VOB file Size Versus H.264

[Subtitles]

I have ripped a DVD that I recorded many years ago. When I copy a part that is 1040MB to the hard disk and convert it to H.264 file, the size is about 50% of the VOB file. I used HD Video Converter Factory Pro at best quality instead of Handbrake, because it made my computer gets very hot.
Is this normal or should the H.264 be the size of the VOB or near about?
The VOB files are 720p x 576p and it is hard to see if the converted video looks bad because with this resolution it doesn't look good to start with.
Using Handbrake did make the converted file about the same size as the VOB, but I can't risk my computer to get too hot using it.

[DB83]

File size = bitrate * run length. So inspect both the vob and the conversion in mediainfo and you will see the difference.

[Cornucopia]

Vobs are MPEG2-encoded. h264 encoding is 2 generations more complex, and are often considered ~2x more efficient (although this varies widely, depending on settings and material).
So it is not uncommon that, for a given material, it is possible for an h264 encoding to be 1/2 the size for equal quality, give or take. This assumes they both are encoded from the same master.
If you are encoding one from the other, there will of course be some quality loss since the 2nd encoding is encoded twice, both of them lossy type.


Scott