SAP-C02 Design for New Solutions Practice Question

A media company is designing a new video transcoding pipeline on AWS. Raw video files (up to 10 GB each) are uploaded by users to an S3 bucket. Each upload must be transcoded into multiple formats (MP4, WebM, HLS) and stored in another S3 bucket. The transcoding job can take up to 30 minutes per file. The company needs a solution that is cost-effective and can handle hundreds of concurrent uploads. The operations team wants to minimize maintenance. Which solution should a Solutions Architect recommend?

⚠ Common exam trap

Many candidates choose Option A (Lambda) without considering the 15-minute timeout limit, or Option D (Step Functions + Fargate) because it sounds serverless, but they overlook that MediaConvert is the fully managed, cost-optimized service specifically designed for this use case.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Use S3 event notifications to invoke a Lambda function that submits a job to AWS Elemental MediaConvert for each file.

AWS Elemental MediaConvert is a fully managed, serverless media transcoding service designed for high-volume, multi-format video processing. Using S3 event notifications to invoke a Lambda function that submits a job to MediaConvert offloads the transcoding complexity, scales automatically to handle hundreds of concurrent uploads, and requires no infrastructure maintenance, making it both cost-effective and operationally minimal.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Use S3 event notifications to invoke an AWS Lambda function that performs transcoding and stores results.
Why it's wrong here
Lambda has a maximum execution timeout of 15 minutes, insufficient for 30-minute jobs.
✓
Use S3 event notifications to invoke a Lambda function that submits a job to AWS Elemental MediaConvert for each file.
Why this is correct
MediaConvert is a managed, scalable service designed for video transcoding; Lambda handles the orchestration.
✗
Use an Auto Scaling group of EC2 instances with transcoding software installed. Configure S3 events to send messages to an SQS queue, which the instances poll.
Why it's wrong here
EC2 instances require patching and scaling management; not as cost-effective as a managed service.
✗
Use S3 event notifications to trigger an AWS Step Functions workflow that runs an ECS Fargate task for each file.
Why it's wrong here
An ECS Fargate task per file would incur idle compute costs while waiting for the 30-minute transcoding job to complete, making it less cost-effective than a serverless, pay-per-invocation service like AWS Lambda for hundreds of concurrent uploads. This option is tempting because Step Functions orchestrating Fargate tasks is ideal for long-running, containerised workloads that exceed Lambda’s 15-minute timeout, but here the requirement for cost efficiency at high concurrency favours Lambda’s sub-second billing granularity over Fargate’s per-second billing with a minimum charge.

Quick reference

AWS S3 Storage Class Comparison

Storage Class	Min Duration	Retrieval	Use Case
S3 Standard	None	Immediate	Frequently accessed data
S3 Standard-IA	30 days	Immediate	Infrequent access, rapid retrieval
S3 One Zone-IA	30 days	Immediate	Non-critical infrequent data
S3 Intelligent-Tiering	None	Immediate–hours	Unknown or changing access patterns
S3 Glacier Instant	90 days	Milliseconds	Archive with instant retrieval
S3 Glacier Flexible	90 days	Minutes–hours	Archive, flexible retrieval
S3 Glacier Deep Archive	180 days	Hours	Long-term compliance archive

Go deeper

SAP-C02 Design for New Solutions Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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