I cannot get videos to play on my LG GT500, despite transferring them to divX as recommended in the manual. This is driving me nuts - can anyone help me?

It is a normal DVD player, so it only can play DVD format and DivX. No self burned disks with other formats you can play on PC and smart phone. It also can play CD (Music format)
The fact it can play DVD-R/RW and DVD+R/RW does not mean it also can play MP4 or MOV, because there are so manny different formats. I think to be able to play DivX, you need to give in a code. Perhaps a code you have to buy.
The compatibility according the manual is down here:

Yes, I know Panasonic DVD S48, if your movie file is right divx avi movie file, you can directly transfer the divx avi movie file to your usb disk and play on your Panasonic DVD S48, but if your movie files isn\'t divx avi movie file, you have to use a right software to convert your movies to right divx avi movies, then transfer to your usb disk, convert any movies to divx avi movies.

figured this out, lg dp122 uses DivX Home Theater profile, so the technical specs of the video must match that.
Those specs can be found here: http://www.divx.com/files/DivX-Profiles_Tech-Specs.pdf

you can't and DIVX is an AVI format. MKV is an entirely different encoding format. There are no TVs or DVD players that support MKV. Also you will not get a DVD player that will paly BlueRay. DVD and BluRay require 2 different lasers on the drive to read the format so your software will not allow for this through a USB or hdmi either. You have what you have and there is nothing you can do aside from using the PC the movies were pirated from and connect it to the TV.

Divx compatibility with this player is limited as follows; available resolution size of Divx is under
720x576 pixel - file name Divx subtitle is avail by 56 characters - if number of the screen is over 30/sec the unit may not operate norm - playable Divx file avi,mpg. .mpeg - playable codec format
DIVX3.xx - DIVX4.xx - DIVX5xx -XDIV - MP43 - 31VX - if the video and audio structure of recorded
file is not interleaved, either video or audio is outputted.- if the fie is rec GMC the unit supports only
1 point of the record level - may be helpful!

It might be that you don't have the proper DivX codec to play it back.

Try downloading and installing the free divx download here and let us know if it works...

http://www.divx.com/en/software/divx-plus/codec-pack

Then you convert your videos to the type of video file or format that works with your phone. Once you get the files converted, then it will be able to view them. It is not on the phone you convert them, you convert them on a computer or laptop before transferring it to the phone. That way your phone will view videos.
Hope this information was helpful

Go here for the camera's operating guide download:  http://esupport.sony.com/perl/model-documents.pl?mdl=DCRHC40   Click here for the guide in PDF:  http://www.docs.sony.com/release/DCRHC40.pdf
Before connecting your camcorder to another device like a computer with a USB or I.LINK cable, make sure to insert the connector plug in the proper direction.  If you insert it forcibly in the wrong direction, the terminal may be damaged or it may cause a malfunction.
If you have inserted it correctly, then your computer should recognize the new device and automatically install the camera driver.  If it does not, then you will have to use the disk the camera came with or go to the manufacturer's website to download the drive.  Connect your camera to your computer again.  A window should pop up giving you the option to transfer the video to your computer.  I recommend choosing your desktop.  Any number of players should play the video.  If your movie is .avi, I would suggest downloading  DivX (http://www.divx.com/) to play your video from your computer.  

Whan you say you can't find the player, do you mean it won't play DivX? The player itself on the phone only runs when you open a video to watch, from there you can open other vids using the next and rewind buttons. The player on the phone is just geared to open DivX should you have some on your phone. The Player that comes with the suite is pretty laim so download the player from the DivX website for your PC.

You can not view from the USB, since the USB port on the DVD player is ver 1.1. The transfer speed is to slow to watch a movie. Alternatively you can copy your movie from your flashdrive to the harddrive and watch from there. You will see what I mean with slow speed when you copy the movie. It takes ages.