feat: add live session diagnostics

TargetBridge-Receiver/TBReceiverC/Makefile

@@ -34,7 +34,7 @@ ifeq ($(UNAME_S),Darwin)
 LDFLAGS  += -framework ApplicationServices -framework AppKit -framework CoreFoundation -framework CoreGraphics -framework CoreText -framework VideoToolbox -framework CoreMedia -framework CoreVideo -framework IOSurface -framework CoreServices -framework CoreAudio -framework SystemConfiguration
 endif
 
-C_SRC = src/main.c src/net.c src/decoder.c src/display.c src/input_queue.c src/receiver_profile.c src/tb_i18n.c
+C_SRC = src/main.c src/net.c src/decoder.c src/display.c src/input_queue.c src/receiver_profile.c src/session_metrics.c src/tb_i18n.c
 OBJC_SRC = src/tb_gesture_bridge.m src/tb_display_tweaks.m
 OBJ = $(C_SRC:.c=.o) $(OBJC_SRC:.m=.o)
 BIN = tbreceiver
@@ -51,7 +51,7 @@ $(BIN): $(OBJ)
 	$(CC) $(CFLAGS) -fobjc-arc -c -o $@ $<
 
 clean:
-	rm -f $(OBJ) $(BIN) $(TEST_BIN) $(TEST_INPUT_QUEUE_BIN) $(TEST_RECEIVER_PROFILE_BIN)
+	rm -f $(OBJ) $(BIN) $(TEST_BIN) $(TEST_INPUT_QUEUE_BIN) $(TEST_RECEIVER_PROFILE_BIN) $(TEST_SESSION_METRICS_BIN)
 
 # Unit tests for the packet parser. net.c is pure POSIX, so this needs no
 # ffmpeg/SDL/pkgconf — it runs anywhere, including CI, with no hardware.
@@ -63,6 +63,7 @@ endif
 TEST_BIN = test_net_parser
 TEST_INPUT_QUEUE_BIN = test_input_queue
 TEST_RECEIVER_PROFILE_BIN = test_receiver_profile
+TEST_SESSION_METRICS_BIN = test_session_metrics
 
 test_net_parser: tests/test_net_parser.c src/net.c src/net.h src/proto.h
 	$(CC) $(TEST_CFLAGS) -Isrc tests/test_net_parser.c src/net.c $(TEST_LDFLAGS) -o $@
@@ -73,9 +74,13 @@ $(TEST_INPUT_QUEUE_BIN): tests/test_input_queue.c src/input_queue.c src/input_qu
 $(TEST_RECEIVER_PROFILE_BIN): tests/test_receiver_profile.c src/receiver_profile.c src/receiver_profile.h
 	$(CC) $(TEST_CFLAGS) -Isrc tests/test_receiver_profile.c src/receiver_profile.c -o $@
 
-test: $(TEST_BIN) $(TEST_INPUT_QUEUE_BIN) $(TEST_RECEIVER_PROFILE_BIN)
+$(TEST_SESSION_METRICS_BIN): tests/test_session_metrics.c src/session_metrics.c src/session_metrics.h
+	$(CC) $(TEST_CFLAGS) -Isrc tests/test_session_metrics.c src/session_metrics.c -o $@
+
+test: $(TEST_BIN) $(TEST_INPUT_QUEUE_BIN) $(TEST_RECEIVER_PROFILE_BIN) $(TEST_SESSION_METRICS_BIN)
 	./$(TEST_BIN)
 	./$(TEST_INPUT_QUEUE_BIN)
 	./$(TEST_RECEIVER_PROFILE_BIN)
+	./$(TEST_SESSION_METRICS_BIN)
 
 .PHONY: all clean test

TargetBridge-Receiver/TBReceiverC/src/decoder.c

@@ -36,6 +36,7 @@ struct tb_decoder {
     struct SwsContext *sws;
     enum AVPixelFormat hw_pix_fmt;
     int               using_software_decode;
+    uint64_t          error_count;
 
     uint8_t          *extradata;
     int               extradata_size;
@@ -130,13 +131,37 @@ int tb_dec_supports_hevc_hwdecode(void) {
     return status >= 0 ? 1 : 0;
 }
 
+const char *tb_dec_backend_name(const struct tb_decoder *d) {
+    if (!d || !d->opened) return "pending";
+    if (d->using_software_decode || !d->hw_dev) return "software";
+#if defined(__APPLE__)
+    return "VideoToolbox";
+#else
+    return "hardware";
+#endif
+}
+
+const char *tb_dec_codec_name(const struct tb_decoder *d) {
+    if (!d || !d->opened) return "pending";
+    switch (d->codec_id) {
+    case AV_CODEC_ID_H264: return "H.264";
+    case AV_CODEC_ID_HEVC: return "HEVC";
+    default: return "unknown";
+    }
+}
+
+uint64_t tb_dec_error_count(const struct tb_decoder *d) {
+    return d ? d->error_count : 0;
+}
+
 void tb_dec_reset(struct tb_decoder *d) {
     if (!d) return;
     if (d->ctx) avcodec_free_context(&d->ctx);
     av_free(d->extradata);
     d->extradata      = NULL;
     d->extradata_size = 0;
     d->opened         = 0;
+    d->error_count    = 0;
     /* hw_dev, hw_frame, sw_frame, pkt stay allocated for reuse. */
 }
 
@@ -289,6 +314,7 @@ int tb_dec_set_param_sets(struct tb_decoder *d, const uint8_t *payload, size_t l
         d->extradata      = prev_ed;
         d->extradata_size = prev_sz;
         fprintf(stderr, "[dec] build_extradata failed\n");
+        d->error_count++;
         return -1;
     }
 
@@ -303,7 +329,11 @@ int tb_dec_set_param_sets(struct tb_decoder *d, const uint8_t *payload, size_t l
 
     av_free(prev_ed);
     fprintf(stderr, "[dec] param sets changed, opening decoder\n");
-    return open_decoder(d);
+    if (open_decoder(d) < 0) {
+        d->error_count++;
+        return -1;
+    }
+    return 0;
 }
 
 /* Convert AVCC (length-prefixed) frame to Annex B (start codes) in scratch. */
@@ -340,25 +370,36 @@ static int avcc_to_annexb(struct tb_decoder *d,
 }
 
 int tb_dec_feed_frame(struct tb_decoder *d, const uint8_t *avcc, size_t len) {
-    if (!d->opened) return -1;
+    if (!d->opened) {
+        d->error_count++;
+        return -1;
+    }
 
     uint8_t *anb = NULL;
     size_t   anb_len = 0;
-    if (avcc_to_annexb(d, avcc, len, &anb, &anb_len) < 0) return -1;
+    if (avcc_to_annexb(d, avcc, len, &anb, &anb_len) < 0) {
+        d->error_count++;
+        return -1;
+    }
 
     d->pkt->data = anb;
     d->pkt->size = (int)anb_len;
 
     int r = avcodec_send_packet(d->ctx, d->pkt);
     if (r < 0 && r != AVERROR(EAGAIN)) {
         fprintf(stderr, "[dec] send_packet=%d\n", r);
+        d->error_count++;
         return -1;
     }
 
     while (1) {
         r = avcodec_receive_frame(d->ctx, d->hw_frame);
         if (r == AVERROR(EAGAIN) || r == AVERROR_EOF) return 0;
-        if (r < 0) { fprintf(stderr, "[dec] recv_frame=%d\n", r); return -1; }
+        if (r < 0) {
+            fprintf(stderr, "[dec] recv_frame=%d\n", r);
+            d->error_count++;
+            return -1;
+        }
 
 #if defined(__APPLE__)
         /* Zero-copy fast path: VideoToolbox decoded frames carry a
@@ -389,6 +430,7 @@ int tb_dec_feed_frame(struct tb_decoder *d, const uint8_t *avcc, size_t len) {
             d->sw_frame->format = AV_PIX_FMT_NV12;
             if (av_hwframe_transfer_data(d->sw_frame, d->hw_frame, 0) < 0) {
                 fprintf(stderr, "[dec] hwframe_transfer failed\n");
+                d->error_count++;
                 av_frame_unref(d->hw_frame);
                 continue;
             }
@@ -410,9 +452,11 @@ int tb_dec_feed_frame(struct tb_decoder *d, const uint8_t *avcc, size_t len) {
             d->nv12_frame->height = out->height;
             if (!d->sws || av_frame_get_buffer(d->nv12_frame, 32) < 0) {
                 fprintf(stderr, "[dec] could not allocate NV12 software frame\n");
+                d->error_count++;
             } else if (sws_scale(d->sws, (const uint8_t * const *)out->data, out->linesize,
                                  0, out->height, d->nv12_frame->data, d->nv12_frame->linesize) <= 0) {
                 fprintf(stderr, "[dec] software frame conversion failed\n");
+                d->error_count++;
             } else {
                 d->cb(d->nv12_frame->data[0], d->nv12_frame->linesize[0],
                       d->nv12_frame->data[1], d->nv12_frame->linesize[1],

TargetBridge-Receiver/TBReceiverC/src/decoder.h

@@ -21,6 +21,9 @@ struct tb_decoder;
 struct tb_decoder *tb_dec_create(tb_frame_cb cb, void *ud);
 void               tb_dec_destroy(struct tb_decoder *d);
 int                tb_dec_supports_hevc_hwdecode(void);
+const char        *tb_dec_backend_name(const struct tb_decoder *d);
+const char        *tb_dec_codec_name(const struct tb_decoder *d);
+uint64_t           tb_dec_error_count(const struct tb_decoder *d);
 
 /* Reset decoder state on client disconnect.
  * Forces re-open on next param sets so a stale FFmpeg context doesn't

TargetBridge-Receiver/TBReceiverC/src/display.c

@@ -33,6 +33,7 @@ struct tb_display {
     SDL_Renderer *ren;
     SDL_Texture  *tex;
     SDL_Texture  *status_tex;
+    char          renderer_name[64];
     int           tex_w, tex_h;
     int           quit;
     int           preferred_fullscreen;
@@ -590,6 +591,9 @@ struct tb_display *tb_disp_create(int fullscreen) {
     SDL_RendererInfo info;
     if (SDL_GetRendererInfo(d->ren, &info) == 0) {
         fprintf(stderr, "[disp] renderer = %s\n", info.name);
+        snprintf(d->renderer_name, sizeof(d->renderer_name), "%s", info.name ? info.name : "unknown");
+    } else {
+        snprintf(d->renderer_name, sizeof(d->renderer_name), "%s", "unknown");
     }
 
     int win_w = 0, win_h = 0, out_w = 0, out_h = 0;
@@ -623,6 +627,11 @@ struct tb_display *tb_disp_create(int fullscreen) {
     return d;
 }
 
+const char *tb_disp_renderer_name(struct tb_display *d) {
+    if (!d || d->renderer_name[0] == '\0') return "unknown";
+    return d->renderer_name;
+}
+
 void tb_disp_destroy(struct tb_display *d) {
     if (!d) return;
     if (d->system_cursor_hidden) {

TargetBridge-Receiver/TBReceiverC/src/display.h

@@ -65,6 +65,9 @@ int          tb_disp_pop_input_event(struct tb_display *d, struct tb_input_event
 /* Query active display/window/drawable information for UI/debug metadata. */
 int  tb_disp_get_info(struct tb_display *d, struct tb_display_info *info);
 
+/* Actual SDL renderer selected at runtime (for example opengl or metal). */
+const char *tb_disp_renderer_name(struct tb_display *d);
+
 /* Render a simple launcher/status UI before the video stream starts. */
 void tb_disp_render_status(struct tb_display *d,
                            const char *ip,

TargetBridge-Receiver/TBReceiverC/src/main.c

@@ -17,6 +17,7 @@
 #include "decoder.h"
 #include "display.h"
 #include "receiver_profile.h"
+#include "session_metrics.h"
 #include "proto.h"
 #include "tb_gesture_bridge.h"
 #include "tb_display_tweaks.h"
@@ -65,6 +66,7 @@ struct app {
     uint64_t frames;
     uint64_t last_fps_tick_ms;
     uint64_t last_fps_count;
+    int      raw_stream_active;
     uint64_t last_ip_check_ms;
     /* Last display-tweak state reported to the sender, so changes made on this
      * Mac (Control Center, System Settings) propagate back and the sender's
@@ -1091,16 +1093,18 @@ static void on_packet(uint8_t type, const uint8_t *payload, size_t len, void *ud
         break;
     case TB_PKT_PARAM_SETS:
         a->session_active = 1;
+        a->raw_stream_active = 0;
         /* tb_dec_set_param_sets is now a no-op if the sets are unchanged,
          * so we don't spam a log line per keyframe. */
-        tb_dec_set_param_sets(a->dec, payload, len);
+        (void)tb_dec_set_param_sets(a->dec, payload, len);
         break;
     case TB_PKT_FRAME:
         a->session_active = 1;
-        tb_dec_feed_frame(a->dec, payload, len);
+        (void)tb_dec_feed_frame(a->dec, payload, len);
         break;
     case TB_PKT_RAW_FRAME:
         a->session_active = 1;
+        a->raw_stream_active = 1;
         handle_raw_frame(a, payload, len);
         break;
     case TB_PKT_CURSOR:
@@ -1261,6 +1265,32 @@ static int send_all(int fd, const uint8_t *buf, size_t len) {
     return 0;
 }
 
+static void tb_receiver_send_session_metrics(struct app *a, uint64_t receiver_fps) {
+    if (!a || a->client_fd < 0 || !a->session_active) return;
+
+    const char *renderer = tb_disp_renderer_name(a->disp);
+    const char *decoder = a->raw_stream_active ? "none" : tb_dec_backend_name(a->dec);
+    const char *codec = a->raw_stream_active ? "NV12 RAW" : tb_dec_codec_name(a->dec);
+
+    char json[512];
+    int len = tb_session_metrics_json(
+        json,
+        sizeof(json),
+        receiver_fps,
+        a->frames,
+        tb_dec_error_count(a->dec),
+        renderer,
+        decoder,
+        codec);
+    if (len < 0) return;
+
+    uint8_t pkt[4 + 1 + sizeof(json)];
+    write_be32(pkt, (uint32_t)(1 + len));
+    pkt[4] = TB_PKT_SESSION_METRICS;
+    memcpy(pkt + 5, json, (size_t)len);
+    (void)send_all(a->client_fd, pkt, 5 + (size_t)len);
+}
+
 static void tb_receiver_send_input_event(struct app *a,
                                          const char *kind,
                                          int has_dx, int dx,
@@ -1803,6 +1833,8 @@ static void close_client(struct app *a) {
     a->session_active = 0;
     a->close_requested = 0;
     a->have_video_frame = 0;
+    a->raw_stream_active = 0;
+    a->last_fps_count = a->frames;
     snprintf(a->input_control_mode, sizeof(a->input_control_mode), "off");
     SDL_EnableScreenSaver();
     tb_receiver_refresh_input_capture(a);
@@ -2038,6 +2070,9 @@ int main(int argc, char **argv) {
                 a.client_fd = c;
                 a.have_video_frame = 0;
                 a.session_active = 0;
+                a.raw_stream_active = 0;
+                a.last_fps_count = a.frames;
+                a.last_fps_tick_ms = t;
                 a.reported_night_shift = -1;   /* force one report per session */
                 a.reported_true_tone = -1;
                 a.last_recv_ms = t;
@@ -2166,6 +2201,7 @@ int main(int argc, char **argv) {
             a.last_fps_count   = a.frames;
             a.last_fps_tick_ms = t;
             if (df > 0) fprintf(stderr, "[main] %llu fps\n", (unsigned long long)df);
+            tb_receiver_send_session_metrics(&a, df);
         }
 
         /* Yield when idle or when a nonblocking active socket had no data,

TargetBridge-Receiver/TBReceiverC/src/proto.h

@@ -29,6 +29,7 @@
  * type 0x35 = brightness update (JSON)
  * type 0x36 = clipboard update (JSON)
  * type 0x37 = volume update (JSON)
+ * type 0x39 = receiver session metrics (JSON, receiver → sender)
  *
  * Compatible with the new TBDisplaySender Swift app.
  */
@@ -59,6 +60,7 @@
  * Both are private CoreBrightness features, so the receiver reports whether it
  * can honour them in its display profile. */
 #define TB_PKT_DISPLAY_TWEAKS   0x38
+#define TB_PKT_SESSION_METRICS  0x39
 #define TB_PKT_TEST_DATA        0x40
 
 #define TB_HDR_BYTES        5   /* 4 length + 1 type */

TargetBridge-Receiver/TBReceiverC/src/session_metrics.c

@@ -0,0 +1,29 @@
+#include "session_metrics.h"
+
+#include <stdio.h>
+
+int tb_session_metrics_json(char *dst,
+                            size_t dst_size,
+                            uint64_t receiver_fps,
+                            uint64_t rendered_frames,
+                            uint64_t decode_errors,
+                            const char *renderer,
+                            const char *decoder,
+                            const char *codec) {
+    if (!dst || dst_size == 0) return -1;
+
+    int len = snprintf(
+        dst,
+        dst_size,
+        "{\"receiverFPS\":%llu,\"renderedFrames\":%llu,\"decodeErrors\":%llu,"
+        "\"renderer\":\"%s\",\"decoder\":\"%s\",\"codec\":\"%s\"}",
+        (unsigned long long)receiver_fps,
+        (unsigned long long)rendered_frames,
+        (unsigned long long)decode_errors,
+        renderer ? renderer : "unknown",
+        decoder ? decoder : "unknown",
+        codec ? codec : "unknown");
+
+    if (len <= 0 || (size_t)len >= dst_size) return -1;
+    return len;
+}

TargetBridge-Receiver/TBReceiverC/src/session_metrics.h

@@ -0,0 +1,20 @@
+#ifndef TB_SESSION_METRICS_H
+#define TB_SESSION_METRICS_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Build the compact JSON payload carried by TB_PKT_SESSION_METRICS.
+ * Returns the byte length (excluding the trailing NUL), or -1 when the
+ * destination is too small. String values must be stable backend names; the
+ * receiver only supplies its own fixed labels, never user-provided text. */
+int tb_session_metrics_json(char *dst,
+                            size_t dst_size,
+                            uint64_t receiver_fps,
+                            uint64_t rendered_frames,
+                            uint64_t decode_errors,
+                            const char *renderer,
+                            const char *decoder,
+                            const char *codec);
+
+#endif /* TB_SESSION_METRICS_H */