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spinxter
02-26-2003, 11:40 AM
I recorded a 2-hour program on my Phillips SA at Best Quality (because I want it to be the best quality). I am using the default bitrate and resolution for Best Quality. My ty file came out over 5GB. Obviously this is useless.

I have been reading about other people having 3-hour programs result in 2GB ty files. Why is mine so huge? Do I need to lower my bitrate down below the default 5215000 and 5960000?

jaja
02-26-2003, 12:30 PM
Just add me to the list of people experiencing similar problems.

I don't think lowering your quality should have anything to do with it. I mean, even your best quality is worse than the quality of a DVD and most movies fit on a DVD, right?

Somehow, smoeway, I think both our problems can be fixed with DVDPatcher. If only I knew how to use it properly. I don't speak German so I can't read the documentation!

Delta
02-26-2003, 03:44 PM
It's all about the bitrate.

5960000 bits/second divide by 8 bits per byte = 745KBytes/Second
745KB * 3600 seconds/hour = 2.6 Gigs/Hour

If you were to chop your bitrate in half (2980000) then your files would be half the size (1.3 Gigs/Hr) but your quality will also will also go down. The trick is to find a suitable bitrate that gives you acceptable video and decent file sizes.

jaja
02-26-2003, 03:48 PM
Are you saying that the quality of our TiVo recordings is greater than that of, for example, a Pulp Fiction DVD?

How does Hollywood fit 2+ hours of incredible DVD quality content on one DVD while spinxter, jaja, and others are not?

newbie
02-26-2003, 04:02 PM
The "hollywood" DVD's use a different format, DVD-9 (dual layers), which has 2X the capacity as the DVD's we burn.

In addition some of the DVD authoring programs don't work with our TY files and will greatly bloat the size of our files.

Jaja--what version of windows are you using? I'll try to get a link to the batch files I use to go from the m2v file to files that IFOedit can use.

spinxter
02-26-2003, 05:43 PM
Originally posted by Delta
It's all about the bitrate.

5960000 bits/second divide by 8 bits per byte = 745KBytes/Second
745KB * 3600 seconds/hour = 2.6 Gigs/Hour

If you were to chop your bitrate in half (2980000) then your files would be half the size (1.3 Gigs/Hr) but your quality will also will also go down. The trick is to find a suitable bitrate that gives you acceptable video and decent file sizes.

Ok. So here's what I did:

I left the Best Quality bitrate alone. I can use it for programs under 1 hour 45 minutes or so.

I changed the High Quality bitrate to 4810000 MAX and 4208750 VBR. This should give me approx. 2.1-2.2 Gigs/hour. This can be used for things from 1 hour 45 minutes to 2 hours (I think).

I changed Medium Quality bitrate to 3660000 Max and 3202500 VBR (and changed it to 480 x 480). This should give me 1.6-1.7 Gigs/Hour. This should (hopefully) be good for 2 to 2 1/2 hours.

Someone check my math. Did I do this right?:confused:

jaja
02-26-2003, 06:16 PM
Originally posted by newbie
The "hollywood" DVD's use a different format, DVD-9 (dual layers), which has 2X the capacity as the DVD's we burn.

In addition some of the DVD authoring programs don't work with our TY files and will greatly bloat the size of our files.

Jaja--what version of windows are you using? I'll try to get a link to the batch files I use to go from the m2v file to files that IFOedit can use.

spinxter
02-26-2003, 06:21 PM
Originally posted by newbie
Jaja--what version of windows are you using? I'll try to get a link to the batch files I use to go from the m2v file to files that IFOedit can use.

Is there a way to use IFOedit and still get chapters? Whenever I use it I get good results, but only one chapter.

spinxter
02-28-2003, 12:24 AM
Originally posted by spinxter
Ok. So here's what I did:

I left the Best Quality bitrate alone. I can use it for programs under 1 hour 45 minutes or so.

I changed the High Quality bitrate to 4810000 MAX and 4208750 VBR. This should give me approx. 2.1-2.2 Gigs/hour. This can be used for things from 1 hour 45 minutes to 2 hours (I think).

I changed Medium Quality bitrate to 3660000 Max and 3202500 VBR (and changed it to 480 x 480). This should give me 1.6-1.7 Gigs/Hour. This should (hopefully) be good for 2 to 2 1/2 hours.

Someone check my math. Did I do this right?:confused:

Since nobody checked my math for me, I just went ahead and used these settings.

My new High Quality settings worked great! I put 1 hour 53 minutes on a DVD and still had a little room to spare. No sync issues or artifacts in the video. I think it's good up to the full 2 hours.

Haven't checked my new Medium setting, but since I was correct on the High calculation, I'm inclined to think I'm right about the Medium. :D

artships
02-28-2003, 01:52 AM
Originally posted by spinxter
Is there a way to use IFOedit and still get chapters? Whenever I use it I get good results, but only one chapter.

There's a couple of posts here about feeding celltimes.txt - a flat file listing frame numbers - to ifoedit to get chapter points.

Fugg
03-01-2003, 09:22 AM
That's what she said!

;)
... i can't believe someone didn't post this before me!!

laserfan
03-01-2003, 05:19 PM
I've played around with these settings quite a lot, and wanted to weigh-in here with a few of my own observations.

First, I think Delta is right--it's all about bitrate. I've tried 720x480 and decided that for archiving shows, 352x480 (legal DVD) is perfectly adequate, even (especially?) for Digital Cable i.e. very high quality programs. So I use Res 1 at 4960000 for my High Quality setting, and this yields about 2160Mb/hour i.e. I can get a 2-hour movie on one DVD easily. And the quality is fine. Think about it, if you used this bitrate at a 720x480 resolution, you have fewer bits to allocate to the program material...I experienced enough blockiness at 720 to abandon it in favor of a lower resolution.

I set-up my Medium Quality to Res 1 352x480 also, but this time I used a bitrate of 2760Kbps which results in 608Mb for a 1/2 hour show. Something I can burn to a CD if I want (right now I'm into cooking shows-don't laugh!).

At the low end (Basic Quality) I use 352x240 (Res 3) at 1510Mbps. Honestly as I sit here I haven't used it much cuz it looks so crappy. Call it an experiment in VCD-level quality.

I don't generally record anything that I intend to save using the high end (Best Quality), but I wanted to make sure "live TV" is as good as can be and I'm using 480x480 (Res 2) at a high bitrate of 6960Kbps (video 6800000). I do like to "tape delay" basketball games this way (if I start watching halfway thru I can cut my time spent watching from 2.5 hours to about an hour!) and the high bitrate gives me an artifact-free viewing experience even at 480x480. But I don't save them, I delete immediately. But if I do decide to save something at Best quality, then I can do it by faking-out SpruceUp and my DVD player likes 480x480 just fine.

But I've abandoned 544x480 (what is that, Res 4?) and 720x480 (Res 0) altogether in favor of smoother video, rather than squandering my "bitrate budget" on higher-res images.

Oh, FWIW I've left the Quality settings for Basic, Medium, High, and Best at 0, 40, 75, and 100 respectively. Also, I watch on a 41" Sony rear projector from about 9 feet away.

I must say I've been very pleased to be able experiment-with and learn about the effects of these settings on my SA Tivo!

laserfan
03-01-2003, 05:22 PM
BTW Spinxter, you should look into a proggie called "Encoding Utility 2001". It's poorly named, but the best one I've seen to automagically calculate between data rates, media size, and program length (time).

dlang
03-01-2003, 06:08 PM
when comparing file sizes of SA and dtivo modles (or comparing them to DVD's) there are a couple things to keep in mind

1. SA tivos start with a medium quality signal (analog signal from a box or an internal tuner)

2. SA tivos have to record in real-time, they have no idea what is coming next

2a. this means a constant bit rate recording so even when there's not much happening on screen it's taking the sama amount of space.

2b. since the mpeg compression is done on the tivo you have only the capibility of the on-board mpeg encoder to process it, studio mpeg encoders are considerably more powerful and don't have to operate in real-time (except for live broadcasts, etc)

the result of this is that a high quality recording on a SA tivo will be 2-3 times as large, but not quite as good a quality as the same thing on a dtivo, and DVD's usually get even more attention on the compression so they get a little better quality then the dtivo for about the same space