Birate calculator for half-D1 needed

[AirTime]

Or can I just double the bitrate calculated for full-D1?
Would be too easy, but who knows....

[Baldrick]

calculating bitrate is not dvd authoring. moving you.

[junkmalle]

File size vs bitrate is the same no matter what the frame size:

File size = bitrate * running time

Just like:

miles traveled = miles per hour * hours

It doesn't matter how big your car is.

[MOVIEGEEK]

Roughly half the bitrate.I use ~4,000kbps for half D1 and can get over 2 hours.

[daamon]

@ AirTime - What junkmalle says is true but, because of the lower resoultion, you can get away with a lower bitrate, hence MOVIGEEK's info.

Hope that ties it all together for you.

[AirTime]

Well, actually it is DVD authoring as I'm trying to fit a TV capture onto a DVD-R as MPEG2 (not DivX, if that's what you thought). The catured file is 10 gig with 720x576 resolution. I want to recompress it with TMPGenc, but I wanted a calculator to give me a better idea of the bitrate value, without moving too much into the trial and error procedure.
But as I see, I won't be able to go too low on the bitrate...probably will have to go for two discs on that.

Thanks for the help!

[rkr1958]

Well, actually it is DVD authoring as I'm trying to fit a TV capture onto a DVD-R as MPEG2 ... I want to recompress it with TMPGEnc

TMPGEnc is an encoder so you're actually talking about encoding and not authoring. Once you encoded it to MPEG2 then you'll need to author that to a DVD Structure if you want your DVD to play in a settop player.

By the way, is your capture an AVI? If so, then TMPGEnc is your tool. If not, then you'll need to go through other steps first. For example, if it's an MPEG2 file already you could either convert that to an AVI and then use TMPGEnc or use a transcoder to make it fit.

[jimmalenko]

The bitrate value itself is independent of the frame size (as junkmalle said). The only two things that affect filesize are running time and bitrate used. Since filesize is set at 4.37GB (1 DVDR), and your running time is obviously set at how long your capture is, then your bitrate is the only unknown. It sounds to me like you already know the "bitrate calculated for Full D1" - if using Half D1 or even Quarter D1, you still need to use this exact same bitrate to fit the same material onto 1 DVDR.

The twist comes when you need to assess the suitability of your calculated bitrate for your chosen frame size. For example, assuming 192kbps audio, a 3 hour cap would need a bitrate of roughly 3200kbps to fit on 1 DVDR. Now 3200kbps is more than likely not gonna give you the quality you expect or deserve if using Full D1. However, it should give typically decent results for Half D1, and it would be overkill for Quarter D1.


Hope that makes sense

[AirTime]

The source file is an MPEG2 video with 192 kb audio. Filesize right now is 12,7GB at 4:48 hours running time.
Videohelp's bitrate calculator gives me 1921 kbit/s.

So, correct me if I'm wrong, but using this bitrate with halfD1 won't have a significant effect on file size but rather on quality. With fullD1 at that rate quality basically sucks, and with half D1 it might be watchable.

I will test that with a part of the video.
Thanks for your efforts.

[rkr1958]

The source file is an MPEG2 video with 192 kb audio. Filesize right now is 12,7GB at 4:48 hours running time.
Videohelp's bitrate calculator gives me 1921 kbit/s.

So, correct me if I'm wrong, but using this bitrate with halfD1 won't have a significant effect on file size but rather on quality. With fullD1 at that rate quality basically sucks, and with half D1 it might be watchable.

I will test that with a part of the video.
Thanks for your efforts.

fullD1 with VBR with an average of 1921, max of 9570 & min of 500 (or 0) might not be that bad. It all depends on the source footage and the TV that you'll be watching played back on. Worth a try anyway.

[jimmalenko]

The source file is an MPEG2 video with 192 kb audio. Filesize right now is 12,7GB at 4:48 hours running time.
Videohelp's bitrate calculator gives me 1921 kbit/s.

So, correct me if I'm wrong, but using this bitrate with halfD1 won't have a significant effect on file size but rather on quality. With fullD1 at that rate quality basically sucks, and with half D1 it might be watchable.

You could use a bitrate of 1921kbps with Half D1 OR Full D1 and you should get exactly the same file size in each case

Yeah, 1921kbps for Full D1 is more than likely gonna blow IMO unless the majority of it is a "talking heads" doco or something. It's probably even on the low side for Half D1, but you might get away with a 2-Pass VBR with settings of say 0 min, 1921 ave and 5000 max. One other more obscure method (and certainly not one I would recommend - simply just putting it "out there") would be to use a bitrate of around 2500 and then DVDShrink it back down to fit a DVD-5.

[lordsmurf]

This may be worth reading:
http://www.digitalfaq.com/dvdguides/capture/intro.htm#mpegbitrate