Only Exporting audio no video

[Selman5C3F]

Hello,

I have tried exporting my video, but some parts of the video that are HEIC format I believe export as black background and audio. how can I fix it. 

[Selman5C3F]

Correction, they are mov files.

[Michael Grenadier]

you might try smart rendering.  Change sequence settings preview format to a full quality format like quicktime:  prores422 hq and render the problematic clips in the timeline and then in the export dialog, make sure you check "use previews."

[Michael Grenadier]

I actually had this problem yesterday.  I was exporting a program for a livestreaming event (that's actually happening now).  When we had the rehearsal for the event, near the end of the program there were a couple of sections of black.  when I ganged the export to the program monitor with the sequence that I exported, I found there were a couple of clips that had a different pixel dimension than the sequence.  Played fine, but when I came in this morning, I rendered those 2 sections and redid the export with "use previews" checked and all is well.