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Processing TS captures with free tools



As digital television (DTV) has gradually become standard in many parts of the world, TV capture has gone from a hobby enjoyed by a small group of hardcore enthusiasts to something easy enough for the novice to figure out. However, once you have your favorite TV show on your computer in the form of a TS (MPEG-2 Transport Stream) file you may not be completely done. Whether you're planning to author to a format like DVD or AVCHD, or even save it for computer viewing, some basic processing beforehand will reduce headaches later on.

Errors


Perhaps the biggest challenge for DTV broadcasting is handling errors. While media like DVD or Blu-ray can be authored with the assumption that every 1 and 0 on the disc will be delivered to the player exactly as written, DTV is subject to interference from the broadcast environment that results in errors being received by your capture hardware. The TS (Transport Stream) container is designed to minimize errors, but it can't eliminate them altogether. Depending on the source of the signal, terrestrial, cable, or satellite, there may be more or fewer errors. While DTV receivers are designed to work around these errors, other equipment that assumes error-free files (like DVD players) may not be so forgiving. Fortunately it's simple to correct the files so they won't cause audio sync problems later on. Depending on how noticeable the errors are you may want to do more to correct them later.


Transport Streams


TS files use the MPEG-2 Transport Stream container. While it's well suited for broadcasting, it's generally not used, and sometimes not even supported, for editing or saving to DVD or hard drive. Once you've corrected any errors you may want to either move the video and audio to a different container or simply demux to elementary streams for editing or authoring. The open source Matroska (MKV) container is a popular choice for storing captures because it accepts both video and audio in a wide array of formats, and is well supported across different operating systems, and in particular by the Windows DirectShow framework. For editing, elementary streams may be used by the free Cuttermaran frame accurate MPEG editor.

Free Tools


There are commercial tools available that can do much of what's covered in this guide, most notably VideoReDo Plus. While this is an excellent tool which we have guides for already, if you'd rather explore what can be done with free and open source tools keep reading.


Required Software For Error Correction


MPEG2Repair

Detects and repairs errors in MPEG-2 TS files. Helps avoid audio sync problems


Required Software For Demuxing


ProjectX

Capable of demuxing elementary streams from TS files


Next: Finding and repairing errors with MPEG2Repair





To demux or not to demux


Before you decide to demux into elementary streams or mux into another container like MKV you should consider what you'll be doing with your capture later on. If you don't want to do anything but store it to watch on a computer you might want to move it to a MKV file using mkvmerge from mkvtoolnix. This requires demuxing to elementary streams since mkvmerge can't read from TS files, The Cuttermaran editor also requires elementary streams, so you'll want to demux before using it as well. ProjectX is a good free tool for this purpose.

If you're going to process with a tool that accepts TS files as input you may even want to leave it that way for now.

Additional Information on MPEG-2 Transport Streams


Although you don't need a technical understanding of transport streams in order to work with them, if you're interested you can find more information in our Glossary entry.

A MPEG-2 Transport Stream, also referred to as MPEG or MPEG-2 TS or simply TS, is a special format for transmitting MPEG-2 video muxed with other streams. It's commonly used for digital television and Streaming across networks, including the internet.... (Read More)

table of contents

  1. 1. Introduction
  2. 2. Fixing Errors
  3. 3. Demuxing
Written by: Rich "vurbal" Fiscus
Last updated: 25 March 2008