The single NAL mode of RFC3984 (or H.241 Annex A) is the default method in H.323 but is not the only method under the standard. These are exchanged and negoitated via the MediaPacketizationCapability of the OLC or TCS H264 Annex A "0.0.8.241.0.0.0.0" RFC3984 NonInterleaved "0.0.8.241.0.0.0.1" RFC3984 Interleaved "0.0.8.241.0.0.0.2" from H.241 7.1 To avoid IP-layer packet fragmentation (which may increase header overhead and the probability of loss due to errors), H.264 NAL Units should be substantially shorter than the MTU size of the network. For example, on an Ethernet network with a 1472 byte MTU, a 1200 byte NAL Unit allows for addition of considerable header overhead without exceeding the MTU size of the network. I hope that helps Simon _____ From: h323plus-bounces@lists.packetizer.com [mailto:h323plus-bounces@lists.packetizer.com] On Behalf Of ooi khai chin Sent: Monday, 23 November 2009 2:04 PM To: h323plus@lists.packetizer.com Subject: [h323plus] H264 PLUGIN in H323Plus Hi All, Currently, my H264 plugin able to work with polycom. I found that the media statistic(polycom PVX ) only show the frame rate video format, and display the image if my sending encoded data is not more than 1.4KB. In my code, I do the fragmentation once it greater than 1.4KB(like libx264 do). However, I had read some documentations and all of them mentioned about H.241 only support the single NAL unit mode(mode 0). I wonder how this mode handle if encoded data greater than 1.4KB(usually happen)??? Any Idea? Thanks.