DRF Analyzer and XviD

[Stammel]

Hi, I'm wondering if anyone can help me with a problem. I've been trying to generate the frame sizes of a XviD encoded video file using DivX DRF analyzer. One thing I noticed is that when I get it to analyze an xvid file encoded with b-frames, it seems to give incorrect frame sizes for every two frames or every other frame (for example, here is the info for frame size taken from the drf file of an b-frame encoded xvid)

0000c3ee
00005fd8
00000007
00012e92
0000ff15
00000007

The frame sizes are correct (this is a full-quality 1st pass file so I could compare frame sizes with that from .pass file) except for the ones with size 7. Also, this problem occurs for files that are encoded 2-pass. I've tried getting frame sizes on a file without b-frames and it seems to work fine.

Is anyone else having this problem? Does anyone know of a program that can generate frame sizes correctly?

Thank you for your time.

[Stammel]

Actually, I just noticed that even some of the ones that are not 7 are not right either.. for the first ten frames of the video:

DRF says: Actual:
50158 50158 *
24536 903
7 23640
77458 77458 *
65301 12725
7 52583
63066 9432
12219 12219 *
7 53641
67419 12944
9885 9885 *

Basically it gets every 2 or 3 right.

[Moitah]

It looks like this video has packed bitstream. The 7 byte frames are N-VOPs (in packed bitstream, a N-VOP is used as a placeholder for a real frame), and the large frames are actually 2 frames packed together.

EDIT: Edited 4 or so times to clarify the N-VOP thing :p.