What are the requirements for a sound card to have Dolby Digital?

Question

Sound cards

I don't understand well, so I can't explain correctly.
Chain:
Movie with Dolby Digital audio track ->
-> computer sound card ->
-> optical toslink wire ->
-> "ReSound TV Streamer 2" device with Dolby Digital support (if I understood it correctly, it has a built-in decoder) ->
-> through the air to hearing aids.

What are the requirements for a sound card (for me to choose the right model to buy)?
Will the built-in sound card work with the presence of an optical toslink output on the motherboard, for example, Realtek ALC887?

Ps ReSound TV Streamer 2 supports the following according to the instructions:
Dolby Digital
Channels: max 5.1
Bitrate: 32 kbs to 640 kbs
Sample rate: 32, 44.1 and 48 kHz
---
Not supported:
Dolby Digital Plus
Dolby True-HD
Dolby Pro Logic
Dolby Digital EX
Dolby Digital Surround EX
AAC (Advanced Audio Codec)

Answer 1

for video playback, hardware support is not essential, except for the presence of a sufficient number of connected outputs 5.1 (3 minijacks)
ps https://ru.wikipedia.org/wiki/Dolby_Digital