How much video can I cram onto a 50gb blue ray data disk?

[samualt]

Looking for advice:
I want to create how-to oil paint videos on a 50gb blue ray data disk (for free). But, I'm unsure about compression and resolution. Ideally it would be 720p (1280x720) at 30fps. But I'm guessing that is out of the question because we want as many hours as possible. Plus there is the audio that goes with it. But that isn't as important as long as you can understand the instructor.
It is all a little confusing in that some messages are talking about raw uncompressed video (Which are huge beyond belief), other talk about regular video disk, and still other talk about data disk. We want to create a data disk.

So, my questions are these:
1. What resolution would you suggest? (Oil painting is all in the details). What is the highest resolution you would use for an instructional video?
2. What is the most super high compression codec out there that would give near loss-less video reproduction?
3. Is there some issue with high compression? Why doesn't everyone use it?
4. Anyone know of a great video size calculator online? I couldn't find a good one for newbies.

Thanks for any replies/ideas...

[jagabo]

file size = bitrate * running time

So you can put as many hours as you want on a disc. But the quality will decrease along with the bitrate. How much bitrate you need depends on the nature of the video. Higher resolutions, higher frame rates, more detail, more action, more noise all require more bitrate.

Use h.264 encoding. x264 is one of the best h.264 encoders. Many tools use it.

[sanlyn]

2. What is the most super high compression codec out there that would give near loss-less video reproduction?
3. Is there some issue with high compression? Why doesn't everyone use it?

Higher compression = lower quality. Really high compression = really crappy video. Lots of people use it. They're blind as bats.

[johns0]

You can get up to 10 hours of good video quality at 720p on a single layer bd as long as the source is high quality to begin with.

[sanlyn]

Yes, that's a big factor: really good quality sources can use lower bitrates, which gets you more time on disc. Average to poor sources are a different story, unless you either do some cleanup first or be willing to live with low-bitrate garbage.

[jagabo]

Since you are considering non-Blu-ray compatible properties you have a lot more flexibility. Consider this: How many JPG images could you fit on the Blu-ray disc? Many thousands (50 GB / 2 MB = 25,000) . You could encode 1000 images at 1/7 fps (one frame every seven seconds, a slideshow), all I frames (much like a JPG image), and it will have good image quality and play for 7000 seconds. That's almost 117 hours. And it would still use only 1/25 of the disc (not accounting for audio). I'm not suggesting you do that, but it shows you what kind of extremes you can go to once Blu-ray player compatibility is ignored.

[Nelson37]

The answer to your question is this - "'50 GB worth"'. The Quality available is a question only you can answer.

Next question is "are you limiting your playback device to a PC ONLY, or do you intend this to be able to work on a standard Blu-Ray player"? This will severely limit the format choices. Also colors the quality question if playback will be on a TV.

[poisondeathray]

Next question is "are you limiting your playback device to a PC ONLY, or do you intend this to be able to work on a standard Blu-Ray player"? This will severely limit the format choices. Also colors the quality question if playback will be on a TV.

He said "data disc" so that implies PC playback





How are you shooting this? (what is you camera/studio/lighting setup) . Is it a 1 camera shoot, or do you have multiple angles/shots ?



You can use a bitrate calculator from megui
https://www.videohelp.com/tools/Bitrate-calculator

It only goes up to 24hours, but it's a linear relationship , so it's easy to extrapolate

filesize = bitrate x running time

For audio , speech rarely requires more than 64kbps AAC. If you look at other professional/paid tutorials , they go much lower usually .

A typical painting tutorial video will compress very well (there is very little motion) . If you look at other professional/paid "tutorial" type 1080p videos, they typically use ~0.5-2 Mb/s only and are very crisp . But they typically use compatible / lower compression settings so videos playback easier on slower systems

With no blu-ray or device compatibility restrictions - You can use very high compression settings, very long GOP intervals, b-frames, even 10bit AVC . The negatives are, the higher the compression settings, the more hardware "power" required to playback. There is no transport stream container overhead either (typically 5-7%). You can even make it VFR (variable frame rate - when there are slow spots, little motion, maybe pauses when the artist is explaining something, the framerate will decrease, so you encode fewer frames)

You can do some small experiments to see what quality /filesize is acceptable to you