User guide
Table Of Contents
- Contents
- 1. About This MegaCore Function Suite
- Release Information
- Device Family Support
- Features
- Design Example
- Performance and Resource Utilization
- 2D FIR Filter
- 2D Median Filter
- Alpha Blending Mixer
- Avalon-ST Video Monitor
- Chroma Resampler
- Clipper
- Clocked Video Input
- Clocked Video Output
- Color Plane Sequencer
- Color Space Converter
- Control Synchronizer
- Deinterlacer
- Deinterlacer II
- Frame Buffer
- Gamma Corrector
- Interlacer
- Scaler
- Scaler II
- Switch
- Test Pattern Generator
- Trace System
- 2. Getting Started with Altera IP Cores
- 3. Interfaces
- Interface Types
- Avalon-ST Video Protocol
- Avalon-MM Slave Interfaces
- Avalon-MM Master Interfaces
- Buffering of Non-Image Data Packets in Memory
- 4. 2D FIR Filter MegaCore Function
- 5. 2D Median Filter MegaCore Function
- 6. Alpha Blending MegaCore Function
- 7. Avalon-ST Video Monitor MegaCore Function
- 8. Chroma Resampler MegaCore Function
- 9. Clipper MegaCore Function
- 10. Clocked Video Input MegaCore Function
- 11. Clocked Video Output MegaCore Function
- 12. Color Plane Sequencer MegaCore Function
- 13. Color Space Converter MegaCore Function
- 14. Control Synchronizer MegaCore Function
- 15. Deinterlacer MegaCore Function
- Core Overview
- Functional Description
- Parameter Settings
- Signals
- Control Register Maps
- 16. Deinterlacer II MegaCore Function
- 17. Frame Reader MegaCore Function
- 18. Frame Buffer MegaCore Function
- 19. Gamma Corrector MegaCore Function
- 20. Interlacer MegaCore Function
- 21. Scaler MegaCore Function
- 22. Scaler II MegaCore Function
- 23. Switch MegaCore Function
- 24. Test Pattern Generator MegaCore Function
- 25. Trace System MegaCore Function
- A. Avalon-ST Video Verification IP Suite
- B. Choosing the Correct Deinterlacer
- Additional Information
Chapter 3: Interfaces 3–21
Buffering of Non-Image Data Packets in Memory
January 2013 Altera Corporation Video and Image Processing Suite
User Guide
Buffering of Non-Image Data Packets in Memory
The Frame Buffer and the Deinterlacer (when buffering is enabled) route the video
stream through an external memory. Non-image data packets must be buffered and
delayed along with the frame or field they relate to and extra memory space has to be
allocated. You must specify the maximum number of packets per field and the
maximum size of each packet to cover this requirement.
The maximum size of a packet is given as a number of symbols, header included. For
instance, the size of an Avalon-ST Video control packet is 10. This size does not
depend on the number of channels transmitted in parallel. Packets larger than this
maximum limit may be truncated as extra data is discarded.
The maximum number of packets is the number of packets that can be stored with
each field or frame. Older packets are discarded first in case of overflow. When frame
dropping is enabled, the packets associated with a field that has been dropped are
automatically transferred to the next field and count towards this limit.
The Frame Buffer and the Deinterlacer handle Avalon-ST Video control packets
differently. The Frame Buffer processes and discards incoming control packets
whereas the Deinterlacer processes and buffers incoming control packets in memory
before propagating them. Because both MegaCore functions generate a new updated
control packet before outputting an image data packet, this difference must be of little
consequence as the last control packet always takes precedence
1 Altera recommends that you keep the default values for Number of packets buffered
per frame and Maximum packet length, unless you intend to extend the Avalon-ST
Video protocol with custom packets.