Average bitrate
 

It's good this method for calculate the average bitrate for use in HC Enc in -b command line (HCBatch)?

I'm go for 2 movies KDVD (audio 192 kbps) in a DVD-5 4.7 GB.


Thanks.

-Maurus

Hi Maurus,

Actually, the latest code is now this:

Some code is not shown (like audio channels 2, 3 and 4 )

So then: Those are some code snips from the latest version of CalcuMatic.
If you use it, try it with any good 2-pass encoder, and you'll see that the encoded file size will match exactly the size calculated by CalcuMatic ;)

-kwag

Thanks, friend.


-Maurus

1) In your code: What is the quantity value?

It's the overhead? What it's the correct DVD overhead?


2) Totaltime is the time of movie in minutes?


Thanks.


-Maurus

Reading the formulas give an easy answer :
- quantity is the number of media you plan to fill (for instance it is 2 when you do 2CD KVCD).
- totaltime is the time in second (as bitrate is given in kbit/s)

For the overhead, it seems to me that the media values given in the code already take in account the overhead.

Yes, quantity seems to me the number of disks, but in the older code (that I previous posted) the Mux Overhead is:


It's correct?
In the new code is not the mux overhead...

Where is actually the mux overhead?

Ok. I did not see that you posted an "old" code.
Karl simply didn't paste all the code tiil the overhead function. But it is still there, and it does not change since the "old" code you gave.

(in plain english, the overhead for each media is 10 MB for SVCD and 25 MB per video stream in case of DVD).

Thanks for all.

-Maurus

Finally (issue 1024 vs. 1000) the average bitrate in CalcuMatic it's valid for HC Enc?

Thanks.

-Maurus

Why for DVD it is usually set 180 Mb of overheat?

Actually, there is no means to determine it (none that anyone ever published at least)

180 is the value that Vmesquita choosed when he did a little bitrate calculator called "KDVDCalc", and he probably used that again with Diko. Karl decided to use an other thing.

Honnestly, all depend on the complexity of the DVD and you can check this with DVDLabPro. The more stream you add the more is the overhead. So using a fixed value (like 180) is not the correct way.

180 was (and is) a good value for that.

I've used 4350MB as the size of the disc with overhead subtracted and have had every disc very close to a full one but not over. Two-three movies (or 6-8 episodes) per disc, one or two audio tracks and one subtitle track per movie/episode on almost all discs.

1) For two movies, what values is for media?

2254438? half?


I go for two movies in a dvd-r 4,7 GB with a audio band MP2 at 192 Kbps.
This movie has 103 minutos total time.

In CalcuMatic the average bitrate is 2599. I selected 2 audio streams with 192 and also 2 video streams.

With the code posted by Karl, I get 2880.

How is calculated this CalcuMatic average bitrate?


Thanks.


-Maurus

The Karl's code works ok for me with a only movie in a dvd-5.

1) For two movies, what is the value for media?

2254438? exactly the half?


I go for two movies in a dvd-r 4,7 GB with 1 audio band MP2 at 192 Kbps.
This movie has 103 minutes total time.

In CalcuMatic the average bitrate is 2599. I selected 2 audio streams with 192 and also 2 video streams.

With the code posted by Karl, I get 2880. I'm sure mistaked....

How is calculated this CalcuMatic (2599) average bitrate for 2 video streams?


Thanks.


-Maurus

Hi maurus,

Are you SURE you are using the latest version of CalcuMatic :?:
The latest is version 1.1.16 here: http://www.kvcd.net/downloads/CalcuMatic.exe

-kwag

If you have a movie that is 1h30 and the second 2h30, do you want to have each one that fit on only one half ? Or do you think it's better to have more space for the second one than the first ?

The media size do not change ! What change is the length of the video. For two movie the lenght is the sum of the two lengths. That's all !

Note: why don't you simply use Calcumatic to compute your bitrate ?

Simple ! You say you have a movie that is 103 minutes, but 2 video stream, then it calculates the bitrate for ONE video of 206 minutes. There is no trick.


Note: be carrefull. Two video streams with 2 audio streams means 4 audio streams in total ! Not two. You have 103 + 103 minutes of video and 103*2 + 103*2 minutes of audio.

If you want a DVD with TWO movies (so 2 video and 2 audio), then you must specify ONE audio stream.

I'm very confused.

I'm writing a script for encode KDVD with HC. I want my script calculate the average bitrate.

I want put TWO movies (with 1 audio 192 kbps MP2 each one) in a DVD-5 4.7 GB...

How I do this in CalcuMatic?

For calculate the average bitrate of my first movie, I put:

Minutes: 102 Seconds: 12

[Audio 1]: 192 and 2 audio streams (I put 2, because I thinking in my other movie)

Media: DVD-5 4,7 GB - 2 video streams (I put 2, because I thinking in my other movie)

It's correct?

How I must do this in Calcumatic?

And.. What are the correct code for calculate this averga bitrate manually for two movies with 1 audio each one?



-Maurus

Okay.

Simply add the length in minutes of the 2 movies and put this in calcumatic !

No, your movie has ONE audio, not two.

If you have two movies, then there is 2 video streams, each one with one audio. So audio is still one.

if you declare 2 video stream, that suppose that they do both the same time in minute (the time taht you indicate to calcumatic).
The best, in any case, is to simply add the lengths and process as if you have only one movie that has this length !

Add... add... add.

Why do you bother to think with two movies if this confuse you ? 103 minutes x 2 or 206 minutes x 1 lead to the same result, doesn't it ?

The only diff is, if you want to use the same computing than calcumatic, in the overhead : for one movie calcumatic use 25 MB as overhead, and 50 for 2 movies. But this does not do a big difference in the final average.