Thanks, Lou, I agree it is overkill, but I really want to know if there is a practical limit. If I'm only going to put one short video on a 25GB Blu-ray and nothing else, why not fill up the unused portion with 40Mbps video? That way, I can have near "uncompressed" video quality.

Anyone done experiments with 40 or near 40 Mbps video on Blu-ray?

Have you tried rendering out at those rates? I thought Vegas is (or was) blocked from avc bitrates over 20Mbs or so....

Good point, Andy. I tried using the "customize template" in the rendering dialog and came up with something interesting. I thought you could manually put in any number in the bitrate window, which you can, but when you hit "O.K,", it reverts it back to a preset maximum. Here is what I discovered:

For rendering to AVC, Vegas 11 will limit you to about 21.9 Mbps no matter if a higher number is entered. So that question is answered.

For rendering to Blu-ray MPEG-2, Vegas 11 will limit you to 80 Mbps.

So, Vegas will allow you to render an AVC file to Blu-ray up to about 21.9 which is well below the maximum of 40 - the Blu-ray spec, but will allow MPEG-2 files to be rendered to 80 Mbps, which is way above the Blu-ray spec.

This is confusing. Why is one allowed within spec and the other not?

The MainConcept .MP4 encoder will allow bitrates higher than 21.9 mbps.

"I really want to know if there is a practical limit.

The templates included with Vegas Pro represent "practical limits". The 40 mbps number is the absolute maximum above which a hardware player manufacturer wouldn't be responsible if a Blu-ray wouldn't play. One thing to consider is that Blu-ray allows multiple audio tacks (some of which can be eight channel PCM) as well as subtitles, etc. All of that data must be read off the disk along with the video. The player reads the data, then selects which streams to present to the user based on local preferences.

"If I'm only going to put one short video on a 25GB Blu-ray and nothing else, why not fill up the unused portion with 40Mbps video? That way, I can have near "uncompressed" video quality."

You have to subtract the audio bit rates from the 40 mbps total bandwidth. Though the video can be quite stunning with MPEG-2, AVC or (VC1) it will never approach "uncompressed" because, for most of the frames, there is not even a whole frame, only the difference, and even the index frames are "compressed".

As a practical matter, if you're only putting a short video on a disk, render it to AVC @ 15 mbps, save the image and write it to a 4.7 GB DVD-5. I do it all the time and it looks good to me.

If you want to experiment with high bit rates on optical media, you could use John Cline's suggestion to render an elementery video steam, make a Blu-ray folder structure with tsMuxer and burn to BD-R with IMGBurn. If it plays on your Blu-ray player you could see if it makes any difference to you without having to deal with the limitations of DVD Architect. I burn content like that sometimes. Most often it is a recorded television show that I will likely watch only once but would like some navigation.

John Cline:

"The MainConcept .MP4 encoder will allow bitrates higher than 21.9 mbps. "


True, however those files will have an .mp4 file extension. I don't believe you can make a Blu-ray out of that without recompression. Is there a way that will not force recompression?