DVD to m4v, Unusual Artifact??

[Galadirith]

Hi guys,

I have just started to rip my DVD's so that I may take them with me to Uni. Now I have started with Startrek Enterprise (My Favourite Startrek Series), and have converted them, having already ripped the disc to my HDD, to m4v containers using Handbrake, Video H264(x264), and audio AAC Stereo, leaving the framerate the same as the source, and setting the output size to 700MB (the episode itself being the pilot at 1h23m12s).

Now after the encoding, I wanted to compare it to the source, so I opened up the original from its VOB, chose some random section, and then opened the encoded at the same time to compare it, but when I did, I saw that they were not the same section.

I did various comparisions at points at the begining the middle and end, and it seems that the encoded starts fine, and also ends fine, but here is a collection of corresponding times (O: 00h05m00s E: 00h05m10s) (O: 00h17m00s E: 00h17m30s) (O: 00h40m00s E: 00h40m11s) (O: 1h00m45s E: 1h00m00s) (O: 1h20m00s E: 1h19m49s). The first time in each pair is a frame of the original, and the second of each pair is the (approximate) coresponding time of the same frame in the encoded.

So it seems that initialy the encoded is behind the original, and then nearer the end it is actually ahead of the original.

In truth, it should make no noticable difference in viewing, but I am sort of perplexed by this. I have never before compared and encoded file to its original in this way, so for all I know this is the norm, but perhaps it is not, could anyone shed some light on this?

Many Thanks