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SPRAA56
DSP/BIOS Real-Time Analysis (RTA) and Debugging Applied to a Video Application 19
The benchmarking routines send out selected benchmark data at a prescribed interval: every
30
th
frame, every I (Intracoded) frame, or only on a dropped frame. The interval can be selected
by controlling the .rtaMode variable within the control structure.
Benchmark data is transmitted to the CCStudio on the host PC via RTDX (Real-Time Data
eXchange), which is used behind the scenes by the DSP/BIOS RTA tools. RTDX allows Code
Composer Studio to read from or write to target buffers in DSP addressable memory at run-time.
For example, the UTL_logDebug2 API command use RTDX to move two variables and a
message to the Message Log window available from the DSP/BIOS menu in CCStudio.
Although the channel used in this example is the standard debugging connection, data could be
sent over any channel with sufficient bandwidth to an endpoint where you can view the data. For
example, the benchVideoProcRta data structure could be sent over Ethernet in a networked
encoder or decoder application to provide statistics to a third-party receiving application.
The current size of the debug structure is small (defined in Appendix A), so sending the structure
once every 30 frames would introduce a negligible load on the system and the network, yet
could still provide useful information at that rate.
4.10 Application-Specific Control via GEL Scripts in CCStudio
As mentioned earlier, run-time control is provided by the h263rateControl.gel script. The menu
item controls in the script allow you to manipulate the global benchVideoProcRta structure from
the host PC.
menuitem "Rate Control --bitrate-framerate";
slider setFrameRate(0, 30, 1, 1, framerate)
{
controlVideoProc.frameRateChanged = 1;
controlVideoProc.frameRateTarget = framerate;
}
For details on the GEL language and its functions, see the “Using the Integrated Development
Environment” section of the Code Composer Studio online help.
5 Viewing Benchmarks in the Instrumented Application
Now that we have described the available benchmarks, this section tells how to measure those
benchmarks while running the application.
5.1 Requirements
To run the application supplied with this note, you need the following components:
• DM642 EVM and Board Support Package
• CCStudio v2.21 or greater
• JTAG emulator
• Input video source – composite or S-Video
• Video display – composite or S-Video