Bitrate and DVD,can someone explaine??

[King-Of-DK]

How do i balance bitrate with quality?? What is the average bitrate people are using when converting f.ex. AVI2MPG2/DVD??
When i use Ulead Moviefactory and i have 1 AVI with 48khz sound and it is about 50 min,when converted with Uled this file is 2.6 GB,if i use the same program on an already converted MPG1 file with 44khz sound and 1:34hrs turns out to be only 1.6GB,how can this be??

[matneaves]

ok bitrate, it depends on what you want the finished product quality to be, what your writeing to and length of movie

and avi is always smaller than mpg1 coz of the compression

i can encode to 1 cd with near dvd quality a movie anywhere upto 1 hr 50 mins, using a dif bitrate, the usual bit rate for vcd is 1150, so if you encode using 1150 the file will be around 1.4-1.6 gig

i use a bitrate calc, i enter the movie length the amount of cd's i want to squeeze it onto (usually 1) and it gives me the bitrate to enter into tmpenc

ive written a smallish word doc to explain how i do it

www.data-uca.150m.com/vcdencoding.doc

anything else let me know

[King-Of-DK]

OK,your guide is for AVI 2 VCD/MPG1,right?? Is it the same for AVI 2 DVD/MPG2?? Is it at all a good idea to convert an AVI to DVD/MPG2, due to the compression of the AVI??

When my AVI is with AC3,can i keep the sound when converting it to MPG2/DVD?? So i will get AC3 sound on my finished DVD??

I am using a DVR-105 burner with 4.7GB media,how much can i fit onto this type of discs?? Is it visible to the naked eye,when going from 8000 to 6000 in bitrate??

[bugster]

Its quite simple really, there are only 2 rules to remember.

1) Garbage in = Garbage out
2) More bitrate = Better quality

Now these are not hard and fast but use them and you won't go far wrong.

As for converting downloaded AVi's to DVD, it is up to you to decide if the quality of the avi is worth it. Some DVD rip Divx movies are excellent and well worth a DVD-r, others are only good enough for (S)VCD and others for the wastebasket.

Personally, for DVD, I mostly use the max bitrate I can for the length of the movie to fit on one DVD (use a bitrate calculator). If it's a long enough movie to require the average bitrate to be less that about 3,500 kbps, I will often split it across two discs, especially if there is a reasonable amount of action.

anyway, hope this helps.

[King-Of-DK]

Thanks good guidelines. Only i have no clue as to all the settings in TMPGenc when doing SVCD or DVD,i have always used the templates for VCD to create my VCDs. But when i got the DVD-burner,all these things i need to know to get the most out of my burner is ALOT.. I find that Ulead Moviefactory is so easy to use,as it will convert,author and burn my AVI´s,but people say it doesn´t convert that good,howcome?? Secondly how do i get the AC3 soundtrack onto the DVD,when converting the file to MPG2?

[King-Of-DK]

Let me jsut give an example,i have an AVI with a bitrate of about 971 kb/s,and i read somewhere in this forum that i can actually worsen the quality by using to high a bitrate,and DVtoll says i can fit this movie on a DVD-R by using a bitrate of about 5700 kb/s will this be ok?? Or is the AVI to bad in quality to use as DVD?? How large should the bitrate of an AVI be, to properly convert it to DVD??

[bugster]

AFAIK, there is no pint comparing the bitrate of a divx to the bitrate of an mpeg. They are different codecs and so you are not comparing like for like. As for too high a bitrate making things look worse, well lets just say that unless you have a very noisy source (like a bad VHS capture) then it will not be the case. With a bad source, re-encoding can amplify the noise or other faults, but bad caps are probably not woth full DVD spec anyway.

Encode your movies at the highest bitrate that will allow it to fit on the disc and you won't go far wrong, just allow a small overhead ( about 200k) for menus and stuff if you want.

AC3. Obviously your divx source must have this to start with.
1st, extract the Ac3 from the avi using virtualdub, direct stream copy. Rename the output file from movie.wav to movie.ac3. run through ac3fix.exe (tools section) to get movie2.ac3. delete movie.ac3 and rename movie2.ac3 to movie.ac3.

Encode your video with TmpGenc, VIDEO ONLY. You will get a silent video file with a .m2v extension. Name it movie.m2v


Authoring. Spruce will accept Ac3 files. Just make sure your movie.ac3 and movie.m2v are in the same directory and have exactly the same names except the extension. Import the .m2v file and spruce will automatically import the corresponding Ac3 file.

For Ulead DVD Workshop (1.3), mux the .m2v and .ac3 files with TmpGenc and import the resulting mpeg.

Hope this helps.

[King-Of-DK]

Thank you very much Bugster. This cleared up a lot of questions. A couple more ? When i load the AVI into TMPGenc,is it good enough to use the DVD templates? Or do i have to mess with the settings? I see that the templates have a CQ instead of VBR,does this have any effect on end result? If i use the bitrate calculator and say no sound i can get a very high bitrate,but this is not right,right? i have to leave space for sound right? Is there any standard for sound on DVD´s i mean is it 192kb or 384kb?

[bugster]

Thank you very much Bugster. This cleared up a lot of questions. A couple more ? When i load the AVI into TMPGenc,is it good enough to use the DVD templates? Or do i have to mess with the settings? I see that the templates have a CQ instead of VBR,does this have any effect on end result? If i use the bitrate calculator and say no sound i can get a very high bitrate,but this is not right,right? i have to leave space for sound right? Is there any standard for sound on DVD´s i mean is it 192kb or 384kb?

You can use the templates if you want, thtas up to you. Personnally I use 2-pass VBR for most encodes. CQ produces very good quality but predicting the final filesize is difficult. With 2-pass VBR its much more predictable.

Yes leave space for audio. A bitrate calculator will usually allow you to specify what audio bitrate you want to use and will take that into account when calculating the video bitrate available. Not sure what the standard for DVD's is but I usually use 384kbps to be on the safe side. After all it takes up relitivley little room compared to the video!

[King-Of-DK]

Thank you once again Bugster.. Does it matter if my source audio is only 192kb/s Or if it is uncompressed about 1500 kb/s??

[bugster]

Thank you once again Bugster.. Does it matter if my source audio is only 192kb/s Or if it is uncompressed about 1500 kb/s??

No problem.