[peel] Re: MP3 lengths variability (technical) (attn Bill)

[Stuart]

No no don't bother fixing anything I was just trying to understand what was
going on! 

 

Windows reports 53.2 as 320kbps, and I've just played it in VLC and it
claims the file is 86 minutes long..

 

I won't actually be joining the files as the running order is speculative
and there's enough to be getting on with! 

 

atb

 

Stuart

 

  _____  

From: peel@yahoogroups.com [mailto:peel@yahoogroups.com] On Behalf Of
billfromnorthwales
Sent: 04 September 2012 22:17
To: peel@yahoogroups.com
Subject: [peel] Re: MP3 lengths variability (technical) (attn Bill)

 

  

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 <mailto:peel%40yahoogroups.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
>