Sylvain
There are various YUV-RGB conversion coefficients, according to https://www.fourcc.org/fccyvrgb.php
I choose the first (from Video Demystified, with integer multiplication),
but the current SDL2 Dither functions use in fact the next one, which follows a specifications called CCIR 601.
Here's a patch to use the second ones and with previous warning corrections.
There are less multiplications involved because Chroma coefficient is 1.
Also, doing float multiplication is as efficient with vectorization.
In the end, the YUV decoding is faster: ~165 ms vs my previous 195 ms.
Moreover, if SDL2 is compiled with -march=native, then YUV decoding time drops to ~130ms, while older ones remains around ~220 ms.
For information, from jpeg-9 source code:
jpeg-9/jccolor.c
* YCbCr is defined per CCIR 601-1, except that Cb and Cr are
* normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
* The conversion equations to be implemented are therefore
* Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
* Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE
* Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE
jpeg-9/jdcolor.c
* YCbCr is defined per CCIR 601-1, except that Cb and Cr are
* normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
* The conversion equations to be implemented are therefore
*
* R = Y + 1.40200 * Cr
* G = Y - 0.34414 * Cb - 0.71414 * Cr
* B = Y + 1.77200 * Cb
Sylvain
Few issues with YUV on SDL2 when using odd dimensions, and missing conversions from/back to YUV formats.
1) The big part is that SDL_ConvertPixels() does not convert to/from YUV in most cases. This now works with any format and also with odd dimensions,
by adding two internal functions SDL_ConvertPixels_YUV_to_ARGB8888 and SDL_ConvertPixels_ARGB8888_to_YUV (could it be XRGB888 ?).
The target format is hard coded to ARGB888 (which is the default in the internal of the software renderer).
In case of different YUV conversion, it will do an intermediate conversion to a ARGB8888 buffer.
SDL_ConvertPixels_YUV_to_ARGB8888 is somehow redundant with all the "Color*Dither*Mod*".
But it allows some completeness of SDL_ConvertPixels to handle all YUV format.
It also works with odd dimensions.
Moreover, I did some benchmark(SDL_ConvertPixel vs Color32DitherYV12Mod1X and Color32DitherYUY2Mod1X).
gcc-6.3 and clang-4.0. gcc performs better than clang. And, with gcc, SDL_ConvertPixels() performs better (20%) than the two C function Color32Dither*().
For instance, to convert 10 times a 3888x2592 image, it takes ~195 ms with SDL_ConvertPixels and ~235 ms with Color32Dither*().
Especially because of gcc vectorize feature that optimises all conversion loops (-ftree-loop-vectorize).
Nb: I put no image pitch for the YUV buffers. because it complexify a little bit the code and the API :
There would be some ambiguity when setting the pitch exactly to image width:
would it a be pitch of image width (for luma and chroma). or just contiguous data ? (could set pitch=0 for the later).
2) Small issues with odd dimensions:
If width "w" is odd, luma plane width is still "w" whereas chroma planes will be "(w + 1)/2". Almost the same for odd h.
Solution is to strategically substitute "w" by "(w+1)/2" at the good places ...
- In the repository, SDL_ConvertPixels() handles YUV only if yuv source format is exactly the same as YUV destination format.
It basically does a memcpy of pixels, but it's done incorrectly when width or height is odd (wrong size of chroma planes). This is fixed.
- SDL Renderers don't support odd width/height for YUV textures.
This is fixed for software, opengl, opengles2. (opengles 1 does not support it and fallback to software rendering).
This is *not* fixed for D3D and D3D11 ... (and others, psp ?)
Only *two* Dither function are fixed ... not sure if others are really used.
- This is not possible to create a NV12/NV12 texture with the software renderer, whereas other renderers allow it.
This is fixed, by using SDL_ConvertPixels underneath.
- It was not possible to SDL_UpdateTexture() of format NV12/NV21 with the software renderer. this is fixed.
Here's also two testcases:
- that do all combination of conversion.
- to test partial UpdateTexture
Steve Robinson
In my existing CMake project, I use add_subdirectory to add the source for SDL2. This worked fine in 2.0.5, but now in 2.0.6 when I build the INSTALL CMake target, I get this error:
file INSTALL cannot find "D:/path/to/SDL2Config.cmake".
Call Stack (most recent call first):
3rdparty/SDL2/cmake_install.cmake:32 (include)
3rdparty/cmake_install.cmake:36 (include)
cmake_install.cmake:32 (include)
To fix this, I changed line 1770 from this:
${CMAKE_SOURCE_DIR}/SDL2Config.cmake
To this:
${CMAKE_CURRENT_SOURCE_DIR}/SDL2Config.cmake
Aaron
As of 2.0.6, all of my games are failing with the following error:
process 31778: arguments to dbus_type_is_basic() were incorrect, assertion "dbus_type_is_valid (typecode) || typecode == DBUS_TYPE_INVALID" failed in file dbus-signature.c line 322.
This is normally a bug in some application using the D-Bus library.
D-Bus not built with -rdynamic so unable to print a backtrace
(patch by Ozkan Sezer)
Evgeny Kapun
Commit 490bb5b49f11 [1], which was a fix for bug #3790, introduced a new bug: now, calling SDL_FreeSurface(surface) deallocates surface->map even if there are other references to the surface. This is bad, because some functions (such as SDL_ConvertSurface) assume that surface->map is not NULL.
Michal
the numbering of the bulletpoints in:
docs/README-ios.md
has been mangled with:
changeset 11365 efd3bc8e5a9b
fix:
12 2. Open SDL.xcodeproj (located in Xcode-iOS/SDL) in Xcode.
13 4. Select your desired target, and hit build.
remove:
28 1. Follow step 1 above.
adapt:
29 2. cd (PATH WHERE THE SDL CODE IS)/build-scripts
30 3. ./iosbuild.sh
Robert Turner
SDL_windowsevents.c contains code to retrieve the x and y coordinate for a requested hit test. It does this as follows:
POINT winpoint = { (int) LOWORD(lParam), (int) HIWORD(lParam) };
LOWORD(lParam) does not correctly mask off high bits that are set if the point is on a second (or third, etc.) monitor. This effectively offsets the x-coordinate by a large value.
MSDN documentation suggests that LOWORD() and HIWORD() are the wrong macros for the task, instead suggesting we should be doing something like the following:
POINT winpoint = { GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam) };
Testing this change on my Windows 10 machine with 2 monitors gives the correct results.
Ozkan Sezer
EMX declares _beginthread() / _endthread() in stdlib.h, not process.h.
The attached patch updates the OS/2 case of SDL_thread.h for it. (It
also tidies the unreadable whitespace in win32 case.)
- Fixing rendering borderless window. Need to force windows to send a WM_NCCALCSIZE then return 0 for non-client area size.
- Adding WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX to borderless windows, for reasons noted in comments.
- Fix SetupWindowData() setting SDL_WINDOW_BORDERLESS. This was being cleared at window creation, causing hanlding for the first WM_NCCALCSIZE message to fail
Mark Callow
Xcode 9 emits a warning to validate project settings. The changes it proposes are
1. [iOS] Update the iOS deployment target to 8.0 since Xcode does
not support anything older.
2. [macOS] Target 'Framework' - Automatically Select Archectures.
3. [iOS & macOS] Turns on a bunch more compile warnings, a *lot* more on iOS.
4. [iOS & macOS] Turn on "Missing Localizability".
I want to confirm if it is ok to accept these changes and submit updated project files.
Since Alex Szpakowski has just removed iOS 7 guard ifdef's, I'm guessing 1 isn't a problem.
2 is probably ok for anyone building themselves. I wonder if it may cause problems for building distribution binaries.
3 shouldn't be a problem either provided any newly emitted warnings are fixed.
4 I am unfamiliar with. The description says "This will turn on the static analyzer to check for "Missing Localizability", because this project is localized for multiple languages." I suppose this may cause new warnings.
Previously, the padding was silence, which was a problem when streaming since
you would sample a little bit of this silence between each buffer.
We still need a means to get padding data for the right hand side, but this
patch makes the resampler output more correct.
Note that apps submitted to the iOS App Store *must* use a modern iOS SDK (currently iOS 10 is probably the minimum), however the SDK used to build is separate from the minimum iOS version an app supports at runtime.
Anthony
This is what's making the software renderer crash with rotated destination rectangles of w or h = 0:
SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2");
This time it's using real math from a real whitepaper instead of my previous
amateur, fast-but-low-quality attempt. The new resampler does "bandlimited
interpolation," as described here: https://ccrma.stanford.edu/~jos/resample/
The output appears to sound cleaner, especially at high frequencies, and of
course works with non-power-of-two rate conversions.
There are some obvious optimizations to be done to this still, and there is
other fallout: this doesn't resample a buffer in-place, the 2-channels-Sint16
fast path is gone because this resampler does a _lot_ of floating point math.
There is a nasty hack to make it work with SDL_AudioCVT.
It's possible these issues are solvable, but they aren't solved as of yet.
Still, I hope this effort is slouching in the right direction.
Sam Lantinga
Brandon Schaefer
Alex Szpakowski
Ryan C. Gordon
Mark Callow