一輩子的買夠：自動迷因圖票選產生系統

MVP Backend System Requirements Specification (SRS)

Project Name: Anime Subtitle Search and Meme Frame Generator MVP
Technology Stack: Node.js, Express, SQLite, FFmpeg
Primary Use Case: Build a backend service that supports video subtitle search and frame extraction for creating memes.

1. Overview

The MVP backend system will enable the following core functionalities:

Accept an anime video and a subtitle file (SRT).
Extract frames from the video based on subtitle timings using FFmpeg.
Provide a search interface to retrieve subtitle blocks and their corresponding frames.
Allow users to vote on the most suitable frames for meme creation.
Store all generated frames, subtitle data, and voting information in a structured and efficient manner.

2. Functional Requirements

2.1 Video and Subtitle Management

FR-1.1 Video Upload and Storage

The system shall accept an anime video file (e.g., MP4) uploaded by the user or obtained from a source (e.g., YouTube).
The video metadata (e.g., title, duration, file path) shall be stored in the videos table in the database.
The uploaded video file shall be saved on the server's filesystem in a predefined folder structure.

FR-1.2 Subtitle File Upload and Parsing

The system shall accept an SRT subtitle file associated with the uploaded video.
The subtitle file shall be parsed, and each subtitle block (with start/end times and text) shall be stored in the subtitles table in the database, linked to the corresponding video.

2.2 Frame Extraction and Storage

FR-2.1 Subtitle to Frame Extraction

The system shall use FFmpeg to extract frames from the video based on the timing of the subtitle blocks.
The system shall generate frames at the midpoint of each subtitle block and ±1 second variations.
The system shall store the extracted frames as PNG files in a structured directory format, organized by video and subtitle.

FR-2.2 Frame Storage in Database

The system shall store the metadata of each generated frame (e.g., video ID, subtitle ID, frame time, file path) in the frames table.
The system shall ensure the generated frames are accessible and retrievable based on subtitle search queries.

2.3 Subtitle Search and Frame Retrieval

FR-3.1 Subtitle Search

The system shall provide an API that allows users to search for subtitles using keywords.
The search results shall return subtitle blocks, including start/end times, subtitle text, and corresponding frames.

FR-3.2 Frame Retrieval

For each searched subtitle block, the system shall return all associated frames (including variations) for display in the user interface.
The system shall allow users to retrieve the file path of a specific frame to download or share the image.

2.4 Voting on Frames

FR-4.1 Voting API

The system shall provide an API that allows users to upvote or downvote frames.
Each vote shall be linked to a specific frame in the votes table, recording the user (or anonymous ID), vote type (upvote or downvote), and timestamp.

FR-4.2 Frame Ranking

The system shall calculate the ranking of frames based on user votes and return the most popular frame for a specific subtitle block when requested.

3. Non-Functional Requirements

3.1 Performance

The system shall process and generate frames in under 5 seconds for a 2-minute video clip.
The search queries for subtitles shall return results in less than 1 second for keyword-based searches.

3.2 Scalability

The system shall be designed to handle multiple video uploads and frame extractions concurrently.

3.3 Data Storage

The system shall use SQLite for local development and testing to store video, subtitle, frame, and vote data. PostgreSQL may be used for future scalability.
The extracted frames shall be stored in the filesystem under /frames/{video_id}/{subtitle_id}/.

3.4 Error Handling

The system shall provide detailed error responses if the subtitle or video files are not valid or fail to process.
The system shall handle API request errors with appropriate HTTP status codes (e.g., 400 Bad Request, 500 Internal Server Error).

4. API Specifications

4.1 Upload Video

Method: POST /api/videos
Input:
- Video file (MP4, AVI, etc.)
- Video metadata (title, series, episode number)
Output: Video ID, status (success/failure)

4.2 Upload Subtitle

Method: POST /api/subtitles
Input:
- Subtitle file (SRT)
- Associated video ID
Output: Subtitle processing status (success/failure)

4.3 Search Subtitles

Method: GET /api/subtitles/search
Input:
- Query string (keywords)
Output: List of subtitle blocks (start time, end time, text) and associated frames

4.4 Retrieve Frames for Subtitle

Method: GET /api/frames/{subtitle_id}
Input:
- Subtitle ID
Output: List of frames (file paths, time stamps)

4.5 Vote on Frame

Method: POST /api/frames/{frame_id}/vote
Input:
- Frame ID, vote type (upvote/downvote)
Output: Vote status (success/failure)

5. Data Models

5.1 Video Model

{
  "id": "xyz456",
  "title": "Anime Episode 1",
  "file_path": "/videos/xyz456.mp4",
  "duration": 1440,
  "created_at": "2024-10-12T12:00:00Z",
  "source_type": "user_upload"
}

5.2 Subtitle Model

{
  "id": "abc123",
  "video_id": "xyz456",
  "start_time": 120.0,
  "end_time": 125.0,
  "text": "This is a sample subtitle."
}

5.3 Frame Model

{
  "id": "def789",
  "video_id": "xyz456",
  "subtitle_id": "abc123",
  "frame_time": 121.0,
  "file_path": "/frames/xyz456/abc123/frame_121000.png"
}

5.4 Vote Model

{
  "id": "ghi101",
  "frame_id": "def789",
  "user_id": "user123",
  "vote_type": "upvote",
  "created_at": "2024-10-12T12:05:00Z"
}

6. Assumptions and Constraints

The MVP will initially focus on one specific anime series where subtitle files (SRT) are available.
The video file sizes should be limited to 500MB for processing efficiency in the MVP.
The extracted frames will be stored on the server filesystem, and further storage optimizations (like CDN integration) can be added in later versions.

相關資料