Added initial MJPG support using stb_image

VisualC-GDK/SDL/SDL.vcxproj

@@ -595,6 +595,7 @@
     <ClInclude Include="..\..\src\video\SDL_pixels_c.h" />
     <ClInclude Include="..\..\src\video\SDL_rect_c.h" />
     <ClInclude Include="..\..\src\video\SDL_RLEaccel_c.h" />
+    <ClInclude Include="..\..\src\video\SDL_stb_c.h" />
     <ClInclude Include="..\..\src\video\SDL_surface_c.h" />
     <ClInclude Include="..\..\src\video\SDL_sysvideo.h" />
     <ClInclude Include="..\..\src\video\SDL_vulkan_internal.h" />
@@ -870,6 +871,7 @@
     <ClCompile Include="..\..\src\video\SDL_pixels.c" />
     <ClCompile Include="..\..\src\video\SDL_rect.c" />
     <ClCompile Include="..\..\src\video\SDL_RLEaccel.c" />
+    <ClCompile Include="..\..\src\video\SDL_stb.c" />
     <ClCompile Include="..\..\src\video\SDL_stretch.c" />
     <ClCompile Include="..\..\src\video\SDL_surface.c" />
     <ClCompile Include="..\..\src\video\SDL_video.c" />

VisualC-GDK/SDL/SDL.vcxproj.filters

@@ -176,6 +176,7 @@
     <ClCompile Include="..\..\src\video\SDL_pixels.c" />
     <ClCompile Include="..\..\src\video\SDL_rect.c" />
     <ClCompile Include="..\..\src\video\SDL_RLEaccel.c" />
+    <ClCompile Include="..\..\src\video\SDL_stb.c" />
     <ClCompile Include="..\..\src\video\SDL_stretch.c" />
     <ClCompile Include="..\..\src\video\SDL_surface.c" />
     <ClCompile Include="..\..\src\video\SDL_video.c" />
@@ -436,6 +437,7 @@
     <ClInclude Include="..\..\src\video\SDL_pixels_c.h" />
     <ClInclude Include="..\..\src\video\SDL_rect_c.h" />
     <ClInclude Include="..\..\src\video\SDL_RLEaccel_c.h" />
+    <ClInclude Include="..\..\src\video\SDL_stb_c.h" />
     <ClInclude Include="..\..\src\video\SDL_surface_c.h" />
     <ClInclude Include="..\..\src\video\SDL_sysvideo.h" />
     <ClInclude Include="..\..\src\video\SDL_vulkan_internal.h" />

VisualC/SDL/SDL.vcxproj

@@ -493,6 +493,7 @@
     <ClInclude Include="..\..\src\video\SDL_pixels_c.h" />
     <ClInclude Include="..\..\src\video\SDL_rect_c.h" />
     <ClInclude Include="..\..\src\video\SDL_RLEaccel_c.h" />
+    <ClInclude Include="..\..\src\video\SDL_stb_c.h" />
     <ClInclude Include="..\..\src\video\SDL_surface_c.h" />
     <ClInclude Include="..\..\src\video\SDL_sysvideo.h" />
     <ClInclude Include="..\..\src\video\SDL_vulkan_internal.h" />
@@ -705,6 +706,7 @@
     <ClCompile Include="..\..\src\video\SDL_pixels.c" />
     <ClCompile Include="..\..\src\video\SDL_rect.c" />
     <ClCompile Include="..\..\src\video\SDL_RLEaccel.c" />
+    <ClCompile Include="..\..\src\video\SDL_stb.c" />
     <ClCompile Include="..\..\src\video\SDL_stretch.c" />
     <ClCompile Include="..\..\src\video\SDL_surface.c" />
     <ClCompile Include="..\..\src\video\SDL_video.c" />

VisualC/SDL/SDL.vcxproj.filters

@@ -672,6 +672,9 @@
     <ClInclude Include="..\..\src\video\SDL_egl_c.h">
       <Filter>video</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\src\video\SDL_stb_c.h">
+      <Filter>video</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\src\video\SDL_yuv_c.h">
       <Filter>video</Filter>
     </ClInclude>
@@ -1292,6 +1295,9 @@
     <ClCompile Include="..\..\src\video\SDL_rect.c">
       <Filter>video</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\video\SDL_stb.c">
+      <Filter>video</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\src\video\SDL_stretch.c">
       <Filter>video</Filter>
     </ClCompile>

Xcode/SDL/SDL.xcodeproj/project.pbxproj

@@ -516,6 +516,10 @@
 		F3DDCC5B2AFD42B600B0842B /* SDL_video_c.h in Headers */ = {isa = PBXBuildFile; fileRef = F3DDCC522AFD42B600B0842B /* SDL_video_c.h */; };
 		F3DDCC5D2AFD42B600B0842B /* SDL_rect_impl.h in Headers */ = {isa = PBXBuildFile; fileRef = F3DDCC542AFD42B600B0842B /* SDL_rect_impl.h */; };
 		F3E5A6EB2AD5E0E600293D83 /* SDL_properties.c in Sources */ = {isa = PBXBuildFile; fileRef = F3E5A6EA2AD5E0E600293D83 /* SDL_properties.c */; };
+		F3EFA5ED2D5AB97300BCF22F /* SDL_stb_c.h in Headers */ = {isa = PBXBuildFile; fileRef = F3EFA5EA2D5AB97300BCF22F /* SDL_stb_c.h */; };
+		F3EFA5EE2D5AB97300BCF22F /* stb_image.h in Headers */ = {isa = PBXBuildFile; fileRef = F3EFA5EC2D5AB97300BCF22F /* stb_image.h */; };
+		F3EFA5EF2D5AB97300BCF22F /* SDL_surface_c.h in Headers */ = {isa = PBXBuildFile; fileRef = F3EFA5EB2D5AB97300BCF22F /* SDL_surface_c.h */; };
+		F3EFA5F02D5AB97300BCF22F /* SDL_stb.c in Sources */ = {isa = PBXBuildFile; fileRef = F3EFA5E92D5AB97300BCF22F /* SDL_stb.c */; };
 		F3F07D5A269640160074468B /* SDL_hidapi_luna.c in Sources */ = {isa = PBXBuildFile; fileRef = F3F07D59269640160074468B /* SDL_hidapi_luna.c */; };
 		F3F15D7F2D011912007AE210 /* SDL_dialog.c in Sources */ = {isa = PBXBuildFile; fileRef = F3F15D7D2D011912007AE210 /* SDL_dialog.c */; };
 		F3F15D802D011912007AE210 /* SDL_dialog_utils.h in Headers */ = {isa = PBXBuildFile; fileRef = F3F15D7E2D011912007AE210 /* SDL_dialog_utils.h */; };
@@ -1079,6 +1083,10 @@
 		F3DDCC522AFD42B600B0842B /* SDL_video_c.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SDL_video_c.h; sourceTree = "<group>"; };
 		F3DDCC542AFD42B600B0842B /* SDL_rect_impl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SDL_rect_impl.h; sourceTree = "<group>"; };
 		F3E5A6EA2AD5E0E600293D83 /* SDL_properties.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = SDL_properties.c; sourceTree = "<group>"; };
+		F3EFA5E92D5AB97300BCF22F /* SDL_stb.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = SDL_stb.c; sourceTree = "<group>"; };
+		F3EFA5EA2D5AB97300BCF22F /* SDL_stb_c.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDL_stb_c.h; sourceTree = "<group>"; };
+		F3EFA5EB2D5AB97300BCF22F /* SDL_surface_c.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDL_surface_c.h; sourceTree = "<group>"; };
+		F3EFA5EC2D5AB97300BCF22F /* stb_image.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = stb_image.h; sourceTree = "<group>"; };
 		F3F07D59269640160074468B /* SDL_hidapi_luna.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = SDL_hidapi_luna.c; sourceTree = "<group>"; };
 		F3F15D7C2D011912007AE210 /* SDL_dialog.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = SDL_dialog.h; sourceTree = "<group>"; };
 		F3F15D7D2D011912007AE210 /* SDL_dialog.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = SDL_dialog.c; sourceTree = "<group>"; };
@@ -1586,43 +1594,47 @@
 				A7D8A60523E2513D00DCD162 /* dummy */,
 				A7D8A72123E2513E00DCD162 /* khronos */,
 				A7D8A5EC23E2513D00DCD162 /* offscreen */,
-				A7D8A61823E2513D00DCD162 /* uikit */,
+				A7D8A76B23E2513E00DCD162 /* SDL_blit.h */,
-				A7D8A76C23E2513E00DCD162 /* yuv2rgb */,
+				A7D8A64C23E2513D00DCD162 /* SDL_blit.c */,
 				A7D8A66223E2513E00DCD162 /* SDL_blit_0.c */,
 				A7D8A6FA23E2513E00DCD162 /* SDL_blit_1.c */,
 				A7D8A66423E2513E00DCD162 /* SDL_blit_A.c */,
-				A7D8A63F23E2513D00DCD162 /* SDL_blit_auto.c */,
 				A7D8A73F23E2513E00DCD162 /* SDL_blit_auto.h */,
-				A7D8A61623E2513D00DCD162 /* SDL_blit_copy.c */,
+				A7D8A63F23E2513D00DCD162 /* SDL_blit_auto.c */,
 				A7D8A76623E2513E00DCD162 /* SDL_blit_copy.h */,
+				A7D8A61623E2513D00DCD162 /* SDL_blit_copy.c */,
 				A7D8A64223E2513D00DCD162 /* SDL_blit_N.c */,
-				A7D8A60223E2513D00DCD162 /* SDL_blit_slow.c */,
 				A7D8A66323E2513E00DCD162 /* SDL_blit_slow.h */,
-				A7D8A64C23E2513D00DCD162 /* SDL_blit.c */,
+				A7D8A60223E2513D00DCD162 /* SDL_blit_slow.c */,
-				A7D8A76B23E2513E00DCD162 /* SDL_blit.h */,
 				A7D8A77323E2513E00DCD162 /* SDL_bmp.c */,
-				F3DDCC4D2AFD42B500B0842B /* SDL_clipboard_c.h */,
 				A7D8A67B23E2513E00DCD162 /* SDL_clipboard.c */,
-				A7D8A60423E2513D00DCD162 /* SDL_egl_c.h */,
+				F3DDCC4D2AFD42B500B0842B /* SDL_clipboard_c.h */,
 				A7D8A6B623E2513E00DCD162 /* SDL_egl.c */,
+				A7D8A60423E2513D00DCD162 /* SDL_egl_c.h */,
 				A7D8A76823E2513E00DCD162 /* SDL_fillrect.c */,
-				A7D8A74023E2513E00DCD162 /* SDL_pixels_c.h */,
 				A7D8A64D23E2513D00DCD162 /* SDL_pixels.c */,
+				A7D8A74023E2513E00DCD162 /* SDL_pixels_c.h */,
+				A7D8A63423E2513D00DCD162 /* SDL_rect.c */,
 				A7D8A60C23E2513D00DCD162 /* SDL_rect_c.h */,
 				F3DDCC542AFD42B600B0842B /* SDL_rect_impl.h */,
-				A7D8A63423E2513D00DCD162 /* SDL_rect.c */,
-				A7D8A76723E2513E00DCD162 /* SDL_RLEaccel_c.h */,
 				A7D8A61523E2513D00DCD162 /* SDL_RLEaccel.c */,
+				A7D8A76723E2513E00DCD162 /* SDL_RLEaccel_c.h */,
+				F3EFA5E92D5AB97300BCF22F /* SDL_stb.c */,
+				F3EFA5EA2D5AB97300BCF22F /* SDL_stb_c.h */,
 				A7D8A60323E2513D00DCD162 /* SDL_stretch.c */,
 				A7D8A61423E2513D00DCD162 /* SDL_surface.c */,
+				F3EFA5EB2D5AB97300BCF22F /* SDL_surface_c.h */,
 				A7D8A61723E2513D00DCD162 /* SDL_sysvideo.h */,
+				A7D8A60E23E2513D00DCD162 /* SDL_video.c */,
 				F3DDCC522AFD42B600B0842B /* SDL_video_c.h */,
 				E4F7981F2AD8D87F00669F54 /* SDL_video_unsupported.c */,
-				A7D8A60E23E2513D00DCD162 /* SDL_video.c */,
 				A7D8A63E23E2513D00DCD162 /* SDL_vulkan_internal.h */,
 				A7D8A64023E2513D00DCD162 /* SDL_vulkan_utils.c */,
-				A7D8A76A23E2513E00DCD162 /* SDL_yuv_c.h */,
 				A7D8A67C23E2513E00DCD162 /* SDL_yuv.c */,
+				A7D8A76A23E2513E00DCD162 /* SDL_yuv_c.h */,
+				F3EFA5EC2D5AB97300BCF22F /* stb_image.h */,
+				A7D8A61823E2513D00DCD162 /* uikit */,
+				A7D8A76C23E2513E00DCD162 /* yuv2rgb */,
 			);
 			path = video;
 			sourceTree = "<group>";
@@ -2458,6 +2470,9 @@
 				A7D8BB6F23E2514500DCD162 /* SDL_clipboardevents_c.h in Headers */,
 				A7D8AECA23E2514100DCD162 /* SDL_cocoaclipboard.h in Headers */,
 				A7D8AF1223E2514100DCD162 /* SDL_cocoaevents.h in Headers */,
+				F3EFA5ED2D5AB97300BCF22F /* SDL_stb_c.h in Headers */,
+				F3EFA5EE2D5AB97300BCF22F /* stb_image.h in Headers */,
+				F3EFA5EF2D5AB97300BCF22F /* SDL_surface_c.h in Headers */,
 				A7D8AE8E23E2514100DCD162 /* SDL_cocoakeyboard.h in Headers */,
 				A7D8AF0623E2514100DCD162 /* SDL_cocoamessagebox.h in Headers */,
 				A7D8AEB223E2514100DCD162 /* SDL_cocoametalview.h in Headers */,
@@ -2950,6 +2965,7 @@
 				566E26CF246274CC00718109 /* SDL_syslocale.m in Sources */,
 				A7D8AFC023E2514200DCD162 /* SDL_egl.c in Sources */,
 				A7D8AC3323E2514100DCD162 /* SDL_RLEaccel.c in Sources */,
+				F3EFA5F02D5AB97300BCF22F /* SDL_stb.c in Sources */,
 				A7D8BBB123E2514500DCD162 /* SDL_assert.c in Sources */,
 				A7D8B3DA23E2514300DCD162 /* SDL_bmp.c in Sources */,
 				A7D8B96E23E2514400DCD162 /* SDL_stdlib.c in Sources */,

build-scripts/check_stdlib_usage.py

@@ -161,6 +161,7 @@ def find_symbols_in_file(file: pathlib.Path) -> int:
         "src/libm",
         "src/hidapi",
         "src/video/khronos",
+        "src/video/stb_image.h",
         "include/SDL3",
         "build-scripts/gen_audio_resampler_filter.c",
         "build-scripts/gen_audio_channel_conversion.c",

src/SDL_internal.h

@@ -191,6 +191,11 @@
 #define SDL_VIDEO_RENDER_SW 1
 #endif
 
+/* STB image conversion */
+#if !defined(SDL_HAVE_STB) && !defined(SDL_LEAN_AND_MEAN)
+#define SDL_HAVE_STB 1
+#endif
+
 /* YUV formats
    - handling of YUV surfaces
    - blitting and conversion functions */

src/render/SDL_render.c

@@ -1281,7 +1281,14 @@ static SDL_PixelFormat GetClosestSupportedFormat(SDL_Renderer *renderer, SDL_Pix
 {
     int i;
 
-    if (SDL_ISPIXELFORMAT_FOURCC(format)) {
+    if (format == SDL_PIXELFORMAT_MJPG) {
+        // We'll decode to SDL_PIXELFORMAT_RGBA32
+        for (i = 0; i < renderer->num_texture_formats; ++i) {
+            if (renderer->texture_formats[i] == SDL_PIXELFORMAT_RGBA32) {
+                return renderer->texture_formats[i];
+            }
+        }
+    } else if (SDL_ISPIXELFORMAT_FOURCC(format)) {
         // Look for an exact match
         for (i = 0; i < renderer->num_texture_formats; ++i) {
             if (renderer->texture_formats[i] == format) {
@@ -1443,7 +1450,9 @@ SDL_Texture *SDL_CreateTextureWithProperties(SDL_Renderer *renderer, SDL_Propert
         texture->next = texture->native;
         renderer->textures = texture;
 
-        if (SDL_ISPIXELFORMAT_FOURCC(texture->format)) {
+        if (texture->format == SDL_PIXELFORMAT_MJPG) {
+            // We have a custom decode + upload path for this
+        } else if (SDL_ISPIXELFORMAT_FOURCC(texture->format)) {
 #ifdef SDL_HAVE_YUV
             texture->yuv = SDL_SW_CreateYUVTexture(texture->format, texture->colorspace, w, h);
 #else

src/video/SDL_stb.c

@@ -0,0 +1,92 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#include "SDL_stb_c.h"
+
+
+// We currently only support JPEG, but we could add other image formats if we wanted
+#ifdef SDL_HAVE_STB
+#define malloc SDL_malloc
+#define realloc SDL_realloc
+#define free SDL_free
+#undef memcpy
+#define memcpy SDL_memcpy
+#undef memset
+#define memset SDL_memset
+#undef strcmp
+#define strcmp SDL_strcmp
+#undef strncmp
+#define strncmp SDL_strncmp
+#define strtol SDL_strtol
+
+#define abs SDL_abs
+#define pow SDL_pow
+#define ldexp SDL_scalbn
+
+#define STB_INTERNAL_SDL
+#define STB_IMAGE_STATIC
+#define STBI_FAILURE_USERMSG
+#if defined(SDL_NEON_INTRINSICS)
+#define STBI_NEON
+#endif
+#define STBI_ONLY_JPEG
+#define STBI_NO_GIF
+#define STBI_NO_PNG
+#define STBI_NO_HDR
+#define STBI_NO_LINEAR
+#define STBI_NO_ZLIB
+#define STBI_NO_STDIO
+#define STBI_ASSERT SDL_assert
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+#endif
+
+bool SDL_ConvertPixels_STB(int width, int height,
+                           SDL_PixelFormat src_format, SDL_Colorspace src_colorspace, SDL_PropertiesID src_properties, const void *src, int src_pitch,
+                           SDL_PixelFormat dst_format, SDL_Colorspace dst_colorspace, SDL_PropertiesID dst_properties, void *dst, int dst_pitch)
+{
+#ifdef SDL_HAVE_STB
+    if (src_colorspace != dst_colorspace) {
+        return SDL_SetError("SDL_ConvertPixels_STB: colorspace conversion not supported");
+    }
+
+    if (src_format == dst_format) {
+        if (src == dst) {
+            // Nothing to do
+            return true;
+        }
+    }
+
+    int w = 0, h = 0, format = 0;
+    stbi_uc *pixels = stbi_load_from_memory((const stbi_uc *)src, src_pitch, &w, &h, &format, 4);
+    if (!pixels) {
+        return SDL_SetError("Couldn't decode image: %s", stbi_failure_reason());
+    }
+
+    bool result = SDL_ConvertPixelsAndColorspace(w, h, SDL_PIXELFORMAT_RGBA32, src_colorspace, src_properties, pixels, width * 4, dst_format, dst_colorspace, dst_properties, dst, dst_pitch);
+    stbi_image_free(pixels);
+
+    return result;
+#else
+    return SDL_SetError("SDL not built with STB image support");
+#endif
+}

src/video/SDL_stb_c.h

@@ -0,0 +1,31 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef SDL_stb_c_h_
+#define SDL_stb_c_h_
+
+#include "SDL_internal.h"
+
+// Image conversion functions
+
+extern bool SDL_ConvertPixels_STB(int width, int height, SDL_PixelFormat src_format, SDL_Colorspace src_colorspace, SDL_PropertiesID src_properties, const void *src, int src_pitch, SDL_PixelFormat dst_format, SDL_Colorspace dst_colorspace, SDL_PropertiesID dst_properties, void *dst, int dst_pitch);
+
+#endif // SDL_stb_c_h_

src/video/SDL_surface.c

@@ -24,6 +24,7 @@
 #include "SDL_video_c.h"
 #include "SDL_RLEaccel_c.h"
 #include "SDL_pixels_c.h"
+#include "SDL_stb_c.h"
 #include "SDL_yuv_c.h"
 #include "../render/SDL_sysrender.h"
 
@@ -2277,6 +2278,10 @@ bool SDL_ConvertPixelsAndColorspace(int width, int height,
         dst_colorspace = SDL_GetDefaultColorspaceForFormat(dst_format);
     }
 
+    if (src_format == SDL_PIXELFORMAT_MJPG) {
+        return SDL_ConvertPixels_STB(width, height, src_format, src_colorspace, src_properties, src, src_pitch, dst_format, dst_colorspace, dst_properties, dst, dst_pitch);
+    }
+
 #ifdef SDL_HAVE_YUV
     if (SDL_ISPIXELFORMAT_FOURCC(src_format) && SDL_ISPIXELFORMAT_FOURCC(dst_format)) {
         return SDL_ConvertPixels_YUV_to_YUV(width, height, src_format, src_colorspace, src_properties, src, src_pitch, dst_format, dst_colorspace, dst_properties, dst, dst_pitch);