[FFmpeg-devel] [PATCH] Long-term prediction for ALS

Thilo Borgmann thilo.borgmann
Thu Nov 12 23:07:35 CET 2009


Stefano Sabatini schrieb:
> On date Thursday 2009-11-12 19:12:52 +0100, Thilo Borgmann encoded:
>> Michael Niedermayer schrieb:
>>> On Thu, Nov 12, 2009 at 10:51:05AM -0500, Ronald S. Bultje wrote:
>>>> Hi,
>>>>
>>>> On Thu, Nov 12, 2009 at 10:45 AM, Stefano Sabatini
>>>> <stefano.sabatini-lala at poste.it> wrote:
>>>>> On date Thursday 2009-11-12 16:37:04 +0100, Thilo Borgmann encoded:
>>>>>> +    // set lag value for long-term prediction
>>>>>> +    if      (avctx->sample_rate >= 192000)
>>>>>> +        ctx->ltp_lag_length = 10;
>>>>>> +    else if (avctx->sample_rate >=  96000)
>>>>>> +        ctx->ltp_lag_length = 9;
>>>>>> +    else
>>>>>> +        ctx->ltp_lag_length = 8;
>>>>>> +
>>>>> Slightly simpler:
>>>>>
>>>>> ctx->ltp_lag_length = avctx->sample_rate >= 192000 ? 10 :
>>>>>                      avctx->sample_rate >=  96000 ?  9 : 8;
>>>> ltp_lag_length = 8 + samplerate >= 96000 + samplerate >= 192000;
>>>> (might need brackets).
>>> ltp_lag_length= 8 + FFMIN(samplerate/96000, 2);
>>>
>>> if one wants the most compact source ...
> 
> Do as you want, but the last is a little too obfuscated...

Hm, it seems like I've submitted updated revisions too fast...
I leave the decision up to you just tell me which way we all can agree
on and I will submit a corresponding patch.

-Thilo



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