Is it possible to pass a text file as stdinput to ffmpegfrom which it can read all the parameters present in the text file?
Something like this:
ffmpeg < foo.txt Where foo.txt contains
-i < file.mkv -c:v libx265 -preset medium "Encoded_file.mkv" Reason: Hide the files/parameters from programs such as htop
2 Answers
Some options can be given to ffmpeg using preset files, check the documentation here. This way, only the name of the preset file should be visible in htop. Some hints on preset files can be found in this answer. From what I have gathered from the documentation, you will not be able to hide the codec parameter, just options given to that codec. More hands-on examples can be found here.
Judging from your example you don't give any of these options that could be written to a preset file.
The input file can be passed via standard input by specifying the special file - and piping the file content to ffmpeg like so:
cat kooky_720p.mp4 | ffmpeg -i - -c:v libx265 -preset medium out.mkv The htop display of this command looks like this: htop extract 1
The output file can, similarly, be changed to the special file - which will redirect the converted file to standard output. To do this, you have to specify the container format manually, as ffmpeg will not be able to guess it from the file name.
Then you can pipe the converted data to the destination file. This could look like that:
cat kooky_720p.mp4 | ffmpeg -i - -c:v libx265 -preset medium -f matroska - > out.mkv The htop display of this command looks like this: htop extract 2
I do not know under which circumstances htop would display the file being piped into, but I guess this is handled inside the shell, so it is likely it will also not show up in shells other than zsh.
To also hide the cat input.ext from htop you could use e.g. a small python script like this to read the filename from a text file and copy the content to stdout:
#!/usr/bin/env python from __future__ import print_function import shutil import sys # Print errors to stderr, since we will pipe to stdout # For an explanation, see def eprint(*args, **kwargs): print(*args, file=sys.stderr, **kwargs) # Check if there is a filename given if len(sys.argv) < 2: eprint("Please specify an input file") sys.exit(1) # Open the file and read the first line try: fl = open(sys.argv[1], "r") filename = fl.readline().strip() fl.close() except Exception as e: eprint("Could not read filename from " + sys.argv[1]) eprint(e) sys.exit(1) # Pipe the content from the file to standard output try: with open(filename, "rb") as ffmpegInput: if sys.version_info >= (3, 0): # Python 3 shutil.copyfileobj(ffmpegInput, sys.stdout.buffer) else: # Python 2 shutil.copyfileobj(ffmpegInput, sys.stdout) except Exception as e: eprint("Could not pipe input file " + filename) eprint(e) sys.exit(1) Usage could be like this, whereas filename.txt is a simple text file containing one line of text that has the video file to be read, kooky_720p.mp4 in our example.
./pipe.py filename.txt | ffmpeg -i - -c:v libx265 -preset medium -f matroska - > out.mkv The htop display of this command looks like this: htop extract 3
I belive this is the closest you will get to hiding information from htop. Remember though, that it is still possible to get the information which files you are processing by looking at the open file handles e.g. using lsof:
$ pidof python3 ... 19013 ... $ lsof -a -p 19013 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME python3 19013 oliver cwd DIR 8,84 4096 31197648 /home/oliver/Videos/Kooky python3 19013 oliver rtd DIR 8,66 4096 2 / python3 19013 oliver txt REG 8,66 9992 7781733 /usr/bin/python3.6 python3 19013 oliver mem REG 8,66 11752 8020773 /usr/lib/python3.6/lib-dynload/grp.cpython-36m-x86_64-linux-gnu.so python3 19013 oliver mem REG 8,66 154344 7743563 /usr/lib/liblzma.so.5.2.3 python3 19013 oliver mem REG 8,66 36856 8012780 /usr/lib/python3.6/lib-dynload/_lzma.cpython-36m-x86_64-linux-gnu.so python3 19013 oliver mem REG 8,66 66960 7739636 /usr/lib/libbz2.so.1.0.6 python3 19013 oliver mem REG 8,66 21400 8012783 /usr/lib/python3.6/lib-dynload/_bz2.cpython-36m-x86_64-linux-gnu.so python3 19013 oliver mem REG 8,66 92056 7736853 /usr/lib/libz.so.1.2.11 python3 19013 oliver mem REG 8,66 36744 8012786 /usr/lib/python3.6/lib-dynload/zlib.cpython-36m-x86_64-linux-gnu.so python3 19013 oliver mem REG 8,66 21384 8020788 /usr/lib/python3.6/lib-dynload/_heapq.cpython-36m-x86_64-linux-gnu.so python3 19013 oliver mem REG 8,66 3268160 7787080 /usr/lib/locale/locale-archive python3 19013 oliver mem REG 8,66 1358168 7735428 /usr/lib/libm-2.26.so python3 19013 oliver mem REG 8,66 10048 7735415 /usr/lib/libutil-2.26.so python3 19013 oliver mem REG 8,66 14144 7735429 /usr/lib/libdl-2.26.so python3 19013 oliver mem REG 8,66 3327592 7785916 /usr/lib/libpython3.6m.so.1.0 python3 19013 oliver mem REG 8,66 2065840 7735493 /usr/lib/libc-2.26.so python3 19013 oliver mem REG 8,66 145336 7735516 /usr/lib/libpthread-2.26.so python3 19013 oliver mem REG 8,66 176880 7735494 /usr/lib/ld-2.26.so python3 19013 oliver 0u CHR 136,1 0t0 4 /dev/pts/1 python3 19013 oliver 1w FIFO 0,11 0t0 1276096 pipe python3 19013 oliver 2u CHR 136,1 0t0 4 /dev/pts/1 python3 19013 oliver 3r REG 8,84 4363354747 31198177 /home/oliver/Videos/Kooky/kooky_720p.mp4 As you can see, it lists the video file I used as an example here. The output file will show up in the handles of the ffmpeg process.
3Simply cat the parameters:
$ ffmpeg $(cat foo.txt) 
