MAJOR Bitrate blues

**khp** · 22 Jan 2003, 02:55 PM

Re: MAJOR Bitrate blues

Originally posted by digital
What do any of you know about flash MX and importing video etc?

I don't have a clue about Flash.

Originally posted by digital

The problem im having is this. I have imported some uncompresed video into FLash MX and let Flash's SPARK codec take care of the compression rate etc.

Forgive me for my ignorance, but why do this ?. I assume that you are working with avi files, why not use virtualdub and compress it with divx ?.

Originally posted by digital
The video i took into flash was a rendered video so in other words i hadnt specified a bitrate etc because you cant with the program im using for my 3D....with me so far?

Assuming you are working with avi files yes. If you are using some other raw file format, I'll admit that I'am a bit lost.

Originally posted by digital

If i was to take the rendered video into a program such as Adobe Premier, would that help at all?

I don't know anything Adobe Premiere, IMHO virtualdub is a far better tool for the job, and much cheaper too

.

Originally posted by digital

And if so, what settings should i use for the bitrate for audio and video?

That would depend on the compression method, the frame size and rate, and of course your desired filesize. But with Divx at a frame size around 640*480@25fps, a bitrate of about 1500 kbps is usually quite resonable.

Originally posted by digital

Also does anyone know where i can get some kind of software that calculates bitrates for formats that are streaing such as mpeg or WMV's? I know theres one for DIVx etc on this site, but thats not much good to me for what im doing

Well bitrate is bitate, a 1000kbps divx movie will take up just as much space as a 1000kbps mpeg movie. The only difference between the two, is how close to the desired bitrate then encoder encodes the movie. One pass encoders naturally fail to be very precise because the don't know anything about the source, which makes prediction impossible.

**digital** · 22 Jan 2003, 11:02 PM

ok thnaks for that

Yes im working with raw AVI's, and theres no point in encoding with DIVx because flash uses its own codec to compress them again anyway when you import them.

also, without wanting to sound rude? whats the point in encoding ANYTHING at 3000kbps for the web when the fastest ADSL connection is only capable of somewhere between 100 and 300 kbps ?

**khp** · 23 Jan 2003, 12:44 AM

Originally posted by digital
also, without wanting to sound rude? whats the point in encoding ANYTHING at 3000kbps for the web when the fastest ADSL connection is only capable of somewhere between 100 and 300 kbps

First of all not every one need to stream their encodings accross the internet.

Additionally I would like to add that the fastest ASDL connections are quite a lot faster than 300kbps, I don't know the exact limits but several isp's here in denmark offer up to 2048 kbps.

Perhaps you are confusing KBytes with kbits ?.

**digital** · 24 Jan 2003, 07:17 AM

2028 kbps hey? right, im moving to denmark lol

So, let me get this straight then. And no i dont think im confusing the two.

Kilobytes is the amount of space that a file/movie takes up yeh?

kbits is the amount of data that can be downloaded per second when streaming?

is that about right?

If not then pleeeeeeeeease help me understand it, id appreciate it.

All i really need to know is the question i asked right at the top of this thread really

this gets confusing

**Enchanter** · 24 Jan 2003, 07:57 AM

Kilobytes is the amount of space that a file/movie takes up yeh?

kbits is the amount of data that can be downloaded per second when streaming?

1 byte = 8 bit
1 Kb (kilobit) = 1024 bit

You do the rest of the calculations.

**khp** · 24 Jan 2003, 08:07 AM

Yes data stream speeds are usually calculated in (m|k)bits/sec while filesizes are usually calculated in (M|K)Bytes.

As enchanter stated 1 Byte = 8 bits.

This means that a 1024kbps internetconnection can transfer 1024/8 = 128 KBytes per second.

**ShuMO** · 27 Jan 2003, 09:08 PM

dont forget the buffer settings as well

streamed video also has a variable buffer size at the client end. so in the case of a 30 sec flash or whatever file, its quite possible that the user may set his buffer to handle the data stream on the front end of the xmission. Additionally, flash has the ability to mux multiple streams with their associated bitrates and uses a 'speed' check to determine which of the streams to xmit. This is a take off of the old .rm method originally started by Real.

If your client base has specific circuit speeds in common, ie; all 192k ADSL or something its possible to optimize the bitrate to meet that. However even that isn't an exact science (ADSL has guarenteed throughputs, but they use a quantisized measurement so it ends up being 'bursty'.) Since most web based playbacks are to a user base of non-predetermined speeds, its most common to provide multiple options to the user. Many sites nowadays allow for 3 speeds to be selected from, with a 4th option for download/save as at best quality. I haven't done any work in a while with the Flash stuff for a couple years now, but it'd be neat to know more about this new codec of theirs. I didn't see it listed in the FourCC list... Can you give us more info on it?

**digital** · 28 Jan 2003, 06:37 AM

OK many thanks for your insight

much appreciated!

Flash MX comes with a codec called 'SPARK', by 'Sorenson Media'

It does a fantastic job of compression and can knock a 15-20 meg AVI down to about 300kb's with very little loss of quality , apart from the audio. Obviously something has to give !

You can actually upgrade from 'Spark' to 'Spark Pro' by puchasing 'Sorenson SQueeze for Flash MX'. This give you far better results and much more control over your inport settings etc aswell as crisper definitions and colours etc.

This tells you about squeeze for flash MX :-

Page not found - Sorenson

http://www.sorenson.com/content.php?cats=5/15/73

Also try this :-

Page not found - Sorenson

http://www.sorenson.com/sparkpro.html

Hope this is of some use

Darren

https://www.digital-canvas.co.uk