AK8858 Datasheet, PDF (47/96 Pages) Asahi Kasei Microsystems – PS/SD Multi Format Video Decoder

[AK8858]
[7.26.1.5] Operating used EAV/SAV
[7.26.1.5.1] Line-locked and frame-locked clock modes
In both of these modes, the output data are compliant with ITU-R BT.656 (525i/625i), SMPTE293M (525p), and
ITU-R. BT1358 (625p), which is requires the following samples and line numbers.
- Number of samples for 1 line:
858 samples (525i/525) / 864 samples (625i/625p)
- Number of lines for 1 frame:
525 lines / 625 lines
It may not be possible, however to meet these requirement if the input signal quality is poor.
[Line drop/repeat processing]
A line drop or a line repeat will result in output signal with 524/624 or 526/626 lines per frame respectively.
Line drop/repeat processing may be performed at any line in the frame.
[Pixel drop/repeat processing]
A pixel drop or a pixel repeat will result in output signals less or more than the required 858/864 samples in
the last line of the frame or field respectively.
Note: In the event of output-stage buffer failure, line drop/repeat processing will be performed even if the
register is for pixel drop/ repeat processing.
Line or pixel drop/repeat
ERRHND-bit
00
01
10
11
Processing mode
Line Drop / Line Repeat
Pixel Drop / Pixel Repeat by Field
Pixel Drop / Pixel Repeat by Frame
Reserved
Sub Address: 0x0D [5:4]
Notes
Default
[7.26.1.5.2] Fixed clock mode
In fixed-clock mode, operation is at an internally generated 27 MHz clock, from a 24.576 MHz input clock. The
output signal is therefore not synchronized with the input signal, and thus not ITU-R BT.656 compliant. Data is
output in SAV format. As shown in the following figure, EAV is guaranteed for 720 pixels from SAV, but the
number of pixels from EAV to SAV is not.
SAV
720 pixels
EAV
858 / 864 ( NTSC / PAL ) pixels ± α
MS1230-E-00
- 47 -
2010/9