I received one of the Modix HD-3510 divx players as a gift recently. It's handled just about every media file I've thrown at it gracefully, save for a few that are obviously unsupported, and I'm wondering about the best way to go about converting them. I'm not a complete newb when it comes to video, but the myriad of codecs and containers do confuse me.

The Modix specs are at:

The supported video formats are:
.DAT (mpeg1)
.VOB (mpeg2)
.MPG, .MPA, .M1V, .M2V (mpeg2)
.AVI (DivX, Xvid)
.AVI (MS Mpeg4)

I've got several older video files that I'd like to convert for play on the Modix, and I'm concerned about re-encoding and losing quality.

The first being a bin/cue pair, prepared for an SVCD. I converted one pair using ffmpegx successfully, but I'm wondering if that was the best choice. What would be the best conversion for bin/cue pairs, that are prepared for SVCD?

Additionally, I've got several DVD backups I encoded to mpeg4 (.mp4), using Handbrake. I no longer have the source DVDs to re-encode. I'd like to convert these with as little loss of quality as possible. I tried streaming output with VLC (using the container format conversion), but AVI output is unavailable for them. Additionally, I tried MPEG Streamclip, and it fails after writing out most of the file. Any thoughts on the conversion of these?

Similarly, I've got one .mp4 that's encoded using the h264 codec. I assume the best, and only way would be to use ffmpegx and convert it to an equivalent .AVI.

I appreciate any insight provided. This forum has been a gold mine of information so far.