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Videonut
09-07-2004, 02:21 PM
I have a project that needs to be on one DVD. The total length is 2hrs 20 minutes. When rendering in TMPEnc, I use the bitrate calculator settings that it suggests (2 Pass VBR - 8000 max - 2750 average - 1150 min) I did lower the max to 6000 and raised the minimum to 2000 and enabled padding. It rendered fine but when I play it, the video freezes and the audio continues. I tried several settings but the same happens. Anyone with any suggestions?

Jim_C
09-07-2004, 02:34 PM
In general, you want your max to be 1.5 times your average.
So 2750 average set your max at 4125.

Eugene? I lost the link to your article again.... :rolleyes:

Jim

Videonut
09-07-2004, 02:42 PM
Jim,

Do you think that the max value is too high which would cause the freezing. I did use the bitrate calculator that Eugene talks about in his article.

Jim_C
09-07-2004, 04:00 PM
Yes, absolutely. that is a lot of swing room the dvd player has to do between min and max.

Here's a blip from Eugene's article

>>>When choosing data rates for VBR encoding, a general rule to follow is that your maximum data rate should be 1.5 times your average data rate. So if your average data rate is 4Mb/s, your maximum data rate should be 6Mb/s. This rule works since any speed above the average must be balanced by an equivalent speed below the average at some other point, and you don’t want to get too large a swing in the data rate, or you will see a quality change in your video. Even non-moving images will look bad at really low data rates.. Always leave your minimum data rate at 2Mb/s and “Enable padding not to be lower than minimum data rate.” It will almost never need to pad the data rate, but this will prevent low data rate problems that some stand-alone DVD players can experience. Also remember that your maximum data rate must never exceed 8Mb/s.
http://www.professionaleventvideo.com/tmpdirections.htm

ScorpioProd
09-07-2004, 05:34 PM
I don't remember mentioning a bit rate calculator in any of my articles... Other than using the wizard as one...

A sharp swing in data rate could cause some DVD players a problem, your average data rate is so low that the max data rate couldn't really swing as high as you set it, but yes, you should only set it to 1.5 times the average.

Now lets get back to what you didn't mention... That your video at that low an average data rate is gonna look like crap! :eek:

Seriously, you don't want to be encoding at that low at data rate ever, certainly not at D1 resolution. Actually, that low a data rate at D1 resolution might be the cause of your freezing problem as well.

And the good news is there's no need for that low a data rate for 2 hours and 20 minutes! I wrote some stuff recently about my experiments with long recordings, and I can get it a lot better than that.

You don't mention what authoring application you're using or what you are encoding your audio as, but you must have not set the wizard for compressed audio if it's giving you that low a data rate for the video!

In TMPGENc render out your MPEG-2 video and your uncompressed PCM wav audio. Then in your authoring application compress the audio to 192kb/s AC-3 stereo. Assuming you're going to do this, for 2 hours and 20 minutes, you can encode your video with an average data rate of 3900kb/s and a max of 5850kb/s. And as long as you're encoding with Highest Quality motion detection, or even High Quality if you're pressed for time, your video won't look like crap. :)

Videonut
09-07-2004, 10:25 PM
Eugene,

Thanks for the info. I am using DVDit 2.5 for my authoring software. Unfortunately I do not have the ability to compress the audio in this version of software. Any suggestions would be helpfull.

In reference to the bitrate calculator, there was a link from a website that you mentioned in the newtekpro article. I have used it on several occasions to get a good feel for typical bitrates to use and it has worked very well for me.

ScorpioProd
09-07-2004, 10:57 PM
Oh, well, I'm very happy with Ulead's DVD Workshop 2.2, it includes an AC-3 2.0 encoder in it. Unfortunately the only "real" AC-3 encoders, other than ones inside of authoring programs, tend to be more expensive than the authoring programs. Actually, take a look at the new Ulead DVD Workshop 2 Express, it really doesn't loose much from the the full version.

Meanwhile, you could do what my really out of date article suggests and encode as MPEG-1 Layer 2 till you get an AC-3 encoder. It's not in the spec, but I honestly never hit any machines that couldn't play it. But again, it's not that I recommend doing this, since there are affordable AC-3 solutions in authoring programs nowadays.

Oh, so the bitrate calculator was from the site that I referenced, OK. I just either use the wizard to estimate it, or I just look at the text file I've created over the years with each of my data rates and the length and size. I've gotta make a graph of it someday.

I've gotta write a new article on all this soon... It's just there was the incentive of money in the old days when there was an actual Newtek product magazine to get it published in... Ah well.

wvp
09-08-2004, 06:39 AM
I just look at the text file I've created over the years with each of my data rates and the length and size. I've gotta make a graph of it someday.
I'm not an excel expert, but I think you can open the text file in Excel & use that for graphing

ScorpioProd
09-08-2004, 04:00 PM
Yeah, that's what I plan on doing eventually, but I'm rather verbose in my commenting, so I gotta clean it up first.

radams
09-09-2004, 03:02 AM
Eugene,

Check out DMN (Digital Media Network) and DV magazine...they might have an interest along with some $$...

Cheers,

Ray