using bash to detect broken video file

rs232 · 05-13-2013, 05:26 AM

Hi all,

I would like to write a script that scans my NAS video folder and detects videos files reporting on problems if any. A future version might even try to automatically repair but that's not what I need now...

Any ways, I'm looking for some input on things that can be detected using a script and how to do it. Things I've though about are:

- broken avi index
- unnecessary black bars
- file extension not matching encoding (e.g. .mov called .avi)
- unusual aspect ratio (not 4:3 or 16:9)

please do feed in any other thing you might think about!

I know ffmpeg can help, but before writing anything I would really appreciate your input!

Thanks!

pan64 · 05-13-2013, 08:05 AM

have you seen this http://606u.dir.bg/avicheck/ ?

schneidz · 05-13-2013, 08:18 AM

Quote:

Originally Posted by rs232

- file extension not matching encoding (e.g. .mov called .avi)

man file

also, look into mkvmerge -i

rs232 · 05-14-2013, 03:48 AM

Thanks both! I really appreciate your inputs

I did write something in the past using information on the link provided above. I basically scanned directory recursively and parse .avi with ffmpeg for errors.

The relevant part can be found here below:

Code:

find -mindepth 2 -maxdepth 4 -type d -printf '%T@ %p\n' | sort -r | cut -b 25- |
while read f; do 
rootdir=`echo $f | cut -b 4`

cd "$basedir/$f" 

	Video=`ls -1 *.avi 2>/dev/null | head -1`
	Videoext=`echo $Video|awk -F . '{print $NF}'`

if [[ $Videoext == "avi" ]]; then
	if [ ! -f error.log ]; then
		/usr/bin/ffmpeg -v 1 -i *.avi -f null - 2>error.log 
		errors=`more error.log | egrep -i 'error|invalid' | wc -l` 
		if [[ $errors -gt "1" ]]; then
			echo -e "$f might have AVI encoding problems \r"
		else
			echo -e "$f is well encoded \r"
		fi
	else
		echo -e "$f has already been processed \r"
	fi
else
	echo -e "$f is not AVI \r"
fi

The output log can be found in attachment. The point where I am at the moment is that I look for "error or invalid" but that's really my best guess on what it might go wrong on a file. I would need help identifying all the possible things that might go wrong with a video file and how ffmpeg would report on those.

About file and mkvmerge, can you please elaborate? I guess mkv merge can help with mkv files only (which is a fair enough to me)

Thanks again for your help/input
:-)

pan64 · 05-14-2013, 04:04 AM

actually you need to investigate and find out what kind of errors you want to take into account at all.
man file is a good start, or just try it.
about your script:
to check these files you do not need to sort them, so find <path> -type f -name \*.avi would be probably better.
rootdir is not used
Video=$f, the ls -1 .... is not required at all (f is the loop variable)
Videoext=${Video##*.} is much quicker than your solution (to get the extension)

errors=`more error.log | egrep -i 'error|invalid' | wc -l` can be replaced by a single grep:
errors=$(grep -ci 'error|invalid' error.log) - (or similar)

schneidz · 05-14-2013, 07:19 AM

Quote:

Originally Posted by rs232

...
About file and mkvmerge, can you please elaborate? I guess mkv merge can help with mkv files only (which is a fair enough to me)

file is a very simple command so it would be hard to elaborate:

Code:

[schneidz@hyper stuff]$ file video.xyz 
video.xyz: RIFF (little-endian) data, AVI, 720 x 480, ~30 fps, video: XviD, audio: MPEG-1 Layer 3 (stereo, 48000 Hz)
[schneidz@hyper stuff]$ mkvmerge -i video.xyz 
File 'video.xyz': container: AVI
Track ID 0: video (MP4V)
Track ID 1: audio (MP3)

Quote:

Originally Posted by pan64

...
Videoext=${Video##*.} is much quicker than your solution (to get the extension)
...

since op mentioned that some file names are mislabeled i think it would be better to find the actual file type using the file command.