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by devmonkey
Tue Jan 28, 2020 3:20 pm
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

Ok no worries. I did a few tests and couldn't get the sensor to just send a single pixel per bayer quad, I don't think my (guessed) understanding TIMING_X/Y_INC is correct. Anyway, good news I've solved my perf problem. My code rips out the red pixels from a 2592x480 rawcam bayer buffer into 1296x24...
by devmonkey
Tue Jan 28, 2020 10:06 am
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

I've just moved my project onto a PI zero and run into lack of CPU. I only use the red pixels and currently have to copy them out of the bayer array which accounts for about 25% of my workload. On the OV5467 do you think I could use TIMING_X/Y_INC registers to just get it to read out red pixels? The...
by devmonkey
Fri Jan 24, 2020 12:18 pm
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

The IMX219 datasheet has a section on defective pixel tables held in NVM on the sensor, I don't know if any of these have been set, presumably not as it would have required the factory to individually calibrate each sensor which would have been expensive. If I wanted to dump the NVM do you have any ...
by devmonkey
Fri Jan 24, 2020 10:36 am
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

My application is detecting the location of the peak of the gaussian profile of a red laser line crossing the raw sensor (no lens, all filters removed other than CFA). I'm extracting just the red pixels from the bayer data. If the detected gaussian is clipped (has a flat top) it means the pixels are...
by devmonkey
Fri Jan 24, 2020 8:59 am
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

Please ignore the exposure question, I've just tried it and it works.
by devmonkey
Thu Jan 23, 2020 11:50 pm
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

Thanks for the response, I understand the difference between crop and frame but I didn't know about mmal_encoding_width_to_stride, but now I've looked further through your code I see you use it for reading pixels out of the buffer, my bad for not reading all of the example app. Just so I understand ...
by devmonkey
Thu Jan 23, 2020 8:54 am
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Re: Raw sensor access / CSI-2 receiver peripheral

v1 and v2 cameras align width/height to 32/16, you can see this in source code fore eg raspivid: https://github.com/6by9/userland/blob/master/host_applications/linux/apps/raspicam/RaspiVid.c#L1629 I see raspivid does 32/16 but raspiraw is doing 16/16 on the rawcam output then later 32/16 on the ISP...
by devmonkey
Wed Jan 22, 2020 6:17 pm
Forum: Camera board
Topic: Raw sensor access / CSI-2 receiver peripheral
Replies: 655
Views: 226327

Raspiraw buffer size bug / line padding

Hi, I've altered raspiraw for my own purposes to take a bayer 3280x480 strip from the middle of the IMX219 sensor. I noticed that the buffers allocated and returned were too large, I also tested this with the OV5497 sensor and the same is true for full resolution. I have managed to decode the data b...
by devmonkey
Fri Jul 08, 2016 3:33 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

I've just updated to get your patch and it works perfectly, Thanks.
by devmonkey
Thu Jul 07, 2016 9:16 am
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

Thanks so much. Is there a commit tag/id I should look out for?

What is the new MMAL parameter?
by devmonkey
Wed Jul 06, 2016 2:45 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

have you also seen https://befinitiv.wordpress.com/wifibroadcast-analog-like-transmission-of-live-video-data/ Yes, my injection code is based on befi's injection code. My project is really about reducing the latency of the wifibroadcast project to the absolute minimum, I believe he is already there...
by devmonkey
Wed Jul 06, 2016 2:23 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

I'm halfway through just re-framing the jpeg data in software … Unless I'm misunderstanding what you're doing (always a possibility with me), jpegtran (in the libjpeg-progs package) will insert restart markers. It's a handy tool to have around for manipulating JPEGs without data loss. Thanks i've l...
by devmonkey
Wed Jul 06, 2016 1:33 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

I'm passing MMAL buffers directly to a wifi card via pcap injection so don't personally need it added to raspi* but others may find it useful.

Thanks again, Joe
by devmonkey
Wed Jul 06, 2016 12:42 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

If you want to test the markers you should see in the JPEG byte stream are: 0xFFDD - restartInterval (followed by two bytes defining the actual interval in MCUs) 0xFFD0 -> 0xFFD7 restart markers between restartInterval runs of MCUs (first will be D0, second D1, after D7 it will return to D0). If res...
by devmonkey
Wed Jul 06, 2016 12:15 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

Re: JPEG encoder restart markers

Good news for you - there does appear to be a property on the codec itself to set the restart interval, so it's just a matter of plumbing that out to the outside world. Hopefully that should be a relatively easy job, so I'll try to fit it in before the weekend and pass it to Pi Towers to release. I...
by devmonkey
Tue Jul 05, 2016 7:56 pm
Forum: Graphics, sound and multimedia
Topic: JPEG encoder restart markers
Replies: 17
Views: 3875

JPEG encoder restart markers

Hi, The scan data in a JPEG is encoded as a stream of MCUs, each MCU contains some number of 8x8 blocks, one block per component (usually a luminance and two chroma components). The JPEGs produced by the PI encoder use chroma sub-sampling to produce an MCU containing 4x8x8 luminance blocks and 2x8x8...

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