Was looking at TI TVP5150 and TVP5151 and Intersil TW9900.
Didn't look very hard though, maybe there's one out there that would output RGB.
Or, maybe not. This ITU-R BT.656 output format is a widely used standard for digital video...
This ITU-R BT.656 output format is a widely used standard for digital video...
Then it is likely to have the lowest cost chips.
Wiki says this ["A BT.656 data stream is a sequence of 8-bit or 10-bit words, transmitted at a rate of 27 Mbyte/s. Horizontal scan lines of video pixel data are delimited in the stream by 4-byte long SAV (Start of Active Video) and EAV (End of Active Video) code sequences. SAV codes also contain status bits indicating line position in a video field or frame. Line position in a full frame can be determined by tracking SAV status bits, allowing receivers to 'synchronize' with an incoming stream.
Individual pixels in a line are coded in YCbCr format. After an SAV code (4 bytes) is sent, the first 8 bits of Cb (chroma U) data are sent then 8 bits of Y (luma), followed by 8 bits of Cr (chroma V) for the next pixel and then 8 bits of Y. To reconstruct full resolution Y,Cb, Cr pixel values, chroma upsampling must be used."]
I think digital camera chips also output this mode by default. The implementations I've seen only use the 8 bit mode (and not the 10 bit mode).
So, they say it's 16-bits per pixel, but it's not exactly that...
You do get a new Y value with each 16-bits, but you have to use the adjacent pixels Cb or Cr value to convert to RGB.
I think this is why they call it 4:2:2 with 4 for Y and Cr and Cb at 2 (half the data, compared to Y).
If I remember right, DVD players also output this mode...
If I remember right, DVD players also output this mode...
IIRC Chip has said Component video comes for free with this, and this output format seems a slight variant on Component. - just taken before the Phase Modulator, and bypass the DACs.
The LCD modes can do this already.
ie P2 should be able to Write ITU-R BT.656 output ?
I don't know about output, but sure hope P2 will be able to input this mode...
The SSD1921 image processor that I'm using now with P1 and 3.5" LCD has this input, meant to connect digital cameras. But, I was already thinking that one of these decoder chips could be used to display a composite signal on the LCD. I'm hoping that P2 will be a 1-chip replacement for that (while also allowing larger LCDs)...
I don't know about output, but sure hope P2 will be able to input this mode...
Being able to do both Input and output should be simple.
The output case looks like a simple special case of Component, with a slight change to MUX ordering & skip final DACs.
- all the hard data flow stuff is already done.
Comments
Do you have a link to those decoders Rayman?
Didn't look very hard though, maybe there's one out there that would output RGB.
Or, maybe not. This ITU-R BT.656 output format is a widely used standard for digital video...
Circuit for the TVP5150 doesn't look too scary. If you wanted to make up some boards I'd be interested, and I think there would be others too.
Wiki says this
["A BT.656 data stream is a sequence of 8-bit or 10-bit words, transmitted at a rate of 27 Mbyte/s. Horizontal scan lines of video pixel data are delimited in the stream by 4-byte long SAV (Start of Active Video) and EAV (End of Active Video) code sequences. SAV codes also contain status bits indicating line position in a video field or frame. Line position in a full frame can be determined by tracking SAV status bits, allowing receivers to 'synchronize' with an incoming stream.
Individual pixels in a line are coded in YCbCr format. After an SAV code (4 bytes) is sent, the first 8 bits of Cb (chroma U) data are sent then 8 bits of Y (luma), followed by 8 bits of Cr (chroma V) for the next pixel and then 8 bits of Y. To reconstruct full resolution Y,Cb, Cr pixel values, chroma upsampling must be used."]
27MHz clocked capture is not too onerous ?
So, they say it's 16-bits per pixel, but it's not exactly that...
You do get a new Y value with each 16-bits, but you have to use the adjacent pixels Cb or Cr value to convert to RGB.
I think this is why they call it 4:2:2 with 4 for Y and Cr and Cb at 2 (half the data, compared to Y).
If I remember right, DVD players also output this mode...
Y Data = 13.5Mhz and Chroma Data = 6.25Mhz
IIRC Chip has said Component video comes for free with this, and this output format seems a slight variant on Component. - just taken before the Phase Modulator, and bypass the DACs.
The LCD modes can do this already.
ie P2 should be able to Write ITU-R BT.656 output ?
The SSD1921 image processor that I'm using now with P1 and 3.5" LCD has this input, meant to connect digital cameras. But, I was already thinking that one of these decoder chips could be used to display a composite signal on the LCD. I'm hoping that P2 will be a 1-chip replacement for that (while also allowing larger LCDs)...
Being able to do both Input and output should be simple.
The output case looks like a simple special case of Component, with a slight change to MUX ordering & skip final DACs.
- all the hard data flow stuff is already done.