Visible to Intel only — GUID: laq1662566055531
Ixiasoft
1. About the Video and Vision Processing Suite
2. Getting Started with the Video and Vision Processing IPs
3. Video and Vision Processing IPs Functional Description
4. Video and Vision Processing IP Interfaces
5. Video and Vision Processing IP Registers
6. Video and Vision Processing IPs Software Programming Model
7. Protocol Converter IP
8. 1D LUT IP
9. 3D LUT IP
10. Adaptive Noise Reduction IP
11. Advanced Test Pattern Generator IP
12. AXI-Stream Broadcaster IP
13. Bits per Color Sample Adapter IP
14. Black Level Correction IP
15. Black Level Statistics IP
16. Chroma Key IP
17. Chroma Resampler IP
18. Clipper IP
19. Clocked Video Input IP
20. Clocked Video to Full-Raster Converter IP
21. Clocked Video Output IP
22. Color Plane Manager IP
23. Color Space Converter IP
24. Defective Pixel Correction IP
25. Deinterlacer IP
26. Demosaic IP
27. FIR Filter IP
28. Frame Cleaner IP
29. Full-Raster to Clocked Video Converter IP
30. Full-Raster to Streaming Converter IP
31. Genlock Controller IP
32. Generic Crosspoint IP
33. Genlock Signal Router IP
34. Guard Bands IP
35. Histogram Statistics IP
36. Interlacer IP
37. Mixer IP
38. Pixels in Parallel Converter IP
39. Scaler IP
40. Stream Cleaner IP
41. Switch IP
42. Text Box IP
43. Tone Mapping Operator IP
44. Test Pattern Generator IP
45. Unsharp Mask IP
46. Video and Vision Monitor Intel FPGA IP
47. Video Frame Buffer IP
48. Video Frame Reader Intel FPGA IP
49. Video Frame Writer Intel FPGA IP
50. Video Streaming FIFO IP
51. Video Timing Generator IP
52. Vignette Correction IP
53. Warp IP
54. White Balance Correction IP
55. White Balance Statistics IP
56. Design Security
57. Document Revision History for Video and Vision Processing Suite User Guide
31.4.1. Achieving Genlock Controller Free Running (for Initialization or from Lock to Reference Clock N)
31.4.2. Locking to Reference Clock N (from Genlock Controller IP free running)
31.4.3. Setting the VCXO hold over
31.4.4. Restarting the Genlock Controller IP
31.4.5. Locking to Reference Clock N New (from Locking to Reference Clock N Old)
31.4.6. Changing to Reference Clock or VCXO Base Frequencies (switch between p50 and p59.94 video formats and vice-versa)
31.4.7. Disturbing a Reference Clock (a cable pull)
Visible to Intel only — GUID: laq1662566055531
Ixiasoft
40.3. Stream Cleaner IP Functional Description
Intel Video and Vision IPs follow the Intel Video and Vision Protocol. In full mode, this protocol consists of metapackets of a specific length and data packets of variable length. For example, an image information packet is four beats in length; end-of-field packets and timestamp packets are two and three beats in length, respectively. For legal packet ordering, refer to the Intel FPGA Video and Vision Protocol Specification
Figure 105. Packet ordering rulesThe figure summarizes the control packet ordering rules
A field must start with an image information packet, followed by 0 to n video data packets and then 0 to m auxiliary and timestamp packets. The field is then terminated by an end-of-field packet. After the end-of-field packet and before the image information packet, the protocol allows any number of auxiliary packets. If in any way this protocol is not adhered to, the video and vision IPs do not work correctly.
All IPs receive and transmit according to the protocol. It is difficult to produce a stream that does not comply with the protocol. In most cases, you do not require a Stream Cleaner IP in the video processing pipeline. However, in situations such as when switching may occur midpacket (crash switching), the output stream may produce broken control packets that do not match their required length, or packet orders which are not permitted by the protocol.
Figure 106. Stream Cleaner fixing broken packet example
In the figure, the Intel FPGA streaming video input receives the first beat of an end-of-field packet followed by the first beat of an image information packet. The end-of-field is therefore missing its second beat. Detecting this fault, the Stream Cleaner pauses the input stream by dropping axi_vid_in_tready low and inserts the second beat of the end-of-field before continuing the input stream by raising axi_vid_in_tready. The packet is now legal, although the data in the second beat is incorrect.
Figure 107. An example of a packet order that violates the Intel FPGA Streaming Video Protocol SpecificationThe figure shows the IP detecting a protocol error.
An end-of-field packet is followed by another end-of-field packet, which is an erroneous sequence. The Intel FPGA Streaming Video Protocol Specification states that an end-of-field packet must be followed by either an image information packet or an auxiliary control packet. The IP drops output axi_vid_in_tvalid low to prevent it from passing the data on to the next component. axi_vid_in_tvalid goes high again when a valid packet is on the output of the Stream Cleaner.
Figure 108. An example of a broken packet and a packet order that violates the Intel FPGA Streaming Video Protocol Specification.The figure shows a protocol error and a packet error.
A broken image information packet (shaded red) is followed by a complete image information packet. The first image information packet is broken due to missing its final beat. The Stream Cleaner produces a fixed packet (shaded green) by recreating the missing beat using the data from the previous beat. It then ensures the axi_vid_out_tlast signal goes high.
The Intel FPGA Streaming Video Protocol Specification states that an image information packet is followed by
- A data packet (with the tuser[0] start-of-field signal high)
- A timestamp packet
- A custom auxiliary packet
- An end-of-field packet.
The Stream Cleaner discards the second image information packet by lowering the axi_vid_out_tvalid signal. The axi_vid_out_tvalid signal raises again when a packet adhering to the specification passes through.
The Stream Cleaner only supports user auxiliary Packets of ID range 16-31 and requires them to be 4 beats in length.