CHDKPTPRemote on SX60HS

Davo

Hi,
I am trying to get CHDKPTPRemote to display the live screen from my SX60HS. When I do, I get this exception when I try to call session.GetLiveImage(live_image).

"could not get live image: Index was outside the bounds of the array.
at CHDKPTPRemote.Session.add_pixel(Byte[] buf, Int32 pos, Byte y, SByte u, SByte v) in D:\Home Data\Visual Studio 2010\Projects\CHDKPTPRemote-master LiveView Branch\CHDKPTPRemote-master\CHDKPTPRemote\Session.cs:line 207
at CHDKPTPRemote.Session.GetLiveImage(Boolean set_active_area, Rectangle& active_area, Bitmap old_img) in D:\Home Data\Visual Studio 2010\Projects\CHDKPTPRemote-master LiveView Branch\CHDKPTPRemote-master\CHDKPTPRemote\Session.cs:line 302"

The 302 line in GetLiveImage(live_image) is highlighted below

// convert uyvyyy to rgbrgbrgbrgb
            byte[] pixels = new byte[vp_max_width * vp_max_height * 3];
            for (int img_idx = image_start, pxls_idx = 0; img_idx < image_end; img_idx += ((vp_buffer_width - vp_max_width) * 6) / 4)
            {
                for (int x = 0; x < vp_max_width; x++, img_idx += 6, pxls_idx += 12)
                {
                    sbyte u = (sbyte)img[img_idx];
                    sbyte v = (sbyte)img[img_idx + 2];
                    add_pixel(pixels, pxls_idx, img[img_idx + 1], u, v); // line 302
                    add_pixel(pixels, pxls_idx + 3, img[img_idx + 3], u, v);
                    add_pixel(pixels, pxls_idx + 6, img[img_idx + 4], u, v);
                    add_pixel(pixels, pxls_idx + 9, img[img_idx + 5], u, v);
                }
            }

The error comes in line 207 in the add_pixel method below

private void add_pixel(byte[] buf, int pos, byte y, sbyte u, sbyte v)
        {
            buf[pos] = clip(((y << 12) + u * 7258 + 204😎 >> 12); // b // line 207
            buf[pos + 1] = clip(((y << 12) - u * 1411 - v * 2925 + 204😎 >> 12); // g
            buf[pos + 2] = clip(((y << 12) + v * 5743 + 204😎 >> 12); // r
        }

I am guessing the numbers like 7258, 2925, etc in add_pixel() are not correct for the SX60 but I don't know where they came from. Any idea on how to solve my problem?

thanks in advance

reyalp

Davo
Hi,
I am trying to get CHDKPTPRemote to display the live screen from my SX60HS. When I do, I get this exception when I try to call session.GetLiveImage(live_image).

Nice to see someone still using this stuff 😀
The display buffer formats changed for digic 6 and later. Since we added digic 6 support long after CHDKPTPRemote was released (14 years ago :o) it does not support the updated protocol.

I am guessing the numbers like 7258, 2925, etc in add_pixel() are not correct for the SX60 but I don't know where they came from. Any idea on how to solve my problem?

Those constants are for the YUV to RGB conversion, shouldn't be causing the index out of bounds, at worst, bad values would result in an incorrect color, but that part shouldn't have changed. What has changed is that Digic 6 buffers are UYVY, not UYVYYY, which affects the logic for the dimensions as well as the which offset Y, U and V values appear.
I suspect the out of bounds access is caused by the dimension logic, but you really need to update the whole conversion function to handle it correctly. You'll also want to update the logic that interprets the header to recognize the digic 6 format.

Digic 6 support was mostly added in CHDK r4680 https://app.assembla.com/spaces/chdk/subversion/commits/4680

live_view.h and live_view.c are probably the most relevant files.

chdkptp client support was added in r712 https://app.assembla.com/spaces/chdkptp/subversion/commits/712
You can find examples of decoding the new UYUV format in liveimg.c (note there are two different UYUV formats, but we ended up only using LV_FB_YUV8B)

In both cases, there may have been additional bug fixes later, so you may want to also refer to the latest source.

Note the bitmap (UI) overlay also changed significantly, in digic 6 it's a YUV buffer with a separate opacity buffer.

Davo

Many thanks for a very detailed and helpful reply which has given me direction. Liveview is displayed fine in CHDKPTP so my backup plan was to set up shots in CHDKPTP and then capture in CHDKPTPRemote. Doing everything in my app thru CHDKPTPRemote is a much preferred option so I will persevere.

btw, the wheel commands for the SX60 are the same as for the SX530

Left = session.ExecuteScript("post_levent_to_ui(0x1134,1) post_levent_to_ui(0x08ae,1) post_levent_to_ui(0x1135,1)");
Right = session.ExecuteScript("post_levent_to_ui(0x1134,1) post_levent_to_ui(0x08ad,1) post_levent_to_ui(0x1135,1)");

Will update if I get results.

reyalp

Davo
btw, the wheel commands for the SX60 are the same as for the SX530

Left = session.ExecuteScript("post_levent_to_ui(0x1134,1) post_levent_to_ui(0x08ae,1) post_levent_to_ui(0x1135,1)");
Right = session.ExecuteScript("post_levent_to_ui(0x1134,1) post_levent_to_ui(0x08ad,1) post_levent_to_ui(0x1135,1)");

The current trunk SX60 uses those events for wheel_left/wheel_right (added in r6308, January this year) you're saying the sx530 should be the same?

Note there were some live view fixes for SX60 around that time, which involved incorrect sizes, so you'll want to use the current trunk build if you aren't already. I haven't backported those to the 1.6 stable branch because 1.6 uses a different display method from the trunk so it wasn't just a straightforward merge.

Also, I just noticed the thread title says SX50, which I assume is typo given the rest of the discussion, but if that is the cam in question, then ignore everything I said about digic 6 😉

Davo

I used those commands for my SX530HS and they worked fine with CHDKPTPRemote. I traded my 530 for a SX60HS which is when I found out the same commands worked for it. The title should be SH60.

I was using the stable build on the SX60 but I loaded the trunk on a new card to see if that helps. Will update with results.