Newbie needs bitrate calculation advice to convert my 1st PAL to NTSC

> Can you help me with the right bitrate calculation to use to convert my PAL to NTSC?
> Movie Length is 2 hours, 23 minutes, 47 seconds
> Audio is 202,208KB for the 2-ch ac3 + 471,805 KB for the 5-ch ac3=674,013KB

No wonder you're confused. You have been getting both good and bad advice, well intentioned as it were.

I suspect your best advice was to calculate the average bitrate using the movie LENGTH and the audio SIZE. Do not use the audio bitrate as some have advised you, given only that you are following FulciLives' PAL2NTSC tutorial which doesn't use audio bitrate for the calculations you are after. He used movie length and audio size instead.

You should zero out all the audio bitrate numbers and just use the 674MB in the ISO box just as FulciLives stated. While he added 200MB for the menus, you should use 0 additional overhead as you have no menus. The videohelp bitrate calculator will still set aside its 92 MB container overhead by default as someone noted.

I'd suggest your desired average bit rate be set roughly around 3600 Kbps
Generally you drop down by roughly 1500 Kbps for a minimum bit rate of 2100 Kbps
That means you'll go up by the same amount for a maximum bit rate of 5100 Kbps

I think everyone ignores the videohelp bitrate calculator suggested maximum video bitrate of 9800 Kbps and just goes up and down 1500 from the calculated average. As was stated earlier, the higher the maximum video bitrate you choose, the larger your final movie size will be.

If I'm wrong, someone should correct me me now so I don't lead you astray further.

If I'm wrong, someone should correct me me now so I don't lead you astray further.

OK, you're wrong. The maximum bitrate has nothing to do with the final file size, as that's based entirely on the average bitrate. When figuring in the audio, I can't see that it makes much difference whether you use the total bitrate or the total filesize, as long as you fill in the correct box. Also, in my opinion, setting the max and min bitrates as 1500 above and below the average bitrate is silly, and a recipe for artifacts. In this example, using a max of 5100 will create mosquito noise, color smearing, unsharp blurry video, and, worst of all, macroblocks, during complex scenes. The more complex they are, the more artifacts you get.

I think everyone ignores the videohelp bitrate calculator suggested maximum video bitrate of 9800 Kbps and just goes up and down 1500 from the calculated average.

I often use 9800 if I have one audio track, DD 2.0@192. It's perfectly legal and allows the video "room to breathe", or room to look its best. Just one man's opinion.

I'm still very much a newbie, but I think I'm almost there on the understanding of the bitrate calculator numbers to use. By way of example, here is John Coleman's recommendation, modified for my situation.

But why do I get different answers depending on the two similar methods I use?

1.) You enter the running time of the video(s) into the VideoHelp bitrate calculator
2a) You either enter "0" for audio tracks and put the total size of the audio file(s) into the OVERHEAD area (next to where it says ISO) ......... or ........
2b) You enter "1" for audio tracks and put the combined bitrate(s) of the audio file(s) into the Custom Audio area and you zero out the "audio bitrate" box
3.) Account for DVD authoring needs by adding 25 MB into the OVERHEAD area (next to where it says ISO) if you're not adding any menus.

According to John Coleman, the average bitrate reported (when doing the recommended 2-pass or multi-pass VBR in TMPGEnc) determines my file size ... regardless of the MIN or MAX bitrates used.

Using both the first and second recommended bitrate calculation methods.....
1.) My video runs 2:23:47 hours:minec long (so I'll use 2 hours and 24 minutes).
2.) There are two audio tracks. One is a 471.8KB 3.2 AC-3 track at 448kbps and the other is an audio commentary track that is a 202.2KB 192kbps 2.0 AC-3 audio file. The two audio files add up to 674MB in total filesize and 640Kbps in combined bitrate.
3a.) I don't even know how to create a "menu" so I'll add just 26MB to the 674MB total audio file size in the DVD authoring overhead box (next to where it says ISO) for a total of 700MB DVD authoring overhead using the audio file(s) size method as shown in the first photograph below.
3b.) Using the combined audio bitrate method, I'd enter 640Kbps and "1" audio track, plus I'd add 26MB for DVD authoring overhead as shown in the second photograph below.

My question is WHY these two similar calculations give DIFFERENT answers (in blue)?

The second picture is closer to being correct in all aspects.
Max spec dvd bitrate for video + audio is 9800kbits/s.
In the second picture you tell the calculator the total audio bitrate which it deducts from total max bitrate. (9800 total - 640 audio - {1kbit for every 40kbits of audio}=9144 max video bitrate)
The actual max video bitrate is 9800-448(highest audio bitrate, only one audio stream is playing with your video at a time)~9340kbits/s

If you set max video bitrate to 9800 and it spikes up there at some point you'll have ~9800kbit + audio bitrate of the selected audio stream, say 448kbits/s which is above spec and is likely to cause a nice coaster.

Also meant to say that when setting max bitrate way above average bitrate, it's highly unlikely the bitrate will spike up that high anyway, but it's good to know these things anyway.

gl

Max spec dvd bitrate for video + audio is 9800kbits/s.

It's "Max spec dvd bitrate for video + audio + subs + overhead is 10080kbits/s." It's perfectly OK to set the video max to 9800 and also have a DD 2.0@192 AC3 track with it, as long as you know your encoder respects the max bitrates set.

...when setting max bitrate way above average bitrate, it's highly unlikely the bitrate will spike up that high anyway,

I'd say the vast majority of my encodes bump up against the max bitrate, even when it's up above 9500 (which is almost all of the time, unless there are 2 audio tracks, as in queen_anne's example).

Thanks for adding specific info

Originally Posted by manono

I'd say the vast majority of my encodes bump up against the max bitrate, even when it's up above 9500

I trust your experience, but that's dependent on a few factors.
Encoder being one.
Using CCE with the V/C setting at 0, may consistently spike to the max,
but one can hardly expect that to be the rule.