DivX to DVDR - Bitrate Too High?

[bigb_y2g]

I converted a DivX encoded movie that was split into two files. The AVIs have a bitrate of 23.976 fps. I followed this guide http://www.dvdrhelp.com/guides.php?guideid=447&howtoselect=4;10#447 to calculate the bitrate for conversion to MPEG-2 using TMPGEnc. The bitrate calculator suggested that I use a bitrate of 4699 for both parts of the movie. Once I converted both parts, I joined the files with VOB Merge and loaded the elementry streams into DVD Lab. I got a warning that the bitrate was "too high" for a standard DVD and may cause jittering upon playback. The program said the bitrate was 11300 or something. Once my DVD was authored I get small pauses every ten seconds or so. Not enough to cause any a/v sync problems or anything, but it is noticeable. Any suggestions on how to correct this?

[steveryan]

adam posted 2003 Oct 24 07:49
9.8Mbits is the video bitrate limit. 10.08 is the total max limit, not that there is a huge difference there. These are the encoding limits though, actual speed the data is "read" off the disk is around 26Mbits.

The 10.08 limit is what the standard designates. Most DVD players can easily play higher bitrates without problem, but anytime you go outside of the standard you risk playback problems and actually, when your dealing with burnt media (dvd -/+) the max bitrate you use is alot more important since this media is harder to read than a pressed disk already.

To be safe I would actually use FOO's numbers since they are slightly more conservative. To calculate your max video bitrate do 9800 - total audio bitrate and if you use subs than subtract a little more.

Also, 23.976 fps is not a valid dvd frame rate, did you convert it? Look at this topic for more info. Try following the info in that topic and lowering the bitrate in TMPGEnc, good luck.

[bigb_y2g]

Also, 23.976 fps is not a valid dvd frame rate, did you convert it? Look at this topic for more info. Try following the info in that topic and lowering the bitrate in TMPGEnc, good luck.

Yeah, I selected the 3:2 Pulldown option the guide suggested to fix that problem. The whole reason I converted the MPEG-2s at 23.976 was to correct an a/v sync problem I was having.

So from what I can gather, the problem lies in the AVIs bitrate. I have read that others have had problems with these files as well. If I re-convert the files at 29.97 fps, is there a way to change the audio to match with the video framerate? The audio is AC3 (another headache) with a bitrate of 384 bps.

[steveryan]

I think BeSweet can do that.

[bigb_y2g]

Thanks. I'll ask in the Audio forum.

[bigb_y2g]

Man, this is frustrating! OK I read that if the video source is 23.976, than I should select "Film Movie" under video content using TMPGEnc. Will that work?

[funkguy4]

Dude if your settings are like 4.6mbits in TMPGEnc, something funny's going on to turn out 11mbit files....wurd

[bigb_y2g]

I think it has to do with the movie being split into two seperate parts. I convert one half and then the other. Then join them after conversion. The bitrate calculator suggested that I use 4699 bps for both parts.

[adam]

For a 23.97fps source you should encode to 23.976fps mpeg2 with the 3:2 pulldown flag enabled. The result will be stored at 23.976fps but it will be played back at 29.97fps. Thus, there is no reason to adjust your source's audio playback speed. 23.976fps and 29.97fps actually playback at the exact same speed, because the increase in framerate is done by creating new frames every second rather than by increasing the playback speed. Even though you have %20 more frames each second you still have the same number of seconds, so everything remains in sync.

What is your audio source? Is it AC3 and you are just multiplexing it in with your newly encoded video stream? Or are you encoding to raw wav? This will surely push your max bitrate way up. Its not the average bitrate that matters so much as your max bitrate. You can have an avg bitrate of 500kbits but if there is a single spike above 10.08 (total audio + video) then you have just gone outside the standard. Let us know what you are doing about audio. I think that is probably what is causing the problem.

[bigb_y2g]

You're correct. The audio is AC3 5.1 (6 ch) at 384 kb/s. Since it's already in AC3 format, I just leave it as is.

[dafreak]

question.
1. how long is the entire length of both the avi's added together?
2. are you encoding with cbr or vbr?

[bigb_y2g]

question.
1. how long is the entire length of both the avi's added together?
2. are you encoding with cbr or vbr?

1. The movie is 1:59:02 when joined together.
2. I encoded the movie in CBR.

[bigb_y2g]

Any suggestions on how to reduce the bitrate? I still can't get it below 10300 kps Should I set the bitrate of the video conversion lower to allow for the audio? How low can I set it?