[Vorbis] bitrate limits don't work with -q settings?
nic at ghs.com
Wed Dec 29 11:25:43 PST 2004
Thanks for the quick response. To get versioning out of the way, I
recompiled the libraries and oggenc from mainline svn yesterday night.
I see the same results.
Unfortunately, I am stuck on a stupid transport. On the IRiver players,
any time the bitrate dips below 96kbps, you'll hear a click or pop, and
the song will usually end. -q3 -m 96 doesn't work. Is there any way to
use VBR and absolutely guarantee that the bitrate won't fall below a
certain level? I figured that's what the bitrate_hard_min option was
for, but it seems to have the opposite effect.
Ralph Giles wrote:
> On Tue, Dec 28, 2004 at 10:23:50PM -0500, Nic Watson wrote:
>>The problem I'm seeing is that oggenc's VBR encoding doesn't seem to pay
>>attention to any sort of bitrate limitation, either the -m or
>>bitrate_hard_min settings. It isn't that it temporarily dips below the
>>minimum; the average for the whole (in this case, easily compressible)
>>file is 10-20% too low.
> Are you complaining that the encoder does too good a job? :-)
> The managed bitrate modes use a different engine from the standard
> constant-quality engine, and is mutually exclusive with -q. You have
> to turn it on with -b or in more recent versions of oggenc with
>>I see roughly the same results on an old 1.0.1 version of oggenc as well
>>as a new vorbis 1.1-linked one I found on rarewares.org.
> The managed bitrate handling was changed in the 1.1 release; I don't
> know if the rarewares oggenc is the updated version from svn or not, so
> it may be using the same logic as the 1.0.1 version.
> If it's underruns you're worried about you probably shouldn't be using a
> managed mode; -q will do a better job. You really only need this if
> you're on some stupid transport that really can't handle the normal vbr
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