bluray folder size way too large

[blacktooth]

Years ago I shot my home videos in 8MM, then later Digital8, then MiniDV. Nowadays, of course, in high definition (AVCHD). I have put together a 'lifetime' video of my 18-year-old daughter, which of course is made up of clips of all 4 of these file types. When I started this project, I was worried about compatibility problems (not sure if I really needed to be worried, but I was anyway), so I made 2 separate VS projects - one with all of the standard definition, 4:3 clips and one with all of the high definition 16:9 clips.
Everything was fine until both projects were finished and I wanted to combine them into one. The combined project is 1 hour and 24 minutes long - 44 minutes of SD and 20 minutes of HD.
When I take the SD project into Share/create disc mode, it lists the project as 1.4GB in size for a bluray disc.
When I take the HD project into Share/create disc mode, it lists the project as 5.28GB in size for a bluray disc.

Here is what I have done to combine the two projects. I have taken each project and used the 'export as template' function to create an instant project template. Then I have taken a new, empty project and dropped each template, both SD and HD, into the timeline. Voila I have a 1 hour and 24 minute video, just as expected. Here is where the problem occurs. When I go to Share/create disc mode, it lists the total size - for a bluray disc - as 21.33GB! I have played with this over and over, and I always get this same way-out-of-proportion size. I have gone ahead and made a BD folder out of this, and it sure enough it creates a huge folder, 19.8GB in size (not sure why it's not 21GB). By the way, if I try to create an AVCHD disc, it says that the size will be 11.04GB. I guess I could go this route and burn the AVCHD file onto a bluray disc, but I really want to know why the bluray size is so large.
Thank you for any help.

[Davidk]

Basically, because on the combined disk, even the SD file is being rendered as an HD file. As a rule of thumb!! HD files are 4x as large as SD ones (because the resolution per frame is 4x). On my calculator, the combined 84 min project rendered in HD (the blu-ray disk) would be 22.176 Gb. There are obviously some render efficiencies in there, so getting away with only 19.8Gb looks good.

[blacktooth]

Thank you - that does put things in a different light. I listed an incorrect figure, by the way, in my first post. The SD project length is actually 1 hour and 4 minutes - not 44 minutes. So this SD project rates out to be 6.53GB in size as a bluray disc - but that's when the project properties is set as DV/AVI. One thing that I hadn't done before was change the project properties on this SD project to AVCHD. I just now tried that, and when I then go to Share/create disc, my SD project now says 16.18GB! So now that makes some sense as to why my combined project is so large.

But I still don't get the difference between bluray and AVCHD discs. My combined project - all 1 hour and 24 minutes of it - comes out to be 11.04GB if I render it into an AVCHD file. Why is it that the AVCHD file would be half the size of what a bluray disc would require - 21.33GB? That's an enormous difference for what in my mind is the exact same quality of video. Also, I know that high definition video takes up a lot of space, but it doesn't seem right that a huge 25GB bluray disc couldn't even hold a project that's 2 hours in length. Can you help me understand please? Thank you.

[Ken Berry]

A Blu-Ray disc can use either AVCHD mpeg-2 or Blu-Ray compatible (transport stream) mpeg-2. The latter produces much larger files than the more highly compressed AVCHD. So it depends what your burn properties are showing in the Burn module. It sounds to me as though they are converting the SD project into BD-compatible mpeg-2. You could always modify that to AVCHD before starting the burn.

[blacktooth]

Wow, that is crazy! I just changed the project settings - in Share/create disc - to bluray H.264. The resulting disc size drops from 21.33GB to 12.30GB! That's the piece of the puzzle that I couldn't figure out. As long as the highly compressed AVCHD files have same high quality, it's mind-boggling to me that the other mpeg-2 is even offered. Thank you so much for the help.

[lata]

Hi
The data rate used to create the video controls the size of the video file
When you do share Avchd the default template uses 18000kbps
When you do Share Disc – Bluray the module will convert the project using 35000kbps
The last option will create a video double the size of the first, we can of course select other templates or create our own.
I guess it may be best for both options to select the same default settings.

Your workflow may need adjusting because you are working with different types which use a different interlacing, changing the interlacing from the original will impact on quality.

Your DV-Avi uses UpperFieldFirst (UFF)
The 16:9 HD may use Progressive ( FrameBased ) or LowerFieldFirst (LFF)
The converted 8MM I suspect as Frame Based.

Clearly if they do use different Field orders then mixing those in one project means one will be converted to the wrong format.
This will show as jagged edges on vertical lines as the video is panned.

Can you right click each type of clip and choose properties what are they?

Your projects….
It may be best to keep them separate, Hd16:9 for one and DV-avi + 8mm for the second project.
Rendering each of these to a new video file using the same render settings for each.
The new BD compliant video files can be used to burn the disc without further conversion.

Choosing the render settings really depends on the original settings.
If 8mm and 16:9 HD use progressive then LowerField would be used, in which case a single project could be used
If you have a mix of Upper and Lower then I would use two projects.

My Panasonic 900 records to AVCHD at 16800kbps UFF, that creates a file at 8Gb ish per hour.
If your HD 16:9 video uses similar settings then I would advise you use those for your projects.

Please read these steps to Burn the disc from compliant video files -- recommended
http://lata.me.uk/corel/all.htm

Typical Settings from my Pana videos
MPEG Transport-Stream Files
24 bits, 1920 x 1080, 25 fps
Upper Field First
(HDMV-PAL), 16:9
H.264 Video
Video data rate: Variable (Max. 16800 kbps)
Audio data rate: 384 kbps
Dolby Digital Audio, 48 KHz, 3/2(L,C,R,SL,SR)

[blacktooth]

Thank you so much for the very detailed information. I gotta be at work much of this weekend, but I'll try to sneak in some time to get more familiar with this. I've always been intimidated by Field Order, although it has rarely sprung up and caused me problems. But this is one of the few combined-format videos I have made.