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BT.656 Video Capture Mode
Table 3-5. Common Video Source Parameters
| Number of Active Lines |
|
|
Video Source | (Field 1/Field 2) | Number of Active Pixels | Field Rate (Hz) |
square pixel | 240/240 | 640 | 60 |
60 Hz/525 lines |
|
|
|
BT.601 | 244/243 | 720 | 60 |
60 Hz/525 lines |
|
|
|
square pixel | 288/288 | 768 | 50 |
50Hz/625 lines |
|
|
|
BT.601 | 288/288 | 720 | 50 |
50 Hz/625 lines |
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|
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For the BT.656 video capture mode, the FIFO buffer is divided into three sections (three buffers). One section is 1280 bytes deep and is dedicated for storage of Y data samples. The other two sections are dedicated for storage of Cb and Cr data samples, respectively. The buffers for Cb and Cr samples are each 640 bytes deep. The incoming video data stream is separated into Y, Cb, and Cr data streams, scaled (if selected), and the Y, Cb, and Cr buffers are filled. Each of the three buffers has a
If video capture is enabled (BLKCAP bit in VCxCTL is cleared), pixels in the capture window are captured in the Y, Cb, and Cr buffers. The video capture module uses the YEVT, CbEVT, and CrEVT events to notify the EDMA controller to copy data from the capture buffers to the DSP memory. The number of double words required to generate the events is set by the VCTHRLDn bits in VCxTHRLD. On every YEVT, the EDMA should move data from the Y buffer to DSP memory using the YSRC location as the source address. On every CbEVT, the EDMA should move data from the Cb buffer to DSP memory using the CBSRC location as the source address. On every CrEVT, the EDMA should move data from the Cr buffer to DSP memory using the CRSRC location as the source address. Note that transfer size from the Cb and Cr buffers is half of the transfer size from the Y buffer since for every four Y samples, there are two Cb and two Cr samples.
3.2.4 BT.656 Data Sampling
Incoming data (including timing codes) are sampled and the HCOUNT counter advanced only on clock cycles for which the CAPEN input is active. Inputs when CAPEN is inactive are ignored. The timing reference codes are recognized only when three sequential samples with CAPEN valid are the FFh, 00h, 00h sequence. A
3.2.5 BT.656 FIFO Packing
Captured data is always packed into
The
SPRUEM1 | Video Capture Port | 49 |