tools/guest-diag: tag BGRA capture records as GZF2 fmt 33

sdl_cap.c wrote the same 32 in the GZF2 record format field for every
capture path, so gzf2_video.py's auto mode decoded ARGB8888/X-surface
frames (BGRA byte order on little-endian) as RGBA and swapped red and
blue. Make the field the documented pixel-order tag: 32 = RGBA8 from
the GL swap path (glReadPixels GL_RGBA), 33 = BGRA8 from
SDL_RenderReadPixels(ARGB8888) and X window surfaces; xgrab.c tags its
ZPixmap BGRA records 33 as well.

gzf2_video.py continues to accept both tags (and old all-32 captures
via --pix-fmt bgra), checks ffmpeg/ffprobe before indexing, and keeps
the final resampled endpoint so a 90-frame 60 fps capture encodes as
90 frames instead of 88.

1 files changed, 13 insertions, 8 deletions

diff --git a/tools/guest-diag/sdl_cap.c b/tools/guest-diag/sdl_cap.c
index 5b9c096..f875ed0 100644
--- a/tools/guest-diag/sdl_cap.c
+++ b/tools/guest-diag/sdl_cap.c
@@ -11,9 +11,12 @@
 // File layout (little endian):
 //   [0]   8B  magic "GZCAPV01"  (+ 4088 B reserved zero)
 //   [4096] frame records:
-//         4B "GZF2" | u32 w | u32 h | u32 stride | u32 bpp
+//         4B "GZF2" | u32 w | u32 h | u32 stride | u32 fmt
 //         u64 ts_ns (CLOCK_MONOTONIC) | u64 seq | stride*h bytes (top-down)
-//   A trailing record with seq = 0xFFFFFFFFFFFFFFFF marks clean stop.
+//   fmt is a pixel-order tag (not bits per pixel): 32 = RGBA8 from the GL
+//   swap path (glReadPixels GL_RGBA), 33 = BGRA8 from SDL_RenderReadPixels
+//   ARGB8888 or an X window surface.  A trailing record with
+//   seq = 0xFFFFFFFFFFFFFFFF marks clean stop.
 //
 // Env: GZCAP (path, default /dev/shm/gzframes.bin), GZCAP_MAXF (0=unlimited)
 #define _GNU_SOURCE
@@ -26,6 +29,8 @@
 #include <unistd.h>
 
 #define ARGB8888 0x16362004u
+#define GZF2_FMT_RGBA 32
+#define GZF2_FMT_BGRA 33
 
 typedef struct SDL_Renderer SDL_Renderer;
 typedef struct SDL_Window SDL_Window;
@@ -87,7 +92,7 @@ __attribute__((constructor)) static void cap_init(void)
         if (h)
             real_glReadPixels = dlsym(h, "glReadPixels");
     }
-    fprintf(stderr, "[gzcap] init pid=%d path=%s present=%p updwin=%p swap=%p read=%p gros=%p\n",
+    fprintf(stderr, "[gzcap] init pid=%d path=%s present=%p updwin=%p swap=%p read=%p gros=%p readpix=%p\n",
             (int)getpid(), p, (void *)real_RenderPresent, (void *)real_UpdateWindowSurface,
             (void *)real_GL_SwapWindow, (void *)real_RenderReadPixels,
             (void *)real_GetRendererOutputSize, (void *)real_glReadPixels);
@@ -102,7 +107,7 @@ __attribute__((constructor)) static void cap_init(void)
     fflush(cap_fp);
 }
 
-static void cap_record(const void *px, int w, int h, int stride, int bpp)
+static void cap_record(const void *px, int w, int h, int stride, int fmt)
 {
     struct timespec ts;
     uint64_t tns, seq;
@@ -126,7 +131,7 @@ static void cap_record(const void *px, int w, int h, int stride, int bpp)
     rh[0] = (uint32_t)w;
     rh[1] = (uint32_t)h;
     rh[2] = (uint32_t)stride;
-    rh[3] = (uint32_t)bpp;
+    rh[3] = (uint32_t)fmt;
     fwrite(m, 1, 4, cap_fp);
     fwrite(rh, 4, 4, cap_fp);
     fwrite(&tns, 8, 1, cap_fp);
@@ -161,7 +166,7 @@ int SDL_RenderPresent(SDL_Renderer *r)
             }
             if (buf && real_RenderReadPixels(r, NULL, ARGB8888, buf,
                                              w * 4) == 0)
-                cap_record(buf, w, h, w * 4, 32);
+                cap_record(buf, w, h, w * 4, GZF2_FMT_BGRA);
         }
     }
     if (real_RenderPresent)
@@ -180,7 +185,7 @@ int SDL_UpdateWindowSurface(SDL_Window *win)
 
         if (s && s->pixels && s->w > 0 && s->h > 0 && s->pitch > 0 &&
             s->w <= 4096 && s->h <= 4096)
-            cap_record(s->pixels, s->w, s->h, s->pitch, 32);
+            cap_record(s->pixels, s->w, s->h, s->pitch, GZF2_FMT_BGRA);
     }
     if (real_UpdateWindowSurface)
         return real_UpdateWindowSurface(win);
@@ -221,7 +226,7 @@ void SDL_GL_SwapWindow(SDL_Window *win)
                             memcpy(tmp + (size_t)y * w * 4,
                                    gbuf + (size_t)(h - 1 - y) * w * 4,
                                    (size_t)w * 4);
-                        cap_record(tmp, w, h, w * 4, 32);
+                        cap_record(tmp, w, h, w * 4, GZF2_FMT_RGBA);
                         free(tmp);
                     }
                 }