How to get imGetSourceVideo called when I want to?

[zhongkez34561360]

Hi all, I am a Premiere Pro plugin developer and I know that imGetSourceVideo is called for every frame when we playback the clip on the timeline. However, I am wondering if I can trigger this selector manually even when the playback is stopped.

Here is the situation: I have created an HTTP server in my importer plugin and it continuously listens to requests from other applications. When the plugin receives a request (e.g., render settings changed), I need to render the current frame again using the latest settings. The question is, how can I achieve this?

Thank you.

[Bruce Bullis]

Why would you want to re-render frames every time something remote changes, rather than waiting until the frame was requested and re-rendering it then? What do you gain out of your pro-active caching? 

[zhongkez34561360]

Thank you for your reply. To address your questions, I would like to ensure that the rendering settings take effect immediately to verify that the current settings are as desired, even if the playback is paused. Otherwise, I would need to start the playback for this purpose.

[Bruce Bullis]

Understood...but why is the pre-emptive rendering desirable? If there is no playback, in what sense is "verifying that the current settings are as desired" even possible? 

We don't understand why 1. rendering only those frames your importer has been asked to render is a problem, or 2. Why performing unrequested work would ever be desirable.

[zhongkez34561360]

 in what sense is "verifying that the current settings are as desired" even possible?

Let's consider a scenario where I have a set of stitching algorithms and I want to evaluate the differences under specific circumstances. In this case, it would be preferable to compare the results on the same frame for a more accurate assessment.

[Bruce Bullis · Accepted solution]

Right, but if PPro doesn't want (request) those frames, what use is that evaluation?

Broadly speaking, PPro requests media from Importers, when it wants to; not when the Importer feels like providing media.

[zhongkez34561360]

 Thank you for your patient explanation, I understand now.