What bitrate to use when exporting to mpeg2 with QT?

[supertoom]

I've tried over and over again to make a dvd (and svcd) from a divx with ffmpegX. never works. the sync is always wrong. i've tried with diffrent frame rates and so on.

so now i'm trying to make it with DVD Studio Pro. first i exported the soundtrack to an aiff and then encoded it to ac3 with a.pack. and now i'm going to export the video to mpeg2 with QT Player... so my question:

what bitrate should i use when i export the file? how high can i go? (btw, my dvd player is a pioneer dv-340 if that helps). i've tried with a test-file with the settings 4.5, 5.2 and 9.8 (highest). DVDSP played the 4.5 and 5.2-files with no problems but stopped playing when i tried the 9.8-file. the 5.2-setting is the highest i can go when i look at the estimated file size (~3.9 GB + 256 mb AC3). is 5.2 too high or will my dvd-player play that with no problem?

also, how much quality do i actually gain when increasing the bitrate?

thanks!

[bilestyle]

you dont gain any quality whatsoever by the bitrate being higher... once its in a crappy format like divx the quality doesnt come back.. once the quality is gone is gone for good. If you were encoding from a larger format like DV then the bitrate would actually make a difference.. the only thing you can really do is set the bitrate too low and lose quality.. none of that quality is comming back though.

[ZeroSix]

to better answer your question, there are two things you might want to consider.

If you are using Quicktime MPEG2 component to create an XSVCD, use a bitrate of 2500 for video and then 224 for audio. This is a standard SVCD bitrate, but it would become an XSVCD since you would be using a DVD resolution of 720x480, instead of the SVCD resolution of 480x480

If you are creating a DVD, the bit rate depends on your source quality, as per Bile's explanation.

Generally speaking, any bit rate between 2000 and 5000 is exceptional.

My best suggestion to you is to use as low of a bit rate as possible. The best way to achieve this is to encode a 5 second sample clip. Start at 2000 and work your way up until you are happy. But don't go over 5000. There is no point unless your source video is of very VERY high quality.

[WiseWeasel]

It also depends on the type of content. Animated content (especially cartoon TV eps) can fit very happily into <3 Mbps, whereas live action movies will be more suited to ~4-6 Mbps, depending on the quality of your source material. The best way is just to try a bitrate and see what the output looks like, and it will be different for different kinds of content. I make my South Park DVDs from eps I capture from satellite to DV, and encode at 3 Mbps, and can't differentiate the source from the output. South Park is an extreme of compressability, since it is drawn so simply. I usually use about 4.5 Mbps for most video content, unless the source was from DVD or something. I can't wait for the Compressor component of DVDSP 2.0, which will have batch capabilities and VBR encoding. Until then, mpeg2enc will give much better quality (using VBR) than the DVDSP MPEG2 QT encoder at any given bitrate, though it is not altivec optimized, and will take *forever* and a half to encode a two hour movie.

[supertoom]

ok, thank you all!

the only time i'ill be encoding to mpeg2 is when converting a divx so i can watch it on my tv, so i guess the bitrate doesn't have to be so high.

but are there any disadvantages if i use a bitrate too high, other than a bigger file size?

[WiseWeasel]

Some DVD players will crap out if the bitrate is too high, but that's usually only above 8 Mbps. You usually want to use as little bitrate as necessary, so that if the DVD gets scratched, there's a better chance the reader can re-read a sector without causing the video to pause or skip, since it will be able to buffer more playtime. The best solution is just to try various incremental bitrates and choose the lowest possible where you don't notice any degradation over higher bitrates.