Specifications

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Cisco TV CDS 2.5 ISA Software Configuration Guide
OL-24788-01
Appendix A Troubleshooting
CDS Content Quality Guidelines
Format Restrictions
Following are the format restrictions for Advanced Video Coding (AVC), H.264, and MPEG-4:
• Sequence Parameter Set (SPS) seq_parameter_set_id flag must be zero.
• SPS pic_order_count_type flag must be zero.
• SPS seq_scaling_matrix_present_flag must be zero.
• SPS profile_idc flag must only be Baseline, Main, or High profile.
Preferred Formats
Using the following guidelines improves the performance of the system, the quality of the tricks, and the
trick transitions.
1. All content should be encoded as a Single Program Transport Stream (SPTS) . If multiple programs
must be included (for example, a Picture-in-Picture [PIP] stream), ensure that the “real” program is
encoded with the lowest program number.
2. All content should follow the process ID (PID) numbering specified in the Content Encoding
Profiles 2.0 Specification (MD-SP-VOD-CEP2.0-I02-070105), section 6.7.5. Regardless, the audio
and video PIDs should be above 0x20.
3. All content should be preceded with a Program Association Table (PAT) and then a Program Map
Table (PMT), and then a Program Clock Reference (PCR) before the first audio or video frame.
Optionally, the discontinuity bit can be set.
4. All content should use the same PID for both PCR and video.
5. All content should begin with a closed Group Of Pictures (GOP) for MPEG-2 or with an
Instantaneous Decoder Refresh (IDR) frame for AVC. This first frame is always accompanied by a
sequence header for MPEG-2 or by an SPS for AVC.
6. To guarantee relatively smooth looking trick modes, the minimum I/IDR-frame frequency should be
eight per second. If the minimum trick speed is 4x or less, the I/IDR-frame frequency should be at
least two per second. In no case should two I/IDR frames be more than two seconds apart.
7. Each I-frame should be preceded by a sequence header and GOP header if any exist for an MPEG-2
video. Each I/IDR frame should be preceded by an SPS and Picture Parameter Set (PPS) for H.264
video.
8. Avoid mixing frame data from multiple video frames in the same transport packet. Specifically, no
data belonging to the prior frame exists following the Packetized Elementary Stream (PES) packet
header for the next frame. Breaking this rule may improve encoding efficiency slightly, but degrades
the quality of the tricks on certain set-top boxes (STBs).
9. All content must be encoded as a single sequence, with no changes in horizontal or video
resolutions, or changes in encoding parameters in the middle of the content.
10. The GOP size may be variable, but GOPs should generally not exceed two seconds. Using longer
GOPs may improve encoding efficiency, but the quality of lower-speed tricks (3x, 4x) may suffer.
11. No more than four B-frames should be used between each pair of I-frames or P-frames.
12. There should be no continuity counter errors in the content.
13. There should be no discontinuities in the content, other than an optional one on the first PCR.
14. The accuracy requirements for PCRs, +/– five parts per million (5 ppm), as stated in ISO/IEC
13818-1, must be adhered to throughout the stream.