CQ and VBR in TMPGenc + bitrate viewer

[dvd_for_me]

I have a DV clip I am converting to MPEG2 usign TMPGenc2.2. The clip has some inside scenes and an outdoor scene of a child in a pool. I ahve encoded it with various settings and then run the mPEG files in TECO bitrate viewer. For one I used VBR at 5000kbit/s avg and 8000 kbit/s peak at high Quality. The bitrate viewer anlaysis showed the clip actually was at 4731 avg and 6277 peak. For CQ=65 at high quality and 8000kbit/s peak, I got 5655 average and 7783 peak. So I seem to get peak bitrates closer to max with CQ vs VBR, but I am surprised the VBR is not getting near max for the pool scene.

Now I also see that the bitrate viewer is giving me suspect numbers in an absolute sense, although I think in a relative sense they are okay. If I take the MPEG2 file sizes after encoding and divide by the length of the clip I get an average for the VBR clip of 5352 kbit/s vs the bitrate viewer calc of 4731 and for the CQ clip I get 6330 vs the calc of 5655.

Has anyone encountered the issue of VBR not getting to max bit rate, and is bitrate viewer accurate?

[Kdiddy]

Actually..I was beginning to wonder the same thing with CCE...I actually think the viewer is accurate....I was looking at some of my low motion scenes, and was thinking it looked pretty bad having specified my min to be 1150...I checked it with the bitrate viewer...and notice a LOT of my scenes were 500-800 bps!?!?!..of course, I was like what the hell??...but looking at the scenes again, they did look about 500-800 bps, so Im wondering if these encoders arent maintaining the min as they say....I also did a CBR test..according to bitrate viewer, it look more like a very narrow VBR...I still had low points as low as 1000 on specified 1400 CBR, and peaks as high as 1800...just not as many the VBR....so I dont know, but you arent in this confusing boat alone...so scoot over..LOL

<font size=-1>[ This Message was edited by: Kdiddy on 2001-12-28 23:41:20 ]</font>

[dvd_for_me]

Thanks kdiddy. Based on these results, I am going to use CQ for making my DV movies into DVD since I seem to get less blocky MPEG2 on the high motion parts. If I have to run a second CQ pass at lower settings to make it fit, I am no worse off timewise than if I used VBR in the first place.