Download Flash videos

Today there is a lot of websites with video contents. Most of them use flash as the platform to deliver the video contents to web browsers.

There can be many reasons to prefer to download the contents instead on watching them online, but unfortunately, many sites do only allow to watch the video contents while the user is connected to the corresponding website.

Older versions of flash player (previous to fall of 2010), just created a temporal file containing a cached copy of the video content. This way, getting a copy was an easy task: The user had just to locate the file containing the cached video to make a copy of such a file.

Current versions does not seem to create anywhere such a copy of the video.

In recent versions, such a file has been hidden trying to difficult to get a copy of the contents shown in the player. The trick is to use a deleted file as video cache. This way, the user is unable to find this file, at least in the usual way.

Here, we present a simple script whose goal is to get a copy of the deleted cache video file used by the flash player:

#! /bin/bash

RECPATH=/tmp
PIDS=`ps aux | grep libflashplayer | grep -v npwrapper | grep -v grep | awk '{print $2}'`
for PID in $PIDS
do
  FFILES=`ls -la /proc/$PID/fd/* | grep Flash | awk '{print $8}'`
  for FFILE in $FFILES
  do
    FNAME=`tempfile -d $RECPATH -p vid_ -s .flv`
    cp -f $FFILE $FNAME
    echo "Recovered file: "$FNAME
  done
done

Usage:

Using your favourite editor, create a script with the above commands.
Place it on any convenient location (for all users, like /usr/sbin, or just for your own ~/scripts ), and do not forget to give it execution permissions, i.e:


$ sudo vi /usr/sbin/capture_flash


Copy the above lines to this file. You can change the destination folder location (/tmp in the sample script) or modify the script to receive the destination as a parameter.


$ sudo chmod +x /usr/sbin/capture_flash


Open your browser, point to a site containing a flash player. Let the player buffer the full video contents and then execute the script.


$ capture_flash


Now you will have a copy of the video being played in the embedded viewer. You can rename it, and eventually move it to a more convenient location.


Explanation:

First of all, the script obtains the PID of all running instances of flash player. The npwrapper is excluded, considering that you can be running the 32 bit version on a 64 bit system

PIDS=`ps aux | grep libflashplayer | grep -v npwrapper | grep -v grep | awk '{print $2}'`

The script iterates through the identified PIDs examining the file descriptors associated with every process. Flash cache files can be identifies easily since they are the only ones containing the pattern 'Flash' on their names. Here we obtain references to the deleted cache files (unreachable and invisible otherwise).

FFILES=`ls -la /proc/$PID/fd/* | grep Flash | awk '{print $8}'`

For every flash file identified, the script generates a unique name on the destination directory, and finally copies the file descriptor of the deleted cache file to an ordinary file.

FNAME=`tempfile -d $RECPATH -p vid_ -s .flv`
cp -f $FFILE $FNAME

You got it!

Note: The script has been successfully tested on Firefox 3.6.x and Chromium-browser 10.0.x with flash 10.2.x running on Ubuntu 10.04 x86_64. Comments and improvements are welcome.