Videostudio 10 - Variable Bit rate won`t work

[bonniemarino]

Hello. I`m using Ulead Videostudio 10. When I produce a video file in MPEG 2 format with VBR the file produced comes out in CBR.

I use Mediainfo to check media properties. I encode from DV AVI files from a Canon camera.
I have also tried Videostudio 11. The same thing there.

Does anyone have the same problem? I could really use the help.
Thanks!

Best regards,
Ole
Norway

[daniel]

You give too little info about what you did to be sure, by my guess is that if you made no mistake when rendering you HAVE a VBR file.

Most programs read the header and don't analyse the file.
I don't know about VS but usually the header either gives the average bitrate or the max bitrate or nothing then the properties modules merely divides file size by time and report that average as bitrate.

Generate the same file in CBR and in VBR, you will see there is a size difference.

IIRC you would be the first one where it doesn't work....

[bonniemarino]

You are probably right. I tried producing a file with the cbr and vbr option. There is a slight difference in size. When i use Powerdvd with bitrate info the CBR files varies from 5,95 to 6,05Mbps. In VBR it varies from 5,3 to 6,1Mbps. I thought the VBR files would vary more, i can`t see the quality boost with so little bit rate change? Does it have something to do with video from dv-camera, maybe they don`t need it or something?

All the files are recognized as CBR in media info.
I have used the LPCM sound. But when i change to 5.1 DD sound the files are suddenly recognized as VBR. Strange.

Thanks again pal.

[daniel]

When i use Powerdvd with bitrate info the CBR files varies from 5,95 to 6,05Mbps. In VBR it varies from 5,3 to 6,1Mbps. I thought the VBR files would vary more, i can`t see the quality boost with so little bit rate change?

The advantage of VBR is heavily dependent on video contents.
Some will literally sink (static shots) others can be even larger if the max bitrate is greater than the CBR but then critical parts will be better encoded.
Try dual-pass for best results (at twice the price).

By default VS does not allow much variation in VBR from average to highest, but will go down very low from average. So the result is usually (ha!) lower file size with similar quality.

IOW to get the same quality, use VBR with a slightly higher max bitrate
f.i. with average video, 6500 VBR will give the same size as 6000 CBR, but with peaks to 6500 when needed. This is an example, not a hard figure.

You can check and tune the numbers if you enable advanced mode.

[GeorgeW]

The advantage of VBR is heavily dependent on video contents.
Some will literally sink (static shots) others can be even larger if the max bitrate is greater than the CBR but then critical parts will be better encoded.
Try dual-pass for best results (at twice the price).

With VBR, filesize is dependant on the AVERAGE VBR BITRATE. So you can actually have a VBR with MAX greater than the CBR bitrate, but if the AVERAGE bitrate is less than the CBR bitrate, your resulting file should be smaller than the CBR encode. For instance:

CBR 6mbps

VBR
-Min 4.5mbps
-Avg 5.5mbps
-Max 6.5mbps

The resulting VBR encode should be smaller than the CBR encode (even though the VBR encode is using a MAX of 6.5mbps vs the CBR encode of 6mbps).

Again, the way Ulead only lets you enter one bitrate (the MAX), it sometimes misleads users into thinking that VBR=smaller filesizes (as a rule that's not true across all encoders, but in Ulead's case, it's true because the single entry is the MAX bitrate).

Regards,
George