video bitrate quick question

[kita]

tried searching but couldn't find it. hard to get the keywords right.

How many bits per byte are there in standard DVD-style m2v video? 8, 16, 24 etc? I'm doing a manual bitrate calculation to fit a video into a certain space. I have x mbytes of space, but need to convert that to kbits/sec to plug into the encoder.

Thanks

[Noahtuck]

That what these are for....

https://www.videohelp.com/calc.htm

Just choose custom and make it whatever size you have to work with.

8)

[jman98]

DVD standards won't let you go above something like 9600 Kbps for DVD video.
I'd advise not going above 8000 Kbps because some DVD players have problems with video that uses higher bitrates and also at around 8000 there's no real advantage to using higher bitrates - you won't notice any difference between video at 8000 and video at 9000.

[kita]

Noahtuck, those calculators usually only calculate for a full disk. And the others include calculations like overhead, etc. Actually, the one you linked was the last one I tried before posting. I need calcs just for the stream.

jman98, I'm not going anywhere near 8000. no worries. i'm trying to figure out disk space. i figure this info is encoding 101 so with all these veterans around someone must know off hand.

[deadrats]

tried searching but couldn't find it. hard to get the keywords right.

How many bits per byte are there in standard DVD-style m2v video? 8, 16, 24 etc? I'm doing a manual bitrate calculation to fit a video into a certain space. I have x mbytes of space, but need to convert that to kbits/sec to plug into the encoder.

Thanks

by definition a byte is a group of 8 bits, so if you have 1000 bits per second that would equal 125 bytes per sec, so a 10 second clip would require 1250 bytes to store it.

an easier way is to just find one of the many bitrate/size calculators out there and use that rather than trying to manually calculate the bitrate.

[kita]

thanks guys.

well, i know they have 8-bit and 16-bit audio, so I thought maybe they have the same distinctions with video? i guess i should have asked that first. and with computers, a byte string can be any factor of 8 right? like isn't windows xp home 32-bits and pro is 64?

plus, with all the recent confusions with megabytes and mebibytes, etc, i thought it would be better just to do the calcs myself. just need this last bit of info. and since i'm doing custom size a good chunk of calculators won't help me.

but anyway, i guess you're answer is 8.
anyone else?

[jagabo]

Bit rate of the encoded video/audio is independent of the number of bits per sample and number of samples per second. A 128 kbps audio file is the same size whether it encodes two channels of 48 KHz 16 bit samples, or one channel of 8Khz 8 bit samples.

[edDV]

thanks guys.

well, i know they have 8-bit and 16-bit audio, so I thought maybe they have the same distinctions with video? i guess i should have asked that first. and with computers, a byte string can be any factor of 8 right? like isn't windows xp home 32-bits and pro is 64?

plus, with all the recent confusions with megabytes and mebibytes, etc, i thought it would be better just to do the calcs myself. just need this last bit of info. and since i'm doing custom size a good chunk of calculators won't help me.

but anyway, i guess you're answer is 8.
anyone else?

Are you trying to stay inside DVD standard? See here https://www.videohelp.com/dvd "What is DVD?"

Or are you going non-standard with divx/xvid/h.264/etc ? Then you are bounded by the capability of the particular player.

[Noahtuck]

Noahtuck, those calculators usually only calculate for a full disk.

Read what i wrote again,

If you choose CUSTOM from the drop down box you can type in what size you want it to be then it will give you the bitrate you need....

[kita]

did you read what i wrote?

Noahtuck, those calculators usually only calculate for a full disk. And the others include calculations like overhead, etc. Actually, the one you linked was the last one I tried before posting. I need calcs just for the stream.

i do want to stay within the dvd standard. all i need to know is in a standardized m2v video stream, how many bits are used per byte. the link didn't say anywhere that i saw.

thanks again

[deadrats]

thanks guys.

well, i know they have 8-bit and 16-bit audio, so I thought maybe they have the same distinctions with video? i guess i should have asked that first. and with computers, a byte string can be any factor of 8 right? like isn't windows xp home 32-bits and pro is 64?

plus, with all the recent confusions with megabytes and mebibytes, etc, i thought it would be better just to do the calcs myself. just need this last bit of info. and since i'm doing custom size a good chunk of calculators won't help me.

but anyway, i guess you're answer is 8.
anyone else?

ok, time for a very hasty and basic computer science lesson: a cpu doesn't understand anything other than an electrical state, either on or off. we represent said states as 1's and 0's, in order to conceptualize what is going on inside a cpu. data likewise is stored as an electrical state, a 1 or a 0 (<it's more complicated than that but for our purposes it will do), and this holds true for ram or a hard disk.

each electrical state, each 1 or 0, is called a bit.

the first personal computers weren't anywhere near as powerful as todays and thus all they could handle was data types up to 8 bits at a time and the range was:

00000000 - 11111111

programmers and engineers adopted the term byte for a collection of 8 bits (note, this is a standard definition, not something open to opinion).

as cpu's got more complex and powerful they were able to handle data types larger, thus a 16 bit cpu could handle a data type, instruction, etc that was 16 bits or 2 bytes, so in effect a 16 bit cpu was twice as powerful as an 8 bit one.

then came 32bit cpu's, likewise a 32 bit cpu is capable of dealing with a data type or instruction that is 32 bits or 4 bytes.

to clarify:

a single cpu instruction, say a fetch, add, mov, jump, what ever, in an 8 bit cpu would be 8 bits in length. now for the sake of simplicity assume that an 8 bit cpu could only do a single instruction per second, thus if a programmer wanted to execute a 16 bit instruction, either the programmer or the compiler would need to break up the instruction into 2 parts and the cpu would need 2 cycles to execute said instructions.

with a 16 bit cpu, again for simplicity's sake assume it can only handle one instruction per cycle), the programmer could issue just a single, more complex, instruction, without the need to break it into 2 parts and the cpu could execute it in one cycle.

the same things holds true for 32, 64, 128, 256 and 512 bit processors (yes, there are processors that can handle instructions 512 bits at a time).

as for as windows 32 and 64 bits, like all programs it just means that the instructions that make up the program itself are either 32 bits or 64 bits in size, and as a consequence they can handle data types as large as the respective instructions that comprise them.

so remember, 1 byte is always equal to 8 bits, when they talk about 8 bit and 16 bit audio what they are really saying is that a single piece of the stream is either describe by 8 bits or 16 bits, they more bits that describe the piece they more detail and thus the more quality, it will have. this does have a practical limit however as you get to a point where you have given as accurate a description as you can and anything else is just a waste.

hope i haven't made your head spin.

[deadrats]

did you read what i wrote?

Noahtuck, those calculators usually only calculate for a full disk. And the others include calculations like overhead, etc. Actually, the one you linked was the last one I tried before posting. I need calcs just for the stream.

i do want to stay within the dvd standard. all i need to know is in a standardized m2v video stream, how many bits are used per byte. the link didn't say anywhere that i saw.

thanks again

allow me to say this as simply as possible: by definition, a byte is a collection of 8 bits, it matter not what kind of data is being represented.

[Noahtuck]

Yeah i read what you wrote, and i gave you a way to accomplish what you wanted to do......
It's not my fault you don't get it 8)

[kita]

Actually, it was pretty clear and easy to follow. I just wasn't sure if video bit and audio bit terminology were directly related to computer bits. Either way, that's 3 votes for 8 (including my own).

And Noahtuck, I'm sorry, but you're a moron. For the third time, that calculator WILL NOT accomplish what I want. If you use custom to input the desired file size, it will take that size and subtract "overhead" and "ISO" and who knows what else, and use the resultant reduced file size to calculate the bitrate. Since I'm only concerned with size of the STREAM, I do not have to worry about all that other stuff. Thanks anyway.

[jagabo]

file size = bitrate * running time

So a 5000 kbits per second video that runs for 3600 seconds (one hour) will occupy:

5000 * 3600 = 18,000,000 k bits.

There are 8 bits per byte so that is 2,250,000 k bytes. Of course, you have to add in MPG or VOB container overhead. And audio.

[Noahtuck]

And Noahtuck, I'm sorry, but you're a moron.

Again... Words of wisdom from another clueless newbie...
LMFAO!!!!!!!

[kita]

"Originally a member since july of 2001
so i'm not a noob!!!!!!!!!!!
LONG LIVE TARANS!!!!!!!!
& if that don't tell you anything.....
Who's really the noob ??"

Yeah. I been here since june 2001. So I got one month on you. Only when I go on forums I try to help people, not annoy them. I'm not surprised you're laughing your ass off, since being an ass is all you're good at. And the fact you have to tell everyone in your sig "I'm not a noob! I'm not a noob!" only proves that's exactly what you are.