CBR (max) vs. VBR(high) in CCE -- when I have space to use high CBR?

[rapjp2001]

Hi All,

Quick question:

I am experimenting with CCE with sample mini DV footage that is firewired to my desktop and captured as DV-AVI...

I do not seem to see a straight answer for it -- Will I get better results by using CBR at max bitrate (8000 kbps) vs VBR where you state high bit rate settings (something like min to be around 6000, average to be 7000 and max to be 8000 or whatever is the highest one can go)...

The reason I ask is that the footage is barely 57 mins long and when I transfer this footage using my standalone Philips recorder, I can easily fit it using HQ(maxed bitrate of 9.8 Mbps - muxed) onto a DVD+R...so I know for a fact that I can perhaps fit this 57 mins with maxed out footage in CCE to a DVD+R...

With that scenario of a less than hour footage to transfer, is CBR at max bitrate better or a VBR at very high bitrate?

Please advise...

Thanks

Rajiv

[RB]

I think that if the average bitrate you could use for VBR is above 6000 kbps, you can just as well use CBR.

[auenf]

Originally posted by RB
I think that if the average bitrate you could use for VBR is above 6000 kbps, you can just as well use CBR.

i dissagree;

if you have a certain part of a clip that requires 9mbit to get the Q under 9, then a CBR of 7mbit isnt going to macroblock at that point.

using VBR and max of 9mbit should get that part of the clip under 9Q and should result with no macroblocks (9Q usually shows jpeg compression like artifacts still tho).

of course that situation is mostly only going to show up in interlaced files (which dont compress down below 4mbit well anyway).

i suggest using VBR, unless you want to do an average of 9mbit ;)

Enf...

[rapjp2001]

Hmmm....Interesting thought...

However, How can I possibly go to 9 Mb avg or even max? Don't i have to also account for the audio and hence lower the video bitstream to about 8 Mbps, that way I have space for the audio as well...

I am making the stream w/ a CBR of 8Mbps...However, I will try and experiment with VBR and avg. bitrate of 8 Mbps and see the difference...

Actually I do not see much or no difference at all in my experiments of different settings...at these high bitrates I am not noticing anything obvious...

This footage was shot in a night club where the band was playing and the minDV camera was on a tripod...However, due to the stage lighting at shows, the camera keeps getting confused and you get slightly out of focus ever few seconds and then back again...

The real issue I am having is that since the footage in dark, there is a lot of grainy areas(mind you -- not posterization or blocks), but inherent grains in the original DV footage itself...I want to try and minimize it...CCE smoothes it out a bit as opposed to my Philips standalone DVD capture, but only a little -- anything else I can do?

[auenf]

Originally posted by rapjp2001
However, How can I possibly go to 9 Mb avg or even max? Don't i have to also account for the audio and hence lower the video bitstream to about 8 Mbps, that way I have space for the audio as well...

2ch ac3 is typically encoded at 192kbit, which means you can make your max bitrate 9800 (depending on subs)

Enf...

[rapjp2001]

However, my audio stream is uncompressed PCM at 48Khz, 16 bit stereo...which is the way I would like to keep it because of this being a musical concert and based on what I hear in the Philips standalone 2 ch AC3 stream, my PCM stream sounds wayyy better...

With that said, what is my max when I have a PCM audio stream?