Need some info on bitrate calculation

[heman28]

Hello guys I was wondering I have several dvd's in pal format that I want to encode to ntsc and I was wondering how do you figure out the proper bitrate so you can fit a certain amount on one dvd? I am trying to fit 5, 22min episodes on one disc. I have seen that my dvd's I make on my recorder are about 6.125 max vbr. I am trying to figure out how much I should set the max and low bitrate for vbr encoding. I hope someone can help me out. I am using tmpeg 4.0 and some other software to try different things. I have really not done much as far as encoding goes. Thanks for any help.

[aedipuss]

you can try this

http://dvd-hq.info/bitrate_calculator.php#Calculator

[jman98]

I don't recommend PAL -> NTSC DVD conversion. Unless you are just going to convert 1 or 2 discs and never do it again, it's not worth the effort. If it's something you will need to do a lot, you would be better served to buy a DVD player that can convert PAL DVD to NTSC output. Many if not all Philips models can do this. If you want something better, Oppo players can do this too.

If you want to convert five 22 minute episodes anyway and you don't care how much trouble it is, then I'd suggest for VBR that you use an average bit rate of 5100, a minimum bit rate of 4100 and a maximum bit rate of 6100. Yes, I used a bit rate calculator. That should get you 5 episodes on a single layer DVD without any fear of running out of space and having to re-encode. TMPGenc tends to ignore maximum bit rate values by quite a lot, so using my settings should give you just enough comfort margin that it will still fit, even though TMPGenc will use a slightly higher bit rate than it should.

[jagabo]

Universal to all video:

file size = bitrate * running time

[RickA]

Greets,

With 5 22minute shows you should have not problems getting them on a single dvd. My rule of thumb with episodes is the more I go over two hours on a 4.3GB dvd the more the quality and bitrate will start to suffer. Dvd's are cheap enough that if you have 6 or 7 episodes of 22 minutes why not just split them across 2 discs with no worries of quality loss and room to spare. I agree with the bitrates jman998 has suggested.

As to converting PAL to NTSC I did not find it all that difficult. Transfered several seasons of one of my fav shows that way. Demux, encode the video as progressive 25fps resizing to NTSC resolutions. Afterwards run DGPulldown 25 to 29.97fps on the vid which sets the proper playback flags. Mux the audio back in. You then have a 25fps NTSC resolution progressive video that plays back on your tv as 29.97fps with perfect audio sync.

I got the idea from a great post that FulciLives wrote some time ago here titled along the lines the Holy Grail of PAL to NTSC Conversion. It is much easier to go from PAL to NTSC than the reverse. I'd do it if I were you. I learned a bunch about the inner workings of video and encoding by doing so. Feel free to PM me if you want more info on how I did it.

Cheers,
Rick