Add sub-stream support and address Copilot review feedback

Sub-stream support (closes discussion #366):
- Add sub_stream_url field to stream config, coupled into migration 0040
- Register sub-streams with go2rtc as "{name}_sub" when URL is provided
- Frontend grid view uses sub-stream (low-res) when available; fullscreen
  and recording always use the main stream
- Sub-stream URL field added to stream config modal (Basic Information)
- MSE, HLS, and WebRTC video cells accept useSubStream prop

Copilot review fixes:
- Single-URL overrides now emit valid inline YAML scalar form
  ("cam": rtsp://...) instead of block form
- Stream names are YAML-escaped in double-quoted keys (handles " and \)
- DB calls in config generation guarded with get_db_handle() != NULL
  to avoid noisy errors when DB isn't initialized yet
- go2rtc_config_override restart dispatch moved outside if(settings_changed)
  so DB-backed overrides actually trigger a go2rtc restart

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: matteius

db/migrations/0040_add_go2rtc_source_override.sql

@@ -1,11 +1,14 @@
--- Add go2rtc_source_override column to streams table
--- When non-empty, this value is written directly into go2rtc.yaml streams
--- section instead of auto-constructing the source URL from the stream URL.
--- Supports single source URLs or multi-source YAML lists for advanced
--- go2rtc features like failover, transcoding, and hardware acceleration.
+-- Add go2rtc_source_override and sub_stream_url columns to streams table
+--
+-- go2rtc_source_override: when non-empty, written directly into go2rtc.yaml
+-- streams section instead of auto-constructing the source URL.
+--
+-- sub_stream_url: optional low-resolution stream URL used for the dashboard
+-- grid view while the main URL is used for recording and fullscreen viewing.
 
 -- migrate:up
 ALTER TABLE streams ADD COLUMN go2rtc_source_override TEXT DEFAULT '';
+ALTER TABLE streams ADD COLUMN sub_stream_url TEXT DEFAULT '';
 
 -- migrate:down
 -- SQLite does not support DROP COLUMN in older versions; migration is left intentionally empty.

include/core/config.h

@@ -103,6 +103,11 @@ typedef struct {
     // streams section instead of auto-constructing the source URL.
     // Supports single URLs or multi-source YAML lists (e.g. "- rtsp://cam/main\n- ffmpeg:cam#video=h264")
     char go2rtc_source_override[2048];
+
+    // Sub-stream URL: optional low-resolution stream for dashboard grid view.
+    // When non-empty, registered with go2rtc as "{name}_sub" and used by the
+    // frontend in grid view while the main URL is used for fullscreen/recording.
+    char sub_stream_url[MAX_URL_LENGTH];
 } stream_config_t;
 
 // Size of recording schedule text buffer: 168 values + 167 commas + null terminator

include/database/db_embedded_migrations.h

@@ -624,7 +624,8 @@ static const char migration_0039_down[] =
     "SELECT 1;";
 
 static const char migration_0040_up[] =
-    "ALTER TABLE streams ADD COLUMN go2rtc_source_override TEXT DEFAULT '';";
+    "ALTER TABLE streams ADD COLUMN go2rtc_source_override TEXT DEFAULT '';\n"
+    "ALTER TABLE streams ADD COLUMN sub_stream_url TEXT DEFAULT '';";
 
 static const char migration_0040_down[] =
     "SELECT 1;";
@@ -905,7 +906,7 @@ static const migration_t embedded_migrations_data[] = {
     },
     {
         .version = "0040",
-        .description = "add_go2rtc_source_override",
+        .description = "add_go2rtc_source_override_and_sub_stream_url",
         .sql_up = migration_0040_up,
         .sql_down = migration_0040_down,
         .is_embedded = true

src/database/db_streams.c

@@ -132,7 +132,8 @@ uint64_t add_stream_config(const stream_config_t *stream) {
                                 "ptz_enabled = ?, ptz_max_x = ?, ptz_max_y = ?, ptz_max_z = ?, ptz_has_home = ?, "
                                 "onvif_username = ?, onvif_password = ?, onvif_profile = ?, onvif_port = ?, "
                                 "record_on_schedule = ?, recording_schedule = ?, tags = ?, admin_url = ?, "
-                                "privacy_mode = ?, motion_trigger_source = ?, go2rtc_source_override = ? "
+                                "privacy_mode = ?, motion_trigger_source = ?, go2rtc_source_override = ?, "
+                                "sub_stream_url = ? "
                                 "WHERE id = ?;";
 
         rc = sqlite3_prepare_v2(db, update_sql, -1, &stmt, NULL);
@@ -215,9 +216,10 @@ uint64_t add_stream_config(const stream_config_t *stream) {
         sqlite3_bind_int(stmt, 44, stream->privacy_mode ? 1 : 0);
         sqlite3_bind_text(stmt, 45, stream->motion_trigger_source, -1, SQLITE_STATIC);
         sqlite3_bind_text(stmt, 46, stream->go2rtc_source_override, -1, SQLITE_STATIC);
+        sqlite3_bind_text(stmt, 47, stream->sub_stream_url, -1, SQLITE_STATIC);
 
         // Bind ID parameter
-        sqlite3_bind_int64(stmt, 47, (sqlite3_int64)existing_id);
+        sqlite3_bind_int64(stmt, 48, (sqlite3_int64)existing_id);
 
         // Execute statement
         rc = sqlite3_step(stmt);
@@ -265,8 +267,9 @@ uint64_t add_stream_config(const stream_config_t *stream) {
           "tier_critical_multiplier, tier_important_multiplier, tier_ephemeral_multiplier, storage_priority, "
           "ptz_enabled, ptz_max_x, ptz_max_y, ptz_max_z, ptz_has_home, "
           "onvif_username, onvif_password, onvif_profile, onvif_port, "
-          "record_on_schedule, recording_schedule, tags, admin_url, privacy_mode, motion_trigger_source, go2rtc_source_override) "
-          "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);";
+          "record_on_schedule, recording_schedule, tags, admin_url, privacy_mode, motion_trigger_source, "
+          "go2rtc_source_override, sub_stream_url) "
+          "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);";
 
     rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
     if (rc != SQLITE_OK) {
@@ -343,12 +346,13 @@ uint64_t add_stream_config(const stream_config_t *stream) {
     serialize_recording_schedule(stream->recording_schedule, insert_schedule_buf, sizeof(insert_schedule_buf));
     sqlite3_bind_text(stmt, 42, insert_schedule_buf, -1, SQLITE_TRANSIENT);
 
-    // Bind tags, admin URL, privacy_mode, motion_trigger_source, and go2rtc override parameters
+    // Bind tags, admin URL, privacy_mode, motion_trigger_source, go2rtc override, and sub-stream parameters
     sqlite3_bind_text(stmt, 43, stream->tags, -1, SQLITE_STATIC);
     sqlite3_bind_text(stmt, 44, stream->admin_url, -1, SQLITE_STATIC);
     sqlite3_bind_int(stmt, 45, stream->privacy_mode ? 1 : 0);
     sqlite3_bind_text(stmt, 46, stream->motion_trigger_source, -1, SQLITE_STATIC);
     sqlite3_bind_text(stmt, 47, stream->go2rtc_source_override, -1, SQLITE_STATIC);
+    sqlite3_bind_text(stmt, 48, stream->sub_stream_url, -1, SQLITE_STATIC);
 
     // Execute statement
     rc = sqlite3_step(stmt);
@@ -419,7 +423,8 @@ int update_stream_config(const char *name, const stream_config_t *stream) {
                       "ptz_enabled = ?, ptz_max_x = ?, ptz_max_y = ?, ptz_max_z = ?, ptz_has_home = ?, "
                       "onvif_username = ?, onvif_password = ?, onvif_profile = ?, onvif_port = ?, "
                       "record_on_schedule = ?, recording_schedule = ?, tags = ?, admin_url = ?, privacy_mode = ?, "
-                      "motion_trigger_source = ?, go2rtc_source_override = ? "
+                      "motion_trigger_source = ?, go2rtc_source_override = ?, "
+                      "sub_stream_url = ? "
                       "WHERE name = ?;";
 
     rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
@@ -497,15 +502,16 @@ int update_stream_config(const char *name, const stream_config_t *stream) {
     serialize_recording_schedule(stream->recording_schedule, update_schedule_buf, sizeof(update_schedule_buf));
     sqlite3_bind_text(stmt, 42, update_schedule_buf, -1, SQLITE_TRANSIENT);
 
-    // Bind tags, admin URL, privacy_mode, motion_trigger_source, and go2rtc override parameters
+    // Bind tags, admin URL, privacy_mode, motion_trigger_source, go2rtc override, and sub-stream parameters
     sqlite3_bind_text(stmt, 43, stream->tags, -1, SQLITE_STATIC);
     sqlite3_bind_text(stmt, 44, stream->admin_url, -1, SQLITE_STATIC);
     sqlite3_bind_int(stmt, 45, stream->privacy_mode ? 1 : 0);
     sqlite3_bind_text(stmt, 46, stream->motion_trigger_source, -1, SQLITE_STATIC);
     sqlite3_bind_text(stmt, 47, stream->go2rtc_source_override, -1, SQLITE_STATIC);
+    sqlite3_bind_text(stmt, 48, stream->sub_stream_url, -1, SQLITE_STATIC);
 
     // Bind the WHERE clause parameter
-    sqlite3_bind_text(stmt, 48, name, -1, SQLITE_STATIC);
+    sqlite3_bind_text(stmt, 49, name, -1, SQLITE_STATIC);
 
     // Execute statement
     rc = sqlite3_step(stmt);
@@ -778,7 +784,7 @@ int get_stream_config_by_name(const char *name, stream_config_t *stream) {
         "ptz_enabled, ptz_max_x, ptz_max_y, ptz_max_z, ptz_has_home, "
         "onvif_username, onvif_password, onvif_profile, onvif_port, "
         "record_on_schedule, recording_schedule, tags, admin_url, privacy_mode, motion_trigger_source, "
-        "go2rtc_source_override "
+        "go2rtc_source_override, sub_stream_url "
         "FROM streams WHERE name = ?;";
 
     // Column index constants for readability
@@ -794,7 +800,7 @@ int get_stream_config_by_name(const char *name, stream_config_t *stream) {
         COL_PTZ_ENABLED, COL_PTZ_MAX_X, COL_PTZ_MAX_Y, COL_PTZ_MAX_Z, COL_PTZ_HAS_HOME,
         COL_ONVIF_USERNAME, COL_ONVIF_PASSWORD, COL_ONVIF_PROFILE, COL_ONVIF_PORT,
         COL_RECORD_ON_SCHEDULE, COL_RECORDING_SCHEDULE, COL_TAGS, COL_ADMIN_URL, COL_PRIVACY_MODE,
-        COL_MOTION_TRIGGER_SOURCE, COL_GO2RTC_SOURCE_OVERRIDE
+        COL_MOTION_TRIGGER_SOURCE, COL_GO2RTC_SOURCE_OVERRIDE, COL_SUB_STREAM_URL
     };
 
     rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
@@ -963,6 +969,14 @@ int get_stream_config_by_name(const char *name, stream_config_t *stream) {
             stream->go2rtc_source_override[0] = '\0';
         }
 
+        // Sub-stream URL
+        const char *sub_stream_url_val = (const char *)sqlite3_column_text(stmt, COL_SUB_STREAM_URL);
+        if (sub_stream_url_val) {
+            safe_strcpy(stream->sub_stream_url, sub_stream_url_val, sizeof(stream->sub_stream_url), 0);
+        } else {
+            stream->sub_stream_url[0] = '\0';
+        }
+
         result = 0;
     }
 
@@ -1015,7 +1029,7 @@ int get_all_stream_configs(stream_config_t *streams, int max_count) {
         "ptz_enabled, ptz_max_x, ptz_max_y, ptz_max_z, ptz_has_home, "
         "onvif_username, onvif_password, onvif_profile, onvif_port, "
         "record_on_schedule, recording_schedule, tags, admin_url, privacy_mode, motion_trigger_source, "
-        "go2rtc_source_override "
+        "go2rtc_source_override, sub_stream_url "
         "FROM streams ORDER BY name;";
 
     // Column index constants (same as get_stream_config_by_name)
@@ -1031,7 +1045,7 @@ int get_all_stream_configs(stream_config_t *streams, int max_count) {
         COL_PTZ_ENABLED, COL_PTZ_MAX_X, COL_PTZ_MAX_Y, COL_PTZ_MAX_Z, COL_PTZ_HAS_HOME,
         COL_ONVIF_USERNAME, COL_ONVIF_PASSWORD, COL_ONVIF_PROFILE, COL_ONVIF_PORT,
         COL_RECORD_ON_SCHEDULE, COL_RECORDING_SCHEDULE, COL_TAGS, COL_ADMIN_URL, COL_PRIVACY_MODE,
-        COL_MOTION_TRIGGER_SOURCE, COL_GO2RTC_SOURCE_OVERRIDE
+        COL_MOTION_TRIGGER_SOURCE, COL_GO2RTC_SOURCE_OVERRIDE, COL_SUB_STREAM_URL
     };
 
     rc = sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
@@ -1199,6 +1213,14 @@ int get_all_stream_configs(stream_config_t *streams, int max_count) {
             s->go2rtc_source_override[0] = '\0';
         }
 
+        // Sub-stream URL
+        const char *sub_url = (const char *)sqlite3_column_text(stmt, COL_SUB_STREAM_URL);
+        if (sub_url) {
+            safe_strcpy(s->sub_stream_url, sub_url, sizeof(s->sub_stream_url), 0);
+        } else {
+            s->sub_stream_url[0] = '\0';
+        }
+
         count++;
     }
 

src/video/go2rtc/go2rtc_integration.c

@@ -1376,6 +1376,19 @@ bool go2rtc_integration_register_all_streams(void) {
             } else {
                 log_info("Successfully registered stream %s with go2rtc", streams[i].name);
             }
+
+            // Register sub-stream if configured (low-res for grid view)
+            if (streams[i].sub_stream_url[0] != '\0') {
+                char sub_name[MAX_STREAM_NAME + 8];
+                snprintf(sub_name, sizeof(sub_name), "%s_sub", streams[i].name);
+                log_info("Registering sub-stream %s with go2rtc", sub_name);
+                if (!go2rtc_stream_register(sub_name, streams[i].sub_stream_url,
+                                           streams[i].onvif_username[0] != '\0' ? streams[i].onvif_username : NULL,
+                                           streams[i].onvif_password[0] != '\0' ? streams[i].onvif_password : NULL,
+                                           false, streams[i].protocol, false)) {
+                    log_warn("Failed to register sub-stream %s with go2rtc", sub_name);
+                }
+            }
         }
     }
     free(streams);
@@ -1480,6 +1493,18 @@ bool go2rtc_sync_streams_from_database(void) {
             log_info("Successfully synced stream %s to go2rtc", db_streams[i].name);
             synced++;
         }
+
+        // Register sub-stream if configured
+        if (db_streams[i].sub_stream_url[0] != '\0') {
+            char sub_name[MAX_STREAM_NAME + 8];
+            snprintf(sub_name, sizeof(sub_name), "%s_sub", db_streams[i].name);
+            if (!go2rtc_api_stream_exists(sub_name)) {
+                log_info("Registering missing sub-stream %s with go2rtc", sub_name);
+                go2rtc_stream_register(sub_name, db_streams[i].sub_stream_url,
+                                       username, password,
+                                       false, db_streams[i].protocol, false);
+            }
+        }
     }
 
     log_info("go2rtc sync complete: %d synced, %d skipped, %d failed", synced, skipped, failed);
@@ -1847,6 +1872,17 @@ bool go2rtc_integration_register_stream(const char *stream_name) {
                                config.backchannel_enabled, config.protocol,
                                config.record_audio)) {
         log_info("Successfully registered stream %s with go2rtc", stream_name);
+
+        // Register sub-stream if configured
+        if (config.sub_stream_url[0] != '\0') {
+            char sub_name[MAX_STREAM_NAME + 8];
+            snprintf(sub_name, sizeof(sub_name), "%s_sub", stream_name);
+            log_info("Registering sub-stream %s with go2rtc", sub_name);
+            go2rtc_stream_register(sub_name, config.sub_stream_url,
+                                   username[0] != '\0' ? username : NULL,
+                                   password[0] != '\0' ? password : NULL,
+                                   false, config.protocol, false);
+        }
         return true;
     }
 

src/video/go2rtc/go2rtc_process.c

@@ -23,9 +23,26 @@
 #include "core/config.h"
 #include "core/path_utils.h"
 #include "utils/strings.h"
+#include "database/db_core.h"
 #include "database/db_streams.h"
 #include "database/db_system_settings.h"
 
+/**
+ * Escape a string for use inside a YAML double-quoted scalar.
+ * Handles " → \" and \ → \\.  Returns dst.
+ */
+static char *yaml_escape_string(const char *src, char *dst, size_t dst_size) {
+    size_t j = 0;
+    for (size_t i = 0; src[i] && j + 2 < dst_size; i++) {
+        if (src[i] == '"' || src[i] == '\\') {
+            dst[j++] = '\\';
+        }
+        dst[j++] = src[i];
+    }
+    dst[j] = '\0';
+    return dst;
+}
+
 
 // Define PATH_MAX if not defined
 #ifndef PATH_MAX
@@ -703,44 +720,60 @@ bool go2rtc_process_generate_config(const char *config_path, int api_port) {
     // other streams will be registered dynamically via the go2rtc API.
     fprintf(config_file, "\nstreams:\n");
     {
-        int ms = g_config.max_streams > 0 ? g_config.max_streams : 32;
-        stream_config_t *streams = calloc(ms, sizeof(stream_config_t));
-        int count = streams ? get_all_stream_configs(streams, ms) : 0;
         bool has_overridden = false;
+        if (get_db_handle() != NULL) {
+            int ms = g_config.max_streams > 0 ? g_config.max_streams : 32;
+            stream_config_t *streams = calloc(ms, sizeof(stream_config_t));
+            int count = streams ? get_all_stream_configs(streams, ms) : 0;
 
-        for (int i = 0; i < count; i++) {
-            if (!streams[i].enabled) continue;
-            if (streams[i].go2rtc_source_override[0] == '\0') continue;
-
-            has_overridden = true;
-            // Quote stream name for YAML safety (handles spaces, colons, etc.)
-            fprintf(config_file, "  \"%s\":\n", streams[i].name);
-
-            // Write each line of the override with base indentation while
-            // preserving any user-provided indentation within the YAML.
-            const char *p = streams[i].go2rtc_source_override;
-            while (*p) {
-                const char *eol = strchr(p, '\n');
-                if (eol) {
-                    fprintf(config_file, "    %.*s\n", (int)(eol - p), p);
-                    p = eol + 1;
+            for (int i = 0; i < count; i++) {
+                if (!streams[i].enabled) continue;
+                if (streams[i].go2rtc_source_override[0] == '\0') continue;
+
+                has_overridden = true;
+
+                // Escape stream name for YAML double-quoted key safety
+                char escaped_name[MAX_STREAM_NAME * 2];
+                yaml_escape_string(streams[i].name, escaped_name, sizeof(escaped_name));
+
+                const char *override = streams[i].go2rtc_source_override;
+                bool is_single_line = (strchr(override, '\n') == NULL);
+
+                if (is_single_line) {
+                    // Single URL: write as inline YAML scalar
+                    //   "cam": rtsp://camera/stream
+                    fprintf(config_file, "  \"%s\": %s\n", escaped_name, override);
                 } else {
-                    fprintf(config_file, "    %s\n", p);
-                    break;
+                    // Multi-line: write as indented block under the key
+                    //   "cam":
+                    //     - rtsp://camera/main
+                    //     - ffmpeg:cam#video=h264
+                    fprintf(config_file, "  \"%s\":\n", escaped_name);
+                    const char *p = override;
+                    while (*p) {
+                        const char *eol = strchr(p, '\n');
+                        if (eol) {
+                            fprintf(config_file, "    %.*s\n", (int)(eol - p), p);
+                            p = eol + 1;
+                        } else {
+                            fprintf(config_file, "    %s\n", p);
+                            break;
+                        }
+                    }
                 }
             }
+            free(streams);
         }
-
         if (!has_overridden) {
             fprintf(config_file, "  # Streams will be added dynamically via API\n");
         }
-        free(streams);
     }
 
     // Global go2rtc config override from system settings
     {
         char global_override[4096] = {0};
-        if (db_get_system_setting("go2rtc_config_override", global_override, sizeof(global_override)) == 0
+        if (get_db_handle() != NULL
+            && db_get_system_setting("go2rtc_config_override", global_override, sizeof(global_override)) == 0
             && global_override[0] != '\0') {
             fprintf(config_file, "\n# User config override\n");
             fprintf(config_file, "%s\n", global_override);