fix: normalize video duration steps

apps/api/internal/runner/param_processor.go

@@ -3,6 +3,7 @@ package runner
 import (
 	"fmt"
 	"math"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -518,7 +519,7 @@ func (durationProcessor) Process(params map[string]any, modelType string, contex
 	resolution := firstNonEmptyString(stringFromAny(params["resolution"]), context.resolution)
 	modeKey := videoModeKey(params)
 	if options := scopedNumberList(capability["duration_options"], resolution, modeKey); len(options) > 0 {
-		normalized := closestNumber(duration, options)
+		normalized := nextAllowedNumber(duration, options)
 		params["duration"] = normalized
 		syncDurationSeconds(params)
 		if normalized != duration {
@@ -528,7 +529,7 @@ func (durationProcessor) Process(params map[string]any, modelType string, contex
 				"duration",
 				duration,
 				normalized,
-				"duration 不在模型固定时长选项内，已调整为最近的允许值。",
+				"duration 不在模型固定时长选项内，已向上调整为允许值。",
 				capabilityPath(modelType, "duration_options"),
 				capability["duration_options"],
 			)
@@ -555,6 +556,23 @@ func (durationProcessor) Process(params map[string]any, modelType string, contex
 				},
 			)
 		}
+		return true
+	}
+	step := durationStep(capability["duration_step"], resolution, modeKey)
+	normalized := normalizeDurationByStep(duration, step)
+	params["duration"] = normalized
+	syncDurationSeconds(params)
+	if normalized != duration {
+		context.recordChange(
+			"DurationProcessor",
+			"adjust",
+			"duration",
+			duration,
+			normalized,
+			"duration 不符合模型时长步进，已按步进向上归一。",
+			capabilityPath(modelType, "duration_step"),
+			capability["duration_step"],
+		)
 	}
 	return true
 }
@@ -1044,28 +1062,38 @@ func durationStep(value any, scopes ...string) float64 {
 }
 
 func normalizeDurationByRange(target float64, minValue float64, maxValue float64, step float64) float64 {
-	clamped := math.Min(math.Max(target, minValue), maxValue)
-	if step <= 0 {
-		return clamped
+	if minValue > maxValue {
+		minValue, maxValue = maxValue, minValue
 	}
-	snapped := math.Round((clamped-minValue)/step)*step + minValue
+	if step <= 0 {
+		step = 1
+	}
+	clamped := math.Min(math.Max(target, minValue), maxValue)
+	snapped := math.Ceil(((clamped-minValue)/step)-1e-9)*step + minValue
+	snapped = math.Min(math.Max(snapped, minValue), maxValue)
 	return math.Round(snapped*1_000_000) / 1_000_000
 }
 
-func closestNumber(target float64, values []float64) float64 {
+func normalizeDurationByStep(target float64, step float64) float64 {
+	if step <= 0 {
+		step = 1
+	}
+	snapped := math.Ceil((target/step)-1e-9) * step
+	return math.Round(snapped*1_000_000) / 1_000_000
+}
+
+func nextAllowedNumber(target float64, values []float64) float64 {
 	if len(values) == 0 {
 		return target
 	}
-	closest := values[0]
-	minDiff := math.Abs(target - closest)
-	for _, value := range values[1:] {
-		diff := math.Abs(target - value)
-		if diff < minDiff {
-			minDiff = diff
-			closest = value
+	sorted := append([]float64(nil), values...)
+	sort.Float64s(sorted)
+	for _, value := range sorted {
+		if value >= target || math.Abs(value-target) < 1e-9 {
+			return value
 		}
 	}
-	return closest
+	return sorted[len(sorted)-1]
 }
 
 func videoModeKey(params map[string]any) string {

apps/api/internal/runner/param_processor_test.go

@@ -180,6 +180,100 @@ func TestParamProcessorVideoCapabilitiesNormalizeAndFilter(t *testing.T) {
 	}
 }
 
+func TestParamProcessorDurationRangeRoundsFractionalSecondsUp(t *testing.T) {
+	body := map[string]any{
+		"model":    "Seedance",
+		"prompt":   "animate it",
+		"duration": 5.5,
+	}
+	candidate := store.RuntimeModelCandidate{
+		ModelType: "video_generate",
+		Capabilities: map[string]any{
+			"video_generate": map[string]any{
+				"duration_range": []any{3, 12},
+			},
+		},
+	}
+
+	result := preprocessRequestWithLog("videos.generations", body, candidate)
+	if result.Body["duration"] != float64(6) && result.Body["duration"] != 6 {
+		t.Fatalf("fractional duration should be rounded up to default 1s step, got %+v", result.Body["duration"])
+	}
+}
+
+func TestParamProcessorDurationWithoutRangeStillRoundsUp(t *testing.T) {
+	body := map[string]any{
+		"model":    "Seedance",
+		"prompt":   "animate it",
+		"duration": 5.2,
+	}
+	candidate := store.RuntimeModelCandidate{
+		ModelType: "video_generate",
+		Capabilities: map[string]any{
+			"video_generate": map[string]any{},
+		},
+	}
+
+	result := preprocessRequestWithLog("videos.generations", body, candidate)
+	if result.Body["duration"] != float64(6) && result.Body["duration"] != 6 {
+		t.Fatalf("duration should default to a 1s upward step without range, got %+v", result.Body["duration"])
+	}
+}
+
+func TestParamProcessorDurationRangeUsesStepCeilingAndRange(t *testing.T) {
+	body := map[string]any{
+		"model":            "Seedance",
+		"prompt":           "animate it",
+		"duration":         6.1,
+		"duration_seconds": 6.1,
+	}
+	candidate := store.RuntimeModelCandidate{
+		ModelType: "image_to_video",
+		Capabilities: map[string]any{
+			"image_to_video": map[string]any{
+				"duration_range": []any{5, 10},
+				"duration_step":  2,
+			},
+		},
+	}
+
+	result := preprocessRequestWithLog("videos.generations", body, candidate)
+	if result.Body["duration"] != float64(7) && result.Body["duration"] != 7 {
+		t.Fatalf("duration should be rounded up by configured step, got %+v", result.Body["duration"])
+	}
+	if result.Body["duration_seconds"] != result.Body["duration"] {
+		t.Fatalf("duration_seconds should sync with normalized duration, got %+v", result.Body)
+	}
+
+	body["duration"] = 10.1
+	body["duration_seconds"] = 10.1
+	result = preprocessRequestWithLog("videos.generations", body, candidate)
+	if result.Body["duration"] != float64(10) && result.Body["duration"] != 10 {
+		t.Fatalf("duration should be capped by range max, got %+v", result.Body["duration"])
+	}
+}
+
+func TestParamProcessorDurationOptionsChooseNextAllowedValue(t *testing.T) {
+	body := map[string]any{
+		"model":    "Seedance",
+		"prompt":   "animate it",
+		"duration": 8.1,
+	}
+	candidate := store.RuntimeModelCandidate{
+		ModelType: "image_to_video",
+		Capabilities: map[string]any{
+			"image_to_video": map[string]any{
+				"duration_options": []any{4, 8, 12},
+			},
+		},
+	}
+
+	result := preprocessRequestWithLog("videos.generations", body, candidate)
+	if result.Body["duration"] != float64(12) && result.Body["duration"] != 12 {
+		t.Fatalf("duration should use next allowed option, got %+v", result.Body["duration"])
+	}
+}
+
 func TestParamProcessorVideoGenerateLogsFirstFrameRemoval(t *testing.T) {
 	body := map[string]any{
 		"model":  "Seedance T2V",