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• avcodec/rl2 : Remove wrong check

  28 septembre 2022, par Andreas Rheinhardt

  avcodec/rl2 : Remove wrong check
  This check is intended to be avoid buffer overflows,
  
  yet there are four problems with it :
  
  1. It has an in-built off-by-one error : len == out_end - out
  
  is perfectly fine and nothing to worry about.
  
  This off-by-one error led to the pixel in the lower-right corner
  
  not being set properly for the back frame of the sample from
  
  the rl2 FATE-test. This pixel is copied to every frame which
  
  is the reason for the update to the reference file of said test.
  
  With this patch, the output of the decoder matches the output
  
  as captured from the reference decoder* (apart from the fact
  
  that said reference somehow lacks the top part of the frame
  
  (copied over from the background frame)).
  
  2. Given that the stride of the buffer may be different
  
  from the width of the video (despite one pixel taking one byte),
  
  there is a second check lateron making the first check redundant
  
  (if one returns immediately ; a simple break at the second check
  
  is not sufficient, because it only exits the inner loop).
  
  3. The check is based around the assumption of the stride being
  
  positive (it has this in common with the other check which
  
  will be fixed in a future commit).
  
  4. Even after fixing the off-by-one error, the check in
  
  question is still triggered by all the non-background frames
  
  in the FATE sample as well as by A1100100.RL2. In all these
  
  cases, they use len == 255 and val == 128. For videos with
  
  background frame this just means "copy from the background
  
  frame", which would be done anyway lateron.* Yet for videos
  
  without it copying it is necessary to avoid leaving
  
  uninitialized parts in the video.
  * : Available in https://samples.mplayerhq.hu/game-formats/voyeur-rl2/
  
  ** : Due to this, the code that copies the rest from the
  
  back frame is no longer executed for any of the samples
  
  available on the sample server. Given that these are only
  
  the files from the demo version of this game, I don't know
  
  whether this code is executed for any file in existence or not.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/rl2.c
  • [DH] tests/ref/fate/rl2

• is there a way to auto trim parts of my video when a specefic color or text shows up on those parts

  10 novembre 2022, par Yousif K Al Ameen 1

  I play a game and record it, but unfortunately many parts of that recording is when my internet connection gets lost for several seconds. During that period it only shows a text that says "connection lost". Then the game resumes normally in few seconds after the connection is back.
Is there a software or a way that allows me to auto trim these connection lost periods from my viedeo ? Please help I need to trim a lot of these periods so that I can post cool gaming videos online without the "connection lost" scenes included.

  


  I tried searching on youtube and found some ffmpeg, python, and opencv methods but none of which is suitabal or easy to apply for my situation

  


• path issues with FFMPEG Bash script to concat and encode across multiple subfolders

  27 décembre 2022, par NoobCoder

  I'm trying to write a bash script for Mac OSx Terminal to compress a series of GoPro .MP4 videos from the SDcard directly into a smaller .MP4s on a local network server. The GoPro saves .MP4s in the 100GOPRO folder on the card. After filming, I will through that folder and manually put .MP4s from each game into subfolders within the 100GOPRO folder, named A1, A2, A3, etc.

  


  Folder structure

  


  /GoPro/DCIM/100GOPRO/
               -------/A1/
                       -----GX01xxx1.mp4
                       -----GX01xxx2.mp4
               -------/A2/
                       -----GX01xxx3.mp4
                       -----GX01xxx4.mp4
                       -----GX01xxx5.mp4
                       -----GX01xxx6.mp4


  


  ...etc

  


  I would like then like to run a script from the 100GOPRO folder that will do these steps :

  


  

  1. Within each subfolder, auto-create a file.txt with the names of the subfolder's .MP4s in the format to concat the files (each line has "file 'GX01xxx3.mp4'")

  


  2. Pass that subfolder's file.txt as the input to ffmpeg to reencode and save to a network folder with the name A1.mp4 or A2.mp4

  


  3. Repeat for each subfolder and quit.

  


  


  I'm getting hung up on the dynamic path to the subfolder's file.txt. My code just creates a file.txt in the 100GOPRO folder, and appends all the subfolder contents into that single long combined text file. The output then would create a correct first MP4, but second MP4 contains folder 1 and 2, then 3 contains 1, 2, and 3, etc.

  


  Here's the script I ran :

  


  #!/bin/bash
for f in A*/*.mp4 ; do
echo file \'$f\' >> list.txt ;
done && ffmpeg -f concat -safe 0 -i list.txt /Volume/Server/Videos/A$f.mp4 && rm list.txt


  


  Clearly, failing in how that path for echo to save in the subfolder A*, how to call that subfolder's file.txt as the input for ffmpeg, and how to name the output after the folder.

  


  Thanks for any help you can offer.