[FFmpeg-devel] [PATCH 06/11] aacpsy: Add energy spread for each band

[Claudio Freire]

On Fri, Jun 26, 2015 at 5:16 PM, Rostislav Pehlivanov
<atomnuker at gmail.com> wrote:
> +++ b/libavcodec/aacpsy.c
> @@ -781,6 +781,7 @@ static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel,
>
>              psy_band->threshold = band->thr;
>              psy_band->energy    = band->energy;
> +            psy_band->spread    = spread_en[w+g];
>          }
>      }
>


Sorry, but I just noticed while reviewing the other patches.

spread_en isn't as good a proxy for band tonality as we'd hoped, but
band->active_lines works (adjusting the rest of the patch set).

So it should read like:

> +++ b/libavcodec/aacpsy.c
> @@ -781,6 +781,7 @@ static void psy_3gpp_analyze_channel(FFPsyContext *ctx, int channel,
>
>              psy_band->threshold = band->thr;
>              psy_band->energy    = band->energy;
> +            psy_band->spread    = band->active_lines;
>          }
>      }
>

The following patch over head (well, git diff) does that:

diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 78232d4..ca21664 100644
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -787,7 +787,7 @@ static void psy_3gpp_analyze_channel(FFPsyContext
*ctx, int channel,

             psy_band->threshold = band->thr;
             psy_band->energy    = band->energy;
-            psy_band->spread    = spread_en[w+g];
+            psy_band->spread    = band->active_lines * 2.0f / band_sizes[g];
         }
     }

The rest of the patch set will need to adapt to this other spread
measure, I'll comment on the relevant patches.