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Configuring your system for Media Playback

Playback of Locked or Incomplete files:
Under certain conditions you may encounter a locked (locked by a 3rd party application currently using the file) or incomplete file. This is most prevalent with Peer 2 Peer networks such as Kazaa or eMule, but may also be a factor with other applications (DVB cards writing video streams to the hard drive, or CDR software locking the file so you can't modify them as they are writing them). In either case, there are certain steps you can take to play your files even under these conditions.

To best handle incomplete AVI files you should obtain (and register) the Gabest AVI Splitter filter. This filter allows you to automatically reconstruct an AVI index, while still allowing you to seek between key-frames (you may see weird motion vectors until a key frame is decoded, but seeking will still be instantaneous).

Next in Zoom Player v3.20 or newer (Professional Version only, I'm afraid), you will have to enable both the "Play Incomplete AVI Files" and "Always open media files" check-boxes on the "Filter Control / Settings" options dialog. After restarting Zoom Player, any locked or incomplete media file should be able to open, play and seek.

In eMule you can safely uncheck the preference to Create a Backup for Preview and if you want preview to always be available under the right-click context menu within eMule, edit the "Preferences.ini" file and set "PreviewSmallBlocks=1" (you'll need a version of eMule newer than 0.29c as in v0.29c there is a bug that prevents preview without copy from working properly). You would still need a few 100's of kb at the beginning of the file in order for playback to work.

The Merit System:
Media Playback under any DirectShow player (such as Zoom Player) is based on the Merit System. Each filter has a function, it can be a reader, parser, decoder or renderer. A reader filter understands the basic file structure and knows how to read it. A parser filter will use this structure to split the file into streams (audio/video/subtitles/etc...), the decoder filter decodes a stream and sends it to a renderer filter which displays the data (or sounds it in the case of audio renderers).

Now, what if you have two filters, both fitting the same job profile? Here's where the merit comes into play... The filter with the highest merit point gets chosen for the job. This is a bit more complex than it may seem. Consider this situation: you can have one filter that decodes more than one format. The same filter can be used to decode AC3 audio and MP3 audio. You can have a second filter which only decodes MP3 audio. You want the filter that only plays the MP3 audio to be used for MP3 playback, but still use the other filter to play back AC3 audio. You do this by assigning the MP3 only decoder a higher merit.

There are several merit usage classes (these numbers are in hex):
80000 - Preferred
60000 - Normal
40000 - Unlikely
20000 - Do not use
10000 - Software Compressor
10050 - Hardware Compressor

You should stay clear of the compressor classes, but basically, you can see where this is going. You can use any number above the class while still maintaining within the class, for example a merit of "400005" is still "Unlikely". By rearranging the merits of filters you can eventually resolve most conflicts. However, if conflicts still occur, you can try unregistering the filter entirely and assuring the system would never be aware of it.

Zoom Player v3.10 and newer contains a Customized Playback Interface which bypasses the merit system. This new interface prevents filter conflicts. You can read more about it here.

To change a filter's merit, see details in SVCD section.

A Clean Start:
If your system is completely screwed up, and you're thinking of reinstalling the operating system from scratch to fix your media playback problems, here is a way to clean start your system prior to taking drastic measures such as a complete reinstall of the operating system. Please make sure to read all the instructions carefully and not skip any of the steps. This process may break certain video-editing software and web cameras from operating. Re-Installing their software/drivers should fix any issue.

Here are the series of actions you will need to take in order to reset your media playback settings to their default values (As they should be after a fresh windows install).

  1. You will first need to obtain Zoom Player v3.10 or newer.
  2. Run Zoom Player and open the "Options / Filter Control / Management" tab and click on the "Registered Filter Manager" button.
  3. Select all the filters in the list (highlight the first filter, hold shift and press the End button on the keyboard).
  4. Press on the "Unregister Filters" Button.
  5. Close Zoom Player.
  6. You will now need to re-register the filters that come with the system on a fresh install. To do this, run this batch file (you will need to extract the ZIP archive first).
  7. To restore DVD Playback capabilities without reinstalling the DVD Player, you may also need to register the DVD Filters that came with your player. You should be able to do that using Zoom Player's Customized DVD Playback interface, by selecting the decoders you use and pressing the "Register" button.
  8. Now go back to the start of this article and configure media playback accordingly.
Final Words:
Make sure you have either the "Overlay Mixer" or "Video Mixer Renderer 9" enabled in Zoom Player (Options / Filter Controls), without it under Windows XP, the VMR7 renderer is used and can conflict with certain media playback (makes it choppy or desynced). Don't be tempted for the quick fix, installing codec packs can cause multiple negative issues, so make sure you know what gets installed.

There is a filter called "mmswitch". This filter is used to provide old media players with the ability to play AVI files with multiple audio tracks. It is not required when Zoom Player is used and can actually cause instability and other odd behavior. Make sure you unregister it (easily done on the Filter Control options dialog).

If you had the "smart" idea of unregistering every single filter within the Registered Filter Manager and suddenly found that media playback no longer works, read "Clean Start" section of this article as it explains how to do this properly and restore default media playback conditions.

If you have any other questions, refer them to the Zoom Player section of the forum.