[opus] opus 1.2.1 regression with --enable-float-approx and --0fast

[Jean-Marc Valin]

Any luck reproducing the problem with opus_demo or opus-tools?

	Jean-Marc

On 02/22/2018 10:14 PM, Stepan Salenikovich wrote:
> 
> 
> On Thu, Feb 22, 2018 at 9:53 PM, Jean-Marc Valin <jmvalin at jmvalin.ca
> <mailto:jmvalin at jmvalin.ca>> wrote:
> 
>     On 02/22/2018 09:34 PM, Stepan Salenikovich wrote:
>     > Its unexpected because the decoder continues to output all samples
>     > of -32768 even when the microphone input is silence or near silence, so
>     > I would expect the decoded values to be at or near 0.
> 
>     Oh, if the output is stuck at -32768, then it's likely some NaNs crept
>     in. The first thing to check is whether the problem is on the encoder
>     side or the decoder side (when if you use a 1.1 encoder with a 1.2
>     decoder and vice versa). In general, -Ofast is not IEEE-compliant when
>     it comes to NaN, so libopus has to work around that non-compliance.
> 
> 
> The encoder in my setup is always the one in chrome m64. I'm pretty sure
> thats 1.2 and I'm not sure but I think they don't compile with -Ofast.
> The decoder which gets stuck at -32768 is 1.2 with -Ofast. 1.1 with
> -Ofast works, and 1.2 without -Ofast works as well.
> 
> 
>     > I will try to reproduce with opus_demo or opus-tools.
> 
>     Thanks, that'll help a lot.
> 
> 
> Having trouble right now compiling opus-tools against a local install of
> opus 1.2 compiled with -Ofast... will ask on irc.
>  
> 
> 
>             Jean-Marc
> 
>     >
>     >
>     >     Optionally, if you could bisect the git repo to see where the
>     problem
>     >     started.
>     >
>     >     Cheers,
>     >
>     >             Jean-Marc
>     >
>     >     On 02/22/2018 07:15 PM, Stepan Salenikovich wrote:
>     >     > Hi,
>     >     > I work on a webRTC application and recently tried updating
>     from opus
>     >     > 1.1.5 to 1.2.1
>     >     >
>     >     > Afterwards I noticed occasionally weird audio glitches. I
>     finally
>     >     > tracked down the issue to the opus decoder in my application
>     >     outputting
>     >     > samples with the value of -32768.
>     >     >
>     >     > This behaviour stopped when reverting to opus 1.1.5 or
>     compiling opus
>     >     > 1.2.1 without configuring --enable-float-aprox and --0fast.
>     >     >
>     >     > The setup is a microphone as audio input into chrome v64
>     which then
>     >     > sends opus encoded audio to my application and my
>     application decoding
>     >     > this audio stream.
>     >     >
>     >     > I could induce the glitches by breathing/blowing really loudly
>     >     into the
>     >     > microphone. I noticed that occasionally this would result in
>     the opus
>     >     > decoder in my application to keep outputting a stream of -32768
>     >     (even if
>     >     > I stopped) until I talked normally for a bit.
>     >     >
>     >     > Is it possible that a regression was introduced between
>     1.1.5 and
>     >     1.2.1
>     >     > when configuring with --enable-float-approx and compiling
>     >     with --0fast?
>     >     >
>     >     > Thanks,
>     >     > -stepan
>     >     >
>     >     >
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