[flac-dev] [PATCH] Improve LPC order guess

[Miroslav Lichvar]

On Wed, Dec 03, 2014 at 03:34:58PM +0100, Martijn van Beurden wrote:
> The recent compression preset retuning improved upon most material
> but it the few tracks that show regression are usually classical
> music. This patch improves compression by improving the LPC order
> guess, of which classical music benefits most.
> 
> Improvement is 0.007% on average but up to 0.1%. I haven't seen
> regressions for any of my test samples.

> @@ -1308,7 +1308,7 @@ FLAC__double FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__double lp
>  
>  	FLAC__ASSERT(total_samples > 0);
>  
> -	error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__double)total_samples;
> +	error_scale = 0.5 / (FLAC__double)total_samples;

Just curious, is there any explanation why this improves the
compression ratio? Is it a bug?

-- 
Miroslav Lichvar