For the H.320 QuickTime Conferencing kit, the only supported codecs when using the ISDN portion are H.320 and it's related codecs. For non-ISDN connections, we support some of the QuickTime compressors.
Audio
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* G.728 - 16 Kbps digital audio samples 3.3 KHz of analog audio (low bandwidth)
* G.722 - 48, 56, or 64 Kbps PCM digital audio from 7 KHz analog audio (higher bacndwidth)
Video
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* H.261
- QCIF 176x144 pixels
- CIF 352x288 pixels
Because there is no penalty for choosing the larger resolution, you should always select it for the best resolution on the receiving end. Also, in Apple Media Conference during an ISDN connection, you can double the CIF window <which is actually 320x240 on your screen> to achieve a 640x480 image size. Keep in mind that it uses pixel doubling, so resolution will suffer slightly.
For an ISDN connection, you can get 12-15 fps in the large window (320x240) if using both B channels. Otherwise, you can get 5-7 fps when using one B channel. Frame rate will vary depending on which audio compressor is being used and whether or not you are sharing data in the shared window. For a single B channel connection, you can only use the G.728 audio compressor if you expect to get video, because there is no bandwidth left with G.722.
Article Change History:
07 Mar 1996 - Corrected typo.