[h323plus] H.261 and G.722

Jan Willamowius jan at willamowius.de
Mon Jan 10 04:30:04 EST 2011


after your change to the H.261 plugin, it stopped working for me: With
the new plugin, I only receive a black video stream with Spranto and
Polycom PVX.

I had tested the old plugin with Polycom PVX, Polycom HDX 9004,
Tandberg T3 and the Mirial Softphone and all worked.

Alessandro, which Polycom device causes you trouble ? Is the new plugin
working any better there ?

I would suggest to revert that patch for now.


Simon Horne wrote:
> Thanks Alessandro
> I have made the change to H.261 plugin please check if it ok.
> I have also checked into the CVS a working G.722.1(16k) codec. The G.722.1c
> (32k) is commented out for now as it has not been properly tested.
> You are welcome to test it and report back.
> Simon
> -----Original Message-----
> From: h323plus-bounces at lists.packetizer.com
> [mailto:h323plus-bounces at lists.packetizer.com] On Behalf Of Alessandro
> Angeli
> Sent: Saturday, January 08, 2011 8:20 AM
> To: h323plus at lists.packetizer.com
> Subject: [h323plus] H.261 and G.722
> [H.261]
> The H.261 VIC codec does not work with hardware devices like Polycom's. 
> The device complains about invalid sbit/ebit values.
> The codec resets the sbit to 0 on a new picture, introducing an apparent
> discontinuity in the bitstream. However the device expects the bitstream to
> be continuos (prev.ebit + this.sbit = 8).
> The fix is quite simple: just comment out
> H261PixelEncoder::PreIncEncodeSetup() { ... sbit_ = 0; ... } in
> "opal\plugins\video\H.261-vic\vic\encoder-h261.cxx".
> [G.722]
> The G.722 codec is never initialized. The codec reports a format of
> "PCM-16-16kHz" (L16Desc[] in "opal\plugins\audio\G722\g722codec.c")
> while the plugin manager only accepts "L16" 
> (H323PluginCodecManager::RegisterCodecs() in
> "h323plus\src\h323pluginmgr.cxx").
> Shouldn't the codec report "L16" in the 8 kHz descriptor? Or is there a
> deeper issue? Replacing "PCM-16-16kHz" with "L16" enables the decoder but
> not the encoder and the decoder doesn't decode anything.
> G.722.2 seems to have the same issue.
> --
> Alessandro

Jan Willamowius, jan at willamowius.de, http://www.gnugk.org/

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