[speex-dev] please test rc2 support in sweep :)

Conrad Parker conrad at vergenet.net
Thu Jan 30 06:34:39 PST 2003


I'm updating speex support in sweep to RC2 and I'd like some advice
on encoder options, and would appreciate some testing of the user

a screenshot of the updated speex encoding dialog:


you can grab a tarball of sweep for testing here:


general info on installation etc. is at:


<p>Speex has many interdependent encoder options, and I've attempted to
make these somewhat manageable in a GUI. There are a few speex options
which override each other or implicitly turn each other on or off, so
I've attempted to consolidate what I could and automate some of the
interactions, as well as greying out options when they are invalid.

I did this based on reading through the speex manual etc. and the
recent thread on --dtx etc. Easiest is if you can build and play with
that tarball, but I'll at least try to describe the behaviour here.
Please let me know where my understanding falls apart :)

first up, quality and vbr_quality are mutually exclusive, so instead
I'm just providing one slider, which goes from 1 to 10. when vbr is
checked, the slider quietly gains a decimal point of precision, giving
floating point values, and when vbr is turned off, it reverts to
integer values.

then, it seems that cbr bitrate and abr bitrate are mutually exclusive,
again dependent on whether vbr is enabled -- so i'm just providing one
field to enter a bitrate. It's cunningly named "bitrate management"
because it provides either maximum or average bitrate depending on the
vbr mode (the phrase "bitrate management" comes from vorbis'
"bitrate management engine"...). if vbr is enabled, the bitrate is
used to set ABR, otherwise it is used to set BITRATE.

checkboxes for VAD and DTX are made sensitive depending again on the
vbr mode. ie. if VBR is on, then VAD is automatically turned on but
greyed out so it can't be changed (to reflect that VAD is implicit in
VBR mode) and DTX is available for turning on/off. But if VBR is off,
then VAD is allowed, and then only if VAD is also on is DTX allowed.


I guess I want to check the following are true:

        * QUALITY and VBR_QUALITY cannot be used at the same time
        * ABR cannot be used unless VBR is on
        * BITRATE (ie. max bitrate) cannot be used unless VBR is off, ie.
          there's no way of setting a max bitrate in VBR mode, and there's
          no way of specifying both min and avg bitrates at the same time
        * there's no way of setting a minimum bitrate

if these are correct, maybe it would make sense to simplify the ctl
interface a little to remove redundancies (ie. mutually exlusive items
with very similar meaning). But of course the logic between these
encoder options makes for a fun interactive game :)


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