User guide

15–2 Chapter 15: Deinterlacer MegaCore Function
Functional Description
Video and Image Processing Suite January 2013 Altera Corporation
User Guide
Figure 15–1 shows a simple block diagram of the Deinterlacer MegaCore function
with frame buffering.
Deinterlacing Methods
The Deinterlacer MegaCore function supports four deinterlacing methods:
■ Bob with scanline duplication
■ Bob with scanline interpolation
■ Weave
■ Motion-adaptive
1 The Deinterlacer does not support interlaced streams where F0 fields are one line
higher than F1 fields in most of its parameterizations. (Bob with one output frame for
each input frame is the only exception.) Altera recommends using the Clipper
MegaCore function to feed the Deinterlacer with an interlaced video stream that it can
support.
Bob with Scanline Duplication
The bob with scanline duplication algorithm is the simplest and cheapest in terms of
logic. Output frames are produced by simply repeating every line in the current field
twice. The function uses only the current field, therefore if the output frame rate is the
same as the input frame rate, the function discards half of the input fields.
Bob with Scanline Interpolation
The bob with scanline interpolation algorithm has a slightly higher logic cost than bob
with scanline duplication but offers significantly better quality.
Figure 15–1. Deinterlacer Block Diagram with Buffering in External RAM
Note to Figure 15–1:
(1) There can be one or two Avalon-MM masters connected to the Memory Reader.
Deinterlacing
Algorithm
Memory
Reader
Memory
Writer
Arbitration Logic
DDR2
SDRAM
Avalon-ST Input
(din)
Avalon-ST Output
(dout)
Avalon-MM Master
(write_master)
Avalon-MM Master
(read_master)