[Bug]: YouTube merge failed: postprocessing conversion error

[feng-haibo]

App version

VidBee v1.2.4

OS version

macOS 26.2.0

Observed behavior

download seems finished but merging failed

Logs or screenshots

Source URL:
https://www.youtube.com/watch?v=zKeKzfEPPvc

yt-dlp command:

yt-dlp --no-playlist --no-mtime --encoding utf-8 -f bestvideo+bestaudio[abr<=320]/bestvideo+bestaudio/best --sub-langs all --embed-subs --no-embed-thumbnail --embed-metadata --embed-chapters -o "/Volumes/APFS/videos/TV/大秦帝国1/Videos/China Zone 剧乐部/%(title)s via VidBee.%(ext)s" --continue --no-playlist-reverse --cookies-from-browser "chrome:/Users/haibof/Library/Application Support/Google/Chrome/Default" --proxy http://10.7.72.81:443 --js-runtimes deno:/Applications/VidBee.app/Contents/Resources/app.asar.unpacked/resources/deno --ffmpeg-location /Applications/VidBee.app/Contents/Resources/app.asar.unpacked/resources/ffmpeg https://www.youtube.com/watch?v=zKeKzfEPPvc

Error:
Error code: 1 Stderr: ERROR: Postprocessing: Conversion failed!

[nexmoe]

yt-dlp Upstream Triage (2026-02-13)

Upstream links:

• Postprocessing: Conversion failed! on already downloaded .opus files when using --embed-metadata and --embed-thumbnail yt-dlp/yt-dlp#11487
• [YouTube] embed-metadata causes conversion failed in some videos. "Could not find tag for codec eac3" yt-dlp/yt-dlp#11122

Conclusion:

• Postprocessing: Conversion failed points to FFmpeg/container/codec compatibility path, not necessarily source extraction.

Next actions:

1. Add automatic retry path without embed metadata/thumbnail.
2. Retry with safer container fallback (e.g., MKV) when conversion fails.
3. Store and expose complete FFmpeg stderr for exact diagnosis.