MPG2 data rate too high for authoring?

[mijman]

I just got my Pioneer DVD-R drive. I have been trying to author a music video (something small to test it out). I have captured it from a tape, and converted it to a DVD compliant MPG2 using TMPGenc 12a. I am using MyDVD to author it. Everything starts out all right, but when I compile a folder, it reports an error that the "data rate of the file may be too high for DVD" and suggests a lower data rate. If I ignore and continue, it still crashes because it's too high a data rate for multiplexing. Even though I've just demultiplexed it. (I've tried both ways) Is there something wrong with the template for 12a? should I do something different? What rate should I be using for captured video?

[Skunkwerx]

If you are using DVDIT, I had the same problem when trying to author. I believe the Tmpegenc DVD template has the bitrate set to CQ(constant quality) or VBR (varible bit rate) and that may be to high? for DVDit's 8000?. In TMPEGENC, after you load the templete, click on the SETTINGS button and you will see the bitrate option. Try setting at CB (Constant Bitrate) of 6000 and DVDit should have no problems burning the file or set the VBR max at 6000 I am still tinkering with bitrates and am also wondering if there is a constant bitrate standard for DVDs or if most use VBR with a max of 8000 or less?. For me, quality did not appear to suffer much from 4000-6000 from a VHS source.

Still tinkering................

[Greg12]

I think DVD's use VBR but with exteremly high power, high descrimination multi-pass encoders the public can't buy.

[mijman]

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[JHebert]

I have heard from people using TMPGEnc with DVDit that there are some issues to be aware of. These may also apply to MyDVD but I don't have it to test with.
First, DVD doesn't use MPEG1/layer2 audio but instead uses either PCM or AC3. I think the low-end LE version of DVDit only supports PCM. The TMPGEnc DVD template uses MPEG1/layer2 audio. DVDit will convert the MPEG audio to PCM, or you can to import the audio seperately as uncompressed PCM wav file.
This leads to another issue, the maximum bitrate. DVD spec calls for maximum 9.8Mb/s total combined bitrate for video and audio. With PCM audio this limits you to about 8.3Mb/s maximum for the video stream. I think the TMPGEnc DVD template is set to 9Mb/s (CQ or CBR?) which could make the video bitrate too high for use with PCM audio. You would need to load the Unlock template and lower the video bitrate so that the average is around 8Mb/s.
TMPGEnc with a seperate AC3 encoder would create smaller audio stream, allowing a higher video bitrate. But the problem is that the LE version of DVDit (low-end OEM version) doesn't support AC3 audio at all. It doesn't have its own AC3 encoder and you also can't import an AC3 file encoded in another program.
So you are limited to PCM audio only with DVDit LE. I found this link that summarizes the different DVDit versions:
http://dvdit.com/about_editions.html
With DVDit LE you can import MPEG1/MPEG2 video and audio, and PCM WAV audio. Any imported MPEG audio gets converted to PCM audio within DVDit. So as I said you should limit your MPEG2 video bitrate to no higher than 8.3Mb/s to stay within the 9.8Mb/s combined limit.

[mijman]

I have noticed that the template had set the bitrate to CQ 9000. I lowered it to CBR 6000. would this help?

Also, are there any programs that convert vobs to dvdmpg2 without the need to re-encode? sort of a vob de-multiplexer.

Would I be able to stick ripped vobs right into the program for re-burning? I haven't seen anything about that anywhere on the site yet.


<font size=-1>[ This Message was edited by: mijman on 2001-12-28 09:42:34 ]</font>

[JHebert]

If the problem you are having is the same as I described, then yes setting the bitrate to 6000 CBR should work. You could go as high as 8000 CBR and still have room for PCM audio without exceeding the maximum bitrate specs for DVD.

I'm not sure about your second question. There are probably programs to do this, check the Tools section here or else go to the Doom9 site and look around. The problem I forsee with this however, if you are planning to rip and backup DVD movies, is that DVD movies commonly use double layer and/or double sided disks and the total size of the movie is likely to be higher than the 4.7GB of a DVD-R disk. You would still probably have to re-encode to fit the movie on DVD-R. Also, DVD movies use mostly AC3 audio that may not be supported in your authoring program unless you obtain a higher-end version.

[mijman]

Well, I was actually using uncompressed wav files, and it hasn't complained about them, as long as they are 48000 instead of 44000.
yes, I'm aware of the size limitation of single vs double layer DVDs, I was waxing theoretical.

I think I understand now what is happening. Since there is a 9000 (9300?) limit combined rate, and TMPGenc encoded it originally at a combined 9000, then de-multiplexed, the video was still at 9000 before re-multiplexing. I'll have to play around with the settings and see what works. Thanks JHebert


<font size=-1>[ This Message was edited by: mijman on 2001-12-28 09:44:20 ]</font>