Rockbox

Tasklist

FS#1699 - %fv displays "(avg)" rather than "(vbr)"

Attached to Project: Rockbox
Opened by Fred Maxwell (fmaxwell) - Friday, 19 September 2003, 01:46 GMT
Last edited by Daniel Stenberg (bagder) - Friday, 05 December 2003, 09:27 GMT
Task Type Bugs
Category
Status Closed
Assigned To No-one
Operating System
Severity Low
Priority Normal
Reported Version Release 2.0
Due in Version Undecided
Due Date Undecided
Percent Complete 0%
Votes 0
Private No

Details

According to the Rockbox .pdf manual:

%fv : "(vbr)" if variable bit rate or "" if
constant bit rate

In fact, it displays "(avg)" for a VBR recording.

I would prefer to see the firmware changed to display
"(VBR)" with all uppercase as shown since that's the
normal way to abbreviate "variable bit rate".

The following are the lines of code which control that
display from the 2.0 release version of the software:

wps-display.c

case 'f': /* File Information */
*flags |= WPS_REFRESH_STATIC;
switch(tag[1])
{
case 'v': /* VBR file? */
return id3->vbr ? "(avg)" : NULL;

Change the "(avg)" to "(VBR)" and we are good to go.
This task depends upon

Closed by  Daniel Stenberg (bagder)
Friday, 05 December 2003, 09:27 GMT
Reason for closing:  Rejected
Comment by Björn Stenberg (zagor) - Saturday, 20 September 2003, 00:27 GMT

The manual is wrong. I think avg is preferrable since the
bitrate shown is the average bitrate, not "the variable bitrate".

However you can easily change this in your own wps by
using the conditional operator: %?iv<(VBR)|>
Comment by Fred Maxwell (fmaxwell) - Saturday, 20 September 2003, 03:19 GMT

Zagor is assuming that the user will always choose to
display a bitrate next to the %fv. Not true. Since %fv is
a standalone parameter, it seems more reasonable to display
"(VBR)" since "(avg)" sounds like a comment on the music or
sound quality (i.e, it's just average).

What makes the most sense for %fv to return/display "VBR" or
"CBR". A player has a 10 character wide display. Taking
20% of it for useless parenthesis and using up five more
characters for VBR recordings ["(avg) " vs ""] is undesirable.

I know about the workarounds such as the one zagor described
(%fv, not %iv, though), but if that's the way that the %fv
parameter is intended to be used, returning a 0 or 1 and
letting the user format the message seems to make more sense.
Comment by Fred Maxwell (fmaxwell) - Saturday, 20 September 2003, 03:32 GMT

Zagor wrote:

> I think avg is preferrable since the bitrate shown
> is the average bitrate, not "the variable bitrate".

If you use the LAME MP3 encoder, you will see that they have
an "ABR" or "average bitrate" mode. From lame --longhelp:

> ABR options:
> --abr <bitrate> specify average bitrate
> desired (instead of quality)

So having Rockbox display "avg" rather than "VBR" could lead
to confusion.

Comment by Björn Stenberg (zagor) - Saturday, 20 September 2003, 15:18 GMT

The --abr option is merely an instruction to the encoder.
The actual average bitrate result can and will at times be
different.

The simple facts are: For VBR MP3s, we display the
average bitrate. This is, in the default wps, clarified by
showing "avg" next to it.

If you don't want to show it next to the bitrate or want to use
the text "VBR" instead, you are free to do so. There is no
need to change Rockbox for that.
Comment by Fred Maxwell (fmaxwell) - Saturday, 20 September 2003, 17:14 GMT

I am disappointed to see the use of industry standard terms
like VBR and CBR rejected -- especially in light of the
manual showing the use of "(vbr)". I am also disappointed
to that useless parentheses are being retained as a default
on a 10 character wide display.

In closing, workarounds should be employed to display
non-standard terminology like "(avg)" and %fv should return
the industry-standard "VBR" (hence the "v" in "%fv").
Comment by Björn Stenberg (zagor) - Saturday, 20 September 2003, 17:33 GMT

Please use the mailing list for discussions.

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