[Speex-dev] Fwd: Encoding quality and CPU requirements

Pablo Rios pablo.javier.rios at gmail.com
Thu Sep 24 14:09:14 PDT 2009


I apologize for my previous e-mail, I will be more specific this time.
I need to encode G711u WAV files to Speex, which are 4 minutes length on
average. For this task I first convert audio to PCM 16 and then run the
Speex command line encoder as follows. OS is WS2003 and Processor is Intel
Xeon 5140 @ 2.33GHz (2 CPUs).
Encoding such a file is taking around 2 seconds and the usage of the
processor core where the encoder is scheduled to reaches 100%.

Goal: I'd need to know if it's possible to lower the encoding time without
sacrificing so much quality and bandwith. I appreciate any suggestion on

*>timeit speexenc --vbr --comp 2 <in>.wav <out>.ogg*
Encoding 8000 Hz audio using narrowband mode (mono)

Version Number:   Windows NT 5.2 (Build 3790)
Exit Time:        2:27 pm, Thursday, September 24 2009
Elapsed Time:     0:00:02.109
Process Time:     0:00:02.078
System Calls:     8571
Context Switches: 2104
Page Faults:      1636
Bytes Read:       3872536
Bytes Written:    432660
Bytes Other:      73416794

*>speexenc -v*
speexenc (Speex encoder) version speex-1.2beta3 (compiled Dec 11 2007)

Thanks so much for your guidance

---------- Forwarded message ----------
From: Pablo Rios <pablo.javier.rios at gmail.com>
Date: Wed, Sep 23, 2009 at 5:18 PM
Subject: Encoding quality and CPU requirements
To: speex-dev at xiph.org


I'm running speexenc on Windows (version speex-1.2beta3 (compiled Dec 11
2007)) with the default encoding quality (--quality 8) and I would like to
have an idea of how much gain in CPU usage I can get by decreasing quality
(of course increasing bandwith).
By the way, is this the latest version of the encoder for Windows ?

Thanks so much !
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