Configuration Reference

FlowPick provides extensive configuration options covering download behavior, filtering rules, storage strategy, and interface preferences. This document explains the purpose, default values, and applicable scenarios for each configuration item.

Quick Reference

Configuration Access Points

Configuration is divided into two levels to adapt to different usage scenarios:

Storage and Synchronization:

• Extension settings are saved in chrome.storage.sync and auto-sync to other devices after signing into Chrome account
• Download panel configuration exists only in current tab session; defaults restore after page refresh
• Save directory name is cached in localStorage under the key flowpick_save_dir_name; does not sync across devices

Download Settings

Concurrent Threads

Controls the number of fragments downloaded simultaneously. Higher concurrency increases download speed but also consumes more network bandwidth and browser memory.

Selection Guide:

Actual concurrency won't exceed total fragment count. For example, if there are only 3 fragments, even if set to 8, only 3 download tasks will start.

Output Format

Output container format after merging stream fragments.

Selection Guide:

• Need maximum compatibility (players, editing software, sharing with others) → Choose MP4
• Want fastest merge speed, will transcode with other tools later → Choose TS
• Source stream is already TS encapsulated and doesn't need secondary processing → Choose TS

When outputting MP4, FlowPick automatically adds -movflags +faststart flag to place moov atom at the front, allowing video to start playing before download completes (useful for progressive download scenarios).

Save Directory

FlowPick supports two file saving strategies:

Strategy 1: Browser Default Download Directory

Without setting a save directory, all files are saved through the browser's Downloads API to the system's default download folder. No additional confirmation needed per download.

Strategy 2: Custom Save Directory (File System Access API)

Click "Choose Save Directory" button in download panel, authorize a folder, then all subsequent downloads write directly to that directory without showing save dialogs.

Directory Permission Notes:

• Authorization status is silently checked via navigator.permissions.query(), no repeated popups
• If permission is revoked (user manually removes in system settings), FlowPick auto-falls back to dialog mode
• Directory name is cached in localStorage under key flowpick_save_dir_name, used only for UI display
• Custom directories don't sync across devices; each device needs separate authorization

Filename

Naming rules for downloaded files:

• Defaults to video page title or filename portion from stream URL
• Supports manual editing—modify in filename input field in download panel
• Special characters (such as \/:*?"<>|) are automatically replaced with underscores
• If same-named file exists in target directory, browser auto-adds numeric suffix (e.g., video (1).mp4)

Filtering Settings

Auto Detection

Controls whether extension auto-scans media resources when page loads.

Enabling auto-detection slightly increases CPU usage during page load, but typically negligible.

Minimum File Size

Filters out resources smaller than specified threshold, used to skip ad segments, thumbnails, and placeholder images.

Typical Scenarios:

Filter by Type

Filter displayed results by media type in popup:

Filter by Duration

Applies only to video and audio resources. Setting minimum duration filters out very short clips.

Interface Settings

Theme Mode

Defaults to follow system preference. Setting saved in chrome.storage.sync, syncs with account.

Notifications

Controls desktop notification behavior after download completion:

Notifications use browser Notifications API, requests permission on first use. If notification permission was denied, can re-enable in browser settings.

Advanced Settings

Quality Selection Strategy

For adaptive streams (HLS Master Playlist / DASH MPD), FlowPick provides two quality selection methods:

Quality list sorted from high to low bitrate, display format: 1080p · 5.2 Mbps · avc1.640028.

Retry Strategy

Automatic retry mechanism when fragment download fails:

Retry only applies to temporary network-level failures (timeouts, connection resets). HTTP 4xx errors (such as 403, 404) won't trigger retry; error reports immediately.

Memory Safety Limits

To prevent browser crashes due to insufficient memory, FlowPick has built-in memory protection mechanisms:

When estimated file size exceeds Blob limit, FlowPick forces use of File System Access API or StreamSaver streaming writes to avoid loading entire file into memory.

Fragment Size Estimation

Before starting download, FlowPick samples to estimate total file size:

• Sample count: min(5, max(1, totalSegments × 0.1))
• Estimation formula: avgSampleSize × totalSegments
• Used to determine whether to enable streaming write mode

Scenario-Based Configurations

Based on different usage scenarios, we recommend the following configuration combinations:

Daily Video Download

Default configuration suitable for most users:

Large File/Live Replay

Downloading live replays or long videos over 5GB:

Gallery Batch Download

Batch downloading images from gallery websites:

Podcast/Audio Download

Downloading podcast episodes or audio files:

Mobile Hotspot/Data Saving

Using mobile hotspot or limited data:

Reset Configuration

To restore all settings to default values:

1. Open extension popup
2. Click gear icon to enter settings
3. Click Clear All Data
4. Confirm operation

This operation clears:

• All extension configuration in chrome.storage.sync
• Cached save directory name in localStorage
• Filter presets and theme preferences

Unaffected Data:

• Browser download history
• Files already downloaded locally
• Extension itself (won't be uninstalled)

Related Documentation

• Installation Guide — Extension installation and initial setup
• Usage Guide — Daily usage guide
• Format Conversion — Detailed technical explanation of output formats
• Video Sniffing — Media detection principles and encryption handling
• Download Engine Architecture — Concurrency control, retry strategy, memory management
• Browser Compatibility — API support and fallback strategies across browsers
• Common Issues Troubleshooting — Diagnostic methods for configuration issues
• Known Limitations — Differences between remuxing and transcoding
• Use Cases — Scenario-based configurations
• Privacy & Security — Auto-detection and privacy notes