Avidemux Green or Black Screen in Preview? How to Fix It

A green or black preview in Avidemux means the video is not being decoded for display — the file opened, but the decoder produced no image. The file itself is usually fine; the problem is somewhere between the decoder, the display pipeline, and the file’s index. Work through the checklist below in order — most cases are fixed by step 1 or 2.

Fix 1: turn off hardware decoding

The single most common cause. Avidemux’s hardware-accelerated decoding (via your GPU) fails on some drivers and files, producing a solid green or black frame instead of video.

1. Go to Edit > Preferences.
2. Find the hardware decoding / HW accelerated decoding option and disable it.
3. Restart Avidemux and reopen the file.

If the picture appears, you have your answer: your GPU decoder and that file do not get along. Leave hardware decoding off for such files — software decoding is slower but reliable.

Fix 2: delete the stale index (.idx2)

When Avidemux opens MPEG-TS, MP4, and similar files, it builds an index file (a small .idx2 file next to your video) to seek quickly. If that index is stale or corrupt — for example after the source file changed — the preview can show black or green frames at positions the index misdescribes.

1. Close Avidemux.
2. Find the .idx2 file sitting next to your video and delete it.
3. Reopen the video — Avidemux rebuilds a fresh index.

Fix 3: check what the file actually contains

Go to File > Information (or Properties) and look at the video codec. A green/black preview with some files but not others usually means an unsupported or partially supported codec — for example 10-bit HEVC or AV1 on builds whose bundled decoder cannot handle that variant. Your options:

• Try a nightly build — decoder support improves there first (see our nightly builds guide).
• Pre-convert the file with ffmpeg or HandBrake to H.264, then edit the converted copy in Avidemux.
• Check the cannot find a demuxer guide if the file will not open at all.

Fix 4: suspect a damaged file

If the same file shows green/black frames in multiple players (VLC, mpv, Avidemux), the file itself is damaged — no Avidemux setting will fix it. Triage:

1. Play the file in VLC. If VLC also shows corruption, the file is the problem.
2. Try repairing the container without re-encoding: ffmpeg -i input.mp4 -c copy repaired.mp4 — this rewrites timestamps and structure.
3. Open the repaired file in Avidemux.

Is it the file or the settings? (decision tree)