On Thu, 30 Dec 2004, Anne Wilson wrote:
> Now I have prepared all the camera output from my holiday I find that it
> totals 4.9 GB. I think I must re-prepare it, dropping the last two chapters,
Oops - the average bitrate was too high ;(
As long as you are going to re-prepare it then lower the bitrate by
adding a '-b' to the encoder command line. As a general guideline
you can use this checklist when preparing a video bit budget:
Total Size of a DVD disk = 4700000000
subtract 5% as a reserve (DVD .ifo,.bup, UDF info,)
subtract audio. With 192Kb/s this works out to 1440000 bytes/minute.
subtract the still menus, guidline is 100000 bytes/menu
As an example, assuming a 90 minute video with 192Kb/s audio and 3
menus:
4700000000 - 427000000 - 129600000 - 300000 = 4143100000
If I haven't made a mistake in the arithmetic that works out to:
4143100000 bytes / 90 min = 767240 bytes/sec or 6137920 bits/sec
you'd use "-b 6140" to the encoder. Maybe a little more but that is
a good starting point. The default of 7500 will be too high.
If you've motion menus, transitions, and so on then they take up
space that needs to be taken into account when figuring the bit
budget.
> and putting them onto a second disk. Is there anything I should be aware of,
> if I do this?
That should work fine. The only other way around the problem is to
use a dual layer disk but the media for that is still extremely
expensive.
Cheers,
Steven Schultz
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