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• How to decode Byte string from continous video frames in python

  15 juillet 2021, par fresch man

  i am trying to get PNG from a video stream. first i connect the server during socket, and i recieve presistent byte string. however when i use Pickel ,i get a Error,that is UnpicklingError : invalid load key, '\x10.

  


  i surpose that ,if i should first do someting to the bytestring before i use pickel.or i should use another methode

  


  i have already search in the internet, but all the answers are , open locally video and so ..but my byte string are acctully presistent RAW video frames(yuv420) during tcp transport.

  


  `import socket,os,struct,numpy,pickle
TCP_IP = '192.168.0.90'
TCP_PORT = 5000
BUFFER_SIZE =1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((TCP_IP, TCP_PORT))
while True :
        data = s.recv(BUFFER_SIZE)
        data = pickle.loads(data) `


  


  thank you

  


• avcodec/bsf : switch to av_get_token to parse bsf list string

  3 juillet 2021, par Gyan Doshi

  avcodec/bsf : switch to av_get_token to parse bsf list string
  The recently added setts bsf makes use of the eval API whose
  
  expressions can contain commas. The existing parsing in
  
  av_bsf_list_parse_str() uses av_strtok to naively split
  
  the string at commas, thus preventing the use of setts filter
  
  with expressions containing commas.
  av_get_token can work with escaped commas, allowing full use of setts.
  

  • [DH] libavcodec/bsf.c

• Filtering string for hidden character when read from file in bash [duplicate]

  19 mai 2021, par BharathYes

  I am writing a bash script to trim video file into small pieces and finally merge them into a single video file using ffmpeg based on specified time.

  


  #!/bin/bash

filename="$1"
linecount=`wc -l "${filename}.txt"`
echo -n "" > to-merge.list

# file split by time
count=0
IFS=''
while read -r fromTime ; read -r toTime; do
    echo "$fromTime and $toTime done"
    ffmpeg -i "${filename}.mp4" -ss $fromTime -to $toTime -c copy "${filename}_pt_${count}.mp4"
    echo "file '${filename}_pt_${count}.mp4'" >> to-merge.list
    count=$((count+1))
done < "${filename}.txt"

# file merge
`ffmpeg -f concat -safe 0 -i to-merge.list -c copy "${filename}-trimmed.mp4"`


  


  The input file contains time (odd lines are taken as start time and even as the end time). A file I use is :

  


  00:00:00
00:39:34
00:39:38
01:23:14
01:23:16
02:03:45
02:03:48
02:43:43


  


  ---

  


  problem faced

  


  The echo in while loop prints this : done02:03:45

  


  The overwriting makes me think the time stored in the variables must contain a special character at the end that makes it invalid in ffmpeg.
ffmpeg throws this error : Invalid duration specification for ss: 01:23:16

  


  Is there a way to cleanup the time variable ?

  


  I have tried to find what is causing this issue or how to get rid of it but drawing a blank.

  


  ---

  


  what I have tried so far

  


  use grep -Eo '[0-9]{1,2}:[0-9]{1,2}:[0-9]{1,2}' to find time. While this works on the shell I am unable to use it in the script.

  


  Tried splitting time by : into hour, min and sec and saving them into an array to then merge them back but this makes it unnecessarily complicated and error prone.

  


  PS :
Is while read to be preferred for reading multiple lines like here or should tools like sed be used for best practice ? Such as sed '2,4 !d' /tmp/test.txt ?