面试题库

14 天用 Agent 搭一条 AI 短剧生产线

D7 一集杀青：把六个环节串成端到端流水线并算清第一笔账

• 怎么度量一条生成流水线的成本？除了钱还要量什么？How do you measure the cost of a generation pipeline, and what besides money should you measure?

  国内高频海外高频基础#observability#cost-accounting#pipeline-design

  分析过程 · 先想清楚再作答

  1. 这题看着是送分题，题眼其实在「除了钱」。只报一个总金额的人，做不出任何优化决策，因为总金额不告诉你该动哪里。
  2. 第一步是确定度量的粒度：**按环节摊开**。一个总数没有信息量，一张按环节分列的表能立刻告诉你钱花在哪、时间花在哪。本课量过一集：五张图一毛二五、配音不到两分、三个镜头的视频十块五，视频占了九成八——这个结论只有摊开才看得见。
  3. 第二步是把「钱」之外的三样一起量：耗时决定一天能出几集；调用次数决定会不会撞上厂商的速率限制；产物数是最朴素的完整性校验，四个镜头就该有四个视频，少一个说明某处静默失败了。
  4. 第三步是把估算和真实分开。离线或压测时拿不到真实金额，可以按公开单价折算，但**必须标明它是折算值**，而且折算逻辑和真实金额不能混在一条路径上算，否则账永远对不上。
  5. 还要提醒一句常被忽略的：离线模式下的耗时排名往往是假的。接口被打了桩，本地的编码步骤反而成了大头，照着这张图做优化会优化错地方。
  6. 可预期的追问是「量完之后先优化哪一项」。答：先优化能被数字证明收益的那一项。这个场景里是失败重跑造成的浪费，因为它直接等于账单上的金额；并发排第二，因为在产出还不稳定时并发只会让你更快地烧钱。

  How to reason about it · think before answering

  1. This looks like a giveaway, but the real question is 'besides money'. Anyone who reports a single total cannot make an optimization decision, because a total does not say where to act.
  2. First decide the granularity: break it down per stage. One number carries no information; a per-stage table immediately shows where the money and the time went. Measured on one episode here: five images cost 0.125 yuan, voice under two cents, three video shots 10.5 yuan — video is 98 percent. You only see that broken down.
  3. Second, measure three things besides money: elapsed time decides how many episodes per day, call count decides whether you hit provider rate limits, and artifact count is the crudest completeness check — four shots should yield four clips, and a missing one means something failed silently.
  4. Third, separate estimates from real spend. Offline or in load tests you have no real amounts, so derive them from published unit prices — but label them as estimates, and never mix the two on one code path or the books will never reconcile.
  5. Also worth flagging: offline timing rankings are usually fake. With the APIs stubbed, local encoding becomes the biggest slice, and optimizing against that chart targets the wrong thing.
  6. Expect the follow-up 'what do you optimize first'. Answer: whatever has a number attached. Here it is waste from failed reruns, because it equals money on the bill. Concurrency comes second — before output is stable, concurrency only burns money faster.

  答题要点

  • 按环节摊开，不要只给一个总数，否则无法定位该优化哪里。
  • 除了金额还要量耗时、调用次数、产物数，各自对应吞吐、限流、完整性。
  • 估算与真实金额分开计算，估算必须标明是折算值。
  • 注意离线模式下耗时排名不可信，别照着假图做优化。
  • 优化顺序按「收益能不能被数字证明」排，不按直觉排。

  Key points

  • Break the cost down per stage; a single total cannot tell you where to act.
  • Besides money, measure elapsed time, call count and artifact count — throughput, rate limits and completeness.
  • Keep estimated and real spend on separate paths, and always label estimates as estimates.
  • Offline timing rankings are unreliable; do not optimize against a stubbed profile.
  • Prioritize by which improvement has a number attached, not by intuition.

D10 审片室：能预览、能改词、能重生成单镜的人机协作后台

• 一条自动化流水线要插入人工审核，你会把卡点放在哪几步？为什么？Where would you place human review checkpoints in an automated pipeline, and why there?

  国内高频海外高频基础#human-in-the-loop#pipeline-design#cost

  分析过程 · 先想清楚再作答

  1. 这题在考你有没有成本意识。答「每一步都让人看一眼」是没做过工程的回答——人是最贵的资源，卡点多了流水线就退化成手工作坊。
  2. 给一条可复用的判据：**卡点放在「下游最贵的那一步」之前**。判断某个位置该不该设卡，只问一句「如果这里错了，往后要白花多少钱」。
  3. 按这条判据落到生成式流水线上，会得到三个位置：剧本定稿之后（此时零成本，却决定了后面所有素材的方向）、首帧出来之后视频生成之前（首帧是最便宜的一档，视频是最贵的一档，同一个镜头差出一到两个数量级）、成片合成之后发布之前（这一道拦的不是质量而是合规风险）。
  4. 补一条生产视角：卡点不等于阻塞。第一和第二道可以做成「默认放行、超时自动继续」，只有第三道必须硬卡——合规问题不能靠超时放行。
  5. 结论里要点出一个反直觉的事实：最容易被跳过的恰恰是第一道，因为这时候还没有画面，看起来没什么可审的；但它是唯一一道改起来零成本的闸门。
  6. 可预期的追问是「人来不及审怎么办」。答案是分级：机器先打分，只把低分的推给人，人的时间花在机器拿不准的那部分上。

  How to reason about it · think before answering

  1. This one tests cost awareness. Saying a human should look at every step marks someone who has not run this in production: humans are the expensive resource, and too many gates turn a pipeline back into handwork.
  2. Offer a reusable rule: put the gate immediately before the most expensive downstream step. To decide whether a position deserves a gate, ask how much money is wasted if something is wrong here.
  3. Applied to a generative pipeline that yields three positions: after the script is locked (free to change, yet it steers every asset that follows), after the first frame but before video generation (the frame is the cheapest step and the clip is the most expensive, one to two orders of magnitude apart), and after the final cut but before publishing (this one gates risk, not quality).
  4. Add the production view: a checkpoint is not necessarily blocking. The first two can auto-continue on timeout; only the compliance gate must hard-block, because you cannot let a legal check pass by timing out.
  5. State the counterintuitive part: the first gate is the one people skip, because there are no visuals yet and it looks like there is nothing to review, while it is the only gate where changes cost nothing.
  6. Expected follow-up: what if reviewers cannot keep up. Tier it. Machines score everything, humans only see the low scores, and human attention goes where the machine is unsure.

  答题要点

  • 判据是「卡点放在下游最贵的那一步之前」，问的是这里错了往后白花多少钱。
  • 三个位置：剧本定稿后、首帧出来后视频生成前、成片合成后发布前。
  • 首帧那一道性价比最高：首帧是最便宜的一档，视频是最贵的一档，同一个镜头差出一到两个数量级。
  • 前两道可以默认放行加超时继续，只有合规那一道必须硬卡。
  • 人力不够就分级：机器先打分，人只看低分的那些。

  Key points

  • Rule: place the gate right before the most expensive downstream step, judged by wasted spend if this step is wrong.
  • Three positions: after script lock, after first frame and before video, after final cut and before publish.
  • The first-frame gate pays best: the frame is the cheapest step and the clip the most expensive, one to two orders of magnitude apart.
  • The first two gates can auto-continue on timeout; only the compliance gate hard-blocks.
  • When reviewers are the bottleneck, tier it: machines score everything, humans only see low scores.

D11 质检与合规：机器审片、内容安全、生成内容标识与版权边界

• 内容安全审核放在生成前还是生成后？为什么两边都要有？Should content safety checks run before generation or after? Why both?

  国内高频海外高频基础#content-safety#moderation#pipeline-design

  分析过程 · 先想清楚再作答

  1. 这题的正确答案是「两边都要」，但拿分的关键不在结论，而在你能不能说清两道关**防的是不同的事**。答成「双重保险更稳妥」就是没答。
  2. 前置那道查的是你要发出去的提示词，省的是钱和账号：违规提示词发过去会命中厂商审核被拒（MiniMax 这边返回 1026 或 1027），白等一轮，严重的会触发风控。它是一层本地词表加规则，几毫秒，拦一条省一次调用。
  3. 后置那道查的是厂商还给你的成片，它更重要，理由是**提示词干净不代表结果干净**——生成模型会自己加戏，你写便利店门口，它可能给你摆一整面货架的品牌包装。前置只保证你没主动要，后置才保证观众看到的没问题。
  4. 前置被拦下之后不能只抛异常，要给替代方案并让流程继续：把命中片段替换成安全表述、打印出来、记进报告，人回头能看到哪一句被改成了什么。
  5. 还要点破一个常见误解：**厂商的审核不能替代你的审核**。厂商审的是它自己的合规风险，边界跟你的业务不同；而且发布责任在你，出事找的是发布者。
  6. 可预期的追问是「后置发现问题怎么办」。按严重程度分流：能自动修的（比如字幕里的词）就修完重跑那一个节点，修不了的直接拦住不许发布并推给人工，绝不能因为已经花了钱就放行。

  How to reason about it · think before answering

  1. The answer is both, but the marks come from explaining that the two gates defend against different things. Saying defence in depth is safer earns nothing.
  2. The pre-check inspects the prompt you are about to send, and it saves money and account standing: a violating prompt gets rejected by the vendor's own moderation (1026 or 1027 at MiniMax), wasting a round trip, and repeated hits can trip risk controls. It is a local word list plus rules, milliseconds, and each catch saves a call.
  3. The post-check inspects what the vendor returned, and it matters more, because a clean prompt does not imply a clean result. Generative models improvise: you ask for a convenience store and get a shelf of branded packaging. The pre-check only proves you did not ask for it; the post-check protects the viewer.
  4. When the pre-check fires, do not just throw. Offer a replacement and keep going: swap the matched fragment for safe wording, print it, and record it so a human can see which line was changed and how.
  5. Call out the common misconception: vendor moderation does not replace yours. The vendor moderates its own risk, with different boundaries, and publishing liability sits with you.
  6. Expected follow-up: what to do when the post-check fails. Triage by severity: auto-fixable issues get fixed and only that node reruns; anything else blocks publishing and goes to a human. Never wave it through because the money is already spent.

  答题要点

  • 两道都要，因为防的事不同：前置省钱与账号，后置保护观众与合规。
  • 前置是本地词表加规则，几毫秒，拦下一条就省一次调用；命中要给替代写法而不是抛异常停线。
  • 后置更重要：提示词干净不代表结果干净，模型会自己加戏。
  • 厂商的审核只兜它自己的风险，不能替代你的，发布责任在你。
  • 后置发现问题按严重度分流：能自动修的修完重跑该节点，修不了的硬拦并推人工。

  Key points

  • Both, because they defend different things: the pre-check saves spend and account standing, the post-check protects viewers and compliance.
  • The pre-check is a local rule pass in milliseconds; on a hit, substitute safe wording instead of throwing and halting the line.
  • The post-check matters more, because a clean prompt does not guarantee a clean result.
  • Vendor moderation covers the vendor's risk, not yours; publishing liability stays with you.
  • Triage post-check failures: auto-fix and rerun that node, or hard-block and escalate.