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• How can I programmatically write and read random video watermarks ?

  13 novembre 2017, par GreenTriangle

  I spent a few minutes trying to think of a clearer way to word my title, but I couldn’t manage it, sorry.

  I want to essentially canary trap video files : I am (hypothetically, this is not real but a personal exercise) offering them up to 5,000 different people, and if one gets leaked, I want to know who leaked it. Metadata is too easily emoved, so what I’d like to do is add a random and subtle watermark to each file, and store information about that in a database.

  For example : on Joe Smith’s copy, a 10x10 pixel 80% transparent red square in the upper left corner for 5 frames. On Diane Brown’s copy, a full-width 5-pixel 90% transparent black bar on the bottom edge for 15 frames. Then, if I find a leaked copy, I could check it against the database.

  I know this still isn’t foolproof : cropping would break co-ordinates, hue/brightness transforms would break colour reading, cutting time would break timestamps. But if I did want to do this anyway, what would be a good strategy for it ?

  My idea was to generate PNG overlays randomly, split the video into parts with mkvtoolnix/ffmpeg, re-encode the middle part with ffmpeg + overlay filter, and then rejoin them. But is this silly when there’s a "proper" way to do it ? And what would I be doing to read the watermarks, which I can’t even really conceive of ?

• x86 : videodsp : Properly mark sse2 instructions in emulated_edge_mc as such.

  24 octobre 2013, par Ronald S. Bultje

  x86 : videodsp : Properly mark sse2 instructions in emulated_edge_mc as such.
  Should fix crashes or corrupt output on pre-SSE2 CPUs when they were
  
  using SSE2-code (e.g. AMD Athlon XP 2400+ or Intel Pentium III) in
  
  hfix or hvar single-edge (left/right) extension functions.
  Signed-off-by : Janne Grunau <janne-libav@jannau.net>
  

  • [DH] libavcodec/x86/videodsp.asm
  • [DH] libavcodec/x86/videodsp_init.c

• Having trouble with color code in batch file

  23 juin 2022, par Lary David

  I'm trying to only have ffmpeg progress to be colored, but for some reason when I terminate or go full-screen this monstrosity occurs :
Issue

  


  @echo off
@echo off
title Stream Recorder
cls
:start
set message=Stream Recorder
echo %message%
echo(
echo [32m1. Chrome [0m
echo [34m2. Edge [0m
echo [33m3. Firefox [0m
echo [31m4. Opera [0m
echo [1;31m5. Vivaldi [0m
:choice
set choice=
set /p "choice=* Pick your browser (between 1-5): "
if not '%choice%'=='' set choice=%choice:~0,1%
if '%choice%'=='1' goto chrome
echo "%choice%" is not valid, try again.
ECHO.
goto choice

:chrome
:url
echo(
set /p "address=* M3U8 Url: "
For /F %%G In ('%__AppDir__%curl.exe -s -o NUL "%address%" -w "%%{http_code}\n"') Do Set "response=%%G"
echo %response%
IF %response% == 200 (
    ECHO [32mURL check was successful.[m &goto :username
) ELSE (
    ECHO [31mURL is not valid, try again.[m &goto :url
)
:username
set /p "filename=* Streamer Name: "
echo(
set message=* Recording:
echo [0m%message%[42;1m
ffmpeg -v warning -hide_banner -stats -user_agent "" -i "%address%" -c copy "%~dp0/%filename%_%DATE:~7,2%-%DATE:~4,2%-%DATE:~-4%_%time:~-11,2%-%time:~-8,2%-%time:~-5,2%.mp4"
pause


  


  Also, would be helpful if my code needs some cleaning up.