Q100297: How to isolate playback issues in Nuke Studio/Hiero



This article aims to help users troubleshoot issues they are having with real-time playback in Nuke Studio and Hiero


Having the ability to playback a sequence in real time is a very useful workflow benefit, that enables users to be more efficient in their use of Nuke Studio or Hiero. In order to achieve a real-time playback setup, the user will need to account predominantly for the following factors:
  • The read speed of the drive the footage is being read from
  • The file type, bit rate and resolution of the file
  • The frame rate the user wants to playback at
  • The complexity of the sequence they are working on
  • The cache settings in the users preferences

Machine specifications and drive read speed:

First you should compare your machine specifications to those listed in Nuke's online documentation to see how your internal drive compares to the certified hardware: 

We then recommend determining your local and network drive speeds, and more information on how to do this are available in the following article: Q100296: How to check the network speed

We recommend that a user reads footage from their local disk, as this is usually the faster location to read from and will not suffer severe fluctuations in read speed dependent on network usage.

File type, bit rate and resolution:

Nuke Studio and Hiero perform optimally when using DPX and EXR file sequences, so it is recommended that you use these file types if you are looking to achieve real-time playback. 

Other file types can be used, but will likely require faster read speeds to read from disk. Also please note that Studio and Hiero work efficiently with file image sequences, as opposed to file containers such as movs and therefore real-time playback is harder to achieve with mov files.

The larger the resolution of the file and the higher the bit rate then the more data that will need to be read from disk. This means for footage that is 4K 32-bit DPX with multiple channels, this would require considerably faster read speeds that a 1080p 8-bit DPX file.
For some information regarding testing we have done in-house with 16-bit RGBA DPX sequences, and the drive speed required for that example, please see our documentation here: Achieving Real-time Playback

Frame Rate:

Similarly to file types, bit rate and resolution, the higher the frame rate you wish to use the more data that needs to be read from disk. As such your read speeds will need to increase accordingly.

Sequence complexity:

Nuke Studio and Hiero operate by playing the top level clips on the given tracks in a timeline and then processing any soft effects that have been applied on top. As such a simple edit, with a single track and no soft effects will require less disk read speed and processing power than a timeline with multiple tracks, clip versions, edits and soft effects. However a more complex track, playing back two 4K tracks, compared to one, would required twice the drive speed, as it is reading double the data.

Cache settings:

When playing a file in Nuke Studio or Hiero, it will start caching on import to help ensure you can start playing the footage as soon as possible. If however, you have very fast read speeds then we recommend reducing the cache size in your Preferences as it is more efficient to read directly from disk in this instance. 

If you have slower read speeds, then we recommend increasing your playback cache size preferences. More information about the preferences can be found in Nuke's online documentation: Performance


The above information should help you to understand what to take into account when troubleshooting real time playback in Nuke Studio and Hiero. If you find that you are experiencing issues with playback then we recommend you perform the following steps:
  1. Determine what your fastest disk to read from is and read the footage from this disk (this will commonly be your local drive)
  2. If playback issues continue, test with a lower resolution 8-bit DPX file to determine if real time playback can be achieved with lower settings
  3. If playback issues continue, reduce the frame rate (for instance if you are attempting to play at 50 fps, try playing at 24 fps)
  4. If playback issues continue, reduce the complexity of your sequence and just import the lower resolution 8-bit DPX file into a new project and its own track and try testing this
  5. If you are using a monitor out device, try disabling it, and see if your playback performance improves
By performing these steps you should be able to determine at what point your setup can achieve real time playback within Nuke Studio and Hiero.


If you believe that you have sufficient read speeds and performance to achieve real time playback in Nuke Studio and Hiero, and find that following the above troubleshooting steps do not allow you to achieve it as expected, then please open a Support ticket with us and provide us with the following information:
  1. Type of files and bit rate: EXR, DPX, Mov, 8-bit, 10-bit etc
  2. Size of files: what resolution are the files? i.e. 4K, 1080HD etc
  3. Max FPS user wishes to play at
  4. A screenshot of your cache settings
  5. Your machine specifications: RAM, SSDs, processors, GPU etc
  6. Screenshots of the read speeds of your local and network drives using the following article: Q100296: How to check the network speed
  7. If you are reading files locally or from the network
  8. If you are using the localize feature in the software or are you copying files manually to disk
With this information we can review your system setup and help to determine why you might be having issues achieving real time playback. 

For more information on how to open a Support ticket, please refer to the Using the Support Portal article.

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