Hi all,

I am sorry that I have post similar question in the MP3 general forum, I guess I put it in the wrong forum tongue.gif, since my question has not really been answered .

I have just run a few experiments with LAME - CBR mode. I use different types of audio such as Pop, Instrument, and even Speeches, all of which have a length of 20 seconds. I notice that the encoding time needed seems to depend a lot on the quality setting being used, this is more obvious when I use -q 0 as my quality setting. So I am just wondering what causes LAME to take a longer time to encode one type of audio and a shorter time to encode other type of audio? For instance the time it takes to encode the instrumental song seems to be significantly longer than the time it takes to encode speech file.

I have tried similar experimentation using Speex -CBR mode (i know that it is not optimised for general audio) and the results show that the encoding time needed by Speex to encode different music genres are approximately the same. My first thought as to why this is not the case with LAME is because of the amount of time needed to do the lossless huffman encoding, speech for example are repetitive and hence perhaps can be represented by using fewer codewords than a pop music. Is this right blink.gif ?

Helps are greatly appreciated. Thank you.