Externally Previewable files design flaw

The externally previewable file feature works, but you have to go into the temporary directory. Also, the temporary directory cannot be changed. how it should work is that with the feature enabled, the temporary file for specifically exports should go to the exact same name and path as the export file parameters.

I double your request that it must be possible to open an exported file for preview while rendering from the context menu in TVAI, no matter if it has a temporary file name or the name specified by the user. It shouldn’t be necessary to open a folder on OS level.

However, it could be that the simultaneously invented feature to pause exports might make our wish impossible, because pausing export seems to split the video into separate chunks, which could also be a design flaw.


This feature that I’m talking about is illustrated here, in which the export uses mov flags, increasing the storage size temporarily before an optimized export replaces it. Making use of these mov flagged exports, which get replaced on completion anyway, I’m pretty sure a partial export would be viewable by a media player, as listed in the title of the feature.

Hope you are right. Just to be clear, I don’t argue against your ideas. I just believe that Topaz are making their (and our) lives harder than necessary.

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Contiguous MOV and MP4 media files do not allow for external preview of partially written files, since the MOOV atom is only written on the final completion of the file. That is more a limitation of these container formats, rather than a design flaw of Topaz or FFmpeg. (Note: There are some tricks you can do with FFmpeg’s -movflags '+empty_moov+cmaf' to force fragmented ISOMBFF, but that is not guaranteed to work for all players).

However, there is a workaround… TS, MKV and NUT files containers do allow for preview of partially written files while a media file is being written. If you want eventual MPV or MP4, and you want to preview in an external player such as MPV or pixops video-compare, it is preferable to work in TS / MKV or NUT and remux to MP4/MOV after.

[Personally, I like the NUT container, due to the simplicity, but that is not enabled in the video-encoders.json presets by default. MKV tends to be more popular as an intermediary container]

I don’t know much about those, and yet it still seems possible, I know it’s happened before

With 5.02 it’s possible to preview MP4 and MOV while rendering. It’s necessary to reveal the exported file on OS level for preview, because preview while rendering invoked from the the GUI doesn’t work. They use a temporary file name (not the file name specified by the user) and it seems that the file is remuxed after rendering has finished. Problems happen as soon as the export is paused.

Personally, I use the ISMV format if I need preview of MP4 and MOV while rendering, but the TVAI command line shows that they do it differently.

It works nicely now, with the export externally previewable in the source directory!