[WIP] Fix download error for video clips

[Copilot]

Fix Download Error - Complete ✅

Changes Made:

• Analyze the issue and understand the code
• Fix format selection to be more robust with better fallback options
• Ensure consistent flags between primary and fallback commands
• Improve error handling with multi-layer fallback strategy
• Test the changes (syntax, error detection, security)
• Run code review and security check

Problem Summary:

Users encountered "Requested format is not available" errors when downloading YouTube videos with download_clips.py, resulting in empty subdirectories despite the script attempting downloads.

Root Causes:

1. Restrictive format selection: Primary format string bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best was too specific
2. Inconsistent flags: Fallback used -c while primary used --no-continue
3. Single fallback layer: Only one fallback wasn't enough for edge cases
4. Narrow error detection: Only caught "Requested format is not available"

Solution Implemented:

1. Improved Primary Format Selection (Line 232):

# Before: "bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best"
# After:  "bestvideo[ext=mp4]+bestaudio[ext=m4a]/bestvideo+bestaudio/best"

Allows any video+audio combination as fallback before going to single best format.

2. Fixed Flag Inconsistency (Line 260):

# Before: "-c", "--no-overwrites"
# After:  "--no-continue", "--no-overwrites"

Maintains consistency with primary command.

3. Multi-Layer Fallback Strategy:

• Primary: Preferred mp4+m4a → any video+audio → best
• Fallback 1: Simple "best" with all features (audio, subs, etc.)
• Fallback 2: Minimal "best" with no optional features

4. Enhanced Error Detection (Line 252):

# Before: if "Requested format is not available" in err_msg:
# After:  if "Requested format is not available" in err_msg or "format" in err_msg.lower():

Catches more format-related errors with case-insensitive matching.

Validation Complete:

✅ Syntax Check: Passed
✅ Security Scan: 0 vulnerabilities found
✅ Error Detection: All test patterns correctly detected
✅ Function Signature: Verified and unchanged

Testing Instructions:

Create a test JSON with the problematic video:

[
  {
    "info": {
      "Video Link": "https://www.youtube.com/watch?v=3kAiPSEnrHI"
    },
    "start-time": 246.846,
    "end-time": 251.888
  }
]

Run: python download_clips.py --input test.json --output test_output --limit 1

The script will now gracefully handle format availability issues through three progressive fallback attempts.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Download error</issue_title>
<issue_description>I use filtered_video_clips_with_captions.json as input json, and use download_clips.py to download the video, than it tell me that FAIL https://www.youtube.com/watch?v=3kAiPSEnrHI 246.846 251.888 ERROR: [youtube] 3kAiPSEnrHI: Requested format is not available. Use --list-formats for a list of available formats, and the dir like:

but I see nothing in the subdir.

Comments on the Issue (you are @copilot in this section)

• Fixes Download error #11

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