I got a Coby MP-C7085 player for my daughter. It is a piece of ****. I finally got it to play videos after 3 days. Here's how. It needs MTV files in 160x128 format. The only way to get these is with the converter supplied with it - MTV Video Converter 188.8.131.52. None of the tools on this site (mp3 player utilities, mtv convert tool, amv convert tool etc etc) produced anything it would play. This might be because nothing else has a 160x128 setting. Or maybe because MTV is not a standard, just a name given to a collection of proprietary file formats. I wanted to put flash videos from Youtube on the player. First I needed to convert into something the Converter would accept. I used Cocoon's quick Media Converter Beta version 3.4.8. I believe this is a GUI for ffmpeg and other ffmpeg GUIs would do the same job if you knew the settings to use. Or just ffmpeg itself if you are a software engineer - I am not and can't cope without at least some basic instructions. ffplay has an mtv decoder so Cocoon's programme also lets you peek at the mtv file on the pc. Other applications of ffplay would too. I don't think ffmpeg/ffplay will encode though. Then I had problems with the MTV Converter. wmv files just crash it. mov files came out with no sound. I got mpg, mpeg4 and avi files to work. 3gp didn't. I didn't try the others it claims to work with. The converter works from a reboot but then if you load a file in, often in crashes when you load another file. Using a tool called regshot, I found that a registry entry (in XP) needed deleting to avoid this. It was HKEY_USERS\S-1-5-21-572598260-2891245555-755471578-1005\Software\Microsoft\Multimedia\ActiveMovie. This saves having to do the reboot each time. The PC needs to be loaded with all the right codecs for the converter to work. I used ffdshow but other packages may work. Then I got my mtv file. It needs to go in the movie directory. You need to toggle the player's settings to the right USB mode before hooking up to the PC in order to find this. When playing, it seems you need to switch off to move between video and music modes.
I only looked into all this because it was my daughter's. I should have thrown it in the bin and bought an Ipod. Like I said, it's a piece of ****. Anyway, maybe someone with the same problems will do a google and find these answers. Good luck!
These are all versions of "mp3 player utilities" with its "mtv convert tool" or "amv convert tool". I tried them all. They do not have the option to produce 160x128 resolution. They do not produce output that the Coby player will recognise. The only way I have found to do it is as described in my initial post. Thanks all the same.