diff --git a/apps/api/app/api/routes/viral_video.py b/apps/api/app/api/routes/viral_video.py
index b55e06bbe..fa37af60b 100644
--- a/apps/api/app/api/routes/viral_video.py
+++ b/apps/api/app/api/routes/viral_video.py
@@ -32,9 +32,11 @@ from app.schemas.viral_video import (
     ConfirmCopyRequest,
     ConfirmIntentRequest,
     CreateViralVideoRequest,
+    CreditsFormulaBreakdown,
     EstimateCreditsRequest,
     EstimateCreditsResponse,
     GenerateCopyRequest,
+    RetryViralVideoRequest,
     StyleTemplateListResponse,
     StyleTemplateResponse,
     ViralVideoHistoryResponse,
@@ -391,14 +393,28 @@ def estimate_credits(
     request: EstimateCreditsRequest,
     authenticated_user: AuthenticatedUser = Depends(get_current_user),
 ) -> EstimateCreditsResponse:
-    """爆款视频积分预估（纯计算，不扣费、不创建任务）。"""
-    from packages.domain.points_rules import calculate_viral_video_credits, resolve_video_dimensions
+    """爆款视频积分预估（纯计算，不扣费、不创建任务）。
 
-    w, h = resolve_video_dimensions(request.resolution, request.ratio)
-    credits = calculate_viral_video_credits(
-        request.duration, w, h, request.model or "seedance-2.5"
+    返回 estimated_credits 与 formula_breakdown（tokens / video_cost / fixed_cost /
+    profit_multiplier / model_price / width / height / fps），便于前端展示计费明细。
+    同时兼容前端传 model 或 video_model、resolution 或 video_resolution、ratio 或 video_ratio。
+    """
+    from packages.domain.points_rules import (
+        calculate_viral_video_credits_with_breakdown,
+        resolve_video_dimensions,
     )
-    return EstimateCreditsResponse(estimated_credits=credits)
+
+    model = (request.model or "").strip() or "seedance-2.5"
+    resolution = (request.resolution or "").strip() or "720p"
+    ratio = (request.ratio or "").strip() or "9:16"
+    duration = int(request.duration or 15)
+
+    w, h = resolve_video_dimensions(resolution, ratio)
+    credits, bd = calculate_viral_video_credits_with_breakdown(
+        duration, w, h, model,
+    )
+    breakdown = CreditsFormulaBreakdown(**bd)
+    return EstimateCreditsResponse(estimated_credits=credits, formula_breakdown=breakdown)
 
 
 @router.get("/history", response_model=ViralVideoHistoryResponse)
@@ -454,10 +470,17 @@ def get_viral_video_job(
 @router.post("/{job_id}/retry", response_model=ViralVideoJobResponse)
 def retry_viral_video_job(
     job_id: str,
+    request: RetryViralVideoRequest | None = None,
     authenticated_user: AuthenticatedUser = Depends(get_current_user),
     session: Session = Depends(get_db_session),
 ) -> ViralVideoJobResponse:
-    """重试失败的爆款视频任务（也支持对僵尸/超时 running 任务强制重置后重试）。"""
+    """重试失败的爆款视频任务（也支持对僵尸/超时 running 任务强制重置后重试）。
+
+    可选 body (RetryViralVideoRequest)：若传入新的 duration/video_resolution/video_ratio/
+    video_model，会重新预估积分并与原 credits_prepaid 做差额多退少补（不足抛 402 阻止重试）；
+    不传 body 或参数无变化时，保持原参数、原预扣金额不变，仅重置状态并入队。
+    credits_prepaid 为 0 的老任务首次重试会走预扣流程（与 confirm-copy 一致）。
+    """
     from datetime import datetime, timezone
 
     repo = _get_job_repo(session)
@@ -478,6 +501,100 @@ def retry_viral_video_job(
     if job.status != ViralVideoStatus.FAILED and not is_stale_running:
         raise HTTPException(status_code=409, detail="只有失败或超时的任务可以重试")
 
+    # ── 参数变更检测 + 积分多退少补 ──────────────────────────────────────
+    req = request or RetryViralVideoRequest()
+    new_duration = req.duration
+    new_resolution = (req.video_resolution or "").strip() or None
+    new_ratio = (req.video_ratio or "").strip() or None
+    new_model = (req.video_model or "").strip() or None
+
+    old_duration = int(getattr(job, "duration", 15) or 15)
+    old_resolution = (getattr(job, "video_resolution", "720p") or "720p").strip() or "720p"
+    old_ratio = (getattr(job, "video_ratio", "9:16") or "9:16").strip() or "9:16"
+    old_model = (getattr(job, "video_model", "") or "").strip()
+
+    # 仅当有任意字段传入且值不同才算"参数变更"
+    param_changed = bool(
+        (new_duration is not None and int(new_duration) != old_duration)
+        or (new_resolution is not None and new_resolution != old_resolution)
+        or (new_ratio is not None and new_ratio != old_ratio)
+        or (new_model is not None and new_model != old_model)
+    )
+
+    from app.config import settings as _settings
+
+    need_points_settle = False
+    new_est = 0.0
+    if _settings.points_enabled and param_changed:
+        from packages.domain.points_rules import (
+            calculate_viral_video_credits_with_breakdown,
+            resolve_video_dimensions,
+        )
+
+        eff_dur = int(new_duration if new_duration is not None else old_duration)
+        eff_res = new_resolution if new_resolution is not None else old_resolution
+        eff_ratio = new_ratio if new_ratio is not None else old_ratio
+        eff_model = new_model if new_model is not None else (old_model or "seedance-2.5")
+        w, h = resolve_video_dimensions(eff_res, eff_ratio)
+        new_est, _ = calculate_viral_video_credits_with_breakdown(eff_dur, w, h, eff_model or "seedance-2.5")
+        need_points_settle = True
+
+    # 写入新参数（即使不开 points 也要允许用户重试时改参数）
+    if new_duration is not None:
+        job.duration = max(5, min(30, int(new_duration)))
+    if new_resolution is not None:
+        job.video_resolution = new_resolution
+    if new_ratio is not None:
+        job.video_ratio = new_ratio
+    if new_model is not None:
+        job.video_model = new_model
+
+    if need_points_settle:
+        from packages.domain.points_service import PointsService
+
+        old_prepaid = float(getattr(job, "credits_prepaid", 0) or 0)
+        svc = PointsService()
+        diff = round(new_est - old_prepaid, 2)
+        if abs(diff) >= 0.01:
+            if diff > 0:
+                # 新预扣更多：补扣差额
+                res = svc.deduct_viral_video(authenticated_user.user.id, diff, job.id, session)
+                if not res.get("success"):
+                    balance = res.get("balance", 0)
+                    raise HTTPException(
+                        status_code=402,
+                        detail={
+                            "code": "INSUFFICIENT_POINTS",
+                            "message": f"重试参数变更后需补扣 {diff} 积分，余额不足（当前 {balance}，需 {new_est}）",
+                            "required": new_est,
+                            "balance": balance,
+                            "delta": diff,
+                        },
+                    )
+                job.credits_prepaid = round(old_prepaid + diff, 2)
+                logger.info(
+                    "[爆款视频][retry] 补扣差额 job_id=%s diff=%.2f new_prepaid=%.2f",
+                    job.id, diff, job.credits_prepaid,
+                )
+            else:
+                # 新预扣更少：退还差额
+                refund = round(-diff, 2)
+                txn_id = getattr(job, "credits_transaction_id", "") or ""
+                svc.refund_points(
+                    user_id=authenticated_user.user.id,
+                    amount=refund,
+                    source="viral_video",
+                    db=session,
+                    ref_id=txn_id or job.id,
+                    description="爆款视频重试参数变更退费",
+                )
+                job.credits_prepaid = round(old_prepaid - refund, 2)
+                logger.info(
+                    "[爆款视频][retry] 退还差额 job_id=%s refund=%.2f new_prepaid=%.2f",
+                    job.id, refund, job.credits_prepaid,
+                )
+        # 差额为 0 则不调整
+
     # 重置状态
     job.retry_count += 1
     job.status = ViralVideoStatus.PENDING
@@ -492,7 +609,10 @@ def retry_viral_video_job(
     # 重新入队
     try:
         celery_app.send_task("worker.run_viral_video_pipeline", args=[job.id])
-        logger.info("[爆款视频] 重试入队: job_id=%s retry_count=%d stale=%s", job.id, job.retry_count, is_stale_running)
+        logger.info(
+            "[爆款视频] 重试入队: job_id=%s retry_count=%d stale=%s params_changed=%s",
+            job.id, job.retry_count, is_stale_running, param_changed,
+        )
     except Exception as e:
         logger.error("[爆款视频] 重试入队失败: %s", e, exc_info=True)
         job.mark_failed(f"重试入队失败: {e}")
diff --git a/apps/api/app/schemas/viral_video.py b/apps/api/app/schemas/viral_video.py
index 06d4d0375..cdc8d758a 100755
--- a/apps/api/app/schemas/viral_video.py
+++ b/apps/api/app/schemas/viral_video.py
@@ -260,18 +260,51 @@ class AnalyzeStyleResponse(BaseModel):
 
 
 class EstimateCreditsRequest(BaseModel):
-    """爆款视频积分预估请求。"""
+    """爆款视频积分预估请求。
 
-    model: str = ""
-    resolution: str = "720p"
-    ratio: str = "9:16"
+    前端可传 model 或 video_model（兼容老字段）；resolution/ratio/duration 为预估所需参数。
+    """
+
+    model: str = Field(default="", alias="video_model")
+    resolution: str = Field(default="720p", alias="video_resolution")
+    ratio: str = Field(default="9:16", alias="video_ratio")
     duration: int = Field(default=15, ge=5, le=30)
 
+    model_config = {"populate_by_name": True}
+
+
+class CreditsFormulaBreakdown(BaseModel):
+    """爆款视频积分计费公式明细（前端展示用）。"""
+
+    tokens: float = Field(..., description="估算视频 tokens 数 (duration*width*height*fps/1024)")
+    video_cost: float = Field(..., description="视频生成成本（元）= tokens/1e6 * model_price")
+    fixed_cost: float = Field(..., description="固定成本（元），含 VLM/LLM/TTS/OSS/服务器")
+    profit_multiplier: float = Field(..., description="利润系数（默认 1.3）")
+    model_price: float = Field(..., description="模型单价（元/百万 tokens）")
+    width: int = Field(..., description="视频宽度像素")
+    height: int = Field(..., description="视频高度像素")
+    fps: int = Field(..., description="视频帧率")
+
 
 class EstimateCreditsResponse(BaseModel):
     """爆款视频积分预估响应。"""
 
     estimated_credits: float
+    formula_breakdown: CreditsFormulaBreakdown = Field(..., description="计费公式明细")
+
+
+class RetryViralVideoRequest(BaseModel):
+    """重试爆款视频任务的请求体（可选，允许改参数重新预估积分多退少补）。
+
+    不传 body 或字段全缺省：保持原参数、不重新扣点，走默认重置+入队逻辑。
+    传入新的 duration/video_resolution/video_ratio/video_model：重新预估积分，
+    与原 credits_prepaid 比较后多退少补（差额补扣不足抛 402）。
+    """
+
+    duration: int | None = Field(default=None, ge=5, le=30, description="重试时新的视频时长（秒）")
+    video_resolution: str | None = Field(default=None, description="重试时新的分辨率，如 720p/1080p")
+    video_ratio: str | None = Field(default=None, description="重试时新的画幅比，如 9:16/16:9")
+    video_model: str | None = Field(default=None, description="重试时新的视频模型，如 seedance-2.5")
 
 
 # -- WebSocket 事件 Schema --
diff --git a/packages/domain/points_rules.py b/packages/domain/points_rules.py
index f62fda66e..d1a53697b 100644
--- a/packages/domain/points_rules.py
+++ b/packages/domain/points_rules.py
@@ -86,6 +86,61 @@ def _infer_resolution_key(height: int) -> str:
     return "480p"
 
 
+def calculate_viral_video_credits_with_breakdown(
+    duration_seconds: int,
+    width: int,
+    height: int,
+    model: str = "seedance-2.5",
+    has_video_input: bool = False,
+    actual_tokens: int | None = None,
+    fps: int = VIRAL_VIDEO_FPS,
+) -> tuple[float, dict]:
+    """计算爆款视频所需积分（1 积分 = 1 元），并返回计费公式明细。
+
+    公式:
+        tokens = duration * width * height * fps / 1024
+        video_cost = tokens / 1_000_000 * model_token_price
+        total = round((video_cost + fixed_cost) * profit_multiplier, 2)
+    若传入 actual_tokens 则用它替代计算值。
+
+    Returns:
+        (credits, breakdown) 二元组：
+        - credits: 四舍五入保留两位小数的最终积分
+        - breakdown: dict，包含 tokens / video_cost / fixed_cost / profit_multiplier /
+          model_price / width / height / fps 字段，便于前端展示计费明细。
+    """
+    prefix = _match_model_prefix(model)
+    res_key = _infer_resolution_key(int(height or 720))
+    key = (prefix, res_key, bool(has_video_input))
+    price = VIRAL_VIDEO_MODEL_PRICES.get(key)
+    if price is None:
+        price = VIRAL_VIDEO_MODEL_PRICES.get(("seedance-2.5", res_key, False), 70.0)
+
+    w = max(1, int(width or 1))
+    h = max(1, int(height or 1))
+    effective_fps = int(fps or VIRAL_VIDEO_FPS)
+    if actual_tokens is not None and actual_tokens > 0:
+        tokens = float(actual_tokens)
+    else:
+        dur = max(1, int(duration_seconds or 15))
+        tokens = dur * w * h * effective_fps / 1024.0
+
+    video_cost = tokens / 1_000_000.0 * float(price)
+    total = (video_cost + VIRAL_VIDEO_FIXED_COST) * VIRAL_VIDEO_PROFIT_MULTIPLIER
+    credits = round(float(total), 2)
+    breakdown = {
+        "tokens": float(tokens),
+        "video_cost": float(video_cost),
+        "fixed_cost": float(VIRAL_VIDEO_FIXED_COST),
+        "profit_multiplier": float(VIRAL_VIDEO_PROFIT_MULTIPLIER),
+        "model_price": float(price),
+        "width": int(w),
+        "height": int(h),
+        "fps": int(effective_fps),
+    }
+    return credits, breakdown
+
+
 def calculate_viral_video_credits(
     duration_seconds: int,
     width: int,
@@ -95,37 +150,33 @@ def calculate_viral_video_credits(
     actual_tokens: int | None = None,
     fps: int = VIRAL_VIDEO_FPS,
 ) -> float:
-    """计算爆款视频所需积分（1 积分 = 1 元）。
+    """计算爆款视频所需积分（1 积分 = 1 元），仅返回积分值（向后兼容包装器）。
+
+    内部调用 calculate_viral_video_credits_with_breakdown，仅返回 credits 部分，
+    保持旧调用方签名与返回值类型不变。
 
     公式:
         tokens = duration * width * height * fps / 1024
         video_cost = tokens / 1_000_000 * model_token_price
-        total = round((video_cost + fixed_cost) * 1.3, 2)
+        total = round((video_cost + fixed_cost) * profit_multiplier, 2)
     若传入 actual_tokens 则用它替代计算值。
     """
-    prefix = _match_model_prefix(model)
-    res_key = _infer_resolution_key(int(height or 720))
-    key = (prefix, res_key, bool(has_video_input))
-    price = VIRAL_VIDEO_MODEL_PRICES.get(key)
-    if price is None:
-        price = VIRAL_VIDEO_MODEL_PRICES.get(("seedance-2.5", res_key, False), 70.0)
-
-    if actual_tokens is not None and actual_tokens > 0:
-        tokens = float(actual_tokens)
-    else:
-        dur = max(1, int(duration_seconds or 15))
-        w = max(1, int(width or 1))
-        h = max(1, int(height or 1))
-        tokens = dur * w * h * int(fps or VIRAL_VIDEO_FPS) / 1024.0
-
-    video_cost = tokens / 1_000_000.0 * float(price)
-    total = (video_cost + VIRAL_VIDEO_FIXED_COST) * VIRAL_VIDEO_PROFIT_MULTIPLIER
-    return round(float(total), 2)
+    credits, _ = calculate_viral_video_credits_with_breakdown(
+        duration_seconds=duration_seconds,
+        width=width,
+        height=height,
+        model=model,
+        has_video_input=has_video_input,
+        actual_tokens=actual_tokens,
+        fps=fps,
+    )
+    return credits
 
 
 # ============ 场景定义 ============
-# 每个场景: base_points(基础积分), unit(计费单位), name(显示名称)
-# 说明：仅保留需要扣点的场景；免费场景不要写入此字典。
+# 每个场景: base_points(基础积分), unit(计费单位), name(显示名称), dynamic(是否动态定价)
+# 说明：爆款视频（viral_video）走动态定价（预扣→结算多退少补），因此不使用 @points_gate
+# 装饰器，base_points=0，dynamic=True；前端展示场景列表时仍可看到。
 
 POINTS_SCENES: dict[str, dict] = {
     "voice_clone_train": {
@@ -140,6 +191,13 @@ POINTS_SCENES: dict[str, dict] = {
         "name": "声音克隆合成",
         "description": "克隆音色合成每分钟消耗 1 积分",
     },
+    "viral_video": {
+        "base_points": 0,
+        "unit": "次",
+        "name": "爆款视频",
+        "dynamic": True,
+        "description": "爆款视频动态定价（按视频时长/分辨率/模型计算，预扣→结算多退少补）",
+    },
 }
 
 # 免费用户积分消耗上浮系数（仅对 voice_clone_synth 生效）
@@ -179,20 +237,26 @@ def calculate_points_cost(
     """计算指定场景的积分消耗。
 
     Args:
-        scene_key: 场景标识（当前仅支持 voice_clone_train/voice_clone_synth）
+        scene_key: 场景标识（当前支持 voice_clone_train/voice_clone_synth/viral_video；
+                   viral_video 为动态定价场景，此处返回 0，由业务侧调用
+                   calculate_viral_video_credits 手动计算）
         is_member: 是否付费会员
         quantity: 数量（按次计费场景）
         duration_minutes: 时长分钟数（按时长计费场景）
         member_type: 会员类型 (monthly/quarterly/yearly)，用于折扣
 
     Returns:
-        实际消耗积分（float；已含免费用户 ×1.15 上浮或会员折扣）；免费/已下线场景统一返回 0。
+        实际消耗积分（float；已含免费用户 ×1.15 上浮或会员折扣）；免费/动态/已下线场景统一返回 0。
     """
     scene = POINTS_SCENES.get(scene_key)
     if not scene:
         # 已下线/未注册的场景统一返回 0（免费），保持向后兼容
         return 0.0
 
+    # 动态定价场景（如 viral_video）由业务侧手动计算，这里统一返回 0
+    if scene.get("dynamic"):
+        return 0.0
+
     base = scene["base_points"]
     if base == 0:
         return 0.0
diff --git a/tests/unit/test_points_routes.py b/tests/unit/test_points_routes.py
index 83f3e5ed3..2b8a7f08b 100644
--- a/tests/unit/test_points_routes.py
+++ b/tests/unit/test_points_routes.py
@@ -129,7 +129,9 @@ class TestPointsRulesDescription:
         from app.api.routes.points import get_rules
 
         resp = get_rules(_current_user=_make_cu())
-        assert len(resp.rules) == 2
+        # 场景列表包含 voice_clone_train / voice_clone_synth / viral_video（爆款视频为动态定价）
+        keys = {r.scene_key for r in resp.rules}
+        assert {"voice_clone_train", "voice_clone_synth", "viral_video"}.issubset(keys)
         for rule in resp.rules:
             assert rule.description, f"{rule.scene_key} missing description"
             assert isinstance(rule.description, str)
diff --git a/tests/unit/test_points_rules.py b/tests/unit/test_points_rules.py
index 6dc7682f3..d3b29598a 100644
--- a/tests/unit/test_points_rules.py
+++ b/tests/unit/test_points_rules.py
@@ -19,9 +19,22 @@ from packages.domain.points_rules import (
 class TestPointsScenesConfig:
     """场景配置完整性"""
 
+    def test_registered_scenes_include_voice_clone_and_viral_video(self):
+        """场景配置：包含声音克隆（训练/合成）+ 爆款视频（动态定价）。"""
+        assert {"voice_clone_train", "voice_clone_synth", "viral_video"}.issubset(set(POINTS_SCENES.keys()))
+
+    def test_viral_video_scene_is_dynamic_with_zero_base(self):
+        """viral_video 必须注册但 base_points=0 且 dynamic=True，不使用 @points_gate。"""
+        vv = POINTS_SCENES["viral_video"]
+        assert vv["base_points"] == 0
+        assert vv["dynamic"] is True
+        assert vv["unit"] == "次"
+        assert vv["name"] == "爆款视频"
+
     def test_voice_clone_scenes_defined(self):
-        # 仅保留声音克隆两个场景
-        assert set(POINTS_SCENES.keys()) == {"voice_clone_train", "voice_clone_synth"}
+        # 保留声音克隆两个场景
+        assert "voice_clone_train" in POINTS_SCENES
+        assert "voice_clone_synth" in POINTS_SCENES
 
     def test_required_keys_present(self):
         for key, scene in POINTS_SCENES.items():
@@ -36,6 +49,11 @@ class TestPointsScenesConfig:
         assert POINTS_SCENES["voice_clone_synth"]["base_points"] == 1
         assert POINTS_SCENES["voice_clone_synth"]["unit"] == "分钟"
 
+    def test_calculate_points_cost_returns_zero_for_dynamic_viral_video(self):
+        """calculate_points_cost 对动态场景 viral_video 必须返回 0（由业务侧手动计算）。"""
+        assert calculate_points_cost("viral_video", is_member=False) == 0.0
+        assert calculate_points_cost("viral_video", is_member=True, member_type="monthly") == 0.0
+
 
 class TestPointsPackages:
     def test_three_packages(self):
@@ -392,3 +410,59 @@ class TestCalculateViralVideoCredits:
         c_none = calculate_viral_video_credits(10, 1280, 720, fps=None)
         assert c_zero == c_default
         assert c_none == c_default
+
+
+class TestViralVideoCreditsWithBreakdown:
+    """calculate_viral_video_credits_with_breakdown：返回 (credits, breakdown_dict)。"""
+
+    def test_returns_credits_matching_plain_version(self):
+        """新函数返回的 credits 必须与 calculate_viral_video_credits 完全一致，且 breakdown 字段齐全。"""
+        from packages.domain.points_rules import (
+            calculate_viral_video_credits,
+            calculate_viral_video_credits_with_breakdown,
+        )
+
+        for dur, w, h, model, hvi in [
+            (15, 1280, 720, "seedance-2.5", False),
+            (10, 720, 1280, "seedance-2.0", False),
+            (30, 1920, 1080, "seedance-2.5", False),
+            (5, 480, 480, "", False),
+        ]:
+            c1 = calculate_viral_video_credits(dur, w, h, model=model, has_video_input=hvi)
+            c2, bd = calculate_viral_video_credits_with_breakdown(dur, w, h, model=model, has_video_input=hvi)
+            assert c1 == c2
+            assert isinstance(bd, dict)
+            for key in (
+                "tokens",
+                "video_cost",
+                "fixed_cost",
+                "profit_multiplier",
+                "model_price",
+                "width",
+                "height",
+                "fps",
+            ):
+                assert key in bd, f"breakdown missing key: {key}"
+            assert bd["fixed_cost"] == 0.15
+            assert bd["profit_multiplier"] == 1.3
+            assert bd["width"] == w
+            assert bd["height"] == h
+            assert bd["fps"] == 24
+            assert bd["tokens"] > 0
+            assert bd["model_price"] > 0
+            expected = round((bd["video_cost"] + bd["fixed_cost"]) * bd["profit_multiplier"], 2)
+            assert expected == c2
+
+    def test_actual_tokens_overrides_computed(self):
+        """actual_tokens 传入时应覆盖按公式计算的 tokens。"""
+        from packages.domain.points_rules import calculate_viral_video_credits_with_breakdown
+
+        c, bd = calculate_viral_video_credits_with_breakdown(
+            15,
+            1280,
+            720,
+            actual_tokens=1_000_000,
+        )
+        assert bd["tokens"] == 1_000_000.0
+        # video_cost = 1M/1M * 70 = 70; total = (70+0.15)*1.3 = 91.195 → 91.20
+        assert c == 91.20
diff --git a/tests/unit/test_viral_video_routes.py b/tests/unit/test_viral_video_routes.py
index d0d9a9629..d81c5e841 100644
--- a/tests/unit/test_viral_video_routes.py
+++ b/tests/unit/test_viral_video_routes.py
@@ -14,6 +14,8 @@ from __future__ import annotations
 from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
+import pytest
+
 
 def _auth_user(uid: str = "u1"):
     return SimpleNamespace(user=SimpleNamespace(id=uid))
@@ -136,6 +138,163 @@ class TestRetryViralVideo:
         mock_send.assert_called_once_with("worker.run_viral_video_pipeline", args=["job-retry"])
         assert resp.id == "job-retry"
 
+    def test_retry_without_body_keeps_original_params(self):
+        """不传 body 时，保持原参数且不调用积分服务。"""
+        from app.api.routes import viral_video as vv_mod
+
+        from packages.domain.viral_video import ViralVideoStatus
+
+        user = _auth_user("u1")
+        session = MagicMock()
+        job = _make_job(
+            job_id="job-retry2", user_id="u1", status=ViralVideoStatus.FAILED,
+            duration=15, video_ratio="9:16", video_resolution="720p", video_model="seedance-2.5",
+            credits_prepaid=5.0, credits_transaction_id="txn1", retry_count=0,
+        )
+        repo = MagicMock()
+        repo.get.return_value = job
+
+        with (
+            patch.object(vv_mod, "_get_job_repo", return_value=repo),
+            patch("app.config.settings") as mock_settings,
+            patch("packages.domain.points_service.PointsService") as MockSvc,
+            patch.object(vv_mod.celery_app, "send_task"),
+        ):
+            mock_settings.points_enabled = True
+            # request=None (未传 body)
+            resp = vv_mod.retry_viral_video_job("job-retry2", None, authenticated_user=user, session=session)
+
+        MockSvc.assert_not_called()
+        assert resp.id == "job-retry2"
+        assert job.status == ViralVideoStatus.PENDING
+        assert job.duration == 15  # 参数不变
+
+    def test_retry_insufficient_points_raises_402(self):
+        """参数变更导致新预估更高且余额不足时，抛 402 阻止重试。"""
+        from app.api.routes import viral_video as vv_mod
+        from app.schemas.viral_video import RetryViralVideoRequest
+        from fastapi import HTTPException
+
+        from packages.domain.viral_video import ViralVideoStatus
+
+        user = _auth_user("u1")
+        session = MagicMock()
+        job = _make_job(
+            job_id="job-retry3a", user_id="u1", status=ViralVideoStatus.FAILED,
+            duration=15, video_ratio="9:16", video_resolution="720p", video_model="seedance-2.5",
+            credits_prepaid=5.0, credits_transaction_id="txn-old", retry_count=0,
+        )
+        repo = MagicMock()
+        repo.get.return_value = job
+
+        fake_svc = MagicMock()
+        fake_svc.deduct_viral_video.return_value = {"success": False, "balance": 1.0}
+        req = RetryViralVideoRequest(duration=30, video_resolution="1080p", video_ratio="16:9", video_model="seedance-2.5")
+
+        with (
+            patch.object(vv_mod, "_get_job_repo", return_value=repo),
+            patch("app.config.settings") as mock_settings,
+            patch("packages.domain.points_service.PointsService", return_value=fake_svc),
+            patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(1920, 1080)),
+            patch("packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                  return_value=(15.0, {})),
+            patch.object(vv_mod.celery_app, "send_task"),
+        ):
+            mock_settings.points_enabled = True
+            with pytest.raises(HTTPException) as exc:
+                vv_mod.retry_viral_video_job("job-retry3a", req, authenticated_user=user, session=session)
+            assert exc.value.status_code == 402
+        fake_svc.deduct_viral_video.assert_called_once()
+
+    def test_retry_higher_estimation_calls_deduct_delta(self):
+        """参数变更新预估更高时调用 deduct_viral_video 补扣差额，并更新 job 参数。"""
+        from app.api.routes import viral_video as vv_mod
+        from app.schemas.viral_video import RetryViralVideoRequest
+
+        from packages.domain.viral_video import ViralVideoStatus
+
+        user = _auth_user("u1")
+        session = MagicMock()
+        job = _make_job(
+            job_id="job-retry3b", user_id="u1", status=ViralVideoStatus.FAILED,
+            duration=15, video_ratio="9:16", video_resolution="720p", video_model="seedance-2.5",
+            credits_prepaid=5.0, credits_transaction_id="txn-old", retry_count=0,
+        )
+        # 用 SimpleNamespace 让属性真正可写
+        from types import SimpleNamespace
+        job.credits_prepaid = 5.0
+        repo = MagicMock()
+        repo.get.return_value = job
+
+        fake_svc = MagicMock()
+        fake_svc.deduct_viral_video.return_value = {"success": True, "balance": 50.0, "transaction_id": "txn-new"}
+        req = RetryViralVideoRequest(duration=30, video_resolution="1080p", video_ratio="16:9", video_model="seedance-2.5")
+
+        new_est = 15.0
+        with (
+            patch.object(vv_mod, "_get_job_repo", return_value=repo),
+            patch("app.config.settings") as mock_settings,
+            patch("packages.domain.points_service.PointsService", return_value=fake_svc),
+            patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(1920, 1080)),
+            patch("packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                  return_value=(new_est, {})),
+            patch.object(vv_mod.celery_app, "send_task"),
+        ):
+            mock_settings.points_enabled = True
+            resp = vv_mod.retry_viral_video_job("job-retry3b", req, authenticated_user=user, session=session)
+
+        assert job.duration == 30
+        assert job.video_resolution == "1080p"
+        assert job.video_ratio == "16:9"
+        # 补扣差额 = 15-5 = 10
+        fake_svc.deduct_viral_video.assert_called_once()
+        call_args = fake_svc.deduct_viral_video.call_args
+        assert call_args.args[1] == 10.0  # credits 是位置参数
+        assert resp.id == "job-retry3b"
+
+    def test_retry_lower_estimation_calls_refund_delta(self):
+        """参数变更新预估更低时，调用 refund_points 退还差额，并更新 job 参数。"""
+        from app.api.routes import viral_video as vv_mod
+        from app.schemas.viral_video import RetryViralVideoRequest
+
+        from packages.domain.viral_video import ViralVideoStatus
+
+        user = _auth_user("u1")
+        session = MagicMock()
+        job = _make_job(
+            job_id="job-retry4", user_id="u1", status=ViralVideoStatus.FAILED,
+            duration=20, video_ratio="16:9", video_resolution="1080p", video_model="seedance-2.5",
+            credits_prepaid=10.0, credits_transaction_id="txn-old", retry_count=0,
+        )
+        job.credits_prepaid = 10.0
+        repo = MagicMock()
+        repo.get.return_value = job
+
+        fake_svc = MagicMock()
+        fake_svc.refund_points.return_value = {"success": True}
+        req = RetryViralVideoRequest(duration=5, video_resolution="480p", video_ratio="9:16")
+
+        new_est = 3.0
+        with (
+            patch.object(vv_mod, "_get_job_repo", return_value=repo),
+            patch("app.config.settings") as mock_settings,
+            patch("packages.domain.points_service.PointsService", return_value=fake_svc),
+            patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(270, 480)),
+            patch("packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                  return_value=(new_est, {})),
+            patch.object(vv_mod.celery_app, "send_task"),
+        ):
+            mock_settings.points_enabled = True
+            vv_mod.retry_viral_video_job("job-retry4", req, authenticated_user=user, session=session)
+
+        assert job.duration == 5
+        assert job.video_resolution == "480p"
+        assert job.video_ratio == "9:16"
+        fake_svc.refund_points.assert_called_once()
+        call_args = fake_svc.refund_points.call_args
+        # 退差额 = 10-3 = 7
+        assert call_args.kwargs["amount"] == 7.0
+
 
 # ── confirm-intent ──────────────────────────────────────────────────────
 
@@ -591,44 +750,62 @@ class TestConfirmCopyPointsDeduction:
 class TestEstimateCredits:
     """POST /estimate-credits: 纯计算预估积分。"""
 
-    def test_estimate_returns_float(self):
-        """正常参数应返回 estimated_credits 为 float 且>0。"""
+    def test_estimate_returns_float_with_breakdown(self):
+        """正常参数应返回 estimated_credits(float, >0, 两位小数) + formula_breakdown。"""
         from app.api.routes import viral_video as vv_mod
         from app.schemas.viral_video import EstimateCreditsRequest
 
         req = EstimateCreditsRequest(model="seedance-2.5", resolution="720p", ratio="9:16", duration=15)
-        # 不需要 db / user 之外的依赖；authenticated_user 仍要传
         user = _auth_user("u1")
 
         resp = vv_mod.estimate_credits(req, authenticated_user=user)
         assert isinstance(resp.estimated_credits, float)
         assert resp.estimated_credits > 0
-        # 应保留两位小数
         assert round(resp.estimated_credits, 2) == resp.estimated_credits
+        # formula_breakdown 必须返回并包含全部字段
+        bd = resp.formula_breakdown
+        assert bd.tokens > 0
+        assert bd.video_cost >= 0
+        assert bd.fixed_cost > 0
+        assert bd.profit_multiplier == 1.3
+        assert bd.model_price > 0
+        assert bd.width > 0
+        assert bd.height > 0
+        assert bd.fps > 0
 
-    def test_estimate_uses_dimensions_resolver(self):
-        """estimate_credits 应调用 resolve_video_dimensions 和 calculate_viral_video_credits。"""
+    def test_estimate_uses_dimensions_resolver_and_with_breakdown(self):
+        """estimate_credits 调用 resolve_video_dimensions 与 calculate_viral_video_credits_with_breakdown。"""
         from app.api.routes import viral_video as vv_mod
         from app.schemas.viral_video import EstimateCreditsRequest
 
         req = EstimateCreditsRequest(model="seedance-2.5", resolution="1080p", ratio="16:9", duration=20)
         user = _auth_user("u1")
+        fake_bd = {
+            "tokens": 1000.0, "video_cost": 1.0, "fixed_cost": 0.15,
+            "profit_multiplier": 1.3, "model_price": 70.0,
+            "width": 1920, "height": 1080, "fps": 24,
+        }
 
         with (
             patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(1920, 1080)) as mock_res,
-            patch("packages.domain.points_rules.calculate_viral_video_credits", return_value=8.88) as mock_calc,
+            patch(
+                "packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                return_value=(8.88, fake_bd),
+            ) as mock_calc,
         ):
             resp = vv_mod.estimate_credits(req, authenticated_user=user)
 
         mock_res.assert_called_once_with("1080p", "16:9")
         mock_calc.assert_called_once()
-        # 传给 calculate 的参数应包含 duration=20, w=1920, h=1080, model="seedance-2.5"
         args, kwargs = mock_calc.call_args
         assert args[0] == 20
         assert args[1] == 1920
         assert args[2] == 1080
         assert args[3] == "seedance-2.5"
         assert resp.estimated_credits == 8.88
+        assert resp.formula_breakdown.width == 1920
+        assert resp.formula_breakdown.height == 1080
+        assert resp.formula_breakdown.model_price == 70.0
 
     def test_estimate_empty_model_defaults_to_seedance_2_5(self):
         """model 为空字符串时，传入 calculate 的 model 参数应为 'seedance-2.5'。"""
@@ -637,13 +814,53 @@ class TestEstimateCredits:
 
         req = EstimateCreditsRequest(model="", resolution="720p", ratio="9:16", duration=10)
         user = _auth_user("u1")
+        fake_bd = {
+            "tokens": 500.0, "video_cost": 0.5, "fixed_cost": 0.15,
+            "profit_multiplier": 1.3, "model_price": 70.0,
+            "width": 720, "height": 1280, "fps": 24,
+        }
 
         with (
             patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(720, 1280)),
-            patch("packages.domain.points_rules.calculate_viral_video_credits", return_value=3.5) as mock_calc,
+            patch(
+                "packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                return_value=(3.5, fake_bd),
+            ) as mock_calc,
         ):
             resp = vv_mod.estimate_credits(req, authenticated_user=user)
 
         args, kwargs = mock_calc.call_args
         assert args[3] == "seedance-2.5"
         assert resp.estimated_credits == 3.5
+        assert resp.formula_breakdown.height == 1280
+
+    def test_estimate_accepts_video_model_alias(self):
+        """前端传 video_model/video_resolution/video_ratio（别名）也应被正确解析。"""
+        from app.api.routes import viral_video as vv_mod
+        from app.schemas.viral_video import EstimateCreditsRequest
+
+        req = EstimateCreditsRequest.model_validate(
+            {"video_model": "seedance-2.0", "video_resolution": "480p", "video_ratio": "1:1", "duration": 5}
+        )
+        user = _auth_user("u1")
+        fake_bd = {
+            "tokens": 100.0, "video_cost": 0.1, "fixed_cost": 0.15,
+            "profit_multiplier": 1.3, "model_price": 46.0,
+            "width": 480, "height": 480, "fps": 24,
+        }
+
+        with (
+            patch("packages.domain.points_rules.resolve_video_dimensions", return_value=(480, 480)) as mock_res,
+            patch(
+                "packages.domain.points_rules.calculate_viral_video_credits_with_breakdown",
+                return_value=(1.0, fake_bd),
+            ) as mock_calc,
+        ):
+            vv_mod.estimate_credits(req, authenticated_user=user)
+
+        mock_res.assert_called_once_with("480p", "1:1")
+        args, kwargs = mock_calc.call_args
+        assert args[0] == 5
+        assert args[1] == 480
+        assert args[2] == 480
+        assert args[3] == "seedance-2.0"