Different bitrate values in Rb-Opt and the new segment editor

[^JazzMan^]

I'm trying to backup Deep Purple - In Concert with The London Symphony orchestra, so I thought I'd check the bitrate values that the new segment editor gets comparing them with the ones from Rb-Opt and theres a significant difference..for instance :

for the 1st cell I get 3.918 Kbps in segment editor, while in Rb-Opt I get 3.135Kbps. Reduction percentage is the same (55.2%).

When I do the encode phase (using HC)encoder takes the values from Rb-Opt.

Anyone else noticed this?

cheers

[jdobbs]

All bitrates aren't the same. In the new editor DVD-RB is reporting the playback bitrate. So if the source is FILM on an NTSC DVD, it will report the bitrate including the frames created via RFF. But it will be encoded at a lower bitrate. Also, if you look at the rates sent to the encoder you will see that NTSC sources are all encoded at a common denominator of 23.976fps as a method of supporting hybrid sources. The rate flags are reset at REBUILD. So the rate you see reported by the encoder may be 25% less than what it will be at completion.

If the output comes out correctly sized... the bitrate has to be right.

[^JazzMan^]

Ah, that makes sence. Thanks for the explaination :)

[jdobbs]

Just as an aside, the reason I've started reporting using playback rates was because so many people were calculating bitrate based upon 29.97fps -- and were asking why my rates didn't match theirs.

[^JazzMan^]

So when it comes about choosing the matrix type, shall we go with the one that we were planning for the higher bitrate value(that is the playback bitrate value)or the other one which adds more compression?

Certainly, a difference of 800kbps can make you change your mind about which matrix to use :)


cheers

[jdobbs]

Internally everything DVD-RB does is with the common denominator bitrate and switches between matrices using it as a basis. That's also where my personal tests were done to determine the points where I thought they should be selected (Normal, Low, and Very Low).