Adds extra, user-selectable dynamic range compression to the liba52 interface, making softer sounds louder. Based on code from liba52's A52Decoder, used in Perian's preferences pane. Set with a job->dynamic_range_compression float, with valid values being 1.0 - 4.0.

Controlled from the CLI with --dynamic-range-compression or -D.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@1108 b64f7644-9d1e-0410-96f1-a4d463321fa5

3 files changed, 36 insertions, 0 deletions

diff --git a/libhb/common.h b/libhb/common.h
index 988ea3d55..be174d17e 100644
--- a/libhb/common.h
+++ b/libhb/common.h
@@ -236,6 +236,7 @@ struct hb_job_s
     int             acodec;
     int             abitrate;
     int             arate;
+    float           dynamic_range_compression;
 
     /* Subtitle settings:
          subtitle: index in hb_title_t's subtitles list, starting
diff --git a/libhb/deca52.c b/libhb/deca52.c
index 94bf8a540..90dd9e738 100644
--- a/libhb/deca52.c
+++ b/libhb/deca52.c
@@ -20,6 +20,7 @@ struct hb_work_private_s
     int           rate;
     int           bitrate;
     float         level;
+    float         dynamic_range_compression;
     
     int           error;
     int           sync;
@@ -56,6 +57,30 @@ hb_work_object_t hb_deca52 =
 static hb_buffer_t * Decode( hb_work_object_t * w );
 
 /***********************************************************************
+ * dynrng_call
+ ***********************************************************************
+ * Boosts soft audio -- taken from gbooker's work in A52Decoder, comment and all..
+ * Two cases 
+ * 1) The user requested a compression of 1 or less, return the typical power rule 
+ * 2) The user requested a compression of more than 1 (decompression): 
+ *    If the stream's requested compression is less than 1.0 (loud sound), return the normal compression 
+ *    If the stream's requested compression is more than 1.0 (soft sound), use power rule (which will make
+ *   it louder in this case). 
+ * 
+ **********************************************************************/
+static sample_t dynrng_call (sample_t c, void *data)
+{        
+        double *level = (double *)data;
+        float levelToUse = (float)*level;
+        if(c > 1.0 || levelToUse <= 1.0)
+        {
+            return powf(c, levelToUse);
+        }
+        else
+                return c;
+}
+ 
+/***********************************************************************
  * hb_work_deca52_init
  ***********************************************************************
  * Allocate the work object, initialize liba52
@@ -80,6 +105,8 @@ int deca52Init( hb_work_object_t * w, hb_job_t * job )
 	pv->out_discrete_channels = HB_AMIXDOWN_GET_DISCRETE_CHANNEL_COUNT(w->amixdown);
 
     pv->level     = 32768.0;
+    pv->dynamic_range_compression = job->dynamic_range_compression;
+    
     pv->next_expected_pts = 0;
     pv->sequence = 0;
     
@@ -201,6 +228,11 @@ static hb_buffer_t * Decode( hb_work_object_t * w )
     /* Feed liba52 */
     a52_frame( pv->state, pv->frame, &pv->flags_out, &pv->level, 0 );
 
+    if ( pv->dynamic_range_compression )
+    {
+        a52_dynrng( pv->state, dynrng_call, &pv->dynamic_range_compression);        
+    }
+    
     /* 6 blocks per frame, 256 samples per block, channelsused channels */
     buf        = hb_buffer_init( 6 * 256 * pv->out_discrete_channels * sizeof( float ) );
     if (pts == -1)
diff --git a/libhb/work.c b/libhb/work.c
index 19c498f0f..daabf9962 100644
--- a/libhb/work.c
+++ b/libhb/work.c
@@ -324,6 +324,9 @@ static void do_job( hb_job_t * job, int cpu_count )
                 "faac" : ( ( job->acodec & HB_ACODEC_LAME ) ? "lame" :
                 "vorbis" ) );
     }
+    
+    if ( job->dynamic_range_compression )
+        hb_log(" + dynamic range compression: %f", job->dynamic_range_compression);
 
     /* if we are doing AC3 passthru, then remove any non-AC3 audios from the job */
     /* otherwise, Bad Things will happen */