IPS-VIDEO Altera, IPS-VIDEO Datasheet - Page 161

• Manufacturer Part Number: IPS-VIDEO
• Description: MegaCore Suite W/ 17 DSP Video/image Processing Functions
• Manufacturer: Altera
• Type: -r

Specifications of IPS-VIDEO

• Software Application: IP CORE, SUITES
• Supported Families: Arria GX, Cyclone II, HardCopy II, Stratix II
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Function: Suite of IP Functions for Video and Image Processing
• License: Initial License
• Lead Free Status / RoHS Status: na
• Lead Free Status / RoHS Status: na

Chapter 5: Functional Descriptions
Stall Behavior and Error Recovery
May 2011 Altera Corporation
Scaler II
■
Error Recovery
On receiving an early endofpacket signal, the Scaler stalls its input but continues
writing data until it has sent an entire frame. If it does not receive an endofpacket
signal at the end of a frame, the Scaler discards data until the end-of-packet is found.
In the Scaler II MegaCore function, the ratio of reads to writes is proportional to the
scaling ratio and occurs on both a per-pixel and a per-line basis. The frequency of lines
where reads and writes occur is proportional to the vertical scaling ratio. For example,
scaling up vertically by a factor of 2 results in the input being stalled every other line
for the length of time it takes to write one line of output; scaling down vertically by a
factor of 2 results in the output being stalled every other line for the length of time it
takes to read one line of input.
In a line that has both input and output active, the ratio of reads and writes is
proportional to the horizontal scaling ratio. For example, scaling from 64×64 to
128×128 causes 128 lines of output, where only 64 of these lines have any reads in
them. For each of these 64 lines, there are two writes to every read.
The internal latency of the Scaler II depends on the scaling algorithm and whether any
run time control is enabled. The scaling algorithm impacts stalling as follows:
■
■
Enabling run-time control of resolutions affects stalling between frames:
■
■
Error Recovery
On receiving an early endofpacket signal, the Scaler stalls its input but continues
writing data until it has sent an entire frame. If it does not receive an endofpacket
signal at the end of a frame, the Scaler discards data until the end-of-packet is found.
Enabling run-time control of coefficients adds a constant delay of about 20 cycles
plus the total number of coefficients to be read. For example, 16 taps and 32 phases
in each direction would add a delay of 20 + 2(16 × 32) = 1024 cycles.
In bilinear mode, a complete line of input is read into a buffer before any output is
produced. At the end of a frame there are no reads as this buffer is drained. Exactly
how many writes are possible during this time depends on the scaling ratio.
In polyphase mode with N
buffers before any output is ready. As with bilinear mode, there is a scaling ratio
dependent time at the end of a frame where no reads are needed as the buffers are
drained.
With no run-time control, there are about 10 cycles of delay before the behavior
described in the previous list begins, and about 20 cycles of further stalling
between each output line.
Enabling run-time control of resolutions adds about 25 cycles of delay between
frames.
v
vertical taps, N
v
– 1 lines of input are read into line
Video and Image Processing Suite User Guide
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