How to check the integrity of a video (avi, mpeg, …) file?

Question

This title could be somewhat misleading, so let me explain ...

I'm downloading a video file ... mpeg, avi - being one of the popular formats. Now, if I am downloading it, and the download breaks in the middle of the uhm ... download, then, for example, Windows Media Player will give out some error and refuse to play it (although the file is, let's say, 98% complete). But, players like KMPlayer, or MediaPlayer Classic will play it up until that point (as the matter of fact, they can play it while it is being downloaded as well).

So, I'm interested, ... without using any means of download (download managers and alike) to secure the file is completely downloaded, how can one verify whether the video file is downloaded whole, and that it is complete ?

Answer 1

You can use a feature in ffmpeg video converter: if you will specify it to recode video to nothing it will just read input file and report any errors that will appear. This is very fast process because video frames are just being read, checked and silently dropped.

Example command line: (for Linux) ffmpeg -v 5 -i file.avi -f null - 2>error.log
-v 5 means a fifth level of verbosity (to show some errors that are normally hidden because they don't affect playability a much). You will get a full error log with some generic information about file ffmpeg will output, so this will probably require your attention, through filters can be written to perform batch check of similar files.

FFmpeg is also available for Windows here. The command line will be almost identical with an exception of stderr redirect:
ffmpeg.exe -v 5 -i file.avi -f null - >error.log

Answer 2

MediaInfo is a great tool for getting info about any video file you care to throw at it. This may be able to highlight the info you want.

Another tool is GSpot but it hasn't been updated in nearly 3 years.

Try giving each one a known good and known bad file and compare the results.

I used to use GSpot until it stopped being updated, then switched to MediaInfo

Answer 3

I liked idea of using ffmpeg -f null above, but I'd actually like to automate process of using that output. In particular, common scenario I have with my music video collection is that I have few clips which have same resolution, and I'd like to diff verification logs for those files to remove ones broken the most.

Unfortunately, ffmpeg so far doesn't have a way to disable its interactive mode, which outputs noise for this case of usage. I ended up hacking simple wrapper script to do filtering:

#!/usr/bin/env python
import sys
import os
import re

t = os.popen('ffmpeg -v 5 -i "%s" -f null - 2>&1' % sys.argv[1]).read()
t = re.sub(r"frame=.+?\r", "", t)
t = re.sub(r"\[(.+?) @ 0x.+?\]", "[\\1]", t)
print t

Example output:

[mpeg1video]ac-tex damaged at 21 17
[mpeg1video]Warning MVs not available
[mpeg1video]concealing 22 DC, 22 AC, 22 MV errors
[mpeg1video]Warning MVs not available
[mpeg1video]concealing 22 DC, 22 AC, 22 MV errors
[mpeg1video]ac-tex damaged at 13 9