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Topic: Disputed claim in Wikipedia Opus (audio format) article (Read 3208 times) previous topic - next topic
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Disputed claim in Wikipedia Opus (audio format) article

Hi,

I wonder if anyone with a thorough grasp of Opus can definitively answer this question and enable us to remove the Disputed claim tag.

The section link is here and it's the last line that is disputed in good faith:
https://en.wikipedia.org/wiki/Opus_(audio_f...ncy_performance

Quote
Opus permits trading-off quality or bitrate to achieve an even smaller algorithmic delay (5.0 ms minimum). While the default Opus frame is 20 ms long, a further 2.5 ms lookahead is required for window overlap in the CELT layer and noise shaping in the SILK layer, typically giving a delay of 22.5 ms.[disputed – discuss] The SILK layer's minimum is 10 ms frames (12.5 ms delay), while the CELT layer's minimum is 2.5 ms (5.0 ms delay).


On the Talk page, we haven't got a definitive answer to the figures that have been queried/disputed in good faith.
https://en.wikipedia.org/wiki/Talk:Opus_(au...ec_delay_values

It's probably best to read that section and the comments of user Bigpeteb which have so far only been followed up by my own (as Dynamicimanyd, I am the editor who introduced the figures in the disputed paragraph in this revision https://en.wikipedia.org/w/index.php?title=...oldid=520642746 )

No need to be kind to me, I'd rather get accurate figures and learn something than save face. I'm certainly fallible.

We can also maintain the accuracy of the HydrogenAudio Wiki article which is based on the same article but less up-to-date and less scrutinized.
Dynamic – the artist formerly known as DickD

Disputed claim in Wikipedia Opus (audio format) article

Reply #1 –
Just confirmed the delay values on the Talk page.
 

Disputed claim in Wikipedia Opus (audio format) article

Reply #2 –
Thanks, Jean-Marc. Very helpful indeed.

For future reference and to tie up loose ends, the paper presented at AES 135 contains the correct information on page 2, column 2:

6.5 ms of additional algorithmic delay (encoder+decoder) is added to frame-size by default to ensure CELT and SILK layers are synchronised.

This is except for the special application mode OPUS_APPLICATION_RESTRICTED_LOWDELAY where SILK is disabled and 2.5ms of additional algorithmic delay is added to the frame-size thanks to CELT-layer MDCT windowing overlap.
Dynamic – the artist formerly known as DickD