4


  


  Out of 10 sample videos, 2 of the them suffered impact on colors. Below I have attached a comparison from the one which was impacted the most.

  


  

  


  NOTE : The one on the right is a frame from the original video and the frame on the left is the one from the processed (down scaled) video. Notice the colors red and green in the image (even the skin color and hair color were changed).

  


  What I am looking for is

  


  

  • Is there any way I can prevent changes like these happening ? Probably some flag on saturation, brightness, contrast or any other parameter.

  


  • I am assuming that ffmpeg uses some default settings while downscaling a video. What made ffmpeg change colors only for these two videos ? If it made similar changes for the rest of the videos as well, how to predict this behaviour before hand ?

  


  


  EDIT :

  


  What I already have Tried ?

  


  

  • -crf with values 0 and 18.

  


  • -preset veryslow as mentioned here

  


  


  None helped

  


  Mediainfo input V/S output

  


  





  


  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  param	input	output
  color range	Limited	NA (attribute not in description)
  color primaries	BT.2020	NA (attribute not in description)
  transfer characteristics	HLG	NA (attribute not in description)
  matrix coefficients	BT.2020 non-constant	NA (attribute not in description)
  bit deapth	8	8

  


  


  Logs of the ffmpeg command

  


  ffmpeg -i ./input.mp4 -vf "scale=640:640:force_original_aspect_ratio=decrease,pad=ceil(iw/2)*2:ceil(ih/2)*2" -movflags +faststart ./output.mp4
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 12.0.0 (clang-1200.0.32.28)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_9 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --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-libsoxr --enable-videotoolbox --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:30.05, start: 0.000000, bitrate: 10366 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt2020nc/bt2020/arib-std-b67), 716x1280, 10116 kb/s, 30 fps, 30 tbr, 19200 tbn, 38400 tbc (default)
    Metadata:
      handler_name    : Core Media Video
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 245 kb/s (default)
    Metadata:
      handler_name    : Core Media Audio
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x7faab4808800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7faab4808800] profile High, level 3.0, 4:2:0, 8-bit
[libx264 @ 0x7faab4808800] 264 - core 161 r3027 4121277 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - 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=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 './output.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
    Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 358x640, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : Core Media Video
      encoder         : Lavc58.91.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : Core Media Audio
      encoder         : Lavc58.91.100 aac
[mp4 @ 0x7faab5808800] Starting second pass: moving the moov atom to the beginning of the file
frame=  901 fps=210 q=-1.0 Lsize=    3438kB time=00:00:30.02 bitrate= 938.0kbits/s speed=7.01x
video:2933kB audio:472kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.974633%
[libx264 @ 0x7faab4808800] frame I:6     Avg QP:22.60  size: 20769
[libx264 @ 0x7faab4808800] frame P:228   Avg QP:24.84  size:  7657
[libx264 @ 0x7faab4808800] frame B:667   Avg QP:27.59  size:  1697
[libx264 @ 0x7faab4808800] consecutive B-frames:  0.9%  0.9%  1.0% 97.2%
[libx264 @ 0x7faab4808800] mb I  I16..4:  9.5% 64.6% 26.0%
[libx264 @ 0x7faab4808800] mb P  I16..4:  2.5% 12.2%  2.5%  P16..4: 37.2% 20.6% 11.2%  0.0%  0.0%    skip:13.7%
[libx264 @ 0x7faab4808800] mb B  I16..4:  0.4%  2.1%  0.2%  B16..8: 42.2%  7.1%  1.2%  direct: 1.8%  skip:44.9%  L0:39.4% L1:52.8% BI: 7.8%
[libx264 @ 0x7faab4808800] 8x8 transform intra:72.2% inter:74.2%
[libx264 @ 0x7faab4808800] coded y,uvDC,uvAC intra: 61.8% 67.2% 20.2% inter: 16.7% 13.9% 1.3%
[libx264 @ 0x7faab4808800] i16 v,h,dc,p: 24% 19%  7% 50%
[libx264 @ 0x7faab4808800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 21% 16% 15%  6%  9% 11%  7% 10%  6%
[libx264 @ 0x7faab4808800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 16% 13%  7%  9% 10%  7%  9%  4%
[libx264 @ 0x7faab4808800] i8c dc,h,v,p: 53% 16% 26%  5%
[libx264 @ 0x7faab4808800] Weighted P-Frames: Y:3.9% UV:1.8%
[libx264 @ 0x7faab4808800] ref P L0: 57.8% 19.5% 14.8%  7.8%  0.1%
[libx264 @ 0x7faab4808800] ref B L0: 90.7%  7.2%  2.1%
[libx264 @ 0x7faab4808800] ref B L1: 95.3%  4.7%
[libx264 @ 0x7faab4808800] kb/s:799.80
[aac @ 0x7faab2036a00] Qavg: 189.523


  


• Why X.Org's X Server has stopped working on Google Colab ?

  20 février 2021, par Rahul

  I am Using X server for the virtual screen on Google Colab and capturing that screen with ffmpeg to record it and live stream it to twitch. (for the reinforcement learning project)

  


  


  The above process was completely working till my last use of my Colab notebook (on mid-January 2021), but now (on 19th February 2021) I am using the same notebook and the streaming code has stopped working.

  


  


  I am adding config and log file data below. (I have never seen these files before because it was working, now it's not so I don't have any idea what wrong)

  


  The config file stored at /etc/X11/xorg.conf have the following data :

  


  # nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 418.67

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/mouse"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       28.0 - 33.0
    VertRefresh     43.0 - 72.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "Tesla T4"
    BusID          "PCI:0:4:0"
    MatchSeat      "seat-1"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "AllowEmptyInitialConfiguration" "True"
    SubSection     "Display"
        Virtual     1920 1080
        Depth       24
    EndSubSection
EndSection


  


  The log file stored at /var/log/Xorg.0.log have the following data :

  


  [   464.605] 
X.Org X Server 1.19.6
Release Date: 2017-12-20
[   464.605] X Protocol Version 11, Revision 0
[   464.605] Build Operating System: Linux 4.15.0-124-generic x86_64 Ubuntu
[   464.605] Current Operating System: Linux 9d3fe3949671 4.19.112+ #1 SMP Thu Jul 23 08:00:38 PDT 2020 x86_64
[   464.605] Kernel command line: BOOT_IMAGE=/syslinux/vmlinuz.A init=/usr/lib/systemd/systemd boot=local rootwait ro noresume noswap loglevel=7 noinitrd console=ttyS0 security=apparmor virtio_net.napi_tx=1 systemd.unified_cgroup_hierarchy=false systemd.legacy_systemd_cgroup_controller=false csm.disabled=1 dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1 i915.modeset=1 cros_efi loadpin.enabled=0 root=/dev/dm-0 "dm=1 vroot none ro 1,0 4077568 verity payload=PARTUUID=555BDB75-CBD7-CD4A-B24E-29B13D7AC0DF hashtree=PARTUUID=555BDB75-CBD7-CD4A-B24E-29B13D7AC0DF hashstart=4077568 alg=sha256 root_hexdigest=42104d547ac104fb7061529e78f53e4f3e8c3d3cbb040dc6e0f84aad68491347 salt=9dc7f3acc4e2ce65be16356e960c2b21b51a917fa31d2e891fd295490c991e41" mitigations=off
[   464.605] Build Date: 30 November 2020  08:01:56PM
[   464.605] xorg-server 2:1.19.6-1ubuntu4.8 (For technical support please see http://www.ubuntu.com/support) 
[   464.605] Current version of pixman: 0.34.0
[   464.605]    Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.
[   464.605] Markers: (--) probed, (**) from config file, (==) default setting,
    (++) from command line, (!!) notice, (II) informational,
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   464.605] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Feb 20 03:10:44 2021
[   464.606] (==) Using config file: "/etc/X11/xorg.conf"
[   464.606] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[   464.607] (==) ServerLayout "Layout0"
[   464.607] (**) |-->Screen "Screen0" (0)
[   464.607] (**) |   |-->Monitor "Monitor0"
[   464.607] (**) |   |-->Device "Device0"
[   464.607] (**) |-->Input Device "Keyboard0"
[   464.607] (**) |-->Input Device "Mouse0"
[   464.607] (==) Automatically adding devices
[   464.607] (==) Automatically enabling devices
[   464.607] (==) Automatically adding GPU devices
[   464.607] (==) Automatically binding GPU devices
[   464.607] (==) Max clients allowed: 256, resource mask: 0x1fffff
[   464.607] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (WW) The directory "/usr/share/fonts/X11/Type1" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[   464.607]    Entry deleted from font path.
[   464.607] (==) FontPath set to:
    /usr/share/fonts/X11/misc,
    built-ins
[   464.607] (==) ModulePath set to "/usr/lib/xorg/modules"
[   464.607] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[   464.607] (WW) Disabling Keyboard0
[   464.607] (WW) Disabling Mouse0
[   464.607] (II) Loader magic: 0x556eb77b8020
[   464.607] (II) Module ABI versions:
[   464.607]    X.Org ANSI C Emulation: 0.4
[   464.607]    X.Org Video Driver: 23.0
[   464.607]    X.Org XInput driver : 24.1
[   464.607]    X.Org Server Extension : 10.0
[   464.607] (EE) dbus-core: error connecting to system bus: org.freedesktop.DBus.Error.FileNotFound (Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory)
[   464.609] (--) PCI: (0:0:4:0) 10de:1eb8:10de:12a2 rev 161, Mem @ 0xc0000000/16777216, 0x380000000/268435456, 0x390000000/33554432
[   464.609] (II) no primary bus or device found
[   464.609] (II) LoadModule: "glx"
[   464.609] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[   464.610] (II) Module glx: vendor="X.Org Foundation"
[   464.610]    compiled for 1.19.6, module version = 1.0.0
[   464.610]    ABI class: X.Org Server Extension, version 10.0
[   464.610] (II) LoadModule: "nvidia"
[   464.610] (II) Loading /usr/lib/xorg/modules/drivers/nvidia_drv.so
[   464.610] (II) Module nvidia: vendor="NVIDIA Corporation"
[   464.610]    compiled for 4.0.2, module version = 1.0.0
[   464.610]    Module class: X.Org Video Driver
[   464.610] (II) NVIDIA dlloader X Driver  418.67  Sat Apr  6 02:51:17 CDT 2019
[   464.610] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs
[   464.610] xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
[   464.610] (II) Loading sub module "fb"
[   464.610] (II) LoadModule: "fb"
[   464.611] (II) Loading /usr/lib/xorg/modules/libfb.so
[   464.611] (II) Module fb: vendor="X.Org Foundation"
[   464.611]    compiled for 1.19.6, module version = 1.0.0
[   464.611]    ABI class: X.Org ANSI C Emulation, version 0.4
[   464.611] (II) Loading sub module "wfb"
[   464.611] (II) LoadModule: "wfb"
[   464.611] (II) Loading /usr/lib/xorg/modules/libwfb.so
[   464.611] (II) Module wfb: vendor="X.Org Foundation"
[   464.611]    compiled for 1.19.6, module version = 1.0.0
[   464.611]    ABI class: X.Org ANSI C Emulation, version 0.4
[   464.611] (II) Loading sub module "ramdac"
[   464.611] (II) LoadModule: "ramdac"
[   464.611] (II) Module "ramdac" already built-in
[   464.637] (EE) NVIDIA: Failed to initialize the NVIDIA kernel module. Please see the
[   464.637] (EE) NVIDIA:     system's kernel log for additional error messages and
[   464.637] (EE) NVIDIA:     consult the NVIDIA README for details.
[   464.662] (EE) NVIDIA: Failed to initialize the NVIDIA kernel module. Please see the
[   464.662] (EE) NVIDIA:     system's kernel log for additional error messages and
[   464.662] (EE) NVIDIA:     consult the NVIDIA README for details.
[   464.662] (EE) No devices detected.
[   464.662] (==) Matched modesetting as autoconfigured driver 0
[   464.662] (==) Matched fbdev as autoconfigured driver 1
[   464.662] (==) Matched vesa as autoconfigured driver 2
[   464.662] (==) Assigned the driver to the xf86ConfigLayout
[   464.662] (II) LoadModule: "modesetting"
[   464.662] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[   464.663] (II) Module modesetting: vendor="X.Org Foundation"
[   464.663]    compiled for 1.19.6, module version = 1.19.6
[   464.663]    Module class: X.Org Video Driver
[   464.663]    ABI class: X.Org Video Driver, version 23.0
[   464.663] (II) LoadModule: "fbdev"
[   464.663] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[   464.663] (II) Module fbdev: vendor="X.Org Foundation"
[   464.663]    compiled for 1.19.3, module version = 0.4.4
[   464.663]    Module class: X.Org Video Driver
[   464.663]    ABI class: X.Org Video Driver, version 23.0
[   464.663] (II) LoadModule: "vesa"
[   464.663] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
[   464.663] (II) Module vesa: vendor="X.Org Foundation"
[   464.663]    compiled for 1.19.3, module version = 2.3.4
[   464.663]    Module class: X.Org Video Driver
[   464.663]    ABI class: X.Org Video Driver, version 23.0
[   464.663] (II) NVIDIA dlloader X Driver  418.67  Sat Apr  6 02:51:17 CDT 2019
[   464.663] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs
[   464.663] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[   464.663] (II) FBDEV: driver for framebuffer: fbdev
[   464.663] (II) VESA: driver for VESA chipsets: vesa
[   464.663] xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
[   464.663] (EE) open /dev/dri/card0: No such file or directory
[   464.663] (WW) Falling back to old probe method for modesetting
[   464.663] (EE) open /dev/dri/card0: No such file or directory
[   464.663] (WW) Falling back to old probe method for fbdev
[   464.663] (II) Loading sub module "fbdevhw"
[   464.663] (II) LoadModule: "fbdevhw"
[   464.663] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[   464.663] (II) Module fbdevhw: vendor="X.Org Foundation"
[   464.663]    compiled for 1.19.6, module version = 0.0.2
[   464.663]    ABI class: X.Org Video Driver, version 23.0
[   464.664] (EE) open /dev/fb0: No such file or directory
[   464.664] (WW) Falling back to old probe method for vesa
[   464.664] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
[   464.664] (EE) Screen 0 deleted because of no matching config section.
[   464.664] (II) UnloadModule: "modesetting"
[   464.664] (EE) Device(s) detected, but none match those in the config file.
[   464.664] (EE) 
Fatal server error:
[   464.664] (EE) no screens found(EE) 
[   464.664] (EE) 
Please consult the The X.Org Foundation support 
     at http://wiki.x.org
 for help. 
[   464.664] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[   464.664] (EE) 
[   464.664] (EE) Server terminated with error (1). Closing log file.



  


  I am using this github repo to setup the video-streamer

  


  If anyone wants the colab notebook for the example then I will add it over here.

  


  For this problem I am really not sure where to file an issue for this so that's why I am writing this here.