Some unusual results in lame 3.99.5
Reply #25 – 2013-05-01 22:17:20
... Im not sure if the following statement is true but if the bitrate is larger, wouldnt the file size also be larger?? ... With several posts I explained to you that the audio data are packaged into frames. Frames are the containers for the audio data. Frames come with fixed sizes corresonding to bitrates of 320, 256, 224, ... kbps. When encoding a track N frames are created. Whenever a bitrate is displayed to you (correctly - not always the case), it's the average frame bitrate of these N frames.Average frame bitrate corresponds with file size. Average frame bitrate however is not exactly what you're interested in. You're interested in average audio data bitrate. But you'll never get an information about audio data bitrate. Audio data bitrate is hidden to you. Things aren't real bad though. The way most users use Lame, audio data are packaged efficiently into frames. Thus audio data bitrate is (nearly) identical with frame bitrate. There are few exceptions: a) when doing the nonsense of turning bitreservoir off (I've demonstrated to you that this blows up frame bitrate, that is file size, because of totally unused bits) b) by requiring Lame to use a very high minimum (frame) bitrate (same mechanism as when turning bitreservoir off) c) maybe by using some other option the user doesn't understand (though none such comes to my mind at the moment). d) by using CBR 320. Audio data bitrate of Lame CBR320 files vary from track to track. On average it's more like 305 kbps, not 320 kbps.