2-pass encodin crashes in MF4, 1-pass does not

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ruggy1
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Joined: Sat Dec 11, 2004 5:51 am
Location: Sydney, OZ

2-pass encodin crashes in MF4, 1-pass does not

Post by ruggy1 »

I have an AVI file I captured from DV. I want it to look as good as possible after rendering so I use 100% quality setting (for motion correctness) and 9000K bitrate setting. I also tick the "2-pass encoding" box hoping it too will result in a better picture. No matter how I try to render this file, to DVD, ISO file or DVD folders it crashes soon after I hit the 'Burn' button. XP-Pro wants to send a message to Microsoft as usual, which I let it do (does anyone ever get feedback from this stuff?) - no error code or message from MF4. I can get it to work by NOT ticking the 2-pass encode button. Can anyone help me here? Thanks
ruggy1
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Joined: Sat Dec 11, 2004 5:51 am
Location: Sydney, OZ

Post by ruggy1 »

OK I may be doing something stupid here, but if anyone else has done the same stupid thing and gotten away with it I would like to know. Many Thaks
daniel
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Post by daniel »

I will let experts respond, but you don't speak about your audio settings;
if you use PCM it looks to me as your are exceeding the DVD's maximum bitrate by using 9000 for video.
Why single pass would succeed while 2 pass-aborts beats me though.

But I would either try MPG audio (PAL) or Dolby (NTSC)
or lower the bitrate to 8500 if you want PCM.

By the way the extra fine-tuning benefits of dual pass are inversely proportionnal to bitrate. At 7000 or above I doubt it makes a difference worth the double waiting time. Or a difference at all.

When you have all the space you need to make it good, it doesn't matter much if you try several methods. Throw a small amount of toys in a big box, every attempt is succesful. Now if the box is small and the toys numerous, then careful placement would matter. (do you feel the expert technobabble here?)
ruggy1
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Joined: Sat Dec 11, 2004 5:51 am
Location: Sydney, OZ

Post by ruggy1 »

Thanks. I will not use 2-pass any more. But when you hear of studios doing 20-pass stuff, how do they get away with it I wonder?
daniel
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Post by daniel »

Yeah but they usually want to fit 3-4 hours on a DVD9, equivalent to 4000-5000kbps. To get good quality with that rate, you benefit from working harder, and trying different strategies.

When you need to squeeze 70mm film into an MPEG stream without too many losses (4K points on a line) you need a helluva work, especially since they are not willing to do it at one week per film...

I said two-pass is probably useless for your high bit rate.
Or if you make a slide show it is of no use.
I also said below 7000 it will make a difference.
Dual pass is the standard encoding (pass one), followed by another encoding with a different algorithm that could produce better results in particular cases, but not overall. Then the program checks GOP by GOP which of the two outputs gives the closest rendering, and keeps that one.
I can assure you that at 4000kbps the difference was dramatic in several cases I had.

I would be happy if someone could elaborate on this, correcting or completing this.
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