TL;DR: In the Torrent Details : Files view, double-clicking a media file always open the Vuze HD Player, regardless of the setting in Interface : Tables : Launch Helpers. The behavior should be the same as right-clicking : Open, which uses said helpers.

Multiple questions on the forums or here in the suggestion tracker point to this: how to use another media player, instead of the Vuze HD Player. The answer is to use Launch Helpers in Options : Interface : Tables. This works fine, except with media files listed under the torrent details : Files view. Double-clicking them always use the Vuze HD Player. Right-clicking : Open on the item will work as intended however. This should not be the case as the "Open" menu item is emphasized which in UI terms means "default action when activated".

I simply suggest to make the behavior consistent by making double-clicking act the same as right-clicking : Open. As an alternative, another menu item "Open with HD Player" could be added and emphasized so that users know that is the default action, although I don't recommend that since many do not use the HD Player, myself included.

Note that I have no complaints about the Vuze HD Player itself or its continued development. It's simply that it will never offer all the features fully-fledged media players do, nor should it try to as many are either too advanced (like custom renderer settings) or completely outside its scope (like simultaneous playback of an external track).

The Problem:

It usually so happens that a media file could be previewed only after a good percentage of it has been downloaded and that too much later, only to be discarded if the file does not contain the required content,quality,etc.

To avoid this common condition, Vuze has provided a feature to download the first and last pieces of a torrent file on priority. However, this solution is not always fruitful.

When downloading a media torrent, I've noticed that media info was incomplete despite downloading the first and last pieces. Moreover, I've also observed that such torrents most likely contained the info in the first "few" and the last "few" pieces of the torrent; typically in the first 2 MB and the last 2 MB (See the Note in the end).

Moreover, this task becomes even more difficult for torrents with multiple media files as it is very cumbersome to identify the file boundaries - the piece where a media file ends and the next one begins within the torrent.

My Suggestion:

I'd suggest the piece-map grid to highlight the pieces that contain media info in a distinctive color so that a user can force the pieces to be downloaded manually. Better still, modify the existing feature to download all these pieces on priority rather than download only the first and the last ones.

I may also add here that in some rare cases, a similar but a very close symptom was observed when despite having all the required media info, the file could still not be previewed, in which case, the same workaround of having to force the pieces further down the grid worked! I'm not deterministic here and tell as to how many of such pieces are required in order to successfully preview the media file. I tried forcing few pieces and was able to preview thereupon.

NOTE:

A user may be interested in the following piece of info:

There's a relationship between the number of pieces and the total size of the torrent being downloaded. Either of them could be a multiple or a factor of the other.

Pieces per MB = Total No. of Pieces listed in Piece Map

                        ------------------------------------------------

                           File size in MB (1GB = 1024 MB)

EXAMPLE:

For Illustration, view the attachments - General Tab (for Size) & Piece Map (for No. of Pieces).

Size in MB = 2.81 GB * 1024 = 2877.44 ~ 2878 MB
No. of Pieces = 721
Size of Each Piece = 2878/721 = 719.5 ~ 4 MB

Most likely, this media torrent had all the require media info with the downloading of the first and last pieces (> 2 MB).

Alternatively,
If it had been a multiple, say for e.g,
2878 MB * 4 = 11512 pieces,
combining 4 pieces will yield 1 MB. In this case, the user will have to force-piece (download) the first 8 pieces (2 MB) and the last 8 pieces (2MB) to capture the media info.