Slideshow bitrate?

[mz_]

I'm using Sony Vegas to create two separate Slideshows, one is about 4m15s and the other is 8m25s. These will be along with a a full 1h40m video on a DVD.

The slideshows contain no fades, just go from picture to picture. My question is, should I use CBR or VBR for slideshows? I'm using VBR right now, but I'm trying to save some space, as I'm about 800MB over the 4.5GB limit.

Settings were;
MAX=8,500,000
AVG=6,500,000
MIN=2,000,000

I know these are HIGH for a slideshow, so I just want to know the optimal settings for this situation.

[yoda313]

I think you might be better off splitting this to two discs or bitting the bullet and use a dual layer blank if you have the ability to burn dl. If you are already over the limit for a single layer disc your only alternative is to shrink it down. That means quality loss. It won't matter what quality setting you set your slideshow to as you'd have to shrink the entire project to get under the limit - granted if your just over 5gigs now it won't be terribly dramtic loss but it will be a loss anyway.

If you're going to do the shrink afterwards then you can use the max setting to try to preserve the slideshow as much as you can before you hit it with the shrink.

But I think your best bet would be to split the main video to two discs and put the slide show on one of them or simply use a dual layer and not worry about it.

[guns1inger]

If you have no movement in the slideshow, and no fades, just hard cuts, you can probably get away with a CBR of around 5000, or a VBR of 2000, 4000, 6000 (Min, Avg, Max). A basically static slideshow will require relatively low bitrates.

If you have fades or x-fades then you will need a higher bitrate.

[classfour]

I'd almost shrink the video using DVD shrink, then re-add the video.

You could also shrink the slideshow by 800MB with shrink and watch the final product to make your determination.

[mz_]

I'm thinking about just using DVDShrink on the whole project, after I compile it with DVD-LAB Pro. Would that be the easiest option?

I can't use DL, as this project is going to multiple people and using LightScribe discs.

The slideshows together with video and audio are only about 354MB of the entire project. The main and bonus video with audio is about 4540MB all using the VBR settings mentioned above, the rest is the menus/graphics.

[jagabo]

I don't know about Vegas in particular but slide shows without transition effects can get away with very low average bitrates with VBR because the repeated B and P frames require almost no bitrate. Set the Min bitrate to 0 and you can get away with less than 2000 kbps. Some DVD players may have problems with min=0 bitrate though.

Here's a 70 second, 10 image, elementary stream created with TMPGEnc Plus using Constant Quality mode at 85, min=0, max=8000. The average bitrate came out around 1600 kbps (~14 MB).

http://www.divshare.com/download/1121432-d2f

Even a 2-pass VBR encoding at 1000 kbps looked decent.

[EddyH]

Huh? I'm confused here...

You have a slideshow that's mainly stillframes with some brief fades.... and want to know if CBR would work better - for higher quality and lower bitrate - than VBR?

...It's pretty much the textbook example of how VBR can benefit your project! hopefully it's just a misunderstanding.

For most of the video, the bitrate can happily be very low; a decent quality I-frame once per GOP (say twice per second), then zero-information P and B frames for the rest of the gop.
Then the fade happens - a pain in the ass for MPG, as there's nothing moving, just changing in-situ, meaning a lot of the P/B frames have to be part-coded as "I" anyway, and so a LOT of bandwidth is needed to make the fade look decent.

So as Jagabo says - set the min rate very low (i'd say more like 256kbit for compatibility's sake) and push the max up as high as can be allowed, and tweak the average to suit how small you need it and what it looks like.

One tip I would offer - try using "wipe" style transitions (starwars style) not fades. It still takes around the same amount of time, and doesn't have any actual moving parts, but only changes a little bit of the frame at a time, allowing the encoder to spread the bitrate deficit (already nicely reduced) across more frames. This little discovery both improved the apparent quality of a slideshow i did at the transitions, and allowed the bitrate to be dropped quite a lot.

No need to use shrink or anything like that.
And if you think the player could deal with longer (nonstandard) GOPs, with more P and B frames, the rate can be dropped even further.

good luck

[Cornucopia]

Why go 1/2 way?

If you're truly using just stills with no transitions, use a DVD slideshow feature (where each image is saved as just 1 I-Frame after another, with flags for timing). You can probably have a bitrate of 200-500kbps (for the each still section) and look great! These can also be mixed and matched with audio and standard video clips. Plenty of room when you encode this way!

Not all authoring apps support this, but you should check out those that do... (I've got Maestro. Scenarist does, pretty sure DLP does, probably others too).

Scott