Skype codec selection

Ever wondered how to manually choose which codecs Skype uses when you make an audio call? Well here's how (by selecting the Skype codecs you don't want to use):

• On Windows/Mobile you set this registry key (HKEY_LOCAL_MACHINE/SOFTWARE/Skype/Phone/Audio/DisableCodecs) to contain the codec's you don't want Skype to use (e.g. for Pocket PC you might want to disable higher CPU codecs: "ILBC G729 EG711U")
• On Linux/OSX you add the disabled codecs inside these tags: <DisableCodecs> <\DisableCodecs> in the config.xml file (usually found in ~/.Skype/your_skype_username/config.xml). They need to be put into the (usually existing) <Call> tag which is within the <Lib> tag.
• Furthermore you can actually force the use of a particular codec by using the <ForceCodec> tag/Reg key in the relevant place.

Skype has a wide range of codecs (e.g: SILK_WB_V3, SILK_NB_V3, ILBC, G729, EG711U, SVOPC, SILK, ISAC) which seems to get expanded every so often. Note: That disabling G729 may interfere with use of SkypeOut. Skype generally does a good job of automatically selecting the appropriate codec and its rate - unless you use this tweak - so be aware that Skype may not perform optimally when it's range of codecs is impaired.

There's also other fun stuff you can tweak - like adding a <video> section and make Skype use a particular resolution (you'll need to convert this to an appropriate Registry entry on Windows):
<captureheight>480</captureheight>
<capturewidth>640</capturewidth>

For an interesting read on Skype see columbia.edu, and for papers on performance see Politecnico di Bari and Politecnico di Torino.

[Updated: 16mar2012: More on location of Codec config tags]

Windows Mobile device sync problem finally fixed!

Finally - after trying a bunch of stuff since November last year I have managed to locate a cure for my 'Error' in WMDC. Amazingly enough this(also ripped off here) was the cure - it cures a related problem I also saw in IE when I attempted to download a cab: "this device is restricted from downloading this file type" - I was led here from the excellent xda forums

• The problem and fix are incredibly created using Mobile Word ??!!** - when saving docs as plain text files - so beware. Here's the proceedure cribbed from the the link above (in case it disappears):
  
• 1) soft reset device
  2) Start / Office Mobile / Word
  3) Create a new document (click on New)
  4) type some text (just plain text - no formatting - it was 'plain text document') just a few characters
  5) File / Save As...
  6) I have selected type 'Plain Text'
  7) It asked me whether I want to save it at 'Word document instead' - I clicked No.
  8) I have powered off the device and did soft reset
  9) Start file explorer, find the file (it was in My Device / My Documents), click on it - it opens Word again.
  10) Add some formatting (I have selected part of text and changed font to bold)
  11) Close Word - it asked whether to save it in Word format - this time I said Yes
  12) Power-off the device and press soft reset again

As to why this works is anyone's guess... I did take the trouble to dump my security registry keys (HKLM\Security\Policies\Policies) before I performed the magical fix but I found no difference in those key values before and afterwards.... But there seems to be a mountain of security related controls in Windows Mobile - see MSDN's Security Policy settings, Provisioning Security Settings - I'm sure somewhere in there is the answer....

Windows Mobile Device Centre fun....NOT [FIXED!]

Hmmm - As someone said WMDC is a great sales tool for the iPhone/GPhone! I plugged in my pesky Windows Mobile 6 phone and it just pops up with "Error" one day... Not useful, at all. I've spent quite a while trying to track down the problem. There's a few sites (pocketpcfaq, modernnomads) out there that do offer useful advice but they didn't solve my problem.

• Firstly I found out how to enable debug logs for WMDC - note you can also see some of the error messages if you use DebugView.
• There are also error logs in the Windows Event Viewer 0x8007274a
  
• Looking at the wmdc logs I see an 0x80004005 error which a general code for permission denied.
  
• Some of these Windows Mobile Power Toys were interesting.
• This guy (translated from French) has some useful info on security on Windows Mobile.
• Microsoft's Vista MDC guide
• Microsoft MDC troubleshooting
  
• Finall - I found a fix! - after following up a solution to this error when using IE to download a cab or pdf file: "this device is restricted from downloading this file type" - see my latest post on the matter.

[updated: 26aug09]

*&%$**'ing Windows mobile device center has wiped my XDA - AGAIN!

I cannot believe it!?! My XDA (Windows Mobile 6 Device) has had all my contacts, diary etc info wiped by Windows Mobile Device center for the FOURTH time. I just plugged it in and it asked if I wanted to set up a new association (when I had one set up already) - all my contacts had been deleted at this point - BEFORE asking me!! I can resync with my desktop but its a big pain in the butt. I don't know why it is happening?!! How can Micro$oft get it sooo wrong?

I am seriously considering bombing my XDA for an iPhone (once it's got GPS I will).

[update]: There are some registry tweaks that affect related behaviour here.