Hi Hans.
On 20/06/16 18:03, Hans Verkuil wrote:
On 06/20/2016 06:20 PM, Sakari Ailus wrote:
The 10-bit packed raw bayer format documented that the data of the first
pixel of a four-pixel group was found in the first byte and the two
highest bits of the fifth byte. This was not entirely correct. The two
bits in the fifth byte are the two lowest bits. The second pixel occupies
the second byte and third and fourth least significant bits and so on.
Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com>
As mentioned, this needs confirmation. I wonder, isn't this specified in the UVC
spec?
Regards,
Hans
I'm assuming this is intended to be the same format as generated by many
Bayer sensors.
Those are defined in both the SMIA CCP2 (section 7.9), and MIPI CSI2
(section 11.4.4) specs. Whilst nominally restricted, they are both
available via unofficial websites if you Google for them (I'm happy to
send links, but didn't want to break mailing list rules by just posting
them).
CSI2 draft spec Figure 98 "RAW10 Data Transmission on CSI-2 Bus Bitwise
Illustration" is probably the clearest confirmation of the bit ordering.
dcraw from http://www.cybercom.net/~dcoffin/dcraw/ can consume Raw10 via
nokia_load_raw
for (dp=data, col=0; col < raw_width; dp+=5, col+=4)
FORC4 RAW(row,col+c) = (dp[c] << 2) | (dp[4] >> (c << 1) & 3);
And checking against the Raspberry Pi hardware simulator, the RAW10
parser code has
for (i = 0; i < width; i++) {
switch ((i + tile_x) & 3) {
case 0: val = (buf[0] << 2) | (buf[4] & 3); break;
case 1: val = (buf[1] << 2) | ((buf[4] >> 2) & 3);
break;
case 2: val = (buf[2] << 2) | ((buf[4] >> 4) & 3);
break;
default: val = (buf[3] << 2) | ((buf[4] >> 6) & 3);
All of those agree with Sakari's update that the first pixel's LSBits
are in bits 1..0 of byte 5, 2nd pixel in bits 3..2, etc.
Regards,
Dave
(working on the Pi CSI2 receiver V4L2 driver as there is now sufficient
data in the public domain to do it. I'll be wanting these formats!)
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