#362: Problem with certain Ogg bitrates on rev7337
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Reporter: humanclay | Owner: admin
Type: Bugs | Status: new
Priority: 1 | Milestone: NEAR FUTURE
Component: Liquidsoap | Version: 0.9.2+svn
Keywords: | Mac: 1
Linux: 1 | Netbsd: 1
Other: 1 | Freebsd: 1
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Comment(by toots):
Ok, I've had a brief review of the code.
* In {{{ogg_formats/vorbis_encoder.ml}}}, the quality parameter is passed
as received to the ocaml-vorbis binding
* in {{{vorbis_stubs.c}}}, the quality parameter is passed as received to
the vorbis library:
{{{
check_err(vorbis_encode_init_vbr(&enc->vi, Int_val(channels),
Int_val(rate), Double_val(quality)))
}}}
* In the {{{vorbisenc.h}}}, this gives the quality of the encoder:
{{{
* \param quality Desired quality level, currently from -0.1 to 1.0 (lo
to hi).
(...)
extern int vorbis_encode_setup_vbr(vorbis_info *vi,
}}}
All in all, I only see a problem in {{{lang/lang_encoder.ml}}} where the
parameters are received and checked:
{{{
let vorbis =
(...)
| ("quality",({ term = Int i } as t)) ->
if i<>0 && i<>1 then
raise (Error (t,"quality should be in [0..1]")) ;
let q = float i in
{ f with Encoder.Vorbis.mode = Encoder.Vorbis.VBR q }
}}}
So, the good news is: we have the standard range for the quality
parameter. As for negative parameter, the only reason why I did not lift
this limitation so far is that I am not sure about the proper way. Idealy,
it would be nice to check that quality is between 0 and 1 for the xiph
implementation and -2 and 1 if it is aotuv.
Is there a way to know from the C code whether we are using the aotuv
library ? Or to know the range of the parameter ?
--
Ticket URL: <http://savonet.rastageeks.org/ticket/362#comment:3>
Savonet <http://savonet.rastageeks.org/>
Let's program our stream !
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