[GH-ISSUE #2250] Video downloads fail to play in Safari due to WebM format and incorrect MIME type metadata #1374

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opened 2026-03-02 11:56:51 +03:00 by kerem · 0 comments

kerem commented

2026-03-02 11:56:51 +03:00

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Originally created by @SqREL on GitHub (Dec 13, 2025).
Original GitHub issue: https://github.com/karakeep-app/karakeep/issues/2250

Describe the Bug

Bug Summary

Downloaded videos are saved as WebM format but metadata incorrectly reports video/mp4, causing playback failures. Safari cannot play WebM at all.

Environment

Karakeep version: 0.29.3
Browser: Safari (fails), Chrome (works)
OS: Ubuntu (Docker)

Configuration

CRAWLER_VIDEO_DOWNLOAD=true
CRAWLER_VIDEO_DOWNLOAD_MAX_SIZE=-1

Steps to Reproduce

Save a YouTube video URL in Karakeep
Wait for video download to complete
Try to play the video in Safari

Actual Behavior

yt-dlp downloads video as .webm (VP9 codec)
Metadata saved as {"contentType":"video/mp4"}
Safari cannot play WebM — video fails silently
Chrome plays it (supports WebM)

Evidence

$ file asset.bin
asset.bin: WebM

$ cat metadata.json
{"contentType":"video/mp4"}

Expected Behavior

Either:

Pass --merge-output-format mp4 to yt-dlp so videos are converted to H.264/MP4 (Safari compatible)
Or at minimum, save correct MIME type (video/webm) in metadata

Suggested Fix

Add to yt-dlp arguments in videoworker.ts:

ytDlpArguments.push("--merge-output-format", "mp4");

#792 (Firefox archived video unsupported format)
#1842 (yt-dlp -f flag issues)

Steps to Reproduce

Set environment variables:

CRAWLER_VIDEO_DOWNLOAD=true
CRAWLER_VIDEO_DOWNLOAD_MAX_SIZE=-1

Restart Karakeep containers
Add a new bookmark with YouTube URL (e.g., https://www.youtube.com/watch?v=jZyPsok9RPk)
Wait for video download to complete (check logs for "Video Download Completed successfully")
Open the bookmark in Safari browser
Click play on the embedded video player

Result: Video doesn't play in Safari. Works in Chrome.

Verification:

# Find the downloaded asset
find /data/assets -name "asset.bin" -newer /tmp/marker 2>/dev/null | head -1

# Check actual file format vs metadata
file <path>/asset.bin           # Shows: WebM
cat <path>/metadata.json        # Shows: {"contentType":"video/mp4"}

Expected Behaviour

Videos should play in all major browsers including Safari. This requires either:

Converting downloaded videos to MP4 format (H.264 codec) using yt-dlp's --merge-output-format mp4 flag, since ffmpeg is already available in the container
Or at minimum, saving the correct MIME type in metadata (video/webm for WebM files) so browsers can handle them appropriately

Screenshots or Additional Context

Device Details

Safari Version 26.1 (21622.2.11.11.9)

Exact Karakeep Version

v0.29.3

Have you checked the troubleshooting guide?

I have checked the troubleshooting guide and I haven't found a solution to my problem

Originally created by @SqREL on GitHub (Dec 13, 2025). Original GitHub issue: https://github.com/karakeep-app/karakeep/issues/2250 ### Describe the Bug ### Bug Summary Downloaded videos are saved as WebM format but metadata incorrectly reports `video/mp4`, causing playback failures. Safari cannot play WebM at all. ### Environment - Karakeep version: 0.29.3 - Browser: Safari (fails), Chrome (works) - OS: Ubuntu (Docker) ### Configuration ```env CRAWLER_VIDEO_DOWNLOAD=true CRAWLER_VIDEO_DOWNLOAD_MAX_SIZE=-1 ``` ### Steps to Reproduce 1. Save a YouTube video URL in Karakeep 2. Wait for video download to complete 3. Try to play the video in Safari ### Actual Behavior - yt-dlp downloads video as `.webm` (VP9 codec) - Metadata saved as `{"contentType":"video/mp4"}` - Safari cannot play WebM — video fails silently - Chrome plays it (supports WebM) ### Evidence ```bash $ file asset.bin asset.bin: WebM $ cat metadata.json {"contentType":"video/mp4"} ``` ### Expected Behavior Either: 1. Pass `--merge-output-format mp4` to yt-dlp so videos are converted to H.264/MP4 (Safari compatible) 2. Or at minimum, save correct MIME type (`video/webm`) in metadata ### Suggested Fix Add to yt-dlp arguments in `videoworker.ts`: ```typescript ytDlpArguments.push("--merge-output-format", "mp4"); ``` ### Related Issues - #792 (Firefox archived video unsupported format) - #1842 (yt-dlp -f flag issues) ### Steps to Reproduce 1. Set environment variables: ```env CRAWLER_VIDEO_DOWNLOAD=true CRAWLER_VIDEO_DOWNLOAD_MAX_SIZE=-1 ``` 2. Restart Karakeep containers 3. Add a new bookmark with YouTube URL (e.g., `https://www.youtube.com/watch?v=jZyPsok9RPk`) 4. Wait for video download to complete (check logs for "Video Download Completed successfully") 5. Open the bookmark in Safari browser 6. Click play on the embedded video player **Result:** Video doesn't play in Safari. Works in Chrome. **Verification:** ```bash # Find the downloaded asset find /data/assets -name "asset.bin" -newer /tmp/marker 2>/dev/null | head -1 # Check actual file format vs metadata file <path>/asset.bin # Shows: WebM cat <path>/metadata.json # Shows: {"contentType":"video/mp4"} ``` ### Expected Behaviour Videos should play in all major browsers including Safari. This requires either: 1. Converting downloaded videos to MP4 format (H.264 codec) using yt-dlp's `--merge-output-format mp4` flag, since ffmpeg is already available in the container 2. Or at minimum, saving the correct MIME type in metadata (`video/webm` for WebM files) so browsers can handle them appropriately ### Screenshots or Additional Context <img width="1261" height="702" alt="Image" src="https://github.com/user-attachments/assets/7f8f4755-2685-4c03-9b56-2687f30526eb" /> ### Device Details Safari Version 26.1 (21622.2.11.11.9) ### Exact Karakeep Version v0.29.3 ### Have you checked the troubleshooting guide? - [x] I have checked the troubleshooting guide and I haven't found a solution to my problem