[TIProtocol-askcisco] TIP Encoder Setting issue

[Aravind S. <ara...@te...>]

Hi David et al @ cisco tip,

We have been trying to interop our TIP Client with a CTS 1000 and whilst 
we are able to make calls from our TIP Client to CTS 1000m we are seeing 
quality issue in the CTS decode. The CTS video is getting decoded fine 
in our TIP Client. So we are wondering if CTS 1000 is extremly strict 
and we are missing out some encoder settings.

If possible,Please share the encoder settings that could troubleshoot 
the problem.


We are referring  1.6b profile to set the settings in our encoder and 
support the following wrt the encoding standard

1. MUST generate H264 Main Profile or High Profile (HiP), if negotiated, 
compatible bit stream : *Using MAIN PROFILE*

2. MUST support CALVC

3. MAY support CABAC as a negotiated option *Using CABAC*

4. MUST support 1280x720 or 1920x1080 resolution *Using 1280x720*

5. MUST support fixed frame rate: 30 fps or 29.97 fps *Configured to use 
30fps*

6. MUST generate one macro block-row per slice

-1280x720: 45 slices per frame, each slice must be 80 macro blocks in 
length *Using 45 * 80 *

-1920x1072: 67 slices per frame, each slice must be 120 macro blocks in 
length

7. MUST support deblocking_filter_control_present = 1 & 
disable_deblocking_filter_idc = 1 Added

8. MUST only use inter-prediction blocks of size 16x16 *Couldn't find 
this setting in our encoder*

9. MUST only use one reference picture and that reference picture must 
be the immediate previous frame or a long term reference picture 
*Couldn't find this setting in our encoder*

10. Each NAL MUST be less than 3320 bytes in size *Couldn't find this 
setting in our encoder*

11. POC (Picture Order Count) MUST increment by 2 every frame *Couldn't 
find this setting in our encoder*

12. MUST NOT USE SPS IDs in the range of 10 to 20 *Uses 0 *

13. Long term reference pictures (LTRPs) MAY be used for error 
concealment. LTRPs requires max_num_ref_frames>=3. LTRPs use H.264 
standard picture buffer management. MUST support long_term_frame_idx < 
2, MUST use memory_management_control_operation = 6. LTRPs are optional 
and can be disabled. Ignored

14. Gradual decoder refresh pictures (GDRs) MAY be used at the start of 
a sequence instead of an instantaneous decoder refresh picture (IDR). A 
recovery point SEI precedes the GDR. The SEI always has the 
broken_link_flag set to 0. GDRs are optional and can be disabled.Ignored

15. When high profile is negotiated, MUST support 
seq_scaling_matrix_present_flag=0 and pic_scaling_matrix_present_flag=0, 
MUST NOT use monochrome pictures, MUST NOT use quantization matrices.Ignored

Observations:

1.When we use GOP length > 1 We see poor jitter status in the CTS and 
the video is bad.

2.We always see the black strip exactly at 2/3 from the top in the 
screen. And Sometimes we have seen this strip slice  catching up late.. 
But most of the time it remains black...

It looks like CTS Decoder is expecting specific AVC bit stream that our 
encoder is not able to send..

There are few settings above ignored and some couldn't configure in our 
encoder. Is that is causing the quality issue?
Also, is it possible to provide a guidance as to how we can debug on the 
CTS side for video quality issue?

regards

Aravind Sethuraman
Chief Software Architect
Teliris, Inc.
55 Broadway, 14th Floor, New York, NY 10006
C +1.917.355.0119 | O +1.212.490.1065 x1408 | F +1.212.269.2869