decavcodec: DRC support.

Adds DRC support for E-AC-3 audio (as well as any future libavcodec decoders with DRC support).


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5995 b64f7644-9d1e-0410-96f1-a4d463321fa5

4 files changed, 70 insertions, 1 deletions

diff --git a/libhb/common.c b/libhb/common.c
index a0e6b7a58..813ece48e 100644
--- a/libhb/common.c
+++ b/libhb/common.c
@@ -3709,6 +3709,28 @@ int hb_subtitle_can_pass( int source, int mux )
     }
 }
 
+int hb_audio_can_apply_drc(uint32_t codec, uint32_t codec_param, int encoder)
+{
+    if (encoder & HB_ACODEC_PASS_FLAG)
+    {
+        // can't apply DRC to passthrough audio
+        return 0;
+    }
+    else if (codec & HB_ACODEC_FF_MASK)
+    {
+        return (codec_param == AV_CODEC_ID_AC3 ||
+                codec_param == AV_CODEC_ID_EAC3);
+    }
+    else if (codec == HB_ACODEC_AC3)
+    {
+        return 1;
+    }
+    else
+    {
+        return 0;
+    }
+}
+
 /**********************************************************************
  * hb_metadata_init
  **********************************************************************
diff --git a/libhb/common.h b/libhb/common.h
index 613338b35..cf037e579 100644
--- a/libhb/common.h
+++ b/libhb/common.h
@@ -161,6 +161,8 @@ int hb_subtitle_can_force( int source );
 int hb_subtitle_can_burn( int source );
 int hb_subtitle_can_pass( int source, int mux );
 
+int hb_audio_can_apply_drc(uint32_t codec, uint32_t codec_param, int encoder);
+
 hb_attachment_t *hb_attachment_copy(const hb_attachment_t *src);
 
 hb_list_t *hb_attachment_list_copy(const hb_list_t *src);
diff --git a/libhb/decavcodec.c b/libhb/decavcodec.c
index 5a4b0513c..1e760583b 100644
--- a/libhb/decavcodec.c
+++ b/libhb/decavcodec.c
@@ -360,12 +360,54 @@ static int decavcodecaInit( hb_work_object_t * w, hb_job_t * job )
     AVDictionary * av_opts = NULL;
     av_dict_set( &av_opts, "refcounted_frames", "1", 0 );
 
+    // Dynamic Range Compression
+    if (w->audio->config.out.dynamic_range_compression >= 0.0f &&
+        hb_audio_can_apply_drc(w->audio->config.in.codec,
+                               w->audio->config.in.codec_param, 0))
+    {
+        float drc_scale_max = 1.0f;
+        /*
+         * avcodec_open will fail if the value for any of the options is out of
+         * range, so assume a conservative maximum of 1 and try to determine the
+         * option's actual upper limit.
+         */
+        if (codec != NULL && codec->priv_class != NULL)
+        {
+            const AVOption *opt;
+            opt = av_opt_find2((void*)&codec->priv_class, "drc_scale", NULL,
+                               AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_AUDIO_PARAM,
+                               AV_OPT_SEARCH_FAKE_OBJ, NULL);
+            if (opt != NULL)
+            {
+                drc_scale_max = opt->max;
+            }
+        }
+        if (w->audio->config.out.dynamic_range_compression > drc_scale_max)
+        {
+            hb_log("decavcodecaInit: track %d, sanitizing out-of-range DRC %.2f to %.2f",
+                   w->audio->config.out.track,
+                   w->audio->config.out.dynamic_range_compression, drc_scale_max);
+            w->audio->config.out.dynamic_range_compression = drc_scale_max;
+        }
+
+        char drc_scale[5]; // "?.??\n"
+        snprintf(drc_scale, sizeof(drc_scale), "%.2f",
+                 w->audio->config.out.dynamic_range_compression);
+        av_dict_set(&av_opts, "drc_scale", drc_scale, 0);
+    }
+
     if (hb_avcodec_open(pv->context, codec, &av_opts, 0))
     {
         av_dict_free( &av_opts );
         hb_log("decavcodecaInit: avcodec_open failed");
         return 1;
     }
+    // avcodec_open populates av_opts with the things it didn't recognize.
+    AVDictionaryEntry *t = NULL;
+    while ((t = av_dict_get(av_opts, "", t, AV_DICT_IGNORE_SUFFIX)) != NULL)
+    {
+            hb_log("decavcodecaInit: unknown option '%s'", t->key);
+    }
     av_dict_free( &av_opts );
 
     pv->frame = av_frame_alloc();
diff --git a/libhb/work.c b/libhb/work.c
index 05f76d46e..abdf19f4f 100644
--- a/libhb/work.c
+++ b/libhb/work.c
@@ -452,7 +452,10 @@ void hb_display_job_info(hb_job_t *job)
                 {
                     hb_log( "   + gain: %.fdB", audio->config.out.gain );
                 }
-                if( ( audio->config.out.dynamic_range_compression != 0.0 ) && ( audio->config.in.codec == HB_ACODEC_AC3 ) )
+                if (audio->config.out.dynamic_range_compression > 0.0f &&
+                    hb_audio_can_apply_drc(audio->config.in.codec,
+                                           audio->config.in.codec_param,
+                                           audio->config.out.codec))
                 {
                     hb_log( "   + dynamic range compression: %f", audio->config.out.dynamic_range_compression );
                 }