Tuesday, December 30, 2008

Commercial Detection Software Battle – Comskip vs ShowAnalyzer

If you use Home Theater PC software, you are probably aware of commercial detection.  Unlike your cable/satellite DVR, TIVO or VCR your HTPC can automatically detect and if you want it to automatically skip commercials.  Matter of fact, this is one of the features that draws people to HTPCs in the first place.  A SageTV user (bialo is his forum name) recently did a comparison of the two most popular commercial detection programs: Comskip and ShowAnalyzer to see which one was the most accurate and fastest at detecting those commercials.  Read on for the results.

Notes about Comskip and ShowAnalyzer:

Note that this comparison did not include Snapstream’s built-in “smartskip” commercial detection.  While it is much easier to set up since it’s built into BeyondTV, I’ve found smartskip to be somewhat less accurate and definitely less reliable for commercial detection especially for those H.264 files output from the popular Hauppauge HD-PVR.  Another advantage of these two over Smartskip is that they have the ability to detect commercials while the recording is still in process.  This is a really nice feature if you tend to watch shows a bit time-delayed, but only by 20 or 30 minutes.  That way I’ll have commercials marked by the time I get to them even if the show just aired.

Another thing to note is that this test was done with the latest “donation” versions of the two commercial detection programs.  You can still get the free versions of these two, but they won’t be the latest, fastest or most accurate versions as the free version is typically several versions behind the paid versions.

For those of you unfamiliar with commercial detection in HTPC’s here’s what you see in SageTV after commercials have been detected and “marked”:

Anything in dark-green notes a detected commercial.  So when you get to that in the timeline, you can just hit the “right” button on your remote control and it will advance you to the end of the commercial.  If you have it set to auto-skip commercials it will automatically skip over those marked commercials without the user doing anything.


MPEG Commercial Detection Results

Commercial detection was run on a single episode of “Bones” (HD 720p, mpg from FOX).

Comskip Version 0.80.008 Results

5.00         133.52	0 (Note: 5 seconds padding used on comskip)
609.43 750.20 0
1259.74 1471.85 0
2019.88 2235.92 0
2677.96 2910.22 0
3154.20 3307.19 0
3734.81 3771.55 0
3839.20 3839.22 0

ShowAnalyzer Version Results

0.00300833     137.565	0
604.587 754.554 0
1254.72 1475.37 0
2014.78 2179.77 0 (Note: ShowAnalyzer incorrectly marked commercial at 2179.77 – 2193.11 as part of the show)
2193.11 2239.83 0
2677.89 2913.31 0
3148.65 3310.6 0
3729.71 3769.7 0
3837.97 3837.97 0

Bialo remarks:  I've got COMSKIP set for 5 seconds padding. So as you can tell, the results are almost identical. ShowAnalyzer had 1 false positive (2179.x to 2193.x marked incorrectly as part of the show). So for mpeg it's pretty much a draw as far as I am concerned.

So far, the winner is a very slight nod to Comskip since ShowAnalyzer made a slight incorrect mark.  In the end though it’s really too close to call for Mpeg recordings though.

H.264 Commercial Detection Results

Comskip Version 0.80.008 Results

    5.00     2.90	0
259.33 374.34 0
1071.50 1121.45 0
1728.09 1806.81 0
2364.93 2538.17 0
3135.80 3185.95 0
3565.96 3597.46 0
ShowAnalyzer Version Results

2.44643    7.6303 0
204.315 403.169 0
6670.72 6670.72 0

As you can see from the results, comskip marked a great deal more commercials than ShowAnalyzer did.  Unfortunately with Bialo’s C2D-based #4300 machine (overclocked to 2.6GHz) the more accurate comskip took a very long time on the H.264.


There is no question that if you have a Hauppauge HD-PVR, the current version of Comskip is the commercial detection program for you.  I'm a donator for both Comskip and ShowAnalyzer and have used both.  Comskip is the version I’m currently using and it’s working perfectly albeit a bit slow on H.264 recordings.  The good news is that the author of Comskip is working on a much faster version (up to 5 times faster) and his releases have been consistent and always improve with each version.  Bottom line, I recommend Comskip for your commercial detection needs and once you’ve tried out the free version and are happy with it, definitely donate to get the latest version of Comskip – it’s worth it and supports the valuable work of the author.

Read More and Download Comskip

via SageTV Forums


For more on how to set up Commercial Detection with your HTPC software, check out the GeekTonic Skip Commercial Detection How-To 

Stay tuned for more HTPC news including SageTV and other HTPC programs as well.
Want to learn more about the many add-ons and inner workings of SageTV?  Check out the GeekTonic Ultimate Guide to SageTV which is updated continually.