1 files changed, 192 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/a52.c b/lib/rbcodec/codecs/a52.c
new file mode 100644
index 0000000000..cb6e66dd05
--- /dev/null
+++ b/lib/rbcodec/codecs/a52.c
@@ -0,0 +1,192 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 Dave Chapman
+ *
+ * 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 <inttypes.h>  /* Needed by a52.h */
+#include <codecs/liba52/config-a52.h>
+#include <codecs/liba52/a52.h>
+
+CODEC_HEADER
+
+#define BUFFER_SIZE 4096
+
+#define A52_SAMPLESPERFRAME (6*256)
+
+static a52_state_t *state;
+static unsigned long samplesdone;
+static unsigned long frequency;
+
+/* used outside liba52 */
+static uint8_t buf[3840] IBSS_ATTR;
+
+static inline void output_audio(sample_t *samples)
+{
+    ci->yield();
+    ci->pcmbuf_insert(&samples[0], &samples[256], 256);
+}
+
+static void a52_decode_data(uint8_t *start, uint8_t *end)
+{
+    static uint8_t *bufptr = buf;
+    static uint8_t *bufpos = buf + 7;
+    /*
+     * sample_rate and flags are static because this routine could
+     * exit between the a52_syncinfo() and the ao_setup(), and we want
+     * to have the same values when we get back !
+     */
+    static int sample_rate;
+    static int flags;
+    int bit_rate;
+    int len;
+
+    while (1) {
+        len = end - start;
+        if (!len)
+            break;
+        if (len > bufpos - bufptr)
+            len = bufpos - bufptr;
+        memcpy(bufptr, start, len);
+        bufptr += len;
+        start += len;
+        if (bufptr == bufpos) {
+            if (bufpos == buf + 7) {
+                int length;
+
+                length = a52_syncinfo(buf, &flags, &sample_rate, &bit_rate);
+                if (!length) {
+                    //DEBUGF("skip\n");
+                    for (bufptr = buf; bufptr < buf + 6; bufptr++)
+                        bufptr[0] = bufptr[1];
+                    continue;
+                }
+                bufpos = buf + length;
+            } else {
+                /* Unity gain is 1 << 26, and we want to end up on 28 bits
+                   of precision instead of the default 30.
+                 */
+                level_t level = 1 << 24;
+                sample_t bias = 0;
+                int i;
+
+                /* This is the configuration for the downmixing: */
+                flags = A52_STEREO | A52_ADJUST_LEVEL;
+
+                if (a52_frame(state, buf, &flags, &level, bias))
+                    goto error;
+                a52_dynrng(state, NULL, NULL);
+                frequency = sample_rate;
+
+                /* An A52 frame consists of 6 blocks of 256 samples
+                   So we decode and output them one block at a time */
+                for (i = 0; i < 6; i++) {
+                    if (a52_block(state))
+                        goto error;
+                    output_audio(a52_samples(state));
+                    samplesdone += 256;
+                }
+                ci->set_elapsed(samplesdone/(frequency/1000));
+                bufptr = buf;
+                bufpos = buf + 7;
+                continue;
+            error:
+                //logf("Error decoding A52 stream\n");
+                bufptr = buf;
+                bufpos = buf + 7;
+            }
+        }   
+    }
+}
+
+/* this is the codec entry point */
+enum codec_status codec_main(enum codec_entry_call_reason reason)
+{
+    if (reason == CODEC_LOAD) {
+        /* Generic codec initialisation */
+        ci->configure(DSP_SET_STEREO_MODE, STEREO_NONINTERLEAVED);
+        ci->configure(DSP_SET_SAMPLE_DEPTH, 28);
+    }
+    else if (reason == CODEC_UNLOAD) {
+        if (state)
+            a52_free(state);
+    }
+
+    return CODEC_OK;
+}
+
+/* this is called for each file to process */
+enum codec_status codec_run(void)
+{
+    size_t n;
+    unsigned char *filebuf;
+    int sample_loc;
+    intptr_t param;
+
+    if (codec_init())
+        return CODEC_ERROR;
+
+    ci->configure(DSP_SWITCH_FREQUENCY, ci->id3->frequency);
+    codec_set_replaygain(ci->id3);
+    
+    /* Intialise the A52 decoder and check for success */
+    state = a52_init(0);
+
+    samplesdone = 0;
+
+    /* The main decoding loop */
+    if (ci->id3->offset) {
+        if (ci->seek_buffer(ci->id3->offset)) {
+            samplesdone = (ci->id3->offset / ci->id3->bytesperframe) *
+                A52_SAMPLESPERFRAME;
+            ci->set_elapsed(samplesdone/(ci->id3->frequency / 1000));
+        }
+    }
+    else {
+        ci->seek_buffer(ci->id3->first_frame_offset);
+        ci->set_elapsed(0);
+    }
+
+    while (1) {
+        enum codec_command_action action = ci->get_command(&param);
+
+        if (action == CODEC_ACTION_HALT)
+            break;
+
+        if (action == CODEC_ACTION_SEEK_TIME) {
+            sample_loc = param/1000 * ci->id3->frequency;
+
+            if (ci->seek_buffer((sample_loc/A52_SAMPLESPERFRAME)*ci->id3->bytesperframe)) {
+                samplesdone = sample_loc;
+                ci->set_elapsed(samplesdone/(ci->id3->frequency/1000));
+            }
+            ci->seek_complete();
+        }
+
+        filebuf = ci->request_buffer(&n, BUFFER_SIZE);
+
+        if (n == 0) /* End of Stream */
+            break;
+  
+        a52_decode_data(filebuf, filebuf + n);
+        ci->advance_buffer(n);
+    }
+
+    return CODEC_OK;
+}