gui: add support for v4l2request hardware decoding (orange pi)

gui/CMakeLists.txt

@@ -403,6 +403,14 @@ target_link_libraries(vanillagui PRIVATE
     ${_vanilla_gui_libs}
 )
 
+if (LINUX)
+    option(VANILLA_BUILD_USE_V4L2REQUEST "Enable V4L2 Request API (Orange Pi/Cedrus)" OFF)
+    if (VANILLA_BUILD_USE_V4L2REQUEST)
+        target_compile_definitions(vanillagui PRIVATE VANILLA_V4L2REQUEST_AVAILABLE)
+        target_link_libraries(vanillagui PRIVATE udev drm)
+    endif()
+endif()
+
 if (APPLE)
 	target_link_libraries(vanillagui PRIVATE "-framework VideoToolbox" "-framework CoreMedia" iconv)
 endif()

gui/menu/menu_game.c

@@ -18,6 +18,13 @@
 #include "ui/ui_anim.h"
 #include "ui/ui_util.h"
 
+#ifdef VANILLA_V4L2REQUEST_AVAILABLE
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <linux/videodev2.h>
+#endif
+
 static char vpi_toast_string[VPI_TOAST_MAX_LEN];
 static struct timeval vpi_toast_expiry;
 static int vpi_toast_number = 0;
@@ -223,11 +230,50 @@ typedef struct {
 enum HwDecoderType {
     HWDEC_TYPE_NVDEC,
     HWDEC_TYPE_VAAPI,
+    HWDEC_TYPE_V4L2REQUEST,
     HWDEC_TYPE_DRM,
     HWDEC_TYPE_SOFTWARE,
     HWDEC_TYPE_COUNT
 };
 
+#ifdef VANILLA_V4L2REQUEST_AVAILABLE
+static int is_v4l2request_available(void)
+{
+    char path[32];
+    for (int i = 0; i < 64; i++) {
+        snprintf(path, sizeof(path), "/dev/video%d", i);
+        int fd = open(path, O_RDWR | O_NONBLOCK);
+        if (fd < 0) {
+            continue;
+        }
+
+        int found = 0;
+        for (int t = 0; t < 2; t++) {
+            struct v4l2_fmtdesc desc;
+            memset(&desc, 0, sizeof(desc));
+            desc.type = (t == 0) ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
+                                 : V4L2_BUF_TYPE_VIDEO_OUTPUT;
+            for (desc.index = 0; ioctl(fd, VIDIOC_ENUM_FMT, &desc) == 0; desc.index++) {
+                if (desc.pixelformat == V4L2_PIX_FMT_H264_SLICE) {
+                    found = 1;
+                    break;
+                }
+            }
+
+            if (found) {
+                break;
+            }
+        }
+
+        close(fd);
+        if (found) {
+            return 1;
+        }
+    }
+    return 0;
+}
+#endif // VANILLA_V4L2REQUEST_AVAILABLE
+
 void vpi_decode_exit(vpi_decode_state_t *s)
 {
     if (s->frame)
@@ -303,6 +349,8 @@ int vpi_decode_init(vpi_decode_state_t *s)
 {
     int ffmpeg_err;
 
+    // av_log_set_level(AV_LOG_VERBOSE);
+
     // Initialize decoding context, preferring hardware decoding when available
     hwdec_t decoders[HWDEC_TYPE_COUNT];
 
@@ -314,6 +362,10 @@ int vpi_decode_init(vpi_decode_state_t *s)
     decoders[HWDEC_TYPE_VAAPI].codec = avcodec_find_decoder(AV_CODEC_ID_H264);
     decoders[HWDEC_TYPE_VAAPI].get_format = vaapi_get_format;
 
+    decoders[HWDEC_TYPE_V4L2REQUEST].name = "V4L2 Request";
+    decoders[HWDEC_TYPE_V4L2REQUEST].codec = avcodec_find_decoder(AV_CODEC_ID_H264);
+    decoders[HWDEC_TYPE_V4L2REQUEST].get_format = drm_get_format;
+
     decoders[HWDEC_TYPE_DRM].name = "DRM";
     decoders[HWDEC_TYPE_DRM].codec = avcodec_find_decoder_by_name("h264_v4l2m2m");
     decoders[HWDEC_TYPE_DRM].get_format = drm_get_format;
@@ -345,6 +397,15 @@ int vpi_decode_init(vpi_decode_state_t *s)
             }
         }
 
+#ifdef VANILLA_V4L2REQUEST_AVAILABLE
+        if (r != VANILLA_SUCCESS && is_v4l2request_available()) {
+            vpi_decode_exit(s);
+            if ((ffmpeg_err = av_hwdevice_ctx_create(&s->hw_device_ctx, AV_HWDEVICE_TYPE_V4L2REQUEST, NULL, NULL, 0)) >= 0) {
+                r = open_decoder(s, &decoders[HWDEC_TYPE_V4L2REQUEST]);
+            }
+        }
+#endif // VANILLA_V4L2REQUEST_AVAILABLE
+
         // See if we can create a DRM context (Raspberry Pi, et al.)
         if (r != VANILLA_SUCCESS) {
             vpi_decode_exit(s);

gui/ui/ui_sdl.c

@@ -82,6 +82,7 @@ typedef struct {
     SDL_Texture *toast_tex;
     struct timeval toast_expiry;
     AVFrame *frame;
+    AVFrame *held_frame; // keeps the displayed dmabuf alive until the next frame replaces it
 	SDL_Texture *pw_tex;
 
 	uint8_t audio_buffer[AUDIO_BUFFER_COUNT][AUDIO_BUFFER_SIZE];
@@ -888,6 +889,7 @@ int vui_init_sdl(vui_context_t *ctx, int fullscreen)
 #endif
 
     sdl_ctx->frame = av_frame_alloc();
+    sdl_ctx->held_frame = av_frame_alloc();
 
 	// Initialize gamepad lookup tables
 	init_gamepad(ctx);
@@ -903,6 +905,7 @@ void vui_close_sdl(vui_context_t *ctx)
     }
 
     av_frame_free(&sdl_ctx->frame);
+    av_frame_free(&sdl_ctx->held_frame);
 
 #ifdef VANILLA_NX_IMU
     vpi_nx_imu_quit();
@@ -1798,7 +1801,14 @@ int get_texture_from_drm_prime_frame(vui_sdl_context_t *sdl_ctx, AVFrame *f)
                 }
             }
 
-            EGLAttrib use_fmt = layer->format == DRM_FORMAT_YUV420 ? DRM_FORMAT_R8 : layer->format;
+            EGLAttrib use_fmt;
+            if (layer->format == DRM_FORMAT_YUV420) {
+                use_fmt = DRM_FORMAT_R8;
+            } else if (layer->format == DRM_FORMAT_NV12) {
+                use_fmt = (image_index == 0) ? DRM_FORMAT_R8 : DRM_FORMAT_GR88;
+            } else {
+                use_fmt = layer->format;
+            }
 
             int w = f->width;
             int h = f->height;
@@ -1966,7 +1976,9 @@ int vui_update_sdl(vui_context_t *vui)
 				get_texture_from_cpu_frame(sdl_ctx, sdl_ctx->frame);
                 break;
             }
-			av_frame_unref(sdl_ctx->frame);
+
+			av_frame_unref(sdl_ctx->held_frame);
+			av_frame_move_ref(sdl_ctx->held_frame, sdl_ctx->frame);
 
             if (sdl_ctx->game_tex) {
                 if (handle_final_blit) {