Commit FS#10422 by Yoshihisa Uchida. Seperates WAV and AIFF parsing from PCM decoding by introducing libpcm, a library for decoding linear and non-uniform PCM independently of the container format.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24346 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 163 insertions, 0 deletions

diff --git a/apps/codecs/libpcm/linear_pcm.c b/apps/codecs/libpcm/linear_pcm.c
new file mode 100644
index 0000000000..2c766bd741
--- /dev/null
+++ b/apps/codecs/libpcm/linear_pcm.c
@@ -0,0 +1,163 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 Dave Chapman
+ * Copyright (C) 2009 Yoshihisa Uchida
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include "codeclib.h"
+#include "pcm_common.h"
+
+/*
+ * Linear PCM
+ */
+
+static struct pcm_format *fmt;
+
+static bool set_format(struct pcm_format *format, const unsigned char *fmtpos)
+{
+    fmt = format;
+
+    (void)fmtpos;
+
+    if (fmt->bitspersample > 32)
+    {
+        DEBUGF("CODEC_ERROR: pcm with more than 32 bitspersample "
+               "is unsupported\n");
+        return false;
+    }
+
+    if (fmt->totalsamples == 0)
+    {
+        fmt->bytespersample = (((fmt->bitspersample - 1)/8 + 1)*fmt->channels);
+        fmt->totalsamples = fmt->numbytes/fmt->bytespersample;
+    }
+
+    /* chunksize is computed so that one chunk is about 1/50s.
+     * this make 4096 for 44.1kHz 16bits stereo.
+     * It also has to be a multiple of blockalign */
+    fmt->chunksize = (1 + fmt->avgbytespersec / (50*fmt->blockalign))*fmt->blockalign;
+
+    return true;
+}
+
+static uint32_t get_seek_pos(long seek_time)
+{
+    uint32_t newpos;
+
+    /* use avgbytespersec to round to the closest blockalign multiple,
+       add firstblockposn. 64-bit casts to avoid overflows. */
+    newpos = (((uint64_t)fmt->avgbytespersec*(seek_time - 1))
+             / (1000LL*fmt->blockalign))*fmt->blockalign;
+    return newpos;
+}
+
+static int decode(const uint8_t *inbuf, size_t inbufsize,
+                  int32_t *outbuf, int *outbufsize)
+{
+    uint32_t i;
+
+    if (fmt->bitspersample > 24)
+    {
+        for (i = 0; i < inbufsize; i += 4)
+        {
+            if (fmt->is_little_endian)
+            {
+                if (fmt->is_signed)
+                    outbuf[i/4] = (inbuf[i]>>3)|(inbuf[i+1]<<5)|(inbuf[i+2]<<13)|(SE(inbuf[i+3])<<21);
+                else
+                    outbuf[i/4] = (inbuf[i]>>3)|(inbuf[i+1]<<5)|(inbuf[i+2]<<13)|(SFT(inbuf[i+3])<<21);
+            }
+            else
+            {
+                if (fmt->is_signed)
+                    outbuf[i/4] = (inbuf[i+3]>>3)|(inbuf[i+2]<<5)|(inbuf[i+1]<<13)|(SE(inbuf[i])<<21);
+                else
+                    outbuf[i/4] = (inbuf[i+3]>>3)|(inbuf[i+2]<<5)|(inbuf[i+1]<<13)|(SFT(inbuf[i])<<21);
+            }
+        }
+        *outbufsize = inbufsize >> 2;
+    }
+    else if (fmt->bitspersample > 16)
+    {
+        for (i = 0; i < inbufsize; i += 3)
+        {
+            if (fmt->is_little_endian)
+            {
+                if (fmt->is_signed)
+                    outbuf[i/3] = (inbuf[i]<<5)|(inbuf[i+1]<<13)|(SE(inbuf[i+2])<<21);
+                else
+                    outbuf[i/3] = (inbuf[i]<<5)|(inbuf[i+1]<<13)|(SFT(inbuf[i+2])<<21);
+            }
+            else
+            {
+                if (fmt->is_signed)
+                    outbuf[i/3] = (inbuf[i+2]<<5)|(inbuf[i+1]<<13)|(SE(inbuf[i])<<21);
+                else
+                    outbuf[i/3] = (inbuf[i+2]<<5)|(inbuf[i+1]<<13)|(SFT(inbuf[i])<<21);
+            }
+        }
+        *outbufsize = inbufsize/3;
+    }
+    else if (fmt->bitspersample > 8)
+    {
+        for (i = 0; i < inbufsize; i += 2)
+        {
+            if (fmt->is_little_endian)
+            {
+                if (fmt->is_signed)
+                    outbuf[i/2] = (inbuf[i]<<13)|(SE(inbuf[i+1])<<21);
+                else
+                    outbuf[i/2] = (inbuf[i]<<13)|(SFT(inbuf[i+1])<<21);
+            }
+            else
+            {
+                if (fmt->is_signed)
+                    outbuf[i/2] = (inbuf[i+1]<<13)|(SE(inbuf[i])<<21);
+                else
+                    outbuf[i/2] = (inbuf[i+1]<<13)|(SFT(inbuf[i])<<21);
+            }
+        }
+        *outbufsize = inbufsize >> 1;
+    }
+    else
+    {
+        for (i = 0; i < inbufsize; i++) {
+            if (fmt->is_signed)
+                outbuf[i] = SE(inbuf[i])<<21;
+            else
+                outbuf[i] = SFT(inbuf[i])<<21;
+        }
+        *outbufsize = inbufsize;
+    }
+
+    if (fmt->channels == 2)
+        *outbufsize >>= 1;
+
+    return CODEC_OK;
+}
+
+static const struct pcm_codec codec = {
+                                          set_format,
+                                          get_seek_pos,
+                                          decode,
+                                      };
+
+const struct pcm_codec *get_linear_pcm_codec(void)
+{
+    return &codec;
+}