High bitrate in Quenc

[Rod]

I am using Quenc Beta 4 to encode a PAL to NTSC. Set a bitrate of 4415 and max to 7000, the actual bitrate spiked as high as 10023. Curiously, this is during the final credits where the screen is mostly black and highest when the amount of text is the highest. Movie in this case is 113 minutes long, with 2 audio and 1 subtitle track. This is causing DVDAuthor to fail due to "Stream e0: data will arrive too late sent" error.
This has happened on several other DVDs. Other examples: bitrate of 5300 spikes at 10554.

Besides trying HCenc or FreeEnc any suggestions?

Thanks

[Encoder Master]

FreeEnc works with the modified libavcodec. QuEnc doesn't. So FreeEnc would be the better choise for you. But HC Encoder is very easy, fast and gives the best quality for you high quality encodes with such high bitrate. Test it out and you will see it.;)

[Mug Funky]

does DVDauthor allow you to do segment re-encodes? quickest way around the spikes is to just re-encode the few seconds that are the problem, and insert them back into the stream. certainly saves having to re-encode the whole thing...

for now i suppose you can use HC (they're both very similar quality, and in your bitrate range there's plenty of headroom for both encoders), but be warned that even HC can cause underflows if you set your max bitrate too high (like 9 mbps). 8.5 mbps is a good all-round max bitrate - it only needs to be lowered if your audio tracks are too high (like 1x LPCM, 1x DTS and 3x ac3...).

better rate-control in QuEnc is coming. i'm not sure in what form though (there's talk about patching in xvid's marvellous rate control).

[Encoder Master]

but be warned that even HC can cause underflows

But the encoder fix this underflows by its own.:)

[Rod]

HC looks like a very good product! It encoded at an average of 4296 kbps with a desired bitrate of 4400 and a peak of 8191. It seems if the peak stays below 9000 - 10000, then DVDAuthor works properly. There were 2 audio tracks of 448 kbps each.
DVDAuthor can join different titles but I do not want to make this too complicated.
I have a question on jagged edges on moving objects but I will put that into a separate post.

[Mug Funky]

encoder master:

HC's rate control (last i checked) is GOP based. it isn't a true VBV buffer. this means there's a discrepancy between what HC calls an underflow and what a decoder will call an overflow. this will only matter when you're scraping your max bitrate for a fair amount of time. you'll be fine if you keep the max at 8.5 or so (9.0 caused underflows for me, though not many).

[Encoder Master]

Oh, now I understand you. So, you think bitrates over 8Mpbs produces underflows? Hope this is a known proplem and will delete by hank.:)

[Mug Funky]

well, it's not a huge problem. to be honest, even hardware encoders often spike out when the max is above 8.5.

but with HC's _very_ careful ratecontrol, i thought i could get away with 9.0 on an encode... looks like i couldn't :)

if i were hank, i wouldn't be worried by this...