Rendering (encoding) takes a very long time to export or fails


DaVinci Resolve may hang, take a very long time, or fail when exporting renders (encodes) on the Deliver page.
Are there any countermeasures? Checking the memory usage, it seems that it is caused by insufficient memory.


There are a number of possible reasons why DaVinci Resolve may hang or take too long to render (encode).

Since it seems that memory is insufficient this time, I will answer how to improve it by reducing the amount of memory used.
It may take a long time or fail for reasons other than lack of memory. We are considering creating a separate article about it in the future.

Why am I running out of memory while rendering or encoding?

During rendering (encoding), encoding processing is performed in parallel with calculations using effects and Fusion functions.
Therefore, even if you export to the same resolution, same frame rate, and same format, the amount of memory will change depending on the effects and Fusion functions used in the exported timeline.
There are various reasons why the render (encode) on the deliver page runs out of memory even though it can be played on DaVinci Resolve, depending on the conditions such as clips and effects and the settings of DaVinci Resolve. This may occur due to differences in handling and processing of memory used as a result.


We believe that there are several ways to deal with this problem, depending on the reason why the memory shortage occurred.

I think there are many ways to deal with it, but it is difficult to tell you what is the best countermeasure in what kind of situation because the judgment conditions are complicated. Also, even if it is an effective response under certain conditions, it may be difficult to recommend because the operation becomes complicated.

For this reason, here we will introduce a method that is easy to understand, effective in many patterns, and not so difficult to operate.

It is a "render and replace" that pre-performs the render processing that is performed on the deliver page.
(This is a function supported in version 17.) This is a function that exports only a specific clip as a separate video and replaces the original clip with the exported video as material. Since the replaced video file is a video file with complex processing such as Fusion and color, it is expected to reduce CPU and GPU load and memory usage.

Using this feature on clips with complex effects has the following effects:

  • Timeline playback is slow within DaVinci Resolve
  • There are many clips that take a long time to deliver (low frame rate when delivered), and it takes a long time every time
  • May not be able to export due to lack of memory during delivery

About Render and Replace

"Render and replace" is a menu that can be used for various purposes other than problems during rendering.
Clips that would otherwise have a high load are written to a video file once and replaced with it, so the load required for processing can be greatly reduced. This time, it is used to improve the processing time and memory shortage in rendering on the deliver page, but it is also effective when processing on the edit page and cut page.
(In the future, when there are more descriptions of other uses for similar "render and replace", we plan to make "render and replace" an independent article.)

How to Use

Performing "render and replace"

Right-click the target clip and select <Render and Replace>.
In addition, if you want to replace multiple clips at once instead of one clip, you can combine the clips in advance with "New compound clip" and then <Render and replace>.

important point
When you execute "Render and replace", the replacement video exported to the media pool is registered. The bin location of the registered media pool will be the location of the open bin when Render and Replace is selected. Also if the power bin is open it will be saved directly to the power bin as well. However, if the smart bin is open, it will be saved at the top level of the master bin. 

Change the format, codec, and type depending on the purpose of use.
The point is, if you export a clip with transparency (alpha), you should choose a codec that supports transparency. The codecs and types that can be selected vary depending on the format.

I think it's best to actually check what's best, but the formats that support transparency processing are limited.
Considering transparency processing, I think it would be better to select "Quick Time" and "Grass Valley" and select the resolution of the timeline for the type. Depending on the format you choose, you can also select compression quality, etc.

In addition, if you leave an additional xx frame handle and enter a number in Trim, the movie will be stretched by that frame and exported.

Select <Render> and specify the destination folder for the exported video to export the target clip.

The exported video is saved in the specified folder. This will be the replacement material. Each time "Render and Replace" is executed, a video file will be created as a new material, so it is recommended to manage the storage locations so that they are not dispersed. 

Once saved, the exported material will be added to the media pool and the clip on the timeline will be replaced with the exported clip.

When re-editing what was replaced with "Render and replace"

Right-click the replaced clip and select <Explode to Original>

Then, the clip will return to the state before "Render and Replace" was executed. The clip on the timeline will be restored, but the video file itself created by "Render and replace" and the registration of the replaced file in the media pool will remain. Also, if you execute "Render and replace" again, a new file will be created and added to the media pool.

♯ Da Vinci Resolve

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