Streamlined WavPack decoder by utilizing dsp functionality where it was

applicable (like mono conversion and clipping) and eliminating the
conversion to 16-bit samples (everything is now returned as 28-bit).
This reduced boost ratio (on iRiver) by about 7% on those tracks that
require it.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8598 a1c6a512-1295-4272-9138-f99709370657

apps/codecs/libwavpack/unpack.c

@@ -675,11 +675,17 @@ static void decorr_mono_pass (struct decorr_pass *dpp, long *buffer, long sample
 // it is clipped and shifted in a single operation. Otherwise, if it's
 // lossless then the last step is to apply the final shift (if any).
 
+// This function has been modified for RockBox to return all integer samples
+// as 28-bits, and clipping (for lossy mode) has been eliminated because this
+// now happens in the dsp module.
+
 static void fixup_samples (WavpackStream *wps, long *buffer, ulong sample_count)
 {
     ulong flags = wps->wphdr.flags;
     int shift = (flags & SHIFT_MASK) >> SHIFT_LSB;
 
+    shift += 20 - (flags & BYTES_STORED) * 8;   // this provides RockBox with 28-bit data
+
     if (flags & FLOAT_DATA) {
         float_values (wps, buffer, (flags & MONO_FLAG) ? sample_count : sample_count * 2);
         return;
@@ -689,7 +695,6 @@ static void fixup_samples (WavpackStream *wps, long *buffer, ulong sample_count)
         ulong count = (flags & MONO_FLAG) ? sample_count : sample_count * 2;
         int sent_bits = wps->int32_sent_bits, zeros = wps->int32_zeros;
         int ones = wps->int32_ones, dups = wps->int32_dups;
-//      ulong mask = (1 << sent_bits) - 1;
         long *dptr = buffer;
 
         if (!(flags & HYBRID_FLAG) && !sent_bits && (zeros + ones + dups))
@@ -707,51 +712,22 @@ static void fixup_samples (WavpackStream *wps, long *buffer, ulong sample_count)
             shift += zeros + sent_bits + ones + dups;
     }
 
-    if (flags & HYBRID_FLAG) {
+    if (shift > 0) {
-        long min_value, max_value, min_shifted, max_shifted;
-
-        switch (flags & BYTES_STORED) {
-            case 0:
-                min_shifted = (min_value = -128 >> shift) << shift;
-                max_shifted = (max_value = 127 >> shift) << shift;
-                break;
-
-            case 1:
-                min_shifted = (min_value = -32768 >> shift) << shift;
-                max_shifted = (max_value = 32767 >> shift) << shift;
-                break;
-
-            case 2:
-                min_shifted = (min_value = -8388608 >> shift) << shift;
-                max_shifted = (max_value = 8388607 >> shift) << shift;
-                break;
-
-            case 3:
-            default:
-                min_shifted = (min_value = (long) 0x80000000 >> shift) << shift;
-                max_shifted = (max_value = (long) 0x7FFFFFFF >> shift) << shift;
-                break;
-        }
-
-        if (!(flags & MONO_FLAG))
-            sample_count *= 2;
-
-        while (sample_count--) {
-            if (*buffer < min_value)
-                *buffer++ = min_shifted;
-            else if (*buffer > max_value)
-                *buffer++ = max_shifted;
-            else
-                *buffer++ <<= shift;
-        }
-    }
-    else if (shift) {
         if (!(flags & MONO_FLAG))
             sample_count *= 2;
 
         while (sample_count--)
             *buffer++ <<= shift;
     }
+    else if (shift < 0) {
+        shift = -shift;
+
+        if (!(flags & MONO_FLAG))
+            sample_count *= 2;
+
+        while (sample_count--)
+            *buffer++ >>= shift;
+    }
 }
 
 // This function checks the crc value(s) for an unpacked block, returning the

apps/codecs/wavpack.c

@@ -24,9 +24,6 @@ CODEC_HEADER
 
 static struct codec_api *ci;
 
-#define FORCE_DSP_USE    /* fixes some WavPack bugs; adds about 12% to boost ratio
-                            (when DSP would not have been used) */
-
 #define BUFFER_SIZE 4096
 
 static long temp_buffer [BUFFER_SIZE] IBSS_ATTR;
@@ -66,8 +63,7 @@ enum codec_status codec_start(struct codec_api* api)
     ci->configure(CODEC_SET_FILEBUF_CHUNKSIZE, (int *)(1024*128));
   
     ci->configure(DSP_DITHER, (bool *)false);
-    ci->configure(DSP_SET_STEREO_MODE, (int *)STEREO_INTERLEAVED);
+    ci->configure(DSP_SET_SAMPLE_DEPTH, (int *)(27));   // should be 28...
-    ci->configure(DSP_SET_SAMPLE_DEPTH, (int *)(16));
 
     next_track:
 
@@ -79,20 +75,9 @@ enum codec_status codec_start(struct codec_api* api)
     while (!*ci->taginfo_ready && !ci->stop_codec)
         ci->sleep(1);
         
-#ifdef FORCE_DSP_USE
     ci->configure(CODEC_DSP_ENABLE, (bool *)true);
     ci->configure(DSP_SET_FREQUENCY, (long *)(ci->id3->frequency));
     codec_set_replaygain(ci->id3);
-#else
-    if (ci->id3->frequency != NATIVE_FREQUENCY ||
-        ci->global_settings->replaygain) {
-            ci->configure(CODEC_DSP_ENABLE, (bool *)true);
-            ci->configure(DSP_SET_FREQUENCY, (long *)(ci->id3->frequency));
-            codec_set_replaygain(ci->id3);
-    }
-    else
-        ci->configure(CODEC_DSP_ENABLE, (bool *)false);
-#endif
    
     /* Create a decoder instance */
     wpc = WavpackOpenFileInput (read_callback, error);
@@ -104,6 +89,7 @@ enum codec_status codec_start(struct codec_api* api)
 
     bps = WavpackGetBytesPerSample (wpc);
     nchans = WavpackGetReducedChannels (wpc);
+    ci->configure(DSP_SET_STEREO_MODE, nchans == 2 ? (int *)STEREO_INTERLEAVED : (int *)STEREO_MONO);
     sr_100 = ci->id3->frequency / 100;
 
     ci->set_elapsed (0);
@@ -141,71 +127,21 @@ enum codec_status codec_start(struct codec_api* api)
             ci->yield ();
         }
 
-        nsamples = WavpackUnpackSamples (wpc, temp_buffer, BUFFER_SIZE / 2);  
+        nsamples = WavpackUnpackSamples (wpc, temp_buffer, BUFFER_SIZE / nchans);  
 
         if (!nsamples || ci->stop_codec || ci->reload_codec)
             break;
 
-        /* convert mono to stereo here, in place */
-
-        if (nchans == 1) {
-            long *dst = temp_buffer + (nsamples * 2);
-            long *src = temp_buffer + nsamples;
-            long count = nsamples;
-
-            while (count--) {
-                *--dst = *--src;
-                *--dst = *src;
-                if (!(count & 0x7f))
         ci->yield ();
-            }
-        }
-
-        if (bps == 1) {
-            short *dst = (short *) temp_buffer;
-            long *src = temp_buffer;
-            long count = nsamples;
-
-            while (count--) {
-                *dst++ = *src++ << 8;
-                *dst++ = *src++ << 8;
-                if (!(count & 0x7f))
-                    ci->yield ();
-            }
-        }
-        else if (bps == 2) {
-            short *dst = (short *) temp_buffer;
-            long *src = temp_buffer;
-            long count = nsamples;
-
-            while (count--) {
-                *dst++ = *src++;
-                *dst++ = *src++;
-                if (!(count & 0x7f))
-                    ci->yield ();
-            }
-        }
-        else {
-            short *dst = (short *) temp_buffer;
-            int shift = (bps - 2) * 8;
-            long *src = temp_buffer;
-            long count = nsamples;
-
-            while (count--) {
-                *dst++ = *src++ >> shift;
-                *dst++ = *src++ >> shift;
-                if (!(count & 0x7f))
-                    ci->yield ();
-            }
-        }
 
         if (ci->stop_codec || ci->reload_codec)
             break;
 
-        while (!ci->pcmbuf_insert ((char *) temp_buffer, nsamples * 4))
+        while (!ci->pcmbuf_insert ((char *) temp_buffer, nsamples * nchans * 4))
             ci->sleep (1);
 
         ci->set_elapsed (WavpackGetSampleIndex (wpc) / sr_100 * 10);
+        ci->yield ();
     }
 
     if (ci->request_next_track())