Hi forum,
We are using TPS 3.0(48) latest FCS version. We connect a third party SIP endpoint which supports H.264 and BFCP (No TIP).
We use this endpoint to display presentation video (video:slides) from TPS conference participants via BFCP.
Our SIP endpoint only supports XGA resolution for presentation (1024x768 @ 5 FPS), and when we answer the call from TPS we indicate it like this in SIP SDP 200 OK message:
Media Description, name and address (m): video 65512 RTP/AVP 126
Bandwidth Information (b): AS:4000
Media Attribute (a): sendrecv
Media Attribute (a): rtpmap:126 H264/90000
Media Attribute (a): fmtp:126 profile-level-id=42801F;max-fps=18000; max-rcmd-nalu-size=3320
Media Attribute (a): content:slides
Media Attribute (a): label:12
When meeting starts and one of the participants in TPS connects a laptop with XGA resolution, content is displayed correctly in our SIP third party endpoint, but...when resolution in laptop is set to a higher value we see TPS sending 720p resolution towards us. (EX60, MX200, EX90)
We analyzed the H264 streams and see the following:
Working
H264 stream:
0100 0010 = Profile_idc: Baseline profile (66)
0001 1111 = Level_id: 31 [Level 3.1 14 Mb/s]
.000 1101 = log2_max_frame_num_minus4: 12
011. .... = pic_order_cnt_type: 2
...0 10.. = num_ref_frames: 1
.... .000 0001 0000 00.. .... = pic_width_in_mbs_minus1: 63
..00 0001 1000 0... = pic_height_in_map_units_minus1: 47
(63+1) * 16 = 1024
(47+1) * 16 = 768
Non-working
H264 stream:
0100 0010 = Profile_idc: Baseline profile (66)
0001 1111 = Level_id: 31 [Level 3.1 14 Mb/s]
.000 1101 = log2_max_frame_num_minus4: 12
011. .... = pic_order_cnt_type: 2
...0 10.. = num_ref_frames: 1
.... ...0 0000 0101 0000 .... = pic_width_in_mbs_minus1: 79
.... 0000 0101 101. = pic_height_in_map_units_minus1: 44
(79+1) * 16 = 1280
(44+1) * 16 = 720
Although there is no profile level defined for XGA in H.264, we use the most suitable which is 3.1.
720×480@80.0 (13)
720×576@66.7 (11)
1280×720@30.0 (5)
Our requirement is that TPS will send to our endpoint exactly XGA, not lower and not higher. We expect the TPS to perform transcoding of the presentation to XGA prior to sending it to us. Is our SIP SDP incorrect, is there a way to achieve this?
We opened TAC case but we need additional help.
Thanks
