opus - Jun 2016 - Patches for adding 120 ms encoding

Hi Felicia,

I still don't quite understand why you need to make 120 ms a special
case, rather than extend the code that already handles 40 ms and 60 ms.

Cheers,

	Jean-Marc

On 06/01/2016 12:58 PM, Felicia Lim wrote:
> Hi all, 
> 
> I've just realized that there's a better and simpler way of doing
this
> which ensures that analysis and selection of the mode/bandwidth etc is
> done on the whole 120 ms frame. I believe that the logic and threshold
> values for making these decisions are still valid for 120 ms, but I
> might be missing something? Please find my updated patches attached. 
> 
> Thanks, 
> Felicia
> 
> 
> 
> On Tue, May 31, 2016 at 7:05 PM Felicia Lim <flim at google.com
> <mailto:flim at google.com>> wrote:
> 
>     Hi all,
> 
>     We (WebRTC/Google) would like to extend Opus to natively support 120
>     ms encoding instead of relying on repacketization as a post
>     processing step. This is to ensure that a valid 120 ms packet is
>     always available. I've attached a couple of patches to add this to
>     opus_encoder(), based on the internal repacketization process
>     carried out by 60 ms CELT. We intend to extend this later for the
>     multistream encoder as well. The first patch refactors out the
>     internal subframe encoding and repacketizing, and the second patch
>     actually adds the 120 ms support.
> 
>     Any thoughts would be appreciated.
> 
>     Thanks,
>     Felicia
> 
> 
> 
> _______________________________________________
> opus mailing list
> opus at xiph.org
> http://lists.xiph.org/mailman/listinfo/opus
>

Hi Jean-Marc,

I still don't quite understand why you need to make 120 ms a
special
> case, rather than extend the code that already handles 40 ms and 60 ms.
>
That was my intention with refactoring out the subframe encoding and
repacketizing bit. Or do you mean I should merge the explicit check for 120
ms frame and the existing checks for 40/60 ms wideband?

Thanks,
Felicia
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.xiph.org/pipermail/opus/attachments/20160601/2ae1d37a/attachment.html>

On 06/01/2016 02:06 PM, Felicia Lim wrote:
> That was my intention with refactoring out the subframe encoding and
> repacketizing bit. Or do you mean I should merge the explicit check for
> 120 ms frame and the existing checks for 40/60 ms wideband? 
What I mean is that this line in opus_encoder.c:

if (frame_size > st->Fs/50 && (st->mode == MODE_CELT_ONLY ||
st->bandwidth > OPUS_BANDWIDTH_WIDEBAND))

can probably be extended to also cover 80/100/120 ms. One difference is
that it would also need to trigger for SILK-only > 60 ms.

Cheers,

	Jean-Marc