Size of encoded Mpeg

[Poldi-1]

Hi!

First of all i want to say that I am pretty new to video encoding and I might come up with some newbie questions. So if there's any source that will cover my questions I will be happy if you point me there.

I have some AVIs with 640x446, 29.97fps, which are encoded DivX;) MPEG4 3 (Low Motion), each about 230MB and 30 minutes long.
I want to bring these on a DVD, so I converted them with Canopus ProCoder 1.5 into MPEG2 files with 720x576, 25fps, and I get a file that is about 1.4GB. I also tried MPEG1 352x288, 25fps, but still the same size.

Can I do anything to reduce the size of the created file?

Regards
Poldi

[celtic_druid]

Lower the bitrate.

[Poldi-1]

Hmmm ok. Then I guess I just have to try which bitrate is best for me between quality and size. Right?

Can anyone point me to an explanation of what the bitrate exactly is and what it does?

[Trahald]

bit rate - (Or "bitrate") A data rate expressed in bits per second. This is a similar to baud but the latter is more applicable to channels with more than two states.

The common units of bit rate are kilobits per second (Kbps) and megabits per second (Mbps). In data rates, the multipliers "k", "M", etc. stand for powers of 1000 not powers of 1024.

The term is also commonly used when discussing digital sampling and sample rates. For example, the MP3 audio compaction algorithm is often set to ouput files with a bitrate of 120 kbps. This means that the file contains an average of 120 kilobits for each second of audio (900 KB per minute). This compares with CD audio which is encoded at 44100 16-bit stereo samples per second or 1408 kbps.

.. the final (average) bitrate will determine the size of your project based on the length (in time). there are bitrate calculators available in doom9 downloads if you need help with the calculations

[Poldi-1]

thx a lot. This was very helpful and made me feel a lot smarter :)

Keep it going!