Reels ads ban edit lists and special boxes: check your MP4

Meta's Reels ad spec says ads cannot include edit lists or special boxes in the file container, and asks for H.264, square pixels, fixed frame rate, progressive scan and stereo AAC at 128 kbps or more. A Sume probe shows codecs, frame rate and audio channels. It does not list container boxes, so check those with your own tool.

What does Meta's page list? (read 2026-10-09)

Which checks can the probe do?

video_inspect returns container, video_codec, pix_fmt, fps, has_audio, audio_codec, audio_channels, audio_sample_rate, width, height, duration_seconds and size_bytes. That covers H.264, stereo (audio_channels 2), AAC, frame rate and size. There is no bitrate field, so compute it as size_bytes times 8 divided by duration_seconds.

What about the edit list?

Docs for the video tools describe the codec and pixel format of an exact trim (libx264 yuv420p) but do not say what the container carries beyond that. So the edit list check is yours to run: open the delivered MP4 with a box reader such as the one in your pipeline and look for the edit list. If a file has one, re-encode it in a tool you trust and re-test.

Also note the size of the frame: Meta lists 1440 x 2560, and Timeline output stops at 2160 on an edge. See Meta lists 1440x2560; Sume stops at 2160 for the nearest sizes.

What should you do before upload?

If Meta rejects a file anyway, the rejection text is the best guide to which line of the spec it tripped. Keep the probe output for the rejected file, fix that one field, and re-render only that cut. Do not change several things at once, or you will not know which one mattered.

• Render with Timeline 1.0 ($0.10 per output minute, rounded up) or cut with video_trim ($0.02 per job).
• Probe the result and compare each field above.
• Run your own container check for edit lists.
• Remove any licensed music before upload; Meta bars it in Reels ads.