MP3 lengths variability (technical) (attn Bill)

[billfromnorthwales]

Uh Oh...

They all go to 16/44.1 wav first of course, then I batch convert to mp3.

I aways used to do the batch convert in Soundforge, but this time I did it in...  erm...  now what did I use?

Well it was either foobar2000 with lame mp3 encoder or Wavelab batch encode with whatever encoder it uses.

Whatever it was it was at nominal 256kbs Vbr

There might be a program to fix the mp3 by changing the VBR flag to the average bit rate in the file header because when you think about it any player program can only give a play length if it knows the average bit rate.

I just played 53.2 in VLC player and the end time jumps about as it plays.

If the average bit rate is not declared then the player program can only give an estimated play length based on the currently playing part.

But I guess you are joining the files in an editor that brings everything to 16 bit 44.1khz wav, so the file length should always be correct in that program

L53.2 has these properties

File name	L053.2.mp3
File size	82.44 MB (84,417,473 bytes)
File attributes	- --a- ----
Last saved	2012-08-05  08:08:16
File type	MP3 Audio
Audio format	MPEG Layer-3
Audio sample rate	44,100
Audio bit rate	VBR
Audio bit depth	16 bit
Audio channels	2  (Stereo)
Audio length	00:43:48.545 (115,918,848 samples)

The DVD's with the wav files are on their way back to Rocker or do you want me to upload a "fixed rate" mp3 version to the Mooo?

Cheers Stuart, thanks for the quality control

Bill

--- In peel@yahoogroups.com, "Stuart" <stuartb@...> wrote:
>
> I've noticed during my project to stitch together the running order of the 1991 SL Tapes (which are split between guitar and dance) when trying to time the various bits of the 1991 shows, Bill's dance edits show up as a different length depending on how I view the file.
> 
> For example, L053.2, shows up in Windows Explorer as 49:55. If I load the file into Audacity, it shows up as a file of 43:48. If I play the file in MediaMonkey, the file appears to be 43:48 in file properties but actually plays on past this on the progress bar, with the time remaining becoming a negative number!
> 
> The MediaMonkey file properties show a bitrate of 256kbps and a file length of 43:48 though with VBR set to yes. I assume that the incorrect file lengths shown on the progress bar of MM when playing the file, or being viewed from Windows Explorer, are due to these elements assuming a fixed bit rate Assuming the 43:48 is the correct length!)
> 
> It must be that the ripping programme actually writes the file Stop time as a tag, which MediaMonkey displays in its file properties, but both the play progress bar in MM and the Windows Explorer do not use this, and estimate the length of the file from a fixed bit rate.
> 
> I also rip to vbr, 220-260, but with slightly different results. The lengths are consistent when viewed from different programs, though the bit rate as displayed on MediaMonkey properties is 251 kpbs. I assume this is written by my ripping program which is Audacity, and is the average bitrate of the file. I do notice that MediaMonkey and indeed WMP have trouble selecting an individual location, you can only fast forward in minute blocks, whereas with Bill's files, the usual fine control is available.
> 
> Bill, just wondered what ripping program and bit rates you are using?
> 
> Stuart
>