Comskip is a free mpeg commercial detector. It is a windows console software that reads a mpeg file and analyses the content based on a large amount of configurable parameters. After analysis it generates a file in various possible formats containing the location of the commercials inside the mpeg file. The formats include input files for Personal Video applications like SageTV or GBPVR, interactive video editors (VideoRedo, Cuttermaran,Mpeg2Schnitt...) command line video cutters (mpgtx, cuttermaran, mencoder) and video players (zoomplayer, mplayer, ...). Comskip can read MPEG and h.264 video and MPEG2, AC3 and AAC audio from PS , TS and dvr-ms files upto HD resolution (max 2000x1200) at 25fps (PAL) and 29.97fps (NTSC). The h.264 version is still in beta test and available for donators.

Before using Comskip it is essential to understand the basic operation of Comskip. Comskip reads and decodes a recorded mpeg file based on instructions Comskip reads from a so called ini file. The recording is analyzed on various characteristics such as black frames, silences and changes in aspect ratio.

Based on this information Comskip segments the recording in blocks and using heuristics, together with additional information such as the presence of logo, the scene change rate, Close Captioning information and other information sources Comskip tries to determine what blocks of the recording are to be characterized as commercials.

After the analysis is done Comskip writes out the information on the detected commercials in various possible formats.

Instalation
This guide describes how to use Comskip in combination with GBPVR. GBPVR is an outstanding free PVR program for Windows. Other PVR software's may also be able to make use of Comskip.

Copy all files from the distribution zip file that start with Comskip into the GBPVR home directory. This is normally c:\Program Files\devnz\gbpvr
Comskip is a console window program.

Usage:

comskip [-h|--help] [-w|--debugwindow] [-n|--playnice] [--zpcut] [--zpchapter] [--videoredo] [--csvout] [-p|--pid=<int>] [-t|--ts] [-d|--detectmethod=<int>] [-v|--verbose=<int>] [--ini=<file>] [--logo=<file>] <file>
-h, --help Display syntax
-w, --debugwindow Show debug window
-n, --playnice Slows detection down
--zpcut Outputs a ZoomPlayer cutlist
--zpchapter Outputs a ZoomPlayer chapter file
--videoredo Outputs a VideoRedo cutlist
--csvout Outputs a csv of the frame array
-p, --pid=<int> The PID of the video in the TS
-t, --ts The input file is a Transport Stream
-d, --detectmethod=<int> An integer sum of the detection methods to use
-v, --verbose=<int> Verbose level
-m, --demux Demux the input file into Elementary Streams
--ini=<file> Ini file to use
--logo=<file> Logo file to use
<file> Input file

Detection methods available:
1 - Black Frame
2 - Logo
4 - Scene Change
8 - Fuzzy Logic
16 - Closed Captions
32 - Aspect Ratio
64 - Silence
255 - USE ALL AVAILABLE

Comskip can operate on 3 types of files. The first file type is an MPEG file. The extension must be mpg, mpeg (for mpeg Program Streams), ts (for mpeg Transport Streams) or dvr-ms for DVR-MS). Maximum resolution is 2000 by 1200 and the content must be MPEG2 video and MPEG2 or AC3 audio as recorded by most mpeg encoders. When an mpeg file is provided as input Comskip will do a full decoding and commercial detection. When the demux switch is used Comskip will demux the mpeg input file into a separate audio and video elemtary stream suitable for many editor tools.

A second input file type is a csv file. This file can be created by a previous run of Comskip by setting output_framearry=1 or using the -csvout parameter. This type of input file is useful when Comskip must be run multiple times to tune certain parameters. This skips the mpeg decoding and results in a substantial faster execution.

The third type of input file is a .txt file with the commercial cutpoints as generated by a previous run of Comskip. When this type of input file is used Comskip will open the debugwindow and it is possible to review quickly the detected commercials and modify the cutpoints if required and write a new .txt file.

The license of this software is Freeware, you can free download and free use this video utility software.