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Re:FreeDV – Digital Voice mode for HF radio by LeoPanthera on Tuesday May 03, 2022 @03:20AM (#31245634)
For context, FreeDV is an SDR system based on Codec2, which is a codec designed to pick up at bitrates lower than where Opus stops being useful, which is about 12kb/s
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Re:FreeDV – Digital Voice mode for HF radio by throw0101a on Tuesday May 03, 2022 @08:11AM (#31247318)
Codec2 goes up to 'only' 3200b/s. Seems like there's a hole there for open codec between 3kb/s and 6/12kb/s.
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Re:FreeDV – Digital Voice mode for HF radio by LeoPanthera on Tuesday May 03, 2022 @02:43PM (#31251919)
That hole is mostly covered by G.729 and AMR-NB.

https://en.wikipedia.org/wiki/G.729

https://en.wikipedia.org/wiki/Adaptive_Multi-Rate_audio_code...

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Re:FreeDV – Digital Voice mode for HF radio by throw0101a on Tuesday May 03, 2022 @02:51PM (#31252018)
> That hole is mostly covered by G.729 and AMR-NB.

G.729 seems to be open with many/most patents expiring in 2017.

AMR-NB appears to need licensing, so not as open as Codec2 or Opus.

Regardless: if Codec2 could be pulled up and/or Opus pulled down, then most audio applications could do with really only two libraries.

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Re:FreeDV – Digital Voice mode for HF radio by ariendj on Tuesday May 03, 2022 @06:17AM (#31246589)
David Rowe's blog at rowetel.com details a lot of the development behind codec2 and is always an interesting read.
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Re:FreeDV – Digital Voice mode for HF radio by Gordonjcp on Tuesday May 03, 2022 @03:08AM (#31245558)
It definitely sounds better than AMBE2 in DMR.
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Re:FreeDV – Digital Voice mode for HF radio by anilakar on Tuesday May 03, 2022 @05:22AM (#31246304)
DMR's AMBE+2 works reasonably well for English, but certain languages sound as if the speaker was drunk and having a stroke at the same time.
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