Real-time Virtual Appliance

Important Notices

Removal Note

The legacy V1 API that the Real-time Virtual Appliance currently supports will be removed by June 2022. We recommend all customers move to using the V2 API. Please see the section How to use the V2 API.

High Level Summary

This release provides new improved language packs for all Speechmatics' commercially available languages. Two new language packs Cantonese (yue) and Indonesian (id) are released. This release improves on existing punctuation in several of these languages, as well as existing custom dictionary features. Common concepts in 11 words called entities are now output in a consistent and predictable fashion. Additional data about these entities can be requested via the API. Transcript segments can flex in length when an entity is detected to ensure accurate output, but fixed behaviour can also now be requested using a new API parameter.

Important Notices

Speechmatics now supports exclusively speechmatics-python for use in both our Real-time Container and our Real-time Virtual Appliance. The older library smwebsocket-py will still work, but is not compatible with the new enhanced model and is no longer supported. Please see here for access to speechmatics-python.

The new enhanced model has increased compute requirements and new recommended AVX flags. Each concurrent worker will require at least 3GB of memory and up to 5GB if using other features such as Custom Dictionary. Please check the updated system requirements in the installation guide and ensure your hardware meets Speechmatics' recommendations. Otherwise you may see a slow down in processing speed when using the enhanced model. It is also now necessary to run the appliance on processors that support AVX2 in order to take advantage of latest performance optimisations for both the standard and enhanced model for all language packs.

If you are importing an appliance through VirtualBox, and AVX flags are not automatically enabled, you can also take advantage of the the performance benefits from AVX 2 following these guidelines.

What's New


  • Improved accuracy for all 31 language packs. Gains will be for both standard and enhanced operating points
  • New Cantonese (yue) and Indonesian (id) language packs
  • Improved formatting of numeric entities such as dates, currencies and large numbers for 11 languages, which are as following
    • Cantonese (yue)
    • Chinese Mandarin (cmn)
    • English (en)
    • French (fr)
    • German (de)
    • Hindi (hi)
    • Italian (it)
    • Japanese (ja)
    • Portuguese (pt)
    • Russian (ru)
    • Spanish (es)
  • Additional metadata about these entities can be requested by using the new enable_entities config parameter. For more information please see our documentation for entities here
  • Max delay has a new configuration option called max_delay_mode
    • max_delay_mode defaults to flexible which introduces a change in max delay behaviour to improve accuracy of entities. To maintain previous behaviour set max_delay_mode to fixed.
  • Improvements to custom dictionary functionality. Custom dictionary entries should now have less false positives
  • Languages with updated punctuation marks
    • Japanese (。 、)
    • Italian (. ? , !)
    • Portuguese (. ? , !)
    • Russian (. ? , !)
    • Mandarin (。 ? ! 、)
    • Hindi (। ? , !)
    • All other languages will not see a change in outstanding punctuation marks
  • The JSON-v2 output format version is now 2.7
  • The transcription can now output words containing non-breaking spaces as a single result
  • Documentation is no longer embedded in the Appliance. Please use this website for all your documentation needs

Known Limitations

The following are known issues in this release:

Issue IDSummaryDetailed Description and Possible Workarounds
REQ-1409Proteus HCL with <unk> causes out of memory errorA custom dictionary list that contains the word '' causes the worker to crash.
REQ-7549Memory leak affecting gRPCThere is a small memory leak in the gRPC Python server
REQ-10160Advanced punctuation for Spanish (es) does not contain inverted marks.Inverted marks [ ¿ ¡ ] are not currently available for Spanish advanced punctuation.
REQ-10627Double full stops when acronym is at the end of the sentenceIf there is an acronym at the end of the sentence, then a double full stop will be output, for example: "team G.B.."
REQ-11792Speaker change token positioning is incorrectWe are aware of a consistent mis-placing of the speaker change token after the first word of the new speakers' sentence rather than before it.
REQ-12202High memory usage when using custom dictionaryIt has been observed that when using custom dictionary an additional 800-1700MB of memory is required (depending on the size of the wordlist used).
REQ-16256Heavy usage of RAM when swapping between 8kHz and 16kHz inputWhere multiple persistent workers are configured with Custom Dictionary that swap between 8kHz and 16kHz input, this can cause a memory leak that causes the container to crash. If this starts to impact services it is recommended to restart all the services with the management API or drop the worker count to 1 and then increase it again

Supported Platforms

Virtual Appliance image (OVA) for installation on:

  • VMware ESXi 6.5+ or VMware Workstation Player.
  • VirtualBox 5.2+
  • Amazon EC2

See the Installation and Admin Guide for details on the minimum specifications for the VM. The maximum number of concurrent jobs (maxworkers) that you can run on a single appliance is 30.

Form Factors

There are five variants of the Real-time Virtual Appliance.

VariantImage SizeMax. Disk SpaceLanguages
mini13GB40GBen, de, es
midi23GB60GBen, de, es, fr, ko, ja, nl, pt
maxi37GB80GBen, de, es, fr, ko, ja, nl, pt, it, da, pl, ca, hi, ru, sv
plus45GB80GBen, cmn, no, ar, bg, cs, el, fi, hu, hr, lt, lv, ro, sk, sl, tr, ms, id, yue

Upgrade Path

Remove the license from your old appliance (see the Admin Guide), then re-import the new OVA and configure networking as per the Installation and Admin guide. You will need to re-apply the license code you have once the OVA has imported.


Upload the OVA to VMWare ESX, VMWare Workstation Player, or VirtualBox. See the Installation and Admin Guide for more information.