1 files changed, 23 insertions, 4 deletions

diff --git a/apps/codecs/Tremor/synthesis.c b/apps/codecs/Tremor/synthesis.c
index 0b93fee0ac..35c09f8ddb 100644
--- a/apps/codecs/Tremor/synthesis.c
+++ b/apps/codecs/Tremor/synthesis.c
@@ -24,6 +24,17 @@
 #include "misc.h"
 #include "os.h"
 
+
+/* IRAM buffer keep the block pcm data; only for windows size upto 2048
+   for space restrictions. No real compromise, larger window sizes
+   are only used for very low quality settings (q<0?) */
+/* max 2 channels on the ihp-1xx (stereo), 2048 samples (2*2048*4=16Kb)  */
+#define IRAM_PCM_END      2048    
+#define CHANNELS          2          
+
+static ogg_int32_t *ipcm_vect[CHANNELS] IDATA_ATTR;
+static ogg_int32_t ipcm_buff[CHANNELS*IRAM_PCM_END] IDATA_ATTR;
+
 int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep){
   vorbis_dsp_state     *vd=vb->vd;
   private_state        *b=(private_state *)vd->backend_state;
@@ -65,10 +76,18 @@ int vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep){
   if(decodep){
     /* alloc pcm passback storage */
     vb->pcmend=ci->blocksizes[vb->W];
-    vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
-    for(i=0;i<vi->channels;i++)
-      vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
-    
+    if (vi->channels <= CHANNELS && vb->pcmend<=IRAM_PCM_END) { 
+      /* use statically allocated iram buffer */
+      vb->pcm = ipcm_vect;
+      for(i=0; i<CHANNELS; i++)
+        vb->pcm[i] = &ipcm_buff[i*IRAM_PCM_END];  
+    } else {
+      /* dynamic allocation (slower) */
+      vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
+      for(i=0;i<vi->channels;i++)
+        vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
+    }
+      
     /* unpack_header enforces range checking */
     type=ci->map_type[ci->mode_param[mode]->mapping];