I just have a query, if I am playing a VBR MP3 in WINAMP, is the displayed bitrate precisely accurate? When it changes between bitrates is that more or less what is occuring in real time, or is that simply a guide?

I guess what I am asking is does LAME produce VBR files with bigger variations than what can be accurately displayed by WinAMP or do players like WinAMP display exactly what is occurring all the time?

There are lots and lots of MPEG frames in a second, and the frame size (the bitrate) doesn't get updated as often.

It's probably a weighted running average or something like that.

maybe little offtopic:
Lossless codecs also have variable bitrates.
If I play *.la in winamp, the bitrate display doesn't vary at all. It's always 14H (=1400kbps).
If I play *.ape insane, the bitrate display varies only very seldom.
It seems that sometimes the displaying function is bugged an/or it depends on the system load (difficulty do decode, in *.ape normal no problems) or the system capabilities. (processor MHz...)

I think it depends on the decoder plugin's capabilities.

The Winamp vbr display is effectively an average over a given time period from what i gathered. The update speed was lowered in a previous version since it was causing a higher cpu usage as it was doing too many updates by being close to real-time from what i remember.

The information which is output is based on the input plugin being used to play that file format back so the rate of change/accuracy is dependant upon how the plugin works.

-daz

Unlike what people said, the displayed bitrate can't be an average because it shows standard mp3 bitrates, and no in-between values. (Unless you check 'show average', in which case it shows a static average).

Also, it seems the displayed bitrate is for what is currently decoding, not what is playing. So depending on your buffer settings, the bitrate displayed is valid for a few seconds forward.

I'm not sure it is updated for every frame, possibly because this may be too fast to read. DrO said it was reduced to decrease CPU usage, but I'm not sure this is right... updating a small display at less than 39Hz (for 44.1KHz mp3s) would have no effect on CPU usage.

All of the above is true for the standard Nullsoft decoder.

There are about 38 frames per second in MP3. You couldn't read the numbers if they changed once per frame. If you are curious about "real time" vbr display, play a file in Foobar with the setting at 1 for "update every ~ frames" under preferences, playback, input, standard inputs. Believe me, it is not enjoyable.

OTOH, I do wish that Winamp had a more frequent update in its VBR display. It would be far more informative if it updated every 8 frames or so.

As for LAME, you can use the command line encoder and watch the histogram during encoding, it will show a distribution of the bitrates. I used to know how to save this histogram in a text file, perhaps someone else remembers how?

Good point. So it can't be a simple running average. I must have been confused with the Vorbis decoder.

Maybe choosing which numbers to display was taking up CPU time?

Anyway, if it was realtime in the worst case it would be updated more than 38 times per second. This would be totally unreadable for regular humans.

But the irregular ones could enjoy fully accurate bitrate reporting. :)

I've heard of some people being able to recognize more than 16 pictures per second...They are able to see cinema films flicker, for example. Must be annoying...

[Off-topic]

It is annoying. Thats why I hate going to the theater. I can't stand CRT monitors set below 100Hz refresh rate either, I don't think this is so uncommon though . . .

I know how you can see a vbr bitrate display in realtime!

I figured it out, Go in forbar2000 in the standard input settings it says vbr bitrate display and you cahnge it to "update every 1 frames" etc..

Though it is real hard too read, And the bottom bar where it displays the stats flickers on my computer Real annoying.

Though i am sticking with winamp perfect for me!

Oh yeah @ music_man_mpc
I can not stand crt monitors refresh rate below 75Hz

You must see pretty well

Double Post (Please Remove Admin)

You are not alone. Refresh rates below 100Hz grind me down as well.