Explanation for Long Render?

[Dieter Moreno]

[Curt Charles] “Shot in HDV (1440x1080i, compressed. Sony Z1 and A1 cameras which record to tape) and rendered to the same. The project is about 1 hour long and I don’t know its disk footprint.”

A 1 hour long 1440x1080i video is going to have a huge disk footprint even using compression. You probably didn’t use enough compression.

This video bit rate calculator says that a one hour uncompressed video with those specifications (1440x1080i, 30fps, R8:G8:B8 (24 bit color), no alpha channel) would be 251.94 Gbytes long at a bit rate of 65Mbytes/s(559.87Mbits/s).

If the bit rate was lowered to 6.5Mbytes/s (55.987Mbits/s) using the video compression codec that you selected, then the file would also be ten times smaller, at a size of 25.194 Gbytes.

You could try making the bit rate smaller to 4.5Mbytes/s and then setting up a proportion using the same units,
(25,194.000Mbytes)*((4.5Mbytes/s)/(6.5Mbytes/s))=17,442.0Mbytes=17.442Gbytes

You could try making the bit rate even smaller to 2.4Mbytes/s and then setting up a proportion using the same units,
(25,194.000Mbytes)*((2.4Mbytes/s)/(6.5Mbytes/s))=9,302.4Mbytes=9.3024Gbytes

When I render a 4.5Mbyte/s video at 720x480p 24 bit color with no alpha channel,that is 5 minutes long, it has a file size of
(9,330Mbytes)*((4.5Mbytes/s)/(31.1Mbytes/s))=1,350Mbytes=1.35Gbytes

Oh, I think I made a mistake, I think “4.5mbps” means “mega BITS per second”, NOT “mega BYTES per second.

So my final file sizes divide by 8.

So 5 minute long video at the settings I mentioned is 168.75Mbytes file size.

So your one hour long video at the settings you mentioned if 4.5megabits/s was used that would be 2.18Gigabytes file size.

[Curt Charles]

Thanks, Dieter, for the details and link on the file size computation. This is stuff I didn’t know.

We have a 2T disk (actually a pair of 2T set up in a RAID), so disk space really isn’t a concern at the present. We do have to expunge prior raw footage periodically, which makes B-roll rather job-specific.

Curt Charles
Lilywood Productions

[Dieter Moreno]

[Curt Charles] “We have a 2T disk (actually a pair of 2T set up in a RAID), so disk space really isn’t a concern at the present. “
There you go, it is taking a long time to render because the file size is so huge.

It doesn’t matter how much file space you have, terrabytes of video are always going to take forever to render.

Hard disc drive memory doesn’t determine how long it takes to render a video.

Hard disc drive RPM, CPU RAM, and GPU RAM determine how long it takes to render a video.

Well when I said “it doesn’t matter how much file space you have”, I mean that how much HDD memory you have doesn’t determine how long it takes to render, but the file size does determine how long it takes to render. Your HDD, CPU, and GPU can render at the same speed for every bit of data. So every bit of data rendered makes the video take longer to render, so the greater the file size, the longer the video will take to render.

[Nigel O’neill]

The render times can be considered normal. If I use NeatVideo to clean up a 1 hour project, it does take 12 hours to render. Without Neatvideo it takes me a little over 1 hour to render a 1 hour project that has color curves, brightness and contrast and color correction. I seldom touch gamma, but I do suspect the zooming and 1 degree rotation is the cause for your long render times. Is the 1 degree rotation absolutely necessary? It does sound trivial and may be more pain than it is worth.

Mirrored drives are great for reading, but not optimal for simultaneous reading and writing. I run a mirrored pair (RAID 1) for storing/reading my source material, and write to a striped pair (RAID 0). My O/S is on a 5th drive. I am considering moving to RAID 5 using a NAS box. Overkill perhaps, but the price of storage is so cheap compared to what it used to be 5 years ago.

My system specs: Intel i7 970, 12GB RAM, ASUS P6T, Vegas Pro 11 (x32/x64), Windows 7 x64 Ultimate, Vegas Production Assistant 1.0, VASST Ultimate S Pro 4.1, Neat Video Pro 2.6