problem joining different MPEG-2 files!

[jaypee]

Here is my problem: I've got two mpg files to merge. I tried to merge then using the tmpeg mpeg tools, and it said the file types were wrong. So i checked them at Bitrate Viewer: here's the info about them:

--------------file1--------------
Num. of picture read: 64181
Stream type: MPEG-2 MP@ML VBR
Resolution: 480*576
Aspect ratio: 4:3 Generic
Framerate: 25.00
Nom. bitrate: 2520000 Bit/Sec
VBV buffer size: 56
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 8
Pic. structure: Frame
Field topfirst: Yes
DCT type: Frame
Quantscale: Nonlinear
Scan type: ZigZag
Frame type: Progressive

--------------file2--------------
Num. of picture read: 136835
Stream type: MPEG-2 MP@ML VBR
Resolution: 480*576
Aspect ratio: 4:3 Generic
Framerate: 25.00
Nom. bitrate: 2520000 Bit/Sec
VBV buffer size: 56
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 8
Pic. structure: Frame
Field topfirst: No
DCT type: Field
Quantscale: Nonlinear
Scan type: Alternate
Frame type: Interlaced

To merge then, i believe that i have to make them look the same in all specs. What I'm trying to do is make the second file match the first one, so I can join them. Note that "Field topfirst", "DCT type", "Scan type" and "Frame type" are the specs that need to be the same. I don't know if the DCT and Scan type can be changed (that is my question #1) and how it can be done (question #2). So i tried to just change 2 specs: field topfirst and frame type. After aplying the pulldown command line below to change the field order and the frame type, here is what i've got for file 2:

" pulldown file2.m2v file2out.m2v -nopulldown -tff[odd] -prog_frames[p] -framerate[25] "

Num. of picture read: 19127
Stream type: MPEG-2 MP@ML VBR
Resolution: 480*576
Aspect ratio: 4:3 Generic
Framerate: 29.97
Nom. bitrate: 2520000 Bit/Sec
VBV buffer size: 56
Constrained param. flag: No
Chroma format: 4:2:0
DCT precision: 8
Pic. structure: Frame
Field topfirst: No
DCT type: Field
Quantscale: Nonlinear
Scan type: Alternate
Frame type: Interlaced

Look that the only change ocurred, was the num. of picture read and the FRAMERATE!

Well, anybody can help me here? What would be the correct procedure to merge this two files?

Thanks,
jaypee.