[h323plus] H.261 and G.722
Alessandro Angeli
packetizer.com at riseoftheants.com
Fri Jan 7 17:19:52 EST 2011
[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
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